Rogue_Ant

I can believe wheelspin is more of a problem on a bike - lowered, rider tucked way down, all the weight on the front wheel... I just don't see it as much of a problem for a car (assuming the car isn't "lifting").

The 997 didn't launch that hard, in fact they bogged it a little bit.
The 951 has a pretty good CD, and quite a bit less weight then a 997. I simply don't see 1000+ hp being necessary.

LUCKY DAVE

We (including me) can guess all we want, until it's actually tried, guesses are all it is.
Less weight isn't much of and advantage in such an event, indeed some competitors add weight to improve traction. It's all about power vs drag.

Rogue_Ant

I agree that guessing != experience. But with a decent educated guess, you can identify necessities and goals.

A.Wayne

Why was your car experiencing so much wheel spin (i really doubt that ) and you do know quite a few cars have broken 200 with less than 800 whp ......



The Gallardos were making 1400 whp ...


Single plug 3.2 911 narrow body , no mods to the body , has more drag than a 951 ..

http://www.youtube.com/watch?v=Y5ebk...ayer_embedded#!

333pg333

Not sure I'd like to be going 200mph in one of ours cars unless there was some significant attention to downforce....which is going to sap top speed. Seeing that RX7 do it's impression of Mark Webber doesn't inspire me a whole lot.


http://www.youtube.com/watch?v=UPGMtLaRXEw

TurboTommy

Like I said, any kind of loss of traction (one of them being Lucky Dave's wheel spin) will cause a wreck at that speed.
So, I'll trust my common sense before I believe that data logging equipment implying wheel spin.
Also, this is in effect an acceleration test (not really a top speed run).
Whenever you're trying to accelerate something in a relatively short amount of time and space, weight is an issue, and not of lesser significance as claimed.

LUCKY DAVE

Do you crash every time you experience 15% tire slippage? Do you ever compete on race tracks, and if so, do you do it without any sliding/corner exit tire spin up?
I can't believe you guys insisting "this is the way it is" when you have no experience in this type of event.
Remember, I compete at the Texas Mile on a bike (where all the weight of the vehicle is on the rear tire)..... we still get slippage.
Watch some vids of car runs there, see if you think they are getting wheel spin.
hint: they get a lot, some guy in a Gallardo kept spinning out at approx 100 mph last time.

azbanks

A while back Car-and-Driver had a nice photo of a Lingenfelter turbo Vette smoking the tires at 125. That was before they put BFGoodrich drag tires on it and it crapped it's entire differential onto the pavement. They had a nice photo of that too.

racerxrick

did I say I LOVE this thread!

TurboTommy

I for one am not saying that wheel spin doesn't exsist, and it happens all the time when force overcomes available traction; like you said, slipping in a corner or accelerative force.
But, generally a corrective action will take place; like backing off for the corner with less steering input or velocity, or in the case of straightline acceleration, backing off on the throttle (and you're Texas Mile run is done).
You're implying with this statement:

that the driver just keeps his foot into it to cross the mile marker at high speed, despite the wheel spin, without negative consequences, and it shows up on your data logging equipment.

adrial

There is a difference between flagrant wheel spin (over 100% slip) and 15% slip.

http://f1elites.com/4d/?p=54 goes over it...

Without some percentage of slip, you are creating 0 grip.

LUCKY DAVE

We can't feel the wheel spin in the upper gears, it's not the "burning rubber" type of spin, (to us ridersit felt like the clutch was slipping.....barely) but the logging -which reads rear wheel speed after the clutch- doesn't lie.
The wheel speed logging and the rpm logging match, so it's not the clutch.
The logging showed 207 mph wheel speed at the point that the lights said we were going 176 mph. The lights don't lie either.

333pg333

Wow, that's a huge amount of wheelspin at super high speeds. I had no idea this occurred.
So is this just because the rear or whole car is lifting at speed, or is it the resistance of air being overpowered by hp? So pushing against something with resistance, but the power is stronger.

porshhhh951

Platfom has everything to do with what power a given car is capable of making, how it makes it, how relaible it will be at that level, and how it puts it to the ground. The above posted car is on another planet in terms of technology. That car can get the power to the ground efficiently, alot better than the crude 951 could.

People who have never been to the mile or don't have much experience with really high hp stuff going fast always seem to believe its just soo easy. It takes big big power to run at the mile fast, no 951 is going to hit 200mph. It's just not going to happen with this platform. I do believe a 951 could possibly hit 175-185mph but, it would take a herculean effort and a ****load of money. I highly doubt anyone here has even made the power reliably it would take to do 185mph in the standing mile in a 951.

I have seen many 600-700-800hp cars looking for their 200mph shirt come up short.

porshhhh951

That's bello. Do you have any idea just how much mile experience he has? lol I bet that 3.2 was making plenty of power and had the suspension setup just right. 600hp with a very light body and good setup with someone with years of mile experience got that car 193mph. It'd need 100-150hp to get the next 7mph needed for 200.