Ok,
the other night on the interstate I ramped the duramax up and she only would run 95 mph at 3000k WOT whats that all about

Trauma

Sorry it is what it is . I've seen 98 and it falls on its nose. It is because of the speed rating on the tires. I would like to know how fast they will go if the speed limiter was off. Any body know?

130

Not a thing about the DMAX that is built for a high top end speed. These things are for hauling and pulling. That's all. Not a road in the US that's suitable for much over 75 and that's pushing it.

aka-Wow you have crappy roads in florida... Our roads are pretty good around here. As stable as my truck is it runs fine down them at 75, and just as fine at 120. I feel safer in my truck at speed than in a vette or other ground dragger-:t going that speed. Of course there is the danger of a ticket, but that's why you don't do that sort of thing often.:cool:

I can't help but notice you post in every thread about doing anything other than stock and say how bad it is. Didn't your mother ever tell you if you can't say anything good, don't? They are going to do it anyway, you just end up sounding like a mean guy. (Dare I say, a crotchety old man even?:eek:) Don't get all mad because I'm telling you this, just thought you might want to know how it appears.


To answer the question, liability. GM doesn't want to be responsible for you going that fast.
You can remove it with a programmer, but do so at your own risk. I would for sure be running better tires than stock before going that fast, because I have seen the stock ones blow out easily. My truck is much more stable on the better tires than it was on the stock car tire 245s.

The truck does feel stable at high speeds, but I don't feel any safer than a vette or other sports car. No way. There just isn't the braking or handling in the truck available to use if you need it. Sure, you may wipe out what you hit, but you are still gonna wipe out yourself.

There isn't rpm available to reach 130, with stock tires 115 is about it before you are out of rpm.

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I heard if you give it fuel to 4500rpms it will do around 130mph

I KNOW that my truck would go all the way to its death before it reached its top speed. At 115 mph which is where I chicken out I can step on the throttle and there is PLENTY more to give. Problem is that the engine is not designed for high RPMs.

My limiter is at 3600 and I can just cover 120 with speedo corrected 285's.

At that rpm it is screaming. If you wanna take yours to 4500rpm then have at it, hope it stays together.

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One thing you all forget about is the Allison is not designed for high speed use either. So what GM did was to design things to all run out at about the same place. The engine, transmission and tires are all rated to just about the same spot so when pushing the envolope in speed you need to be careful or do a fair amount of up grades to the truck. I would say 120 with correct tires is about it's limits before going into the transmission and engine.