Rich Sandor

I'm aiming for 400# to 500# spring rates all around the car. I have the 968m030 sways and they help quite a bit assuming they are mounted correctly and the bushings are perfect. Add slicks to the equation and now I have to worry about strut tower flex!!!

What I want to discover is how much of a difference there will be between AutoX and DE setups.

Songzzz

Clayton, you are right.

gnosis

Well to return to a suggestion in the original post, here's my suggestions for a good setup:

1. Minimise body roll, squat, and dive with stiffer springs and anti-sway bars. Set camber accordingly to maximise contact patch area during cornering.

2. Maximise grip with the softest springs you can get away with, without compromising point 1.

3. Use spring rate ratios from front to rear to alter the balance of the car by affecting weight transfer.

4. Use damping rates to alter the RATE of weight transfer from both front/rear as well as side to side. Use high and low speed damping to isolate damping effects for body roll and bumpy surfaces.

5. Use the brakes for stopping and the accelerator for both accelerating and matching the engine revs to the rotational speed of the driveshaft while the car is moving. The goal is smoothness of power delivery, both in acceleration and deceleration.

6. Always maximise the grip of your tyres to the limits of the car's ability. The sum of the forces laterally and longitudinally must approach 1, where 1 is the limit of traction. Strive to be as close to this limit as your vehicle's power will allow. This means that, yes, you MUST learn to turn and brake at the same time. It's essential to being fast, despite being counter-intuitive.

7. And here's a tip from Michael Schumacher. Don't just drive fast at some places. Always ask yourself how you can be faster at the point on the track you are right now, no matter where that is. Then work it until you are faster. Use data logging to be sure.

Sorry for the track bias. But this applies equally to road driving too, except the bit about going as fast as you can all the time. Only go as fast as you can when you see red and blue lights behind you ;-)

Clayton

adrial

I think this is a VERY good point.

Friendan

Wow great thread guys. For someone who hasn't tracked a car yet, I've learned alot! BTW, nice friggin car, Clayton.

gnosis

Thanks Brendan. It's just a standard 968CS, though. Except for the rims in the pic. They're rip offs of the standard rim that I use for the track. The originals are white.

Your car looks nice too. You should definitely take it to a track day and get some driver training from experienced owners and then get out there any enjoy it. All Porsches should be taken on the track regularly!

Clayton

Z-man

Yes: this is true: the slower and less you move yourself in the car, the less wasted movement there is in the whole car. If you see a driver flailing his arms as he saws the steering wheel while getting around the cones, you'll also see that his car is doing much the same: lurching into the corners, and basically upsetting the balance of the car via extreme weight transfer. However, a smoothly driven car will be more precise and thus quicker around the course. The same can be applied to track driving or street driving for that matter.

A side note to that is: sometimes you have to drive slow to go fast. Often you'll see people charging into a corner at too fast a speed, only to have to slow down too much through the apex, thus greatly reducing their exit speed. This slower speed is carried through the whole straight! This bad method can be often seen at autocrosses.

Kevin: (Not the braking thing again!) Just a quick comment: throwing a boat anchor out the window is also an effective way to slow a car down! But it isn't an effecient method! Much the same way, using the engine to slow a car down 'works,' but not too well. Just because everyone is doing it, that doesn't mean it's the best way to do something! (Which is why this thread was started! )

Great input and comments guys! Keep them coming!!
-Z-man.

W88951

First off, Engine Braking should not be use to slow down a car on a race track (Unless your brakes are Malfunctioning) You should downshift continuosly while on the brakes to match gears with engine rev. 120 in 4th hard on Brakes, Downshift to 3rd (Still hard on brakes) Downshift to 2nd (Still hard on brakes) Release brakes Make turn in Maintain throttle level Reach Apex Slowly apply Gas Reach Exit Feather on Full throttle. Repeat for next turn.


Second. If you ask anybody that drives a large truck (Aka a Semi with full load) in the mountains and they will certainly tell you that you use the engine to slow down. Ever heard of a Jake Brake? If they used their brakes to slow down the entire time, they would have not brakes left halfway down the hill. Same applies for them on the highway. Also, I am sure that you guys that trailer your car fully understand how it can be very necessary to engine brake while towing.

gnosis

Yep, this is definitely true. You'll see skilled drivers lining other drivers up for overtaking manoevers. This can start two, three, even more corners before the actual overtaking happens. Clearly those drivers are going slower before so they can be faster at the right time to get an advantage over their competitors.

The same thing applies when you're out there by yourself. The fastest you've ever been at a particular spot is great in itself, but it isn't a lot of use to a good lap time if it messes up your progress in the next spot.

I'm sure you must keep this in mind when thinking about Schumacher's comment. He means always think about how to be fastest wherever you are, but if that means reducing speed to ensure you are even faster later on then so be it. A fast exit to one corner may not make for the fastest entry to the following one.

Always try to think as many parts of the track as you can ahead, and try to keep things flowing so the overall pace is fastest. It's the total lap time that goes in the record books, after all.

Clayton

gnosis

Yeah, but they're geared really low, so the mechanical advantage of compression braking is high. Not to mention the air assisted braking mechanisms they have (which I know exist because they make a noise, but I don't know how the actually work).

I don't get lapped by too many trucks on the circuit, though.

Clayton

FSAEracer03

Mario Andretti, among many other purists like to engine brake to stabilize the rear... just a thought...

Clayton, I didn't understand his comment as well.... but anyways, explain to me how where the jacking force in corning comes from. If it isn't a part of the cornoring force, as Carroll Smith seems to show (correct me if I'm wrong) in his books, where DOES it come from??

iloveporsches... yyuuuupp, it sure is how ya drive an FSAE car, though we have the benefit of a sequential

-Kevin

W88951

Clayton, Did you read my first paragraph? My second paragraph was only to illistrate the point that in some applications Engine Braking is necessary.

Z-man

Please supply a valid reference for this claim.

I have no idea how engine braking can stabilize the rear. :?:

-Z.

gnosis

Andrew, I wasn't disagreeing with you. I just wanted to emphasise the distinction you make between cars and trucks.

Clayton

gnosis

Is this in Smith's book "Tune to Win"? If so, give me a page reference. I want to see what he's on about.

Clayton