Prior to picking up my 2007 duramax tmorrow morning, I test drove it today as well as my alternate deal 2006 Dodge Ram. Even with the 360 HP in the Chevy, it felt weaker than the Ram with 325 HP. Comparing both at spedds below 60. However, once above 60 they both had equal accleration. Any thoughts as to why the Chevy has less low end acceleration? Also, both 3.73 axle, and the Ram only a 4 speed auto.

Never been in a ram,

Line them up and tell us which one has better acceleration.

Line them up and tell us which one has better acceleration.


The ram with less HP & Torque, and 600 lbs heavier, accelerates faster with better throttle responce. However, the Checy has more pep in 6th gear over 60mph w/o having to down shift to previous gear.

My question is, does it have something to do with the EGR, ad the Ram doesn't have an EGR even with its CA emissions.

Are you going by SOTP or did you line them up side by side? I have never heard of a stock Cummins running 15s, much less mid - low 15s like a stock LBZ will do.

How are you basing this difference in performance?

If it's SOTP (seat of the pants), it's a really lousy way to measure things.

We heard this with the LLY also, but nobody has yet to prove an LLY is underpowered when you actually measure the performance.

How are you basing this difference in performance?

If it's SOTP (seat of the pants), it's a really lousy way to measure things.

We heard this with the LLY also, but nobody has yet to prove an LLY is underpowered when you actually measure the performance.

SOTP may not be accurate within a second or 2, but this test was noticeabley night and day. The LBZ felt sluggish in comparison.

The ram with less HP & Torque, and 600 lbs heavier, accelerates faster with better throttle responce. However, the Checy has more pep in 6th gear over 60mph w/o having to down shift to previous gear.

My question is, does it have something to do with the EGR, ad the Ram doesn't have an EGR even with its CA emissions.

I'll bet dollars to donuts you are only perceiving this because the Cummins is so much louder than the Dmax.I just hope you're looking at more than just speed in your buying decision because obviously that's not what most truck owners are only looking at.I

I test drove an 06 Dodge when I bought my 06 LLY. No comparison. The Chevy blew the Dodge's doors off. They have to de-tune that truck because they still don't have a tranny that can run with the big dogs - hello Ally!.
Also, my old truck was a 98 Dodge. Entire Fuel injection system is a mess and they are still using the same system today. In fact if you have problems with the lift pump (and you will if you buy one because they only get 40-50K miles out of them), the dealer will not replace it. They have a new directive to abandon the pump in place and put a new, separate electric pump in line. I loved my Dodge because it was my first diesel and just like my Dad's but I had a lot of problems with it over the years. Had it 7 years and only had 70K miles on it. They wanted $5,000 to fix the injection system (lift pump went bad and ruined the rest of the system - they think). Traded it in on the 06LLY! Just my 2 cents.

I think the Chevy is so much quieter you don't realize what it is actually doing. Line them up side by side and see which one really goes.

Gearing could be different down low also, rearend ratios and tranny rations??

Tim

SOTP may not be accurate within a second or 2, but this test was noticeabley night and day. The LBZ felt sluggish in comparison.
"felt" and "was" are two drastically different words. I refer you to my earlier post. How many stock Cummins trucks do you see running 15s in the 1/4 mile. I haven't heard of an LBZ that didn't run 15s stock. My LLY ran a 15.7 and I'm at a supposed 50 horse disadvantage to the LBZ.

The LBZ should smoke the cumminapart, I mean cummins!:driver:

"felt" and "was" are two drastically different words. I refer you to my earlier post. How many stock Cummins trucks do you see running 15s in the 1/4 mile. I haven't heard of an LBZ that didn't run 15s stock. My LLY ran a 15.7 and I'm at a supposed 50 horse disadvantage to the LBZ.

Did anyone ever compare the LLY to the LBZ? Is it probable that because of the LBZ bigger EGR tube, that the actual HP at the fly wheel is less than the LLY?

Entire Fuel injection system is a mess and they are still using the same system today.

I'm sorry, but this is COMPLETELY AND TOTALLY incorrect. Other than the fact that both a '98 and a new dodge both use 6 injectors, there's not much else similar between them. First of all, which '98 engine are you referring to? The early '98 12v, or the 98.5 24v? If it's the 24v, you're right-the fuel system IS a mess. A mess of a dumbass lift pump that gives up the ghost whenever it wants to, and a vp44 that then dies as a result of the lift pump not supplying enough fuel to cool and lubricate the vp44. (Oh, and there's also the internal electronic failures plenty of vp44's have experienced even when the lift pump is good.)

If you're talking about the 12v engine, that one used the bosch p7100 pump in those days. That's probably the absolute most reliable injection pump ever installed on a diesel pickup truck. I'm not joking-that thing is a freakin legend. It's literally nicknamed the million mile pump, and for damn good reason-they hardly EVER go out unless contaminated fuel takes them out. Not coincidently I'm sure, that pump is the only one ever put in a dodge with a cummins that's lubricated by engine oil-it does not rely on the fuel for its lubrication. In keeping with that, the list of alternate fuels acceptable for use in a p pump-equipped engine is larger than for any other 5.9 in a dodge truck, because it can tolerate fuels with less lubricity than any other pump.

