Tms951

I was at the track with the Audi Club, the next events I will be doing at limerock are PCA events. I did not believe the lap time when I saw it but, the lap times after it made sense so I don't think the time was off. I will see next time if I dod any laps that fast, It was much faster than my other laps which were a little more constistent at around 1.06.xx now that I look at it. There was alot of traffic to deal with which slowed me down, learning to drive the car made the laps very inconsistant. I was told that the 59sec lap was when there were no cars holding me up the whole lap.


Me and the GT3 passing an Audi S4

TurboTommy

trucho;

That question #3 is just misleading because it didn't ask: "If the car was lowered (but also the roll axis height was increased)"
Basically, if a vehicle is lowered, the there is less weight transfer, and therefore less body roll (ALL ELSE BEING EQUAL)

Why wouldn't open wheeled race car manufacturers just increase the roll axis height so there would be no body roll to contend with.
Something I'm not gettin'.

333pg333

Nice pic's. Can't wait to get back out to the track. That time seems amazing if you were doing 1.06's. Even with traffic 7 secs is some improvement, but it's in the books now so well done!!!

anders44

120N/mm rear on the way...

333pg333

Wow that's going to be about 750lb/in? From what I understand the springs for a 'Burger-ring' car don't need to be as stiff as other, smoother tracks?

anders44

I thin the factor is 5.7? if so its 684

and yes it's a pretty uneven track, its always good fun jumping your car doing 200+

pete95zhn

5.709 to be exact.

Van

I came across this thread searching for something. I mean no disrespect, but I call BS on your claim to run a 59.0 second lap on the old lime rock. That simply cannot be done in your car - by anyone.

Especially if your other times are 1:06. There's some mistake or miscalculation.

A 7 second difference is equal to a 10 MPH faster AVERAGE speed on the whole track. That kind of jump just isn't possible unless you ran all the "slow laps" in 2nd gear.

Factory Escort cup cars (on the old bumpy track) don't get below 1:01. Now with the smooth new pavement, they're in the 1:00s. Factory GT3 cup cars are in the 58s.

A streetable 951 with 400 HP doing a 59.0?? No way.

---------------------------------------------

The reason for my search: does anyone have any data on the roll center geometry and center of gravity geometry for 951s?

RPHARRIS

Can't help you with the center of gravity but finding the roll center of the front suspension shouldn't be that difficult. IIRC you find the instantaneous centers of each side, draw lines from the contact patch through the centers and see where they intersect. It shouldn't be too tricky to estimate but if you want factor in caster, that will complicate things a bit.

For the semi trailing arms, it involves the intersection of lines through each of the pivots with lines sticking out of the spindles. Take these points and connect lines to the contact patch on the opposite side.

RPHARRIS

The vertical line here represents the center of the chassis. If you want to study roll center migration, you need to follow that procedure for both sides and find the intersection.

sweanders

I have friend here in Sweden who is chasing down Cup cars in the Club racing scene with his 350 rwhp 951 running Michelin Cup tires while the GT3 Cup cars are running slicks.

His car is street legal.

Just a reference point - it can be done.

333pg333

How light is that car Sweanders? That is pretty incredible. Those Cup cars are very fast.

95ONE

The types of cars never matter.. It's more often the driver. That's why I like to compete on Senior discount day.

sweanders

Nothing spectacular. Normally stripped shell with cage and plastic fender and hood. The regulations mandate that the cars pass through the annual Swedish safety and emissions tests (which is impossible for a GT3 Cup). With that in mind it is not overly crazy.

But it is a very well setup car with advanced suspension and a competent driver. I co-own another race car with him and when we did a 24h race this winter (on snow and ice) he was consistently faster than me even though I came close enough to be happy.

333pg333

I guess it depends on the track and the drivers. You've probably seen this video. It's out of Holland. IIRC the car is pretty light but maybe only 300whp. Gives the Cup guy a scare. In fact he was held up at various times but those Cups just have such good traction and get their power down so well. We do lose out to technology.
http://www.youtube.com/watch?v=vExPd...e=channel_page
Just as an exercise, what do you think would help bridge that tech gap? We don't have PASM etc but we could have traction control. What else would you want on a hypothetical 951?