My Dmax tops out at 156-8 Km/h and is pretty close to the redline. Lets say I remove the limiter, can I run the truck for extended periods of time at 3800 to 4000 rpm? My goal is to be able to go 180 to 190 Km/h.

i dunno what that works out to in mph but for the 01 as of right now the only way to get extra rpms is with a tts reflash.i think that will get you 3750 rpms and about 110-115 mph.dont hold me to this could be wrong on ecaxt mph and may be off on rpms a bit to.also i think quadzilla power is supposed to be getting close to figuring the 01s out....jess

Thanks for the info. Is there a problem with the '01's seeing that quadzilla can't reflash them?

i think the over ride for rpm and mph is in a different spot on 01s than 02s and 03s,but they are working on it i am sure

go to a taller tire, that will keep the rpm lower at a givin speed. 295`s will give you about 9.5-10% higher mph/kph. But don't forget, you will also lose some power.

my dmax does 4grand easy mine topsthe same as yours

Why would anyone want to do that? Get a taller final drive, or a GV unit. That way you can go much faster, and have the lower RPM to go along with it. Not to mention the better mileage. But I dont think they make a GV for the Allison.


I dont think that spinning the Duramax at 4 grand is going to do it any favors...

I'll be installing 37's soon so I'll see what that yields me. I'm sure the Attitude/Juice combo should help some but I really want that limiter gone.

FWIW, with the 315/70-17's (34.6 tall) the governer doesn't kick in until 108mph. You'll probably be in the 112 range with 37's.

I also think the ZF runs at a higher RPM in 6th than the Allison does in 5th...

My Truck only hits 3,300 RPM and I get at least 120 MPH?


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What I meant was if your speedometer governor still stops you at 96mph, you'll actually be doing 108mph with the 315's that I have, probably around 112 with 37's. I don't know what RPM that is at, I've never taken my truck that high.Edited by: Camstyn

I did 96mph(100 corrected) this morning, RPM = 3k

This is no joke. I hit the govenor at 96MPH and I was only turning 2600RPM?? I only have 265/75/R16's. They are about 32" diameter.


From what everybody else is saying I should of been at around 3000RPM?


ON EDIT: I have never reclibrated my speedo. DUNNO if the dealer has ever taken it apon them selves?Edited by: Bronco

I just went out for a ride to see at what rpm the limiter kicks in. With 245/75/16 tires I hit 158Km/h and the limiter kicks in at 2800 RPM. That leaves 400 RPM's left before I hit the redline.

I would agree that you'll be frustrated by adding power and not being able to exceed the limiter. IIRC, my limiter kicked in at 160km/h around approx. 2800 RPM.


I often go up to 170 - 180km/h for very brief periods but I don't think you want to be cruising for long periods, esp. at 180-190! You might also want to review your insurance which likely won't cover you if you blow a tire at these speeds and your tires likely aren't rated for this velocity either. I'd be checking my tire pressure weekly, if not daily. I'm considering the Michelin Pilot LTX 285/60-18 which is HR (210km/h) speed rated with a 3086 lb. max load rating but the cost of new rims is a little prohibitive.