By comparison, the current ('03 and up) dodges use a common rail system. The injection pump for that is the bosch cp3. GUESS WHAT ELSE USES THAT PUMP? That's right-the duramax. Those seem to work ok, don't they? The pumps are not absolutely identical of course-one feeds 8 cylinders, the other only 6, and the routing of the various lines and wires attached to the pump is different. They're still both cp3 pumps. The gm uses no lift pump, which to me is an advantage-one less thing to fail. As most of you probably know, the common rail system is not at all like the earlier systems used on the older dodges (or older gm's for that matter). For starters, the injection pump on the older cummins is a completely different model, using different innards to develop the high pressure. The common rail has just that-a common rail, one fuel "log" from which all injectors are fed. The injectors are controlled electrically, like in an efi gas motor. On the older dodges (all injection setups, back to and including the bosch VE rotary pump on the '89-'93's) there's a separate line from the pump to each injector. The PUMP determines when any given injector "fires", the injectors are not directly electrically controlled. You can loosen an injector line on any of the pre-cr systems and will only lose that one cylinder. Not so on a cr setup-loosen any part of the high pressure system on a common rail motor, and none of the injectors will get enough fuel pressure to spray effectively. That's because they're all tied together by the common rail. Speaking of pressure, that's another major difference with the cr setup-the fuel pressure is MUCH higher than on the earlier systems. On the dodges, the spec for max fuel pressure developed on a stock motor (at least for the 5.9's) is 23,400 psi. The older systems are considerably lower, half that or less. (funny thing, not coincidental-the duramaxes and the dodges both need to go to a dual cp3 setup at basically identical hp levels. That's a direct result of them using the same basic injection pump.)


In fact if you have problems with the lift pump (and you will if you buy one because they only get 40-50K miles out of them), the dealer will not replace it. They have a new directive to abandon the pump in place and put a new, separate electric pump in line. I loved my Dodge because it was my first diesel and just like my Dad's but I had a lot of problems with it over the years. Had it 7 years and only had 70K miles on it. They wanted $5,000 to fix the injection system (lift pump went bad and ruined the rest of the system - they think). Traded it in on the 06LLY! Just my 2 cents.

Which generation of truck are you talking about? The '98.5-2002 24v? If so, you're pretty much right about lift pump life. I don't know what the dealers are doing with those, I'll take your word that they're replacing faulty stock lift pumps with something else. If you're talking about the '03 and up cr trucks, I don't know what you're talking about. There has been no rash of trouble with those lately. The '06 (or '05, can't remember) trucks use an in-tank lift pump, with good results. The earlier cr trucks use a lift pump mounted up on or near the engine. There was a moderate amount of trouble with those, but that seems to have really settled down. The dealers are supposed to replace those with an in-tank pump like the newer ones if they give trouble. In most cases, a failed lift pump on a cr motor does NOT take out the injection pump like it does on a vp44 motor. It might eventually, but the high rpm bucking and cutting out should tell any driver with functional brain cells to take it in to be looked at. Meanwhile, if the truck has not been driven for long periods while actively misbehaving because of a dead lift pump, the injection pump is usually fine.

Oh, on the question if which is faster/quicker unloaded, I find it hard to believe that a stock 325 hp cummins would keep up with a stock lbz. I can't even see how it could FEEL similar, let one like the dodge was faster, unless something was wrong with the lbz. Like someone else said, I don't know of any stock cummins that will run in the 15's. I had an '04.5 2500 4x4 dodge that was STONE stock. I ran it in 4 hi so I could run it up against the converter and build boost w/o blowing the tires away. It ran a best of 16.48. The newer ones aren't really any faster stock, so how an lbz would get beaten by a stock dodge with a cummins is a mystery to me.

The fueling system on a 98 Cummins and an 07 Cummins are absolutely night and day. Absolutely nothing is the same.

I trade a 2006 Cummins with the auto for the truck below. The Cummins makes an incredible amount of torque down low and feels very strong off idle through a couple of gears. However mine would get outrun anyday by fellow coworkers with DMAX trucks from any speed although it was less obvious from 0-60. A big ole inline just does not accelerate like a V8.

The fueling system on a 98 Cummins and an 07 Cummins are absolutely night and day. Absolutely nothing is the same.

I trade a 2006 Cummins with the auto for the truck below. The Cummins makes an incredible amount of torque down low and feels very strong off idle through a couple of gears. However mine would get outrun anyday by fellow coworkers with DMAX trucks from any speed although it was less obvious from 0-60. A big ole inline just does not accelerate like a V8.

Exactly. In testing both the cummins had better low end, but once above 60 mph, the duramax had more power without having to downshift as often as the cummins.

WHen I bought my 06 D-max, I test drove an 06 Cummins right after the D-max. I left the Dodge dealer laughing at the lack of performane. it may pull good, but in traffic, around town, and acceleration, it was a dog.

I have been through this before you can only get a 3.73 gear axle ratio with the duramax, with cummins you can get a 3.90 or bigger rear axle ratio.People tell me all the time that the cummins feels snappier and quicker then I race one just to prove a point and they shut up.

I have been through this before you can only get a 3.73 gear axle ratio with the duramax, with cummins you can get a 3.90 or bigger rear axle ratio.People tell me all the time that the cummins feels snappier and quicker then I race one just to prove a point and they shut up.

Cummins comes in 3.73 & 4.10. The 3.90 is only with the Hemi in a 1500 1/2 ton. The model I compared was with a 3.73.

A big ole inline just does not accelerate like a V8.


I wouldn't say it's so much a question of inline 6 vs v8, but more just a little lighter truck, the lbz makes significantly more torque and hp, and has a transmission much better able to get that power to the ground. There's nothing stopping an equally powerful inline 6 from running with a v8, all else being equal. If straight sixes were inherently unable to accelerate as quickly as v8's, the 5.9 cummins wouldn't perform as well as it does in drag races. The torque curve is different and is in a different rpm range, but as long as you account for that with the gearing, they do just as well as any other equally powered engine.

A buddy of mine used to have an '04 chevy with a duramax. I don't know which version of the duramax that was, but he had a 70 hp chip on it. It would FLY for what it was, very impressive. He traded that one in on an lbz, and I want to go drive it to see what it's like. He said it feels as fast as the older one did with the extra 70 hp.

Inline 6's simply do not rev as fast as a V8. They have a mechanical disadvantage plain and simple. They have low end torque out of the hole, but horsepower on the high end wins. They are not made to drag race. They are designed to make large amounts of low end torque that their heavy reciprocating masses do not give up easily. The same mass is harder to spin fast as well giving the V8 engine design the advantage in a drag race. Ford and GMC like the V8's...they seem peppy around town and rev quickly feeling more like the customary gas V8. The Cummins runs like a slow revving tractor....a very good one.

