This past weekend I was towing my (2) snowmobiles back from up north. My friend was also towing his two machines back with his 2001 chev 1/2 ton and decided to see if he could take my duramax on a long 6% uphill grade. He pulled beside me and let her rip, I followed suit. I could not go over 75 MPH up the whole damn pass! He slowly pulled away and left me eating sand and rocks being flung up by his 285 tires. What the heck is going on? It seems my truck doesn't shift down when already going 65mph and when it does it goes to 3500rpms and stays there, which is 75 mph. The tranny then shifts to OD and the engine actually looses speed. I have heard people on here towing 80+ with 8-10k lb loads up hills. My total trailer weight is only 1750lbs. I figured I should have spanked the 285hp 340ft-lb gasser, but no such luck.
I am running #1 diesel right now, so that my have something to do with the lack of ass kicking performance. I am stock except for 265 BFG tires.

do you have a chipmunk lodged in your air filter, or exhaust?

Is the fuel filter pretty clean? Or does it need to be changed? Just wondering. Those 5.3s run pretty good at lower elevations. Would think you would stick with him at least though.

No 1 is part of your problem and 3500 in 4th should be getting you close to 85 mph unless my math is wrong. I can personally tow a 5.3 faster that it can go under it's own power. :D Later! Frank

ah, that chiprmunk line is golden!!! seriously though, my truck will not run over 70 in 4th gear if its floored, it will go into 5th. do yourself a favor and get the juice. it will be a totally different story after that. wil

Should not need a Juice to take a 5.3!

LOad another dozen snowmobiles behind each truck and see who eats rocks. :D

LOad another dozen snowmobiles behind each truck and see who eats rocks. :DDitto! With 1750 lbs. It was near to an unloaded race.

i have driven a couple of 5.3 2wd's and they run strong. less than 2K is not much of a load for either truck. although i am suprised your truck would not go over 75, might be something wrong? wil

you may find a little more power when your rpm's are lower. I know if I pull out to pass and hit it to the floor there is a lot of noise but when it shifts into fifth there's not many that can keep up between 60 and 90

No need to run tow/haul with a load that size either. An easier upshift might have been in order.

Sounds like something's wrong, check your buddy's truck for a super charger or nitrous(j/k). I pulled 2 Sea doo's from LA to Lauglin last summer and up a grade(maybe not as steep as yours) pulled out to pass a long line of 18 wheelers, had no problem getting from 65 to 85 mph in moments. Check air filter. When was the last time you changed fuel filter?
LA DMAX

Yeah, unless the 5.3 is heavily modified, you definitely have a problem with your D-Max. I've driven several 5.3's as well as logged thousands of miles in the 6.0's, and there is no way one of these can even come close to a D-Max in stock configuration in my experience. Loaded or unloaded, you should be able to blow the doors off a 5.3! Why are you running straight #1 diesel? Unless you're in Siberia, there's no need to run #1 in my opinion. With a quality additive and blended #2, you should be protected from gelling to -40° F.

I don't think you have anything wrong. I made my annual trip over the rockies from CO to AZ last week only this time I had a new Duramax instead of my old 8.1 gasser. The gasser can definitely outrun the Max on hills due to the RPM ranges of each. I tow a heavy 5'er and end up running in 4th up a lot of the hills. With the Duramax/Allison, you peak at 3200RPM. You can run the 8.1/Allison up in the 4000rpm's easily. Same rear end, same transmission, more RPM's, you are going to go faster.

Dave

Same rear end, same transmission, more RPM's, you are going to go faster.




I respectfully disagree. First off, the original post was not simply about gassers in general, it was about the 5.3 GM gas-a vastly different engine than the 8.1 GM gas.

Second, more RPM's doesn't necessarily mean more power. From what you posted, this means that I could put a Honda lawnmower engine in my truck, mate it to the same tranny and rear end and would go faster as long as I could wind it to high RPM.

Basically, we've demonstrated the logic behind diesels in the first place. They make a tremendous amount of torque at relatively low RPM. Just because the 8.1 will rev higher doesn't mean it is making more realistic, useable power at these engine speeds.

