Have almost 600 miles on the new truck and I have a question:


From a dead stop I get anemic performance up to around 2500 RPM and then it wakes up and almost breaks the tires loose. I'm aware of turbo lag but it seems like the truck has been engineered that way to keep owners from going through too many tires or something.


Anyone experience this? Any way to correct it?


Thanks.

First gear is a slug! I think it has something to do with protecting the Allison.

i believe the general calls this torque managment, if its electronically controlled its electronically disabled right? why hasnt anyone (aftermarket i.e. edge, quadzilla or any other big name) come out with a fix for this?

So the aftermarket chips definitely don't correct this? Does the LB7 behave the same way?

SKyhook , try an edge juice chip and check out the "Disconnect EGR?" post . Then i think you will be happier . I am !!

I unplugged the EGR yesterday afternoon. With only 600 or so Duramax miles under my belt I don't have enough experience to be able to pinpoint the gains made by that mod. It does [seem] to make a difference in throttle response but not in any way related to the "bridled" performance up to 2500 RPM I'm experiencing.


My Edge/Attitude should be here early next week. While I know it will boost performance I don't expect it to make a difference regarding this particular phenomenon.

the allison's 1st and 5th gear where never touched when the new lly engine came out. so basicly the allison thinks u still got 300 hp and 520 lbft torque insteed of 310 590. kinda get it? its hard to explain

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I unplugged the EGR yesterday afternoon. With only 600 or so Duramax miles under my belt I don't have enough experience to be able to pinpoint the gains made by that mod. It does [seem] to make a difference in throttle response but not in any way related to the "bridled" performance up to 2500 RPM I'm experiencing.


My Edge/Attitude should be here early next week. While I know it will boost performance I don't expect it to make a difference regarding this particular phenomenon.





What you feel with the EGR disconnected, is how the '01-'03 trucks feel off the line. It's that close of a comparison....Even when you get the Juice, 1st gear will still seem sluggish unless you brake torque it. The juice is a mid range power chip. You will notice it most while passing traffic or lugging around 35 mph and then "getting on it"! Don't worry it's the best $$ you'll ever spend... http://www.dieselplace.com/forum/smileys/Big Smile.gif

Skyhook,


I got my Juice/Attitude today when I got home from work. Installed everything. Set low boost fueling to 4, level 1. It really seems to help off the line, especially if I roll into the throttle. When the TC locks, it squirts pretty hard. I'm planning to drive around like this for a couple weeks, then up to level 2, same thing, then up to level 3. I think there will be a pretty big difference off the line. I may go up to level 5 low boost fueling, too, but 4 seems pretty good. A little puff of soot, too.


I was in front of a Ford Powerstroke, so I decided to give him a little show, brake torqued it and smoked the tires, but I did get a turbo bark when I let off. I should have eased off the throttle, but just got out, like I used to do in the Impala.


But I digress, bottom line is, when you get the Juice/Attitude, you will like the performance off the line a bit better. Might not be a jackrabbit, but much better.


Dennis

Have you tried brake torquing it? If you build some boost before you let it go, it makes a HUGE difference. I am pretty easily able to get the back wheels spinning off the line with brake torquing. If I just roll into the throttle or hammer it without building boost. . . nothing but a dog until late in first as you suggest.


Dennis

I started to reply but had to go out and run some brake torquing tests first. This is what I see:


I can brake torque and that will help off the line but I still see a distinct difference at 2400 or 2500 RPM. At that point I not only get a power surge but I can also hear a difference in the sound of the engine. At that point the engine sounds completely different. It's like it just started getting a bunch more fuel or something. Does anyone else hear and feel that change at 2400 RPM?


Remember my truck is completely stock except for the EGR disconnect.

I wonder if that could be the pilot injecion turning off that you hear.


Dennis

The TTS tune "wakes up" the first gear lag quite a bit.

Ran a few more tests this evening:


I put the shift lever in "2" and brought the truck to speed and then let it coast back down to 20 or 18 MPH. I then floored it and ran it up to redline. The same surge in power and difference in sound occurs at 2400 RPM.


I then did the same with "3" and started from around 35 MPH. The same surge and sound difference at 2400 RPM.


This doesn't appear to be limited to first gear. A full throttle run from a dead stop doesn't reveal the torgue limitation in other gears because the shifts don't bring the RPM to below 2400 RPM.