Ah, I see. There are some guys you ought to get in touch with to tell about all that. The guys dragracing the cummins, and the guys turning them to and sometimes past 6k rpm. They apparently did not get the message. Neither did the guys who turn them to 5k or so on STOCK BOTTOM ENDS.

You're right to an extent...the 5.9 cummins does indeed have much heavier bottom end components than the duramax and powerstroke, along with a longer stroke. But, you're failing to consider some things like gearing. If you have an engine that doesn't rev quickly or high, you don't relegate it to tractor status, you instead make intelligent gear selections such that the engine can operate where it needs to while achieving the needed wheelspeed to win the race or accomplish whatever you're trying to do. Last time I checked, the cummins was not exactly getting beaten right and left by v8 diesels in the power arena.

Similarly, I can think of a good example of an inline 6 gas engine not being exactly hobbled by the fact it's an inline engine...the engine toyota put in the supra. I'd imagine you've heard the ridiculous power it can make with a stock bottom end, and how much higher it can go with aftermarket rods and pistons. Wanna make 1500 hp? Ok, can do. A stock crank and block will get it done. I know it sounds farfetched if you haven't read up on it, but it does seem to be a fact. It's that theory vs reality thing again.

I traded my '03 1-ton single rear wheel 4x4 Dodge for the truck I have today. I love my new truck, and yes, I'm very happy. However...my cummins was hardly a "tractor". My truck came with the 6 speed manual, because Dodge autos are terrible from the factory. One call to ATS or any other vendor will turn the 48re into a monster, capable of holding well over 1300 ft/lbs of torque. I went to the Diesel thunder at Indy raceway park 2 years ago, and at that time, dodge was still kicking everybody's hind end. Dyno/drag races/and the sled pull. And as far as the lift pump, I wish my truck had one like dodge installs theirs now...in the tank. It's well known that the duramax will "drain" the common rail pressure at high rpm. Adding a lift pump, like with a FASS system helps this greatly. I know my new LBZ is faster than my old dodge,(stock) but I wouldn't call the old beast *slow*. Sorry for the long post, but I wanted to give an alternative opinion. I realize this is a chevy/gmc forum, but someone did mention reality...Later, Cat Cracker.

Let's see here...racing venues. F1, Nascar, CART, IRL, Powerboat...all V style engines. I wonder why? F1 engines are around 20K RPM now. I would love to see an inline 6 try that. ANY engine can be built to the extreme. It does not mean that makes it the best nor can it be used to make a point. How they are modified has nothing to do with the inherent strong points of the various designs. There are plenty of crazy fast Cummins engines out there behaving nothing like what we the consumers purchase. It is a niche market making an engine do what it was never in a million years designed to do.

I have all the respect in the world for the Cummins. I have put over 500K combined on 3 of them. They are good engines...they simply operate or give a different driving experience than a V8 diesel.

Which is all good and well, and has ABSOLUTELY NOTHING to do with why a 350 hp duramax with 6 forward speeds will beat a 325 hp cummins with 4 forward gears in a slightly heavier truck.

lol the cummins is a dog. You cant beat the allison in shifting. Smooth and Quick! And with an extra 35hp it a huge difference. Are you sure the tires didnt brake loose (as mine will do stock) taking away from the feel of acceleration.

Its good to have torque down low to get stuff moving, but its a whole other ball game keeping it moving. When you go to pull a hill at 50mph that 600lb-ft that kicks in at 1400rpm doesnt come into play. Now that 650lb-ft at 1600rpm helps a little more ;)

My bro in law has the Ram 2500 with 325 HP and the Cummins is a great engine, the truck not so great though kinda cheesy if you ask me. Anyway to my real reason for posting - We have lined up many times me stock LBZ and he had an exhaust i always beat him hands down no problem. Now i have upgrades and well you can guess what happens.

I just traded my 04.5 Dodge 3500 for a Dmax 3500. Apples for Apples, my Dodge, even with the 4:10 gear wouldn't come close to the Dmax in acceleration. The Dodge is a great towing machine but if it felt stronger to you than the Dmax you're buying, I'd take a hard look at a different Dmax. Somethings wrong with this picture.

When you go to pull a hill at 50mph that 600lb-ft that kicks in at 1400rpm doesnt come into play.


Wellll, I dunno about that. Actually I do-the torque peak of the cummins comes in with all gears, not just first to get it moving. In fact, the word "peak" is kinda misleading as applied to the cummins. It would make you think that the 610 ft/lbs occurs at one certain engine speed, when in fact it occurs over a fairly wide range-like up to 2400 or something like that. I'm not sure anymore, it's been a while since I've looked at the actual range the 610 occurs at. Believe me, when you get it good and spooled up at 50 mph, it pulls just fine. Not as hard as an lbz at its torque peak (range there too I think), but plenty hard.

V8440 - I had the 12V. The problem was the lift pump in the fuel tank. When that goes bad and you do not realize it, it will destroy the timing in the injection pump. Having that injection pump removed and timed is costly for those of use who don't tear these trucks appart on our own. I have been told they are still using this same lift pump today.
It's also my understanding that my 06 Dmax does not use a lift pump in the tank.

Let's see here...racing venues. F1, Nascar, CART, IRL, Powerboat...all V style engines. I wonder why? F1 engines are around 20K RPM now. I would love to see an inline 6 try that. ANY engine can be built to the extreme. It does not mean that makes it the best nor can it be used to make a point. How they are modified has nothing to do with the inherent strong points of the various designs. There are plenty of crazy fast Cummins engines out there behaving nothing like what we the consumers purchase. It is a niche market making an engine do what it was never in a million years designed to do.

I have all the respect in the world for the Cummins. I have put over 500K combined on 3 of them. They are good engines...they simply operate or give a different driving experience than a V8 diesel.


If you designed an I6 with pneumatic valve closure and a dry sump oiling sytem, i guarantee you could get it to rev to 19,000rpm+

Configuration has NOTHING to do with RPM. V configurations are designed purely for packaging and handling in those cars, along with the fact if you can squeeze more cylinders into a given space, you can make more power.