If a 5.3 with 285's pulled away from you dragging 1750# up a 6 degree grade you have a problem of some kind... :eek:... for God sakes don't tell any of the Dodge guys this, you'll make a bad name for all of us :D

You could probably pull him and his trailer about as fast as your trailer alone and I agree, he has something he isn't telling you about if he ran away from you so easily. These things pull hard above 65 mph even without goodies.

I know what the issue here is...

Ol' Alaska here forgot to raise the snowplow blade on the truck...

In all honesty, I would be looking at fuel filter, air filter, stuck trailer brakes, left the parking brake on... everything and anything. My truck likes grades even when loaded down! Everyone drops back and I keep on going...

Mjollnir YOU are wright with that statement!!!!!

Do you have big-ass floormats? I have seen them stuck under the fuel pedal where people are only getting 80% throttle when they think it is floored. You will know this because you will not be able to reset the change oil light. Fuel/Air filters arent a bad idea either. No SES light?

I believe byron makes a valid observation. Our trucks are very speed limited because of RPM limitations compared to gassers. The gasser is just obtaining it's max torque at the high RPM (fast speed). The diesel's torque curve falls off a bit as RPM's increase. Above 2500 RPM, the gassers performance is increasing, ours is decreasing.

Exactly right, put 10,000 lbs behind, and it's a different race. Just a thought: For the scenario described, you might have had a better shot with taller tires, which will make the truck go faster at lower constrained RPM. Similar to lowering your gear ratio, it makes the truck work less at higher speeds (I think). That same mod is detrimental to pulling power but better high speed use.

I had a 99 silverado with a 5.3, 4 inch rancho, 285's motor and tranny,gears stock, it ran fairly strong, but comparing it to my LLY with a six inch lift turning 315's with everything stock there is no comparison. It would not even be worth comparing.

At that speed, the 5.3 downshifted TWO gears, while the Duramax doesn't. A LITTLE slower and your truck would have downshifted also. Anything less than that speed, you would have won. For the record, the 5.3/6.0/8.1 run identical to the Duramax in a race (stock), right around 16.4 in the 1/4 mile.

Wow!!! Thanks for all the replies on this subject.
To Clarify, he didn't exactly blow my doors off. By the time I got into the throttle he was right next to me already accelerating. I could stay right up with him, but I could not pass him, which I thought would be no problem to do. With such light loads and me running the Alaska Winter fuel I expect I am only running about 90% of my max power. So, that would be 270hp, but I thought my torque would over power him, not the case. In the summer towing up the pass with my 7000lb boat I can also go 70-75mph, and the 5.3 wouldn't be able to go 55mph, but it should all be relative right? A lightly loaded duramax should be able to haul balls compared to a 5.3 gasser. I know when I am running summer fuel my truck has great power.

I was just pissed when my buddy got on his radio and said " let's see what the mighty Duramax has" and he was able to stay ahead of me.
After our little race, I was pissed and went further up the pass and threw it into tow/haul mode. I was able to hit 80-85mph at the same grade in tow haul mode. Maybe that will be the trick when I get a chance to smoke him later.
Another friend has a 99 gmc 5.3 and I can walk all over him up hills. The one with the 2001 chevy 5.3 has always had good towing power, I just didn't think it was as good as my duramax.
Maybe a chip is in line, but I don't want to cause engine problems. Not many 27 yr olds can afford new duramx engines if I screw it up by performance products.

I just changed my fuel filter about 2000 miles ago and the air filter about 3 months ago.

I have read somewhere on a GM site that the allison computer will not exceed 76mph in order to not cause problems. At least when they are stock as you can see in my sig I have a few things done and I towed a boat back from Alabama about a month ago with no problem or speed limitation my only fear was jerking the trailer out from under the boat

I always race in tow/haul. The shifts are really lazy in regular. I pull 13K over 6% at 55 mph in 3rd. The same grade I held 5th easily empty.

"Maybe a chip is in line, but I don't want to cause engine problems. Not many 27 yr olds can afford new duramx engines if I screw it up by performance products."

Get the juice. You will never be 2nd again. It has all kinds of safety built into saving the drivetrain, and the LB7 version is highly refined. Have some fun. With your cold air up there, you will be king of the road.

My 2002 2WD Tahoe would flat out spank my LLY in an unloaded or lightly loaded race.

I don't know what kind of fuel we're running here in anchorage. I think we're still running normal diesel, not any winter blend or anything that I know of.

