Whalebird,
You have hit the nail on the head: "I recall many 911 drivers with torsion bar cars were having a hard time finding a nice round-edged tire - almost an all season tire by todays standards. The current trend in square, stiff walled low profile tires were not optimal for the T-bar chassis. Remember the Yoko A008P(for porsche). The complaint was a lack of slip angle in the newer tires that so many 911 owners had become used too."

This is exactly my concern!

Guys,
Please understand, I am NOT setting up the car for the track right now, ok?
I want some slip angles and fun at less than racing speeds because that's where I use the car, for now. Tires get more non linear at higher vertical loads, so reducing weight transfer with a wider track postpones the transition.

Whalebird and Rusnak, that's why I'm lost with the next sentence: "get some 9" rears and a modest set of performance tires."
(17" 245s I assume)

How does this buy me slip angles?? The stock 16x7" with 225/50 are fine for road use. Any wider or lower profile tire will reduce slip angles and have sharper breakway. All I want is to use the space available in the body WITHOUT stiffening the tires. Of course the spacers are not a max performance track solution. The time for track wheels and tires and the rest of the goodies will come. In the meantime I do promise you all to do a DE exploration this fall 1 day with and 1 day w/o the spacers and report my impressions honestly!! The never ending learning process is what makes this nonsense so much fun.

I don't want 245's in the rear and 205's in the front because I believe the car will understeer even more, and in road use there is little you can do about it.
I also don't want 17" ultra low profile street tires because I live in Michigan and will end up bending rims and destryoing tires on a weekly basis.

When I get into track wheels and tires this will be a completely different story. I do appreciate everybody's interest and am saving all your good inputs for the "performance phase".

Cheers,

Yoram

 

Theoretically, yes. But the change will be imperceptible. See my post above. BTDT.

If all you want is a high slip angle, just get some mud and snow tires.

FWIW, my car and 9" wide wheels in front and 11 1/2" wide in the back with 17" R tires. The "breakaway" is very controllable contrary to your theoretical position and I am certainly not an expert driver. True, the grip level is pretty high for the street (I mainly auto-cross the car), but the car is a blast on mountain roads. Caveat - I have put a fair amount of time and money into suspension upgrades and settings.

And, from the department of redundacy, 14 mm spacers make no discernible difference whatsoever to the handling of my car. They do help with tire clearance at the inner fenderwell.

Whatever. Get some quality spacers, some extended lug studs and give it a whirl. It won't hurt (the theoretical disadvantages of increased track are real, but pretty small in my experience), and it will probably look better.

 

Again, I think the statements here are being made with no real experience in driving the car.

Just get out and use it.

 

If you want some fun slip angles, dial in some toe-out and save yourself some money.

I was not addressing slip angles. What I'm saying is that you'll realize that you're wasting your money on spacers, and when you come to your senses....when...you...come....to....your....senses....you will realize that you should have gone with 9"x16" with 245s.

 

Rusnak, I don't believe you got my point. Toe out has nothing to do with cornering stiffness and will not substitute for tire properties. Toe out is a bad idea unless you like your car darty and unstable, which is not my goal.

If I wanted "slot car" feel and abrupt breakaway I would go with your wheel and tire recommendation.

 

Iv'e been driving Porsches for 25 years and find your conclusions strange.

 

Yoram: You don't get the point. You came on here looking for support to your theory that spacers are a magic bullet to improve your car's handling. It's obvious now, you don't have a lot of takers, if any.

The "book" has long been written on how to improve t-bar 911's in the handling dept. It can be as simple as a suspension refresh or more rubber, or it can be quite costly. It can be many levels in between. Spacers are only good to make the wrong wheels fit, or as a cheap way to maybe improve aesthetics (only while looking at tire to fender clearance from the side), and nothing else. Maybe it is time to start a new thread on how to truly improve your car, and give this hypothesis a rest?

 

Ed, your point is (or at least ought to be) well-taken.
Whale's contention about the handling of a stock set-up is solid, too. There are reasons the factory did what it did - it is advisable to thoroughly understand those reasons when making mods.

I have a long-held theory concerning "the increasing importance of the smaller difference".
This (entertaining) thread is a powerful counter-argument. Since I like my theory alot, I'll consider the spacers issue to be an object case of "exceptions that prove the rule".
Yoram - good luck in your endeavor.

 

Yoram. Your thinking about this too hard. Which is good; your thinking, seeking answers, and came to the right place. May I relate my experiance.
I will preclude by saying that I am not "fast". I have restored, repaired, raced, and driven many Porsche models. I currently own an 87 924S with slight suspension mods - otherwise stock. I use it for PCA DEs and a daily driver and have for 7 years. You have used a 951S as a measuring stick and that is not a good comparison. I have developed a smooth and consistant driving style that was forged in various 911s that I owned or preped for track use, some stock, some highly modified. The same goes for 951s, 951Ss, 930s, and 964s, and 965s. A 924-based chassis(your 951S) is not the best track car. Let the flaming begin - but I feel safe in this forum. The balance of the 24-based chassis is obvious, but does not make a good handling car all the same. A 951 is heavy and I find that the numerous examples I have tracked(including my 924S) does not transition well and is hard to place on the track/line. Thats probably more me than the car. The perceived balance of those cars has risen to mythical status, but have hard-to-cure ills. I can real a 951 in on a road coarse with a properly set up stock suspension in a 911.
Properly set up is the key. Replace old original shocks hell, KYB cheapos are better than originals and make a nice compliment to the stock 911 springs. Replace the old worn bushings I suggested earlier with good welt/racers edge, elephant racing pieces. Lower to euro ride height and corner balance. Get a set of spherical bearing rear sway bar links. "But whaebird, won't that isolate the rear even more?". Not really, it will isolate the rear bar and provide good feedback - not bias. Get a good set of street tires as posted earlier. Tire technology has come a long way since the days of the A008 yokos. Go to a drivers Ed and forget all latent theory you have catalogued in your mind. Talk to your instructor, listen to him and do exactly what he says. When he says go - that means floor it. You will quickly loose the trepidation about the rear swapping ends with the front. A 911 is fast in- slow thru- and fast out of the curves."But whalebird everyone says you can't trail brake in a 911" Forget it for now, learn to heel-toe and listen to your instructor. The rear bias in a 911 has reach mythical status. Go find a good shop for 911s and get a good set up done. Go do a drivers Ed and let your honed skills translate to safer driving experiance on the street. You will get home, drive the 51S and it will be on Ebay the next week. Me nor anyone else on this board will illadvise you. All of us and our hobby have stake in your safe and satisfied 911 ownership. Let the spacers go for now and lets talk about improving what you have - you don't need training wheels on a 911.
Good luck.

 

Kind of on this topic- I'm pissed! My 255's in the rear are shot, and I have two days of time trial at Buttonwillow on 9/18-19. The kicker is they are discontinued! So, I had to move down to 245's to get some new rubber back there. I guess 3500 miles is good tire life? My fronts are still good, so this will take ne to next spring or so, and I'll decide what to switch to. Even 17's are getting scarcer.

The good news is I ordered them Tues nite from Tire Rack, and even got the heat cycle option. My wife called me this afternoon to tell me a "present" arrived. That's fast...

 

Dude, who needs 255 race rubber? Put some spacers on that puppy...you know, like 6" on each side. You'll be able to experiment with slip angles and you can even keep inferior tires on there all the while improving your driving experience.