Best mod to reduce "float"/oversteer in early car

[masraum]

Actually the early cars did have better aerodynamics than the bellows bumper cars until you get to the 964 which was designed with aerodynamics in mind.

[jluetjen]

I have done the "bounce" test and have concluded that there is room for improvement (2-3 bounces depending on how hard I jump).

That settles it. I'm with Randy now -- your shocks are shot. Before I typed my previous post I went and did the same test on my car in the garage and it didn't bounce at all. If you're getting 2-3 bounces, they're junk.

Are you going to install them yourself or have a shop do it? If you're going to do the job yourself, I'd recommend that you also check the ride-height and corner weights (if you can borrow the scales or a checker). Those two jobs are somewhat labor intensive, but can be done at home before you do the alignment. Do a search on "corner weight" or "do it yourself alignment" on this BBS and you'll find lots of reading.

Welcome to the world of 911's and Pelican's BBS!

[alfizzo]

I KNOW ITS BEEN A WHILE SINCE A POST ON THIS TOPIC BUT MY CAR FRONT END FLOATS FROM 90+ WHATS GIVES? I HAVE THE FOLLOWING DONE 77 S

BILSTEIN RSR FRONT REAR
22/ 28 TB
BRONZE BUSHING FRONT AND NEATRIX REAR WITH SOME NEW FACTORY STUFF ALSO
SMART RACING REAR SWAY BAR
FACTORY TURBO UNDER THE BODY SWAY BAR
FRONT RSR BUMPER W/ 2" LIP
STRUT TOWER BRACE
RACK SPACERS
GETTY REAR WING 3.8 FOR SC
RIDE HEIGHT 25.5 FT 25 REAR
996/BOXTER 17" TWIST RIMS
1.5" FRONT AND .75" SPACER IN REAR
215/40/17 FT
245/35/17 REAR


CAR WAS ALIGNED WITH STOCK FRONT BUMPER IT FLOATED
RSR FRONT BUMPER IT FLOATED
REAR SWAY BAR IT FLOATED
NEW TOYO T1S IT FLOATED
FLOATES ON OR OFF THE GAS

SHOULD RSR FRONT STRUTS RIDE LOWER THAN REGULAR BILSTEIN?

WHAT GIVES???

[Randy Webb]

Do you have that rubber lip that the later cars can use to get some front spoiler effect?

And... has it always done this?

[HarryD]

One other thing to consider is to verify that your car is properly corner balanced. Some of the float may be attributable to improper corner balance.

[alfizzo]

the rsr bumper has a 2" lip and help it a tad. the problem seems to be the the suspension setup. i have not corner balanced it yet. just a 4 wheel aligment.

[911pcars]

Replacing worn out stuff is not upgrading is it? Assuming shocks, bushings and alignment are all in order, that should be what the factory spec'd and provided. It's fairly easy to "upgrade" when the old part is NG, but in my book that's called repair. That's why X brand spark plug wires are such an improvement compared with wires that have broken conductors and cracked insulation. Replace the worn out stuff, then try it again.

If you still need assistance, I'd say, minimally, lower the front slightly for a slight rake, then add a front spoiler. If you have the budget, add everything else that's been suggested. It all helps, in other areas as well.

Sherwood

[911-32]

I would reiterate the suggestion that you also replace the rear spring plate bushings. I would prioritise this ahead of the front bushings. The reason IMHO is that the rear toe and camber adjustments both come from the spring plate. If the spring plate is not held firmly by bushings in a good state of repair, you get toe and camber change under load. Particularly unhelpful is that you get toe out under load. If you have ever seen 30 year old spring plate bushings you will know that they change from being round to being quite oval - if they have not been replaced, they will certainly need it. Most people use Neatrix rubber bushings to replace OE bushings as the OE ones are vulcanised onto the spring plate and an OE replacement involves buying new springplates at much greater cost. The Neatrix bushings (available from Pelican) are very close to OE in the key ride/handling characteristics.

The bad news is that this is not the easiest job in the world and reqires removal of the rear torsion bars and normally requires re-indexing of the rear torsion bars. If you are getting the ride height adjusted and a corner balance completed this removal/re-indexing may be necessary anyway - so its a good to do these altogether.

I promise you that new rear spring plate bushings will make a big difference to the way the rear of your car feels. I also agree with the consensus that the floating feeling is primarily shock related, although you should remember that the light front end of the 911 will always feel a little more floaty (or at least lighter) than "normal" cars.

HTH
Richard

[jluetjen]

I'm assuming that this is a track car so I'm responding within that context. I'm also assuming that the mechanicals for your car in reasonably fresh shape. I believe that you are describing an aero problem.

Can you post a picture of your rear wing (GETTY REAR WING 3.8 FOR SC). I wonder if it is still too agressive and overwhelming the RSR front bumper/spoiler. Are you running any sort of adjustable lip/gurney on it? Have you tried (just for kicks) to replace it with a standard whale tail or duck tail? How about adding an adjustable front splitter?

If you absolutely can't change the aero package, I believe that a combination of spring and shock changes might help (but not solve the problem), but to be honest it would be a crutch and not a solution to the problem.

[911pcars]

We now have two different owners (and cars) looking for a solution on this thread, but not necessarily the same answer. Let's keep them straight.

Sherwood

[alfizzo]

i dont have an adjustable splitter. the getty wing is a tad samller than a standard 3.8 to look better with sc flares. i think the front ride height and coner balance is off. perhaps the rsr raised spindles require a lower ride height.

[jluetjen]

Alfizzo, the RSR raised spindles by definition require a lower ride height by about 3/4 an inch -- basically the 18 mm that I believe that the spindle is raised. If you are running at something close to stock ride height with RSR spindels, the affect would be the same as raising the front ride height with stock spindles. Does that make sense?

[atlporsche]

replace the 6 cylinder in the rear with a 4 cylinder WRX engine. the WRX engine weighs 250 lbs less, and the radiator in front gives the car more nose...

50/50 weight disty, makes for way less oversteer and a much happier driver.

sjd
ducking and running.

[alfizzo]

john,

iam running euro ride height 25.5 front 25 rear. so your saying to drop it an additional .75"?

thanks
fracno

[masraum]

Your rear spoiler may be too agressive over powering the affects of the front spoiler. In these cars changing the spoiler can affect the car like a see-saw. If you put a big spoiler on the back it can cause the front to get lighter, so if your rear spoiler is too effective then it can cause your front end to get light despite a front lip/spoiler.

[jluetjen]

fracno, Yes, I'd lower both ends by 18 mm (.71 inches). While you're doing that of course I'd check the alignment, bushing condition and corner weights to make sure that they are where you want them to be.

sjd;

[RSBob]

When I first purchased my 73 S, it was scarey as hell to drive fast. I implemented all the recommended changes on the first page of this thread except the Neatrix, and also had the car aligned and corner balanced and the difference was phenominal. The car is confidence inspiring, agile, and predicable. When you get enough funds to do the whole thing - follow these guys advice - they know of what they speak. Until then get a front spoiler and invest in new shocks and an alignment.

[stlrj]

A good first step may be an alignment which seems like the logical approach when confronted with basic handling issues and would be a good baseline for further major suspension modifications.

Believe it or not, too much toe can make your car feel floaty at speed and oversteer like crazy.

Always good to start with the basics.

Cheers,

Joe