Just always leave at 2500 rpm with the Edge juice, wallah" no more lag ! joking


IF my G-Tech is correct i just ran a 0-60mph time of 5.89 with a healthy 2nd gear scratch IN 4WD HIGH ! Backed it up with another one of 5.91. Best time so far (according to G tech is 14.39 and 96.3 mph.) Beat a Late model camaro w/LS1 motor by a truck length in a quarter mile distance run. The look on his face was priceless when i jumped ahead of him out of the hole with a Diesel crew cab farm truck ! heheheEdited by: FASTOYS

FASTOYS,


Were you running the the Quad and EDGE? What level were you running? Do you have SCIII or ATS?


Nice Kill,
Dennis

Im running Edge Juice w/level 5 and Quad tuner w/70 hp and raise speed limiter/rpm. Stock trans ! I know , i know , im crazy but it hasnt limped it yet . Believe it or not the Quad box doesnt do much for the times when ran with the Edge though. I ran my quickest 0-60 mph with just the Edge. But gain about 1 mph in 1/4 with the Quad. Trans starts to try to slip when running any higher on the Quad when stacked with Edge on 5. For the runs against the Camaro i ran tow/haul (as it seems to always be faster) defuel 4-5 shift Edge level 5 and Quad 70hp. It worked as i beat him by a truck length and now he is gonna go get 4.10 gears or something. lol

Installed the Juice today. First gear is still a dog.


I've read many posts with reference to pilot injection turning off at 2400 RPM. I've also found many references in this forum and others to "torque management".


At least one aftermarket product (Wester's) is able to disable and/or manage torque management on the GM gasser trucks.


It may just be a coincidence that the torque increases just as the pilot injection turns off (if indeed pilot injection is causing the change in sound from the engine).


I'm still dumbfounded as to why more members don't find the sluggish first gear very annoying.

FASTOYS,


I guess it's just a matter of time before the tranny goes. You might have the one in a million that never does, wouldn't that be nice.


skyhook8,


was the truck fully warmed up before you tried your runs. Until the truck gets up to full operating temperature, the juice doesn't deliver full power. I went up to level 2 today, fully warmed up, noticed a pretty good shot of power out of first. It's no rocket, but it is pretty fast off the line now. Even without brake torquing, there is much better acceleration. Maybe you were 'over-psyched' about the expected performance. The guys that are running reallly quick times on this board are modded out a lot more than I probably ever will be, but my truck is still D*MN fast for something that can tow a house.


Dennis

I installed the Edge Juice w/Attitude on my LLY. I am thoroughly impressed in how much faster my truck is. The low boost fueling is set to 4 and first gear is noticeably faster. It doesn't spin the tires on dry ground, but the turbo lag is reduced. The power level set to 3. If I floor it, I get a good puff of black smoke at each shift.


If you spent the money on a Juice box, you should get the Attitude controller too.


I want exhaust next.

Truck is warm; Attitude is plugged in and on level 5. Defuel on 4-5 shift only. Low Boost is level 5. The truck HAULS A$$!


BUT, I'm losing a half second or so because of the pilot injection, torque management, or whatever it is that is holding the engine back up to 2400 RPM in first gear.


Yeah, I'm used to the instant, kick in the butt, torque of the 5.4L Triton with the Kenne Bell supercharger but I guarantee you that we're slow out of the gate and that's why we see only Ford and Dodge tail lights through first gear.

At 2500 rpm you are hearing the pilot injection shut off.


What you are feeling is turbo lag. Next time you stomp on it from a stand still watch your boost guage. It will make more sense then. To make it a bit better, set low boost fueling to 5, disconnect your egr, remove your cat and get a 4" exhaust. You will still expierence some turbo lag but it should be better. When you are racing, power brake. That will get your boost up earlier.


The only other thing I can recommend is to go with a TTS tune. Apparantly it is a lot better out of the hole. Perhaps they play with the turbo vanes to get it to boost up faster. Only Mr. Cole knows for sure.Edited by: Max Power

I'm not ready to buy the turbo lag argument yet.


Yeah, the pressure is low until 2400 RPM but is that because it hasn't spooled or because fuel is being held back or maybe because pilot injection piston strokes aren't "explosive" enough?


I ran a few more rolling tests with the shift lever in 2 and 3. In all tests, with Juice/Attitude on 5 and Low Boost Fuel on 5, the same lag in performance and sound differential occurs. At 2400 RPM I hear a distinct change in sound and feel a surge in acceleration. And, it's always right on 2400 RPM; in every test, in every gear. If it were turbo lag I would think that the pivot point would be different if I were launching from idle as opposed to a rolling stomp with the RPM already at 1800 or so.