Toss a tuner on it, edge, banks, whatever floats your boat. You'll love it. I like mine and am researching some stuff for the future...

I have read somewhere on a GM site that the allison computer will not exceed 76mph in order to not cause problems. At least when they are stock as you can see in my sig I have a few things done and I towed a boat back from Alabama about a month ago with no problem or speed limitation my only fear was jerking the trailer out from under the boat
I climb over Summit County in Colorado on I70 doing atleast 80 (sometimes 85). That is 10K feet of elevation, and 6-7% grades :ro) . My rig is totally stock.

Funny, red light to red light I out ran my buddies 5.3 several times in a row. And my truck has 150,000 miles on it....;\ :ro)

Funny, red light to red light I out ran my buddies 5.3 several times in a row. And my truck has 150,000 miles on it....;\ :ro)
That is consistent with these posts. But 60-90 will be a problem, from what I understand.

I don't know what kind of fuel we're running here in anchorage. I think we're still running normal diesel, not any winter blend or anything that I know of.

Toss a tuner on it, edge, banks, whatever floats your boat. You'll love it. I like mine and am researching some stuff for the future...You'll be almost full winter blend by now.

put the pedal down,now dont be afraid !

Was your motor warmed up to operating range? Cold diesels don't make as much power.

Yes, it was at full operating temp, I had been on the raod for 4 hrs before then. I think it was a case of winterblend fuel and not putting it into tow/haul mode. Like everyone has been saying, hook up a 6000lb load to both the trucks and I would see him in my rear view mirror.

[QUOTE=B_Alaska]Maybe a chip is in line, but I don't want to cause engine problems. Not many 27 yr olds can afford new duramx engines if I screw it up by performance products.

QUOTE]



WHAT??!!!! I am only 18 and i rape mine..Teat her just like a cheap whore,lol...(drive her hard and put it away wet)

Just got th Predator and Str8 piped..nd now she realy get its rough....

Oh...just for the record..i am not some rich kid who's momy an daddy buys verything..i pay for it all..(i any of you werewondering)so when she breaks..its my ass...but heck..who cares..she's a champ..



Oh also..I was in the WV mountains pullin my 14ft enclose trailer w/ a Race Quad and generator (maybe a 400lber) (total maybe 1800) i was hittin arond 80mph..so i dunno what the deal is...

You'd change your tune sligtly if you bent a $15000 engine. But hey, I'm generally the guy saying, "Hooray for today, F--k tomorrow!"

i remember one of the first times pulling our 6600lb holiday trailer threw the mountains and before i had any chips on, a yukon or something came along side of me and the same snarieo had happen, i just could not get buy him, really pisses you off, because your looking for a excuse, he is heaver, modded, or something, that is the way it is

but now after my third duramax, and running all types of chips and stuff, if your happy with stock, great enjoy, but for my self, i could never, and i say never go back to stock again, for just a single chip,(300$) you can add another 100 plus hp and 200 plus tq, and not touch one other thing and have reliable hp( afew family members that run this setup very hard and pull all sorts of things, and after 50k have never had a problem) and the best is my own gm dealer even sells the chip, and does the warenty work for the truck? i just see it as a no brainer, and you ussally see a mpg benifit after, my two cents

Consider this, the 1/2 ton 5.3 weighs 5000 something pounds and the dmax is 7000+. You have 2000 pounds more to pull around with roughly the same horsepower as the 5.3. Get to the same HP/weight ratio (about 400) and you can run with and probably beat any 5.3.

I moved from a modded 5.7 1/2 ton to my dmax and stock the dmax didn't feel any faster, in some areas slower. HP/weight is the key.

For the record, the 5.3/6.0/8.1 run identical to the Duramax in a race (stock), right around 16.4 in the 1/4 mile. Yah what now? I have raced at least one of each, all stock except 285s just like me, and several older 98s with chips and 285s, and I stomped them really badly. All were boosted launchs and most times I spun a bit more than they did, especially the 8.1 as he ran in 4wd. Still I had them from the line all the way untill I hit 95 no problem at all. We tried multiple times because they wanted another chance and the ending never changed. Duramax wins again.<img>

I got beat by a 5.3L suburban towing ~2000 lbs each a while back.