Porsche can make PLENTY of power out of a Flat 6....and those along with Inline motors are inherently more balanced. They just have a power limit because of the size. Any gas 6 banger over 4.0 liters is simply going to be too physically "Big" to make sense.

But yea, the design for a diesel is great, as is the DMAX. Both great motors

V8440 - I had the 12V. The problem was the lift pump in the fuel tank. When that goes bad and you do not realize it, it will destroy the timing in the injection pump. Having that injection pump removed and timed is costly for those of use who don't tear these trucks appart on our own. I have been told they are still using this same lift pump today.
It's also my understanding that my 06 Dmax does not use a lift pump in the tank.

Ok, start ignoring whoever told you all that stuff. The 12v does not HAVE a pump in the tank-it's a pickup assembly with the fuel gauge sender, no pump at all. The lift pump is a mechanical pump that is bolted to the side of the block, like any old carbureted engine. That's part of why they're so reliable. The lift pump failing on a 12v will not destroy the injection pump, and it has nothing to do with the timing. Whoever told you that has obviously never worked on the fuel system of a 12v. If you in fact had a 12v and you wanted the timing reset for some reason, the person doing the procedure does not have to remove the pump at all. It does involve some special tools, like a dial indicator with a certain fixture on it to measure pump plunger travel, but not removal of the pump.

The vp44 24v trucks used an electric lift pump, but I don't THINK (not 100% sure) it was mounted in the tank, and it certainly isn't the same as what they're using today. Regardless, the duramax not having a lift pump is a nice feature to me.

Configuration has NOTHING to do with RPM. V configurations are designed purely for packaging and handling in those cars, along with the fact if you can squeeze more cylinders into a given space, you can make more power.


Yeah, you're right of course, but you're wasting your breath. Packaging constraints have NOTHING to do with it, because it doesn't fit the "theory". What, an inline engine would be to long and heavy to work well in F1? Nah, that has nothing to do with it, they run v engines because they make more power. It's like arguing with Stevie Wonder about what the color red looks like-you'll lose, no matter how right you are.

Yeah, you're right of course, but you're wasting your breath. Packaging constraints have NOTHING to do with it, because it doesn't fit the "theory". What, an inline engine would be to long and heavy to work well in F1? Nah, that has nothing to do with it, they run v engines because they make more power. It's like arguing with Stevie Wonder about what the color red looks like-you'll lose, no matter how right you are.

Are you a racing engineer? Whats your backround?
V configurations have everything to do with packaging.

The motor is a stressed member of the chassis in an F1 car.

I bet you didn't know the angle of the motor actually effects the handling.

The golden era of F-1 motors didn't use V motors at all.

If you can tell me how big they are,how many cylinders and how much power those motors made I'll be very impressed, because you obviously know NOTHING about racing.

Are you a racing engineer? Whats your backround?
V configurations have everything to do with packaging.

The motor is a stressed member of the chassis in an F1 car.

I bet you didn't know the angle of the motor actually effects the handling.

The golden era of F-1 motors didn't use V motors at all.

If you can tell me how big they are,how many cylinders and how much power those motors made I'll be very impressed, because you obviously know NOTHING about racing.

Read my response again. I agree with EVERYTHING you said-I was being sarcastic about boy wonder above, who thinks the layout of the cylinders determines potential power output.

I'm sorry man, didn't pick up the sarcasm, lol. I really am sorry:(

Prior to picking up my 2007 duramax tmorrow morning, I test drove it today as well as my alternate deal 2006 Dodge Ram. Even with the 360 HP in the Chevy, it felt weaker than the Ram with 325 HP. Comparing both at spedds below 60. However, once above 60 they both had equal accleration. Any thoughts as to why the Chevy has less low end acceleration? Also, both 3.73 axle, and the Ram only a 4 speed auto.


Alot of this has to do with the Alli learning how you drive. Since it is a new truck, maybe someone else drove it after you did initially and babied it. The dodge's trans doesn't learn how you drive and in the beginning it will seem faster but in the long run the LBZ will be faster.

Alot of this has to do with the Alli learning how you drive. Since it is a new truck, maybe someone else drove it after you did initially and babied it. The dodge's trans doesn't learn how you drive and in the beginning it will seem faster but in the long run the LBZ will be faster.


Just picked up my silverado, and it seems to have a bit more power. Drive home from dealer included some intersate. I did however test the Ram before buying the Chevy, and this time, I was more content with the Chevy. Not only quieter during throttle, but allison shifts smoother.

Sorry guy, you are wrong. The LBZ will walk the Cummins right from the jump and forever after that. As was said, line them up and see, everything else is a guess.

I don't diagree. I bought the Chevy promarily because I like the Allison. The only advantages for the the Cummins, is that its a medium duty motor, and NO EGR on the 5.9.

I thouroughly test drove the lbz, and the mega cab cummins before buying my lbz. The cummins and the duramax were almost identical punch on the bottom end. I felt as if the engines were very similar power feeling, possibly with the cummins having a slightly more torquey feel, but the allison just smacked the dodge 4 speed across the face. I was driving the dodge on the highway at about 75 and clicked it out of overdrive and the thing almost red-lined. If you were on the freeway and punched it, the dodge felt slow because it did not have another gear to downshift to. I might have bought the cummins mega if they had a decent tranny in it. I felt like the dodge was going to eat way more fuel due to the massive amount of rpm it was running on the highway, as compared to low rpm on the dura. The 6 speed manual may have solved this, but I am not going to a manual when I am paying 38k for a truck. The deciding factor for me was that my wife thought the dodge seats were uncomfortable, and the warranty on the powertrain other than the engine (100k) was 36k. My thoughts were that dodge must not feel too confident in their tranny or drivetrain then. The 100k powertrain from chevy sealed the deal.