I did a few power brake tests. On one, I broke the tires loose and sat spinning for a second. I then put it in 4x4 and got a rocket launch compared to starting from idle. That's great, but for everyday driving I need to be able to make decisive maneuvers from a slight roll. Right now there's a bit of apprehensiveness when moving onto city streets from a parking lot or a side street.


Again, why does the "turbo lag" always disappear right at 2400 RPM no matter the conditions. And, why does that transition coincide with a distinct change in the engine sound?


I almost get the feeling that folks are so emotional and excited about the extreme overall power and performance of the Duramax that they overlook this glaring flaw in the power delivery.

As said before 2400rpm is the end of pilot injection which gives the increase in noise.


Put it on a dyno, since u don't give a state or town in your info it's kind of hard to help out w/ a nearby dyno.


SOP isn't the best gauge of power.


A dyno like John Kennedy has would be the real test, he has tested some LLYs on it already, PM him and see if has any ideas.

I'm not ready to buy the turbo lag argument yet.


Yeah, the pressure is low until 2400 RPM but is that because it hasn't spooled or because fuel is being held back or maybe because pilot injection piston strokes aren't "explosive" enough?


I ran a few more rolling tests with the shift lever in 2 and 3. In all tests, with Juice/Attitude on 5 and Low Boost Fuel on 5, the same lag in performance and sound differential occurs. At 2400 RPM I hear a distinct change in sound and feel a surge in acceleration. And, it's always right on 2400 RPM; in every test, in every gear. If it were turbo lag I would think that the pivot point would be different if I were launching from idle as opposed to a rolling stomp with the RPM already at 1800 or so.


I did a few power brake tests. On one, I broke the tires loose and sat spinning for a second. I then put it in 4x4 and got a rocket launch compared to starting from idle. That's great, but for everyday driving I need to be able to make decisive maneuvers from a slight roll. Right now there's a bit of apprehensiveness when moving onto city streets from a parking lot or a side street.


Again, why does the "turbo lag" always disappear right at 2400 RPM no matter the conditions. And, why does that transition coincide with a distinct change in the engine sound?


I almost get the feeling that folks are so emotional and excited about the extreme overall power and performance of the Duramax that they overlook this glaring flaw in the power delivery.





I think the only thing left to try is to sell the truck, buy a used Formula 1 race car and then practice decisive maneuvers with that. Maybe you should consider not pulling out right in front of someone, but what kind of 'decisive maneuvers' are you performing that you need something with a 0-60 under 7 seconds?


Dennis

Fasttoys, If you are beating an LS1, then that LS1 driver does not know how to drive his car! Those are easy mid 13 sec cars bone stock!


Skyhook8, I am with you 100%, I was expecting the edge to do more than it does (hyped myself waiting for it and reading about it on here) But, the truck is what it is, a slug in first gear--I am living with it because the wife would sh-t herself if I told her I was buying another new truck--that Dodge is looking very tempting!

I know I'm taking this a bit far.


There are some issues with the truck that are correctable and some that are not. This one, I'm guessing, is computer related and so I was hoping to spark some dialog and then maybe get the attention of a vendor who might be willing to investigate.


If I find any additional information I will be sure to update.

I'm not ready to buy the turbo lag argument yet.


Yeah, the pressure is low until 2400 RPM but is that because it hasn't spooled or because fuel is being held back or maybe because pilot injection piston strokes aren't "explosive" enough?


Again, why does the "turbo lag" always disappear right at 2400 RPM no matter the conditions. And, why does that transition coincide with a distinct change in the engine sound?


I almost get the feeling that folks are so emotional and excited about the extreme overall power and performance of the Duramax that they overlook this glaring flaw in the power delivery.





Some of you guys amaze me. First, how many times do people have to tell you the noise IS PILOT INJECTION SHUT OFF


IT IS IT IS IT IS.


Second the lly has the same power levels as the lb7 in gears 1 and 5-that is so it doesn't tear your transmission up. YOU can fix that by putting a suncoast stage III in it. If you read through the forum you would find a lot of this stuff out.


Third, how can you be upset at a 7000 lb truck that will do 0-60 in the high 8's or 9's?


And lastly, as far as turbo lag- A variable vane turbo has some of the least amount of turbo lag of any turbo-you would not experience turbo lag at 2400. If your boost gauge is showing low boost at 2400 RPM's-you have something set wrong on your edge. Your turbo will spool up how ever fast the computer tells it to by adjusting the 9 vanes.


