FireAm94

So in effect...you're saying gravity doesn't have much play in top speed? I will have to disagree with you on that.

Joe

Canadian z28

So do i have a 110mph speed limiter in my 95 Z?

FireAm94

Actually....the car with higher weight would have more rolling resisitance.....correct due to the effect the weight has on the tires. But of course.....drag is the largest factor.....that is quite obvious.

Joe

rskrause

Absolutely, it's kind of been beaten to death. But FWIW, the cars with Z-rated tires have a 255mph limiter. It has to do with the way the PCM stores data in hex. I am not enough of a math guy to quite understand, but I do know that 255 = ff in hex and that's the largest value you can store in that register. I don't think anyone has hit it yet though.

Reminds me of one of the few math jokes that I know. There are 10 kinds of people in the world, those who understand binary and those who do not.......

Rich Krause

FireAm94

Definately....my hypercrap had the 255zr.

Joe

94formulabz

Whew, thank God for OldSS, I literly felt my heartrate change and my throat knotted up when i read the original statement, but when i saw 17 responses I knew someone must have already chimed in.

I remember having a similar debate with an fbody owner who claimed that a stock neon SRT4 had started pulling on a LS1 topend. His justification, they don't have as much HP but they are lighter. Of course we put an end to that with the good Sir Newtons law and a quick rehash of drag being proportional to velocity squared.

Yeah top speed is in the 150s, only gone 145 myself and because of the handling I don't care to again unless I make it up to Pocono on one of their open days. I already did ~ a 1300° at 100mph with someone else driving and they had to do an emergency lane change, not fun.

FireAm94

If you're talking theoretical top speed...that's one thing. This whole thing started from a question about what the top speed of his z is. Do you guys consider the theoretical top speed to be the top speed? I don't know of any places besides the salt flats where you can get anywhere close to the theoretical top speed of an fbody. Thank god for common sense.

Joe

rskrause

There are lots of public roads where this could be done. Not suggesting that anyone actually do it, but a typical Interstate very early in the AM would give plenty of road. If you came on a straight stretch already at 90-100mph it probably would take a mile or mile and a half to hit top speed.

Rich Krause

FireAm94

Are you talking about theoretical top speed? I don't think so. I'm not talking about the listed top speed.

KeVMaN

its not that hard to find out.... its the pedal on the right. but uh, if you have the guages that only go up to 110 or 120 or whatever then it probably does have the speed limiter...

snorkelface

Even the cars with the Z rated tires have a governer, it's 159 MPH. Our gages just don't go that high, so most would never know.
Also, I've had my 155 MPH speedo pegged, and still accelerating (my 159 MPH gorverner was removed). It still felt smooth nice and smooth.

FireAm94

No...like RSKrause said....they do have a speed limiter...but it's 255 MPH. Effectively....we have no speed limiter...unless you know a car that can go 255MPH.

Joe

FireAm94

Here ya go....

All cars that came with stock touring tires (Good Year Eagle GA 235/55R16) were speed limited to 108 MPH. In addition, they got a 115 MPH speedometer. Cars opting for the QLC package (Good Year Eagle 245/50ZR16 GS-C tires) or the QFZ package (Good Year Eagle 245/50ZR16 RS-A tires, available in 1995 and after), automatically got the 155 MPH speedometer and did NOT have a speed limiter. This is because GS-Cs and RS-As are Z-rated for speeds over 165 MPH. Any car leaving the factory with a Z-rated tires, should also have the 155 MPH speedometer and no speed limiter.

That came from.... http://ls1.divetx.org/4thgenfaq.html

SlowAssTA

i had my speedo to 150 or 155 in 5th gear at 6k rpms with my 4.10's.... but id really like to try it with a GPS, those are supposed to be pretty accurate...

OldSStroker

A couple of us are talking about how fast any given car will go with the power available at the drive wheels. Call that actual top speed, for want of a better term.

Here theory and observable fact get together: power available = power required. Try it, as has been suggested. It works.

If your car goes 150 with the power/gearing/drag it now has, note that rpm. If you can increase power at that rpm and somewhat above that rpm, your car will go faster, all else being equal. 10% more rwhp wil equate to about 7mph around 150.

As far as how fast an f-body has actually gone: a gen 3 with the long 'Bird nose and upwards of 1400 turbo'd hp as topped 300, but not without years of work. So, theoretically and actually, an F-body can go over 300.

Yeah, without gravity we'd have to change the method of getting the power to push the vehicle. With a reaction engine (eg. rocket or jet), we'd get a certain thrust or push. Strangely enough, tires produce a forward push or thrust which is transferred to the chassis thru the axle housing and control arms.

Oh, yeah, without gravity we'd need either aero downforce or thrusters to keep the f-bod on the ground.

But we digress...