Personally, I think the SOTP feel that the LBZ has less acceleration has something to do with the programming of the throttle position verses fueling curve. My LB7 was very throttle sensitive and just touching the throttle would make the truck jump. It made it feel like it had more power than my LBZ. However, it also made the truck tough to maneuver in tight spots, like where you just wanted to move forward or backward just a foot or so. My theory is that GM made the throttle less responsive on the LBZ because with its greater torque, it would be more touchy in a tight spot. Until I got used to it (the LBZ) , I thought my LB7 had more "get up and go" to it. Now, my LBZ seems just as fast on acceleration, or faster, and of course it is much quieter so you don't "feel" like you're going as fast. Maybe Dodge wants to give the impression of a quicker truck, so their throttle response curve puts in more fuel for less throttle.

Read my response again. I agree with EVERYTHING you said-I was being sarcastic about boy wonder above, who thinks the layout of the cylinders determines potential power output.


Why the name calling??

Theory versus reality has nothing to do with it. The FACTS are that a V8 engine is going to produce more HP than an inline at a given CID in almost every instance. It is going to do it at a higher RPM and give up low end torque, but it will do it. It is the best racing design period. The reciprocating mass is lighter which enables it rev quicker and higher producing more and more HP.

Inline engines pull harder at lower engine speeds mainly due to a longer stroke than bore. Inlines major weakness is in the crankshaft. As the engine gets longer the crank gets weaker. This can be offset by making the crank out of stronger materials, adding mains and webbing. This is expensive since it involves more oil passages and precise machining.

I own a 2002 BMW M3. The engine is a masterpiece as far as I am concerned. Over 100HP per liter out of a 3.2 liter inline 6. It has a redline of 7900. Guess what...it was recalled in 2004 for crank bearings. Seems that they were not capable of keeping up. BMW replaced them all...requireing all owners to now run a castrol oil with a weight rating only available at BMW. The M version motor has an RPM redline 1200rpm higher than the normal 3 series motor enabling it to reach the 333HP level. Not anymore...they dumped the inline 6 and went to a V8 which makes more power at an even higher RPM. They are KING bar none of inlines and have gone to a V8 and a V10 for their top line cars now...which had inlines laying on their side under the same hood two years ago.

Current F1 cars are limited to around 2.5 liters in a V8 configuration if memory serves me...their rules seem to change weekly. The engines are making 700-800HP naturally aspirated due mainly to the RPM's at which they are capable of turning. These engines spin at close to 20K rpms because they have bores sizes 2-3 times the stroke length. This goes against an inlines design which almost always has a larger stroke than bore. The V8 cranks are short and nearly bullet proof. The design limits torsional vibrations, are more rigid and are stronger than the crank would be in the same CID inline design. This simple fact keeps inlines out of the racing venues. Their cranks are longer for the same CID which makes the design inherently weaker. While packaging plays a part in any manufactuers design dont think for a minute they would not build a car/truck around a superior powerplant. What the gear heads in their 5K rpm Cummins diesels are doing does not mean that since they did it the design is just as good or better. Hypermax is spinning the V8 IHC motors up to 6200-6400 RPM now.

An inline 4 cylinder is absolutely horrible from a vibration standpoint. Millions are built every year, but almost all of them, unless they are built in a third world country are hobbled by balance shafts to cancel flex and vibration caused by the inner two cylinders going up and the outer two going down. A V6 suffers from the same issue, but not as bad, although most if not all have balance shafts as well which eliminates them from the race track as well. More parts to break for the same power equals not in my race car. F1 will stick to a V configuration since an inline 4 with a balnce shaft or an inline 6 with an inherently weaker crank setup will not turn 20K rpms as realiably as the V design.

Horizontally opposed engines are naturally balanced which eliminates large counterweights which makes the engine lighter. The cranks are short and stiff. They make their way into sports car for their low center of gravity and very good lowend torque.

i think the seat of the pants feel you may be getting may be attributed to the larger tire size on the Dodge. Place 18s and 20s on the LBZ and try it again.

My dad was once a Mopar man, now he has been converted over the last 4 years to GM. My mom drives a caddy and my dad has his 04 GMC sierra 1500, which he is selling to my cousin, and he is now driving my 04.5 lly that he loves.

I have my left over 06 LBZ and haven't gone to playing with it yet. WIll do soon though.

I used to tease him about MOPAR. It was some good old Kentucky boy trying to get through the mountains of West Virginia driving a dodge and saying I need MOPAR MOPAR. As the chaw would distort the word MORE POWER.

Just a little MOPAR humor.

Happen to agree with Cobrajet. Don't cheat simple physics.

Show me a high revving inline motor and I'll show you a piece of junk. Too expensive to build to make it hold together and too many other deficiencies to not use a V-configuration or even horizontally opposed. Reliability = Money and at some point in time even F1 is constrained by money.

how is the cummins a meduim duty motor?? I dont see any 325/610 5.9ls in any medium duty trucks. Correct me if im wrong.

how is the cummins a meduim duty motor?? I dont see any 325/610 5.9ls in any medium duty trucks. Correct me if im wrong.

You can get the 275/660 version of the 5.9L Cummins in a Ford F-650/750.

Tim

you can get the duramax in the 4500 and 5500

I would try a different Duramax and make sure it is at temp.
I test drove a new MegaCab for the heck of it and it sure didnt feel like the Chevy LBZ I drove an hour later.I did notice a much smoother ride and the Allison was alot smoother too.

I wish that Chevy would come out with a truck that looks like a truck. I parked next to a new Dodge today and it was easily 4-6 inches taller and much more aggressive looking. Same with a Ford, taller and more aggressive looking. But boy are they noisy. I remember the days of sitting in my 7.3 yelling on the cell phone and keep tapping the brakes to take it off high idle. I love my LBZ, nothing a little lift or bigger tires can't solve!