THERE IS NO GLARING FLAW IN THE POWER DELIVERY

Well, maybe I hadn't had any breakfast or something, no hard feelings. It just seemed like there wouldn't be any acceptable solution to you.


I look at it this way. This is a 7000 pound truck that will spank a lot of stuff on the road without any problem. If it takes a second to get that much mass moving and GM decides to limit torque to keep the driveline from grenading, so be it. I can live with that. The Juice/Attitude makes it pretty quick, so nothing to complain about here. My truck isn't as fast as either of my other cars, and I wouldn't expect it to be without dumping a lot of money into it, it weighs almost twice what the Impala weighs, and nearly three times the Mini, and it can tow a house. It's a great truck, take it for what it is.


There is also the 'what are you going to do with it' factor. If you are just driving it around town, then why do you need it to do a sub 6.0 second 0-60. If you are racing it, different story, I understand the frustration of trying to get a few tenths extra out of it. Another question is what were you driving before? A corvette? Maybe it would seem slow comparatively.


The ECM programming on these trucks is probably going to be pretty hard for the average joe to just figure out. TTS/Edge/Quad and others get paid a lot of money by guys like us to figure it out and give us a product that kicks butt. So far, it seems that none have done it (completely). Maybe in time, but until someone does, I'm happy with the performance.


DennisEdited by: baimpala

By Redneck:


Fasttoys, If you are beating an LS1, then that LS1 driver does not know how to drive his car! Those are easy mid 13 sec cars bone stock!





Well Redneck, i was there doing the sootin and that is how it went down (3 times) ! Im not saying i can beat EVERY LS1 Camaro out there but in a street race (if you will) i would feel pretty confident about trying . How hard can it be to stall it up (like he did) and punch it getting about 6 ft of posi-trac (like he did) and let the automatic shift once , maybe twice in a quarter with only 3.23 gear and a high winding LS1 ? It was a good kill none the less so dont try to take anything from me ! There was also a Mustang Gt (1989) that couldnt even keep up at all . IT DID have issues though.


Sorry some of you arent happy with your 1st gear issues but mine is running good WITH what i have now and will pert-near change lanes in 4wd if i spool it hard enough. My fastest 0-60 according to the G-tech was with the Edge by itself and was 5.89 seconds. Im happy with MY Edge chip ! Pretty darn good for a 7000 lb diesel ("farm truck" NOT) truck . Of course we always want more, so come Edge where is the HOT juice for the LLY?


http://www.dieselplace.com/forum/smileys/Clap.gif

By Redneck:


Fasttoys, If you are beating an LS1, then that LS1 driver does not know how to drive his car! Those are easy mid 13 sec cars bone stock!


Well Redneck, i was there doing the sootin and that is how it went down (3 times) ! Im not saying i can beat EVERY LS1 Camaro out there but in a street race (if you will) i would feel pretty confident about trying . How hard can it be to stall it up (like he did) and punch it getting about 6 ft of posi-trac (like he did) and let the automatic shift once , maybe twice in a quarter with only 3.23 gear and a high winding LS1 ? It was a good kill none the less so dont try to take anything from me ! There was also a Mustang Gt (1989) that couldnt even keep up at all . IT DID have issues though.





Your right, a wins a win on the street but don't get too excited in this case unless you know the car. A 99+ Z28 can have the 2.73 rear and with Good Year GSC tires the best he'll ever hit is a 2.1 60' time with mid 13s and 105-108mph. He puts a set of Nitto Drag Radials on there and it's a different story. If he did have a 3.23 the Good Year 275/45/17 on there then he is racing challenged and should promptly give you the title to his car and never drive an F-Body again. http://www.dieselplace.com/forum/smileys/Big Smile.gif


That being said, you have a strong truck and I'd like to see your times at a real track rather than the G-tech. The can be +/- .2 seconds easy in the quarter. The general weight math and likely RWHP is pretty close but it's not the real deal until you get the paper time slip so you can carry it in your wallet. http://www.dieselplace.com/forum/smileys/Cool.gif


For those that are interested in GM's evil tencency to apply Torque Management, the car in qustion above, 99+ F-bodies are probably the best example of how TM can kill you. The 10-bolt rear end in these cars was never meant for the punishment of a LS-1 engine. So Gm uses a combination of a target TQ ceiling to cap the abuse management and traction control detection to yank timing like it's going out of style.


