Larry Herman

Bob, how did Chris Cervelli's suggestions work about slightly increasing the understeer to allow for more trailbraking?

RE: Suggestion from Chris C halfway down page 5 about sway bar adjustments & more trailbraking

Bob Rouleau

Larry see the thread called Trail Braking Test. It did not work (for me) on the corner I tested, on the other hand it did work on a corner where I already TB. I tried turning in even earlier and TBing harder and I got 200 RPM at the exit> Very rewarding although it is very delicate during the TB phase.

Rgds
Member LC FD Club

Larry Herman

Bob, I have always prefered a car that slightly understeers for exactly that reason, I can go in deeper on the brakes, although it may be just what I am used to because all of my cars seem to have had slight understeer.

carreracup21

I think if you have a choice, setting up a car for slight understeer is the way to go. I mean you can work around understeer, but fighting oversteer all day can really be draining. Yeah I know oversteer is fun and all and it helps get you turned, but try dealing with it in a high speed sweeper at 100 plus. Not as much fun then !!

PT

Carreracup21... just a thought (and a question in my mind) after my F2000 experience - if we add more "high speed downforce" with a bigger wing in the back, that would offset the high speed oversteer while enabling slow corners to take advantage of easy turn in.

Comments from anyone?

M758

PT...
I tend to think that is ideal. Low speed oversteer and high speed understeer. Of course I have never driven a car with any sort of wing so I am just figuring that it might be good.

Bob Rouleau

Larry and Carrera - my car is set up to understeer in slow corners and be close to neutral in faster ones. Toe is 5 mins F and 34 mons rear. Neg 2.5F 2.4R.

Chris Cervelli suggested more understeer so I softened the rear bar one notch. It didn't work in one corner and it did in another so I was glad I tried it.

Rgds

Larry Herman

Low speed oversteer & high speed understeer. That is exactly what you can dial in with aerodynamics. Just crank up that rear wing & voila. But you will pay for it's drag down the straight. I think that after I get a little more track time in with my car, I will start adjusting the wing and the sway bars. That RS wing looks like it can generate some real downforce.

M758

Hey guys I don' t think I will worry. I am not sure a 131 rwhp 944 can go fast enough for any wing to create downforce.

sjanes

PT,

This is why I'm not going to put a splitter on the front of my car until I can get some sort of meaningful rear wing. The way you have your car setup now (I know PT's car) with the splitter, you would have additional downforce in the front during a high speed corner, but none in the rear with your stock spoiler. This is basically the opposite of what you really want IMHO.

Currently, I set my swaybars so the car is neutral to very, very slight oversteer in the fastest corner on the track, and use various amounts to TB to balance the car everywhere else. Maybe I'll try a little more understeer next time to see how that feels (assuming I ever get my car back from the painters ).

PT

sjanes, funny thing is that my car seems quite neutral now and TB allows me to avoid severe understeer so I am relunctant to spend major $$$ unless its been "proven" that there's an improvement. Kinda similar to my own debate of needing (or not) adj sway bars.

Plus, the stock rear spoiler does give the stock look that I'd still need/want since I drive to the track.

Maybe I can convince you to be the guinea pig & get a new wing ?

sjanes

Actually, Glen Clarke (currently running the Targa Newfoundland) is the guinea pig He is using the setup (3.8 adjust rear wing + splitter) that I'm looking at buying.

sjanes

I re-read my post, and I don't think it came out the way I wanted. I didn't mean your car specifically was out of balance. I've been in it, and at Tremblant, it seems neutral to me. The point I was (poorly) trying to make was the theory about increasing downforce on a 911 in the front only.

My theory is, I would want to increase the downforce in the rear with a wing, so then I could increase the mechanical grip in the front (with a swaybar adjustment). At a slow speed, the lack of rear downforce would help the car turn due to the increase mechanical grip in the front, reducing understeer. At high speed, the wing prevents high speed oversteer. Although, I don't know if the size of the splitter or the 3.8 rear wing is big enough to generate any noticable downforce anyway. Maybe I need to bring a bunch of parts and a DAS to Mosport for a weekend

PT

Make sure your DAS can monitor everything including tire pressure in real time

ok - back to the real topic... that is exactly why I delay / can't decide on getting a 3.8 rear wing - nobody seems to have objective comments on positive/negative effects on a car.

ColorChange

Bob:

The only comment I would make is that exit speed is not the best test. Segment times are. As they discussed in the articles, some times exit speeds can be slower but segment times still faster. This will also be discussed in an upcoming SAE article. Usually will exit speed work, yes, but you can never be certain without segment times driven at similar g-sums.