Tim

With all this talk of inline versus v-style, is there anyone here that remembers our good ole Cummins' 903 V8. My dad was a diesel mechanic and I grew up doing 24 hr road service in Houston TX. Also on drilling rigs for H.S. Anderson Drilling, they used some pretty big Autocar trucks. The Cummins 903 was a disaster! They never could figure out how to build a V style. They do have an awesome inline. In my memories, my dad would build 400 "big cam" Cummins to run against 3406 A and B series Cats with a 5 x 4 air shift, Thats 20 forward gears if ya dont know. I respect Isuzu diesels for the amount of abuse I have seen them take in their local delivery trucks over the years. Time will tell for me, if its bad I'll post it but so far I havn't got that smile off my face when I get out of the truck!

With all this talk of inline versus v-style, is there anyone here that remembers our good ole Cummins' 903 V8. My dad was a diesel mechanic and I grew up doing 24 hr road service in Houston TX. Also on drilling rigs for H.S. Anderson Drilling, they used some pretty big Autocar trucks. The Cummins 903 was a disaster! They never could figure out how to build a V style. They do have an awesome inline. In my memories, my dad would build 400 "big cam" Cummins to run against 3406 A and B series Cats with a 5 x 4 air shift, Thats 20 forward gears if ya dont know. I respect Isuzu diesels for the amount of abuse I have seen them take in their local delivery trucks over the years. Time will tell for me, if its bad I'll post it but so far I havn't got that smile off my face when I get out of the truck!
I hear ya'!I've seen a few Detroits scream by in my time driving too!;)

I hear ya'!I've seen a few Detroits scream by in my time driving too!;)
The biggest engine I personally worked on was a 32V Detroit in a boat. When I was a kid my dad stood me in a cylinder and took a pic of me in a Wauka-Shaw Pierce (spelling) 24 cylinder, it was used as a generator engine to go to Egypt back in the 70's

Prior to picking up my 2007 duramax tmorrow morning, I test drove it today as well as my alternate deal 2006 Dodge Ram. Even with the 360 HP in the Chevy, it felt weaker than the Ram with 325 HP. Comparing both at spedds below 60. However, once above 60 they both had equal accleration. Any thoughts as to why the Chevy has less low end acceleration? Also, both 3.73 axle, and the Ram only a 4 speed auto.

Disclaimer: I really don't know much about any of this but....

I have heard that straight six engines (gas and diesel) still exist and are good engines for trucks and cars are that;

#1) They are somewhat more simple to engineer and build than “V” engines.
#2) They are very reliable due to the fact they contain fewer parts than “V” engines.
#3) They can be more easily serviced and maintain than “V” engines, particularly when housed in small spaces.

All this heartache about what’s better, a straight six or V eight is really and endless argument.

I think if one allows themselves to make a purchasing decision based in large part, on a Seat of the Pants feel, that’s great. When I did the research before buying my truck I relied on;

Seat of the Pants feel (it felt good too) as well as many other things like quietness, smoothness, comfort. I also read articles in diesel magazines that reported test results of actual pulling performance (loaded and unloaded), acceleration, mileage and stopping power. Only then did I make my final decision on the LBZ.

You seem to feel strongly about the feeling you get when you drive the Dodge. Based on the information in this one thread, you have been given a lot of reasons why we (Chevy owners) like our trucks.

Maybe the Dodge is really the right truck for you?

Whatever you decide, good luck and happy trucking.:)

how is the cummins a meduim duty motor?? I dont see any 325/610 5.9ls in any medium duty trucks. Correct me if im wrong.


The cummins is a medium duty engine because it's classified by the EPA as being a medium duty engine. I looked this up one time, and it was hellishly hard to find on the internet. I got deep into some EPA website, and I'll admit that I'm not willing to go to the trouble to do it again. I'll also admit that I don't know exactly why one engine is classified as medium duty by the EPA and another as light duty-I only know that this is the way it is. One factor (not the only factor) MAY be the manufacturer's rated lifespan between major overhauls, I dunno. I think it's 350k for the cummins and 250k for the duramax and powerstroke. There are other things that would indicate, but not prove, that the cummins is a medium duty and the other 2 are light duty. One of those is the ridiculous bottom end strength of the 5.9. Another similar thing is the heavy weight of it-it's heavier than an all iron 7.3 international, by at least a little. Having 7 main bearings to support the output of 6 cylinders vs 5 bearings to support the output of 8 cylinders is also a step in that direction.

I realize that I haven't proven the cummins is a medium duty engine to anyone not inclined to believe this is the case, and my claim to have seen it in black in white won't make them accept it. Nevertheless, that is what I saw. A lot of the other little stuff I mentioned just tends to support this.

The fact that the Cummins was designed for and used extensively in medium duty trucks and heavy equipment is why I would classify the 5.9 Cummins as a medium duty engine. My uncle has a Case 1155 track loader and a 93 Dodge with a Cummins. The only difference between the two engines is the one in the case is painted a different color than the one in the Dodge. Face it fellas, the Cummins in stock form can take way more abuse than the Duramax without beefing internals, but then again that isn't even what this thread was about in the first place. Even knowing that though, I still chose to buy and drive a Duramax.

The cummins is a medium duty engine because it's classified by the EPA as being a medium duty engine. I looked this up one time, and it was hellishly hard to find on the internet. I got deep into some EPA website, and I'll admit that I'm not willing to go to the trouble to do it again. I'll also admit that I don't know exactly why one engine is classified as medium duty by the EPA and another as light duty-I only know that this is the way it is. One factor (not the only factor) MAY be the manufacturer's rated lifespan between major overhauls, I dunno. I think it's 350k for the cummins and 250k for the duramax and powerstroke. There are other things that would indicate, but not prove, that the cummins is a medium duty and the other 2 are light duty. One of those is the ridiculous bottom end strength of the 5.9. Another similar thing is the heavy weight of it-it's heavier than an all iron 7.3 international, by at least a little. Having 7 main bearings to support the output of 6 cylinders vs 5 bearings to support the output of 8 cylinders is also a step in that direction.

I realize that I haven't proven the cummins is a medium duty engine to anyone not inclined to believe this is the case, and my claim to have seen it in black in white won't make them accept it. Nevertheless, that is what I saw. A lot of the other little stuff I mentioned just tends to support this.




