The stock PCM tops out at 255, in whatever unit you're using. MPH, KMH, etc. It has an 8-bit memory space allocated for the speed variable and cannot go over 255. That doesn't mean you can't go faster, it just means the PCM will be unable to interpret and use a speed higher than 255 in any of its calculations.

 

wow... dont think i have ever gone above 115... and i was gettin pretty nervous even then. I guess i need to find a good country road by me to try this out. I live right outside of chicago so i dont have much opportunity to do so. I did 115 on I-294 (that was dumb... cop central)

 

I hit 150 relatively easy with some pull left. T-Tops down and windows open... hahahaha

That was a CAM only car... not even bolt ons. haha

 

It's no wonder our insurance rates are so high. You guys never need wonder about that.

 

i think the 96-97 models z28/SS were tested at 158mph (governed) and teh LS1s were at 162 (governed)

 

from what i read your top speed is going to be in 5th, cause when you shift to 6th it takes alot of power to push the car at those speeds. just like the Vipers, their top speeds are in 5th.

oh yea i did 135mph and wont do it again, its stupid and reckless, i was lucky and learned my lesson without killing anyone. Its stupid guys, dont do it.

 

My insurance only comes out to 400 every six months and i am the primary driver at age 23. I dont think that is too high.

 

Yea your right but if you do it under the right circumstances.
There is a high way by me that goes to Moroso it's dived strait no heavy traffic either.
A good road to do that on but the cop's realize this too and are out there when there is a big event.
Just don't make it a habbit.
And just don't kill yourself or anybody else "and for god sake don't kill your Camaro"
You can kill your self as long as you "don't kill the Camaro".


Chris G.

 

I will take it up to 120 but after that you need a lot of road cuz it doesn't pull that hard in 5th. I know a spot where I can do it, I'll just have to try to peg it sometime.

 

i would love to got 185 to 190 mph on my new set-up

383ci with all of the boltons and even the bottle too

 

i wouldn't normally do what i did if there were other cars around. the road i was on was 5 lanes wide and flat and straight, only one car in sight and that was the one i caught up to. it was around 10:30 at night on a sunday. Before i try anything like that again i'll need some new tires for sure, possably alluminum drive shaft, strut tower brace, BRAKES, roll cage. I have stock brakes that suck.

and

Demus, are you mistakenly saying 255 insted of 155 mph? our speedos top out at 155 not 255.

 

i got a 95 z A4 and i be took mine passed 150 more than a few times(with a passanger),it just takes great control and some real power

 

The LS1's aren't governed to 162. They hit the rev limiter in 5th at that speed. The engine doesn't have enough power to accelerate past that point in sixth. Add enough power, though, and look out!

jer4251, no, Demus means 255. The engine computer used in F-body cars was not designed to handle speeds greater than 255. It has an 8-bit memory space, which can store 2^8=256 values. Since it starts at zero, that means it ends at 255. If you managed to mod your f-body enough to go 256mph with the stock engine computer ( ), bad things would happen.

 

That's awfully conservative.

Tire speed ratings are conservative to begin with. Most street cars come from the factory with S-rated tires, which is certified to 112mph. T- and U-rated tires are pretty rare. Mid-performance cars are usually H-rated (130), and then you'll see V (140) and Z (149+).

The "Z" rating means that the tire is certified for 149+ mph. After that standard was created, they discovered a need for more specific certifications, so you will see a tire with "ZR" in the size specification (e.g. 245/50ZR16), and a W (168) or Y (186) in the load/speed specifcation (e.g. 89W).

My tires are W-rated, and I've had my car up to about 145 before I decided I couldn't spare any more braking room.

-Jake

 

I got my bone stock a4 93 z28 up to 120 no problem but i was gonna hit traffic soon so i slowed down lol. I was also wondering how much would my top speed drop by if i get 3.73's instead of the stock 3.23's? lol and if you think his insurance is high i'm 19 and pay $180 a month lol.