When hit that ceiling TQ number the timing pulled leaves you stumbling until you get out of the throttle and the shift completes so that you can get all over it again in the A4 trannies. The 1-2 shift is by far the worst and it's probably safe to assume that they have stuck it to us with the Allisons too to keep from burning clutch packs. The 1-2 and the 4-5 shifts would be very sensitive with the TQ these engines can toss at the tranny. Remember, that 1st gear is to get your load moving, not score a holeshot off the tree at the track.


The way we get around this in the LS-1 world is with a Tuning software like LS-1 Edit by Carputing. You can actully go in and raise the targeted TQ trigger point and also set the timng pull to 0 degrees. These leaves you free to break your stock drive shaft and 10-bolt rearends. Not that I would know this from personal experience. http://www.dieselplace.com/forum/smileys/HiHi.gif


The trick is that GM is not too friendly with releasing the PCM code. So it's going to be up to some gearhead to go through and

I don't know, but my buds '02 T/A is a 6speed (don't know why people buy these cars with an auto), and he can't drive for sh--, and can run low 13's all day! I know I can get it into the 12's, but he won't let me drive it (he can't drive, but he is smart). I don't see my dmax every beating him (atleast not with stock tranny runnin in level 3). By the way, last night I ran a 14.91 @ 91.1 mph and figured out how to lose the 1st gear blues! Power brake it up to 2500rpms then let er rip--level 3 in 4X4, low boost fuelin at 5, defuel 4-5 shift in T/H mode. OMG, talk about a launch, my heart fell into my stomach and everything loose in the truck was on the back seat!! I ran one more defuelin all shifts and went 15.0. Funny thing, in 2X4 leaving the line at 1500rpms I had no wheel spin, and ran a 15.5, but the mph was 94! I did it both ways twice--seems 4X4 slows it down, but the launch is worth it!

Anything can happen in a street race. Heck, anything can happen at the dragstrip! I beat 4 Vipers (4-0) with a very lightly mod'd 2000 Camaro M6. It ran consistant 12.5's@111-112. And I beat a LS1 Firebird to the 1/8 mi marker in my truck.


My truck seems to have good power in first, but OMG power in 2,3,4. If I spool the turbo at stoplight, it blows off the tires in the first 3 gears in 2wd.


This is a fairly large displacement V8 with a single turbo and a ton of intercooler volume. It will always have lag until the turbo pressurizes the entire intake tract. It will never make serious power until the boost kicks in. The hardest gear to make boost in is first gear. The engine is not loaded down as hard, so it will take longer to get full boost.


When I powerbrake it, it takes a few seconds for the boost to build, no matter what. It won't go over 2000 rpm until it spools.

Have you guys tried launching in 4wd and then going to 2wd after it's hooked good?Not sure how it would be on the transfercase.

Won't shift unless you lift.

Thanks.I thought that might be a problem too.

I don't know, but my buds '02 T/A is a 6speed (don't know why people buy these cars with an auto),


The main reason is for drag racing. There are only a few guys getting to 9.6s with a M6. My last package was like clockwork running 10.5x sec at 129.5mph on a built 4L60E. I used to think there was nothing quite as fun as showing up to the track, putting on the slicks, running 10s driving home on the drag radials and taking the kids to school in the car the next day. :)


Now the plan is a mid 13s tow vehicle and low 9s TA on the trailer. Mid October should be fun in the cool air. :)


There are a lot of nice trucks here too that have helped me map out a plan to get there after a lot of reading. Which I'd like to thank everyone for the great source of info by the way. http://www.dieselplace.com/forum/smileys/HiHi.gif





This is a fairly large displacement V8 with a single turbo and a ton of intercooler volume. It will always have lag until the turbo pressurizes the entire intake tract. It will never make serious power until the boost kicks in. The hardest gear to make boost in is first gear. The engine is not loaded down as hard, so it will take longer to get full boost.


When I powerbrake it, it takes a few seconds for the boost to build, no matter what. It won't go over 2000 rpm until it spools.





Ohhh it can make power down low but it will require a specifically tuned converter and likely more than a level 3 tranny could handle with that much torque at launch. It wouldn't be the best compromise for those that want to tow. We also need a fully enabled tuner package like LS-1 Edit to manage all the pieces. http://www.dieselplace.com/forum/smileys/Big Smile.gif


When it comes to race converters, I go with Neale Chance converters. I'm not sure they've had a chance to play with the Allisons yet but if they have, they can create some torque magic with the but level 5 trannies out there. They build for a lot of boost cars in the Ford and GM world. I've got a nice one waiting for the car to go back together in October for a big cubes-single turbo project. http://www.dieselplace.com/forum/smileys/Hug.gif


Rick