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Is it me ,or is my 08' lmm more slugish then my 06'lbz

dmaxx3500

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well ive had this truck[08' 3500 4x2 ext cab dually] for 1 week and it seems to be slower off idle then my older 06'lbz 3500 cc 4x4 dually,,also it seems to be quieter ,inside and out
 

Ed HD

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They're definitely quieter, I'm guessing it's the torque management and the emissions stuff that makes it feel more sluggish.

You bought a 4x2 in Chicago? That's ballsy, LOL.
 

dmaxx3500

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my 02 cc d/a was 2wd,,i bought this 08' because i needed a truck 'right now'' and i couldn't find as good a truck as this ,i really wanted a cc 4x4,but this is a real clean 50k mile piece,and will work till i find something better
 

BoostN

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My fathers LMM is more responsive then my previous LBZ. His LMM has a tune also, but so did my LBZ.
 

WarWagon

Well it hits on 7 of 8...
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Then only thing that responds when you mash the pedal is something that has a cable on it like a DB2 or throttle body. The rest of GM electronics tend to hesitate and de-throttle you except when you want to get off the throttle then they hang at 1200 - 2000 RPM. Gas and diesel both suffer from this to some degree. Some have you slammed into the seat when the computer finally decides to open the throttle you are already 1/2 way to the floor.

Tuning, and I mean CUSTOM tuning is the only way to improve this. After My LMM was tuned it would smoke while the turbo spooled and then hop side to side as one then the other rear tire broke loose. You could break them loose at 35 MPH. The only delay it had was waiting for the turbo for full power... No, not a 'safe' tune!

The LMM will really scare you if you back out of the throttle completely them mash it with the hesitation it has from having to change the turbo vane angle and refusing to put out fuel till the turbo is producing boost. Less smoke to plug the DPF means it waits for boost to pour the power on.

The mush built into the throttle and then the LLY hyper throttle with delay - is it any wonder EFI live is so popular?
 

Ed HD

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Gas and diesel both suffer from this to some degree. Some have you slammed into the seat when the computer finally decides to open the throttle you are already 1/2 way to the floor.
This is our new Suburban to a T. I hate taking off at busy intersections with ppl in it, because they either whine about how "hard" I'm hitting the throttle or how slow I went through the intersection. I need to get a tuner on there that removes the lag.
 

treegump

Romans 3:22-24
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Old thread, I know, but I'm glad I came across it. It's a bit reassuring... I was wondering if this lag was normal in these newer trucks. I've felt in the diesels I've test driven, and in the 6.0 gasser that we have for work. Didn't know if it was because I'm so used to driving a stick, or if I just wasn't handling an automatic right...
 

THEFERMANATOR

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The LMM stock is laggy due to the DPF programming insiude the ECM to reduce soot loading of the DPF. With a tune teh LMM runs just as strong as an LBZ does, and they are virtually lagless. I tuned one for somebody and it is just about brutal how instant the power is on a stock trans safe tune I built for it. You can take a bone stock LMM though and eliminate the DPF and make the changes in the ECM to shut off regen, DPF protection as well as kill the EGR and it will RUN STRONG!
 

treegump

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The LMM stock is laggy due to the DPF programming insiude the ECM to reduce soot loading of the DPF. With a tune teh LMM runs just as strong as an LBZ does, and they are virtually lagless. I tuned one for somebody and it is just about brutal how instant the power is on a stock trans safe tune I built for it. You can take a bone stock LMM though and eliminate the DPF and make the changes in the ECM to shut off regen, DPF protection as well as kill the EGR and it will RUN STRONG!
But if I kept the DPF to keep the warranty, will the tune still work? Also, does the instant power damage the allison any (because the allison is built for how the truck is built?), or is the allison built for how the duramax runs before dpf is installed?
 

btfarm

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All of these trucks in stock tune are plenty powerful but they do not have the instant throttle response of a gasser because they: 1) have to spool some and 2) because they are made to not throw a boatload of power into the trans all of a sudden.
There isn't a comparison to any gassers for the amount of power. That's why the DMaxes got the Allison. It handles the load and is NOT something to worry about. I had an 8.1 / Allison and since it was lower torque, it came on quick. The DMaxes, you ROLL into it. It takes a while to get used to it but it's second nature after a while.
 

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All of these trucks in stock tune are plenty powerful but they do not have the instant throttle response of a gasser because they: 1) have to spool some and 2) because they are made to not throw a boatload of power into the trans all of a sudden.
There isn't a comparison to any gassers for the amount of power. That's why the DMaxes got the Allison. It handles the load and is NOT something to worry about. I had an 8.1 / Allison and since it was lower torque, it came on quick. The DMaxes, you ROLL into it. It takes a while to get used to it but it's second nature after a while.
You need to ride in the LMM I tuned, it will flat fool you it is a diesel with how quick it comes on. The ALLISOn gets damaged during shifting, so the power coming in quick doesn't hurt it. This is why a mild built ALLISON will hold 1000HP sled pulling, but put 700HP to the same trans and race it and you will be lucky to get 30 passes out of it. And ANY tune, and I do mean ANY tune will void your warranty on an LMM. GM can see if a tune or even an add on power box is installed on an LMM by doing a CVN history search in the ECM, a torque input check of teh TCM, or a fuel used history check in the BCM. And changing the tuning with a DPF is about pointless. Adding any fuel or timing changes will just cause the DPF to load faster and cause more regens.
 

Mad Maxx

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When I had the Edge Evo in my LBZ, then Switched to the PPE, I could Immediately tell a Difference in the Throttle Response. The Edge Response was ALOT Better and more Touchy than the PPE.
 

tanman_2006

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The edge I have on my LBZ seems ok as far as throttle response. It does have some lag in certain situations that I am still getting used to though (compared to my 6.5s). Gotta wait for my tranny to "pick" a gear before fully mashing on it.
 

Mad Maxx

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The edge I have on my LBZ seems ok as far as throttle response. It does have some lag in certain situations that I am still getting used to though (compared to my 6.5s). Gotta wait for my tranny to "pick" a gear before fully mashing on it.
That's like how it is in my Truck with EFI now. If I'm on the Highway Cruising at about 60mph, and I put the Petal to the Floor, it's almost like (in this Order, but very Fast) the Engine Shuts Off, the Trans Downshifts, the Engine comes back On, and I take off.

It's def. not something I'm used to.
 

btfarm

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Maybe that's a good way to describe the lag I see from the Predator on 85. I'll take off with lots of oomph from 60 mph or thereabouts AFTER the lag.
 

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That's like how it is in my Truck with EFI now. If I'm on the Highway Cruising at about 60mph, and I put the Petal to the Floor, it's almost like (in this Order, but very Fast) the Engine Shuts Off, the Trans Downshifts, the Engine comes back On, and I take off.

It's def. not something I'm used to.
You can cut some of this back, but your putting your trans in danger in doing so. It is just the nature of the beast so to speak.
 
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