She was kinda cold, but if the 5.3L can get up to 4000+ rpm, itl be a tough race unless you can get it to shift just right. I just floored it at about 2000 rpm, and watched him pass me.

I did catch up with him and pass him later though.

for just a single chip,(300$) you can add another 100 plus hp and 200 plus tq, and not touch one other thing and have reliable hp( afew family members that run this setup very hard and pull all sorts of things, and after 50k have never had a problem) and the best is my own gm dealer even sells the chip, and does the warenty work for the truck? i just see it as a no brainer, and you ussally see a mpg benifit after, my two cents
100% agree. I run a Juice 90 horse plug in and it makes the truck FUN :ro)

Running without it is a real bummer dude :(

The 1/2 ton truck is a BUNCH lighter than your truck (~1500lb?), and the 5.3 is not as wimpy of an engine as people think.

With the TTS Tow, which is a very "mild" tune, I can pull 10,000 extra weight up a 6% at high altitude in 5th gear at 80mph without breathing hard.

The heavier the trailer, the more advantage the diesel has.

nar,
The 285's on the gas motors will slow them down more than the Duramax. I've raced the 5.3/6.0/8.1, all extended cab short box, all running 265's. Stock, we were side by side at the speed limiter. I've also raced an extended cab short box 3/4 ton Dodge Hemi, and got him by two truck lengths in the 1/4 mile-all stock.

What hill were you on? The Turnagan Pass?
I was going to mention the weight difference also. Plug by the time he got next to you he his momentum was faster and he was in a better power band then you were.
Does your freind have 4.10 gears? He can get a better launch while cruising than you can with the 3.73 gears.
And knowing and seeing a lot of the trucks around Alaska, if he had the 285's on he also had dual exhaust, and probably more things as well. The exhaust will help him out better in the power dept. than it will you.

Change the fuel filter one more time. I know you just did it... but it could have collapsed on itself internally causing a restriction. And yes I have seen this on someone elses Duramax.
It's an easy test.

Originally Posted by fredw
for just a single chip,(300$) you can add another 100 plus hp and 200 plus tq, and not touch one other thing and have reliable hp( afew family members that run this setup very hard and pull all sorts of things, and after 50k have never had a problem) and the best is my own gm dealer even sells the chip, and does the warenty work for the truck? i just see it as a no brainer, and you ussally see a mpg benifit after, my two cents

one thing i did forget to say is by doing the chip thing, you will see that your tranny will not shift as much, mostly because of the extra power produced, a much smother quieter ride, and probally better for the tranny, than shifing all the time when pulling

Got 65000 miles on my chiped 2002 5.3 Chevy pickup (hypertech). I thought (and proved, relitvely) no none could out run me. I am a cop and have chased my share of villans with the 5.3. I have pulled some heavy trailers with the 5.3. BUT I WISH I had my Duramax to drive on my regular shift........

Let me get this straight. Your patrol vehicle has a programer/chip in it to make ungodly amounts of power. If I am correct those for the gassers only really make about 30 rwhp.
Do all of the patrol vehicles have this type of power addtion? I mean I thought they modified the engine in more detail instead of just slapping on a programmer, like a performance cam and etc...

My truck was bought off the lot and then chipped, mostly to get rid of the speed limiter. 100 is plenty for any truck, but sometimes you must go faster. 126 mph on the radar once, scared me and I had to back off. NO comparison to the Duramax though.):h

Yes, it was towing up Turnagain pass. I forgot, but after reading dome of the later posts, my friend does have the hypertech programer chip and dual exhaust for his 5.3. With the light towing loads and his performance mods, I guess my stock duramax did what it should have.

Now you just have to give him a little suprise next time you go riding. Although the roads now are not exactly the best condition for rubing it in, sota speak.

Pulled my 5er over Turnagain Pass several times and don`t remember it as being much of a pull. In fact some old f--t in a motorhome called in to the State Patrol and said we were going much to fast. Anyway, your right, this is the time of year you had better watch your speed up there. Wouldn`t mind being there for a while though just to see what it`s like.

You can still see the bathroom houses. Not like in the past when walk over the top of the roofs. Makes for a fun day up there when there is 30+ trucks with trailers in the parking lot that only has room for about 15 vehicles - trailers due to the amount of snow in the lot.