The EPA does do the rating. It use to and likely still has something to do with the emissions the engine puts out and what vehicle the engine was FIRST certified to be in. The 5.9 use to be found in 66K CGWV trucks...ie single axle tractors. I am not sure if this can still be had, but it use to be. The tear down ratings have never been "equally rated" by the builders. The Cummins gives a B life rating...which is when 50% of the engines will need a rebuild. The Duramax and PSD have ratings which say when 50% of them will need something major repaired...not necessarily a complete rebuild. I believe it is called the A life rating. This is all buried in websites which can be found with a couple of cups of coffee and some aspirin. Comparing the cranks and mains can be a little deceiving since the inline crank is longer requiring it to be built stronger with the extra bearings for support.

Most of us will see the rest of the truck fall apart, or trade it in before the engines give up in any of the three brands. If I worked the life out of mine towing everyday I would own the Cummins. It has simply proven that it can do it for decades.

Happen to agree with Cobrajet. Don't cheat simple physics.

Show me a high revving inline motor and I'll show you a piece of junk. Too expensive to build to make it hold together and too many other deficiencies to not use a V-configuration or even horizontally opposed. Reliability = Money and at some point in time even F1 is constrained by money.

The fastest F1 motors of all time (Turbo-Era) were 4-bangers...so go figure. Also, I wouldn't call some of the B-Series honda motors pieces of Junk. B18C5's can rev to 9000rpm+ and you can easily put 150k+ miles on it (yea, its NOT a diesel...but thats pretty good).

Flat motors are inherently the most balanced...can't wait for the Subaru WRX diesel coming soon (09 reportedly).

Inline motors are inherently more balanced than V-8's. The E46 M3's motor was a relatively VERY long stroke (as far as high RPM motors are concerned) motor. At 8200rpm the piston speed approaches that of an F1 motor. BMW can't make any more power since the deck and bore's are essentially maxed out at 3.4litres, so they're going to a 4.4 V-8 (derived from the v-10). Those failures are a cause of piston speed and how violent the change in direction is....causing a lot of stress on the motor.
Destroked to 2.8L it'll spin to 9000rpm and last forever.
(I've driven e28 BMW's with over 400,000k miles on them...trust me, they're pretty strong).

Hands down the best "V" design is a V-12. They use them in locomotive Diesels and in any luxo-cruiser like the S600 Benz Bi-Turbo (nasty....604hp and 738lb ft...can make 880lb ft but the tranny won't take it). They just are smoother than V-8's simply because the crank rotates less per firing of each cylinder. Drive one and you'll agree. :)

But back on topic, the "V-8" is overall the most convenient design. Not the most balanced, but much more compact than a V-12 or I-6, smoother than a V-6 and V-10, etc. It has the least amount of compromise, that's why its a great motor:)

My understanding is that v8's can't be perfectly balanced-it's a mathematical impossibility. I've read this time and again, though I've never studied it enough to be able to tell the exact reason why. They can be balanced well enough, and the rest absorbed with vibration dampers. It's also easy to pack displacement into a v arrangement, which might lead one to the mistaken belief that v engines inherently produce more power per unit of displacement. As just one example of a good high revving inline, there's an engine honda developed that makes 1.2 hp per liter naturally aspirated. That's pretty impressive, it would be roughly the equivalent of a 350 v8 producing 700 hp on the motor. Not too many 350's do that, though a few do. More impressive? It does it on pump gas. Now you're REALLY getting into something hard to accomplish. Now, what class of racing do they produce these engines for? The daily rat race. That's right-they're the stock motor in the honda s2000-full warranty, etc. V8 who? Opposed what?

I don't own one of those and have no real desire to, but I have to admit I'm impressed by that sort of power from that size. Just another example of non-v engines getting it done.

The fastest F1 motors of all time (Turbo-Era) were 4-bangers...so go figure. Also, I wouldn't call some of the B-Series honda motors pieces of Junk. B18C5's can rev to 9000rpm+ and you can easily put 150k+ miles on it (yea, its NOT a diesel...but thats pretty good).

Flat motors are inherently the most balanced...can't wait for the Subaru WRX diesel coming soon (09 reportedly).

Inline motors are inherently more balanced than V-8's. The E46 M3's motor was a relatively VERY long stroke (as far as high RPM motors are concerned) motor. At 8200rpm the piston speed approaches that of an F1 motor. BMW can't make any more power since the deck and bore's are essentially maxed out at 3.4litres, so they're going to a 4.4 V-8 (derived from the v-10). Those failures are a cause of piston speed and how violent the change in direction is....causing a lot of stress on the motor.
Destroked to 2.8L it'll spin to 9000rpm and last forever.
(I've driven e28 BMW's with over 400,000k miles on them...trust me, they're pretty strong).

Hands down the best "V" design is a V-12. They use them in locomotive Diesels and in any luxo-cruiser like the S600 Benz Bi-Turbo (nasty....604hp and 738lb ft...can make 880lb ft but the tranny won't take it). They just are smoother than V-8's simply because the crank rotates less per firing of each cylinder. Drive one and you'll agree. :)

But back on topic, the "V-8" is overall the most convenient design. Not the most balanced, but much more compact than a V-12 or I-6, smoother than a V-6 and V-10, etc. It has the least amount of compromise, that's why its a great motor:)


The turbo era cars of the 80's were almost all "V" configurations. The only notable exclusion was the BMW inline 4 which won it all in 1983....mainly due to the fact they had been working with the design 1.5L powerplant before anyone. The car was modified a year later laying the engine at a slant for better ariflow across the rear wing. It never won again and was gone by 1986.

All of the other turbo F1 engines displacing 1.5 liters with unlimited boost were "V" style. This included the ALFA V8 as well as V6's from Ferrari, Ford, Honda, Renault, and Tag Porsche.

The inlines 6's are certainly more balanced than a V8 by design...not all inlines.

