Perry 951

I was on the way home this evening and decided to put 951 to it's 1st real test. Firstly, this was intensionally done at 2:30am with no cars on the road. Secondly... the setup:

Suspension:
Stock Torsion Bars
Stock Springs
M030 Front Bar
M030 Rear Bar at middle setting
Koni Yellows Front, middle dampning
Koni Yellows Rear, middle dampning
All new OEM bushings

So.. here's what happened...

I was taking an off ramp at high speed, as I have before, and ended up spinning on the exit. I applied power just as the *** end came around, trying to save it. I came pretty close to bringing it back around, but the *** end seemed to be so squatty, it would not bite. Through the turn, the car was firm and neutral in handling. . Prior attempts at this same ramp on stock 951 suspension with 125,000 miles resulted in a neutral balance, and no drama, even at the limit.

Shortly after, I thought about the event and tried a 1st to 2nd gear burnout to see how straight it would stay. I had some right hand drift in 1st, and a substantial right hand drift into 2nd on hard flat pavement. The *** end was very soft.

Should I stiffen the front Konis and leave the rear alone to prevent over steer? Should I stiffen the rear end to keep it more level? Should I change torsion bars and springs to stiffen the entire chassis?

I do not want to lose the daily driver comfort of how it feels now. Inside the limits, it is a wonderful driver, but at the limit and beyond, it is as responsive as a Ford Escort.

Any help is appreciated. (before you lecture, I will be at the track to sort it out)

badcoupe

I've got rear end probs too my car goes one way on the gas and then the other direction when I let off hmm go figure. As for your problem I'm not sure. Did you add all the stuff at the same time? Makes it hard to figure that way

Perry 951

Yea.. it all went in at the same time. I have not made any changes from my inital setup. It was reccomended that I run it this way for the most "neutural" handling.

I was expecting some oversteer, but this was to the point where I could not save it... and I have rarely been in that position.

Again,.. unless I am pushing it, it is a great driver. Beyond that, there is no forgiveness.

89magic98

Not a 100% useful reply, but...

What kind of tires are you using? Is it a "hard" or "soft" tire?

What was the road surface like (I assume asphalt in Ohio)? Has it rained recently up there?

