Hypothetical autox scenario for feedback

[ttweed]

Originally posted by Teutonics
Where does one find used racing slicks?

That would be John Berget @ (262) 740-0180. Do a search on "Cantilever slicks" in this forum and you will turn up a lot of interesting information regarding price, availability and setup.

I would not recommend jumping from street tires to slicks to anyone except for the most gifted drivers. You must learn to walk before running, as they say. Slicks put you automatically into Prepared class in SCCA Solo2, and into Improved class in our PCA Zone 8 rules.

TT

[DanS911]

Great stuff guys. As always the value of the experience here is incalculable. Is that really a word??
My .02. Tires are a must for competitive autocrossing. That means two sets of wheels. Buy a set of 7 and 8 x 16 Fuches. While more expensive than other set ups they will be worth at least what you pay for them years from now. (I hope)

[Teutonics]

Now here's a crazy question.... again hypothetical: If I want to use 15's to improve gearing, why not just on the rear? (as in 15x8's in the rear, and 16x7's in the front) Wouldn't that give you the best advantages of both? Has anybody tried it? What are the technical reasons not to do it?

Okay, so maybe a beer or three was involved during the development of this question, but why not?

[Dave at Pelican Parts]

That's not a bad thought, but I would prefer to have the 15s on both ends. Assuming similar-aspect tires, the 15s with tires will be lighter than the 16s with tires. Weight reduction is A Good Thing, and reducing unsprung rotating mass is especially Good.

--DD

[jhadler]

Originally posted by ttweed
Josh, this is absolutely correct, but I have to disagree with you that adjustable shocks are the way to accomplish this. The correct way to balance the car is with spring rates first and adjustable anti-roll bars secondly, to fine tune.
TT

TT is spot on there. The true way to balance a car is by suspension spring rates, alignment, and sway bars (if any). However, I wasn't saying that shocks were -the- way to do it. I was just saying that they were the right place to start if you haven't already invested in the suspension. Everyone is gonna need shocks to be competitive. A big set of springs and sway bars won't do you didly if you don't have a good set of shocks to match. Shocks are the initial investment. If that's all you can afford to do, then there are things you can do with adjustable shocks that allow you to tune the handling. The same goes for alignment and tire pressures. All of these are basic things that an otherwise stock chassis can utilize. For some people, that's as far as the budget allows. For others, it's just square one...

As for the super duper shocks? They make a dramatic difference even in the higher prep levels, not just stock. I was amazed at the transformation of cars when they went from single adjustable Konis to custom adjustable shocks. With no other changes. And this is on a car with a heavilly devloped suspension and running on big fat wheels and tahrs. Shocks make a big difference. Moreso than I would have believed....

-Josh2

[Rob Channell]

15 x 8's and 16 x 7's........I would think it might work if you are in a bind or on a tight budget. I knew one guy that used to run 4 different brands of tire on the four corners of his 911 just to get more seat time(he was a little slow then). I use different size wheels front and rear. 8x16 front, 9x17 rear. They work pretty well for me. Whenever I put on my old 7&8 inch wheels I am amazed at how much less grip the tires have.

I would think tires would be first after driver upgrades. If I was running 7&8x15, I would try to find the Hoosier 225/245 combo in 45 aspect ratio. These are supposed to be really fast, but they are strictly track only. I would not drive them to the track on the street.

Since I'm on a budget I opted for a cheaper, longer lasting tire, the Toyo RA1(currently on my 79). When I get my 72 back on the road I plan to try 225's on 7&8x15 wheels. I met a racer using this combo on an early car and asked him if he had too much oversteer from this combo and he said "No. It works great. The turn-in is awesome!"

One thing to consider with the smaller diameter tires is where you will be running. In our local autocross with my larger rear tires I can stay in 2nd gear through the whole course. When I run the smaller 15's I have to go to 3rd in the faster sections.

A cheap driver help would be a CG Lock. It keeps your seatbelt tighter and keeps you in the seat better. My officemate runs with one and it works surprisingly well. The less you have to use your hands to balance your body, the more you can use them for driving.

My list in order of help and/or cost:
1. All the autoX, driver's Ed seat time you can get $ - $$$
2. CG lock or other method to lock your seatbelt $30
3. Proper track alignment/corner balancing $60-$250 ?
4. Add lightness when you can from here on $Free-$Lots
5a. Toyo RA1's for whatever wheel you have$500-$600
5b. R compound tires for new used 7&8s $1400-$2000
5c. 8&9 inch wheels + tires $2200-$4000
6. larger adjustable swaybars front/rear $500-$1100
7. better shocks, matched Bilsteins or adjustable Konis $600-$800
8. Quaife or limited slip $1300 + install cost
9. stiffer torsion bars $500-$700
10. better seating + 5 point harness $700-$2000

There. That should take care of the first $10000-$12000 or so.

I know others would arrange this list differently. I swapped order on a few things myself and that was just in the last 15 minutes.

Since you are in Atlanta, I recommend coming to one of the TGPR(www.tgprace.com) DE events with the Alabama Region (http://ala.pca.org/)as one of your events for this year. It's a good group and the events are fun. And feel free to come have lunch sometime with the Trackaholics support group we have here in the Huntsville/Madison area.

[Joe Ricard]

Not to horn in on this topic but this is facinating.
I guess I forgot to mention the suspension mods of my 914.
I bought the car this way so it is the cards I am dealt right now.
Weltmiester 21mm front sway bar stock rear bar. 150lb rear springs some guy called them coil overs (look stock configuration to me) just smaller diameter coils. and I believe stock front torsion bars. I have Polygraphite bushings in the rear trailing arms. and poly bushings in both swaybars.
I will start with what you recommended and see how it goes. Biggest thing for me to overcome is keeping my right foot down. and learning to brake with left foot.

I also plan on getting into one of those AX driving schools.

[Rob Channell]

[i]..............Biggest thing for me to overcome is keeping my right foot down. and learning to brake with left foot.
[/B]

Right foot down is good. Also think about wheels. Given two theoretically equal cars that use the gas and brake identically, whichever car keeps the wheels more straight will be faster. More turning is not always better.

When the less experienced autocrosssers start catching up with us more experienced people we tell 'em about the benefits of left foot braking. Slows 'em right down....

[Joe Ricard]

well that also sounds like very good advice. Just a recap of yesterdays event. I was much faster with the set up of the shocks. The car was much better behaved and balanced. I have closed into 3 seconds from the leader of my class which is also FTOD. Last month I was near 10 seconds back. Nearly the same course layout.
Other things that are different about the car are Autocross alignment. 2 degrees neg camber all around, 1/16 toe out front near zero toe rear (slightly in) all the caster I could get keeping them the same.

So thanks to all.

[Howard M]

I'm surprised that smaller wheel diameter is permitted in Stock classes. Along with a proper alignment and corner balance, don't forget to lower the car to at least European specs. In my experience (early 911) the biggest bang for the buck is experience, followed by tires (DOT aproved to remain Stock), and lowering/alignment. Then, sway bars. After those you are into significantly diminishing returns IMHO. See you at Hershey?

Howard