Didn't know that about the others....just the BMW. I've seen in-car footage of Eddie Cheever and Andretti running those turbo era cars.....damn....a friggin light switch. No boost then BAMMM...haha.

I think ron54 is test driving a 1ton, my 06 1ton has full time traction control(torque management). My dad,and 3 of my other friends all have 1ton's they feel very slow at the takeoff with light spooling of the turbo. My GF brother just got a 06 2500 3 weeks ago, that truck will move with no problem from a take off.

Their will be a lot of people who will say iam wrong, thats ok. Hopefuly thae can anwser this question.

If my truck is unloaded and it is in drive, and I floor it the tires wont spin?
But if I hook my 7000lbs trailer on is will spin the tires in first and second gear?
Truck not in tow/haul, no programer.
This is not a bashing post, Ive keep hearing the trucks dont have traction control, but I think they do. Unless its on paper that states otherwise.

My understanding is that v8's can't be perfectly balanced-it's a mathematical impossibility. I've read this time and again, though I've never studied it enough to be able to tell the exact reason why. They can be balanced well enough, and the rest absorbed with vibration dampers. It's also easy to pack displacement into a v arrangement, which might lead one to the mistaken belief that v engines inherently produce more power per unit of displacement. As just one example of a good high revving inline, there's an engine honda developed that makes 1.2 hp per liter naturally aspirated. That's pretty impressive, it would be roughly the equivalent of a 350 v8 producing 700 hp on the motor. Not too many 350's do that, though a few do. More impressive? It does it on pump gas. Now you're REALLY getting into something hard to accomplish. Now, what class of racing do they produce these engines for? The daily rat race. That's right-they're the stock motor in the honda s2000-full warranty, etc. V8 who? Opposed what?

I don't own one of those and have no real desire to, but I have to admit I'm impressed by that sort of power from that size. Just another example of non-v engines getting it done.



All things being equal the more pistons you can pack into a given displacement the more power you will have. Simple engineering . Smaller cylinders equal higher revs which equal higher HP. The S2000 enigne is a masterpiece...albeit it has no torque to speak of below 5K RPM. The same displacement and "tuning" in a V6, V8 or V10 would have a more powerful engine due to higher RPM capabilities. An inline 6 starts to get into that nasty crank thing again which limits reliable RPM turning.

Didn't know that about the others....just the BMW. I've seen in-car footage of Eddie Cheever and Andretti running those turbo era cars.....damn....a friggin light switch. No boost then BAMMM...haha.


1000HP..rumored to be close to 1300 in some would be an insane ride. They out accelerate Superbikes like there is no tomorrow. It is no wonder they were all using the computer to "cheat" the wheel slip.

I think ron54 is test driving a 1ton, my 06 1ton has full time traction control(torque management). My dad,and 3 of my other friends all have 1ton's they feel very slow at the takeoff with light spooling of the turbo. My GF brother just got a 06 2500 3 weeks ago, that truck will move with no problem from a take off.

Their will be a lot of people who will say iam wrong, thats ok. Hopefuly thae can anwser this question.

If my truck is unloaded and it is in drive, and I floor it the tires wont spin?
But if I hook my 7000lbs trailer on is will spin the tires in first and second gear?
Truck not in tow/haul, no programer.
This is not a bashing post, Ive keep hearing the trucks dont have traction control, but I think they do. Unless its on paper that states otherwise.

Wow, my truck does the exact same thing. When I am hitched up to my 6,000 pound trailer, I have to be careful not to smoke the tires. Empty I can even chirp the tires

When this first happened, I dismissed it as being a side effect of my weight distribution hitch.

What do you think?

Prior to picking up my 2007 duramax tmorrow morning, I test drove it today as well as my alternate deal 2006 Dodge Ram. Even with the 360 HP in the Chevy, it felt weaker than the Ram with 325 HP. Comparing both at spedds below 60. However, once above 60 they both had equal accleration. Any thoughts as to why the Chevy has less low end acceleration? Also, both 3.73 axle, and the Ram only a 4 speed auto.

I thought this also when I first bought my 07 duramax. After I drove the duramax for about a month and the tranny "learned" my driving habits WOW, the dodge dont compare! Give the duramax time to break in and you will be amazed at the difference. As I learned from this site if you drive it like a "granny" it will run like a "granny", drive it like you stole it for about a week and you will see a big difference. Trust me I was very disappointed in the truck the first month or so. My buddys 04 duramax felt more "peppy" than my 07 at first, but not now. I have about 8500 miles on my truck now and its only getting better.:gr_grin:

Wow, my truck does the exact same thing. When I am hitched up to my 6,000 pound trailer, I have to be careful not to smoke the tires. Empty I can even chirp the tires

When this first happened, I dismissed it as being a side effect of my weight distribution hitch.

What do you think?


I believe that 1st gear in the D-MAX defuels to manage the torque.

What do you think?

I think that when you strap a 7000# rolling anchor to the back of a DMax..of course the tires are going to spin when you hammer it. It's simple physics :D

As far as the tires spining i can get mine to spin a lil empty sometimes but loaded i can spin them. I think this is because the torque from the enigine can't be stuck to the ground, not enough traction for the power. When it is empty there is enough traction to launch the truck. my geuss.

The vp44 24v trucks used an electric lift pump, but I don't THINK (not 100% sure) it was mounted in the tank,

It was not in the tank, it was bolted to the engine block, behind and below the fuel filter canister, just above the starter.
I owned a 2001 Dodge and I'll tell ya the fuel system really was a nightmare. Converting the VP to a p-pump was a common mod for real serious racers and pullers... but far to expensive for most "regular" people.
-D

Yep, that's about the impression I have gotten about the 24v too. That's the main reason why I have a p-pumped 12v, and probably a good part of why my truck does so well for me.

My buddy has a 2004 Cummins Ram 2500 Crew. Used it to tow a few times, nice truck. But ran it about 3 times against my dad's 99 Yukon (350 V8) from a stop and rolling start, and the Yukon took it both times. Both trucks were stock. The Yukon had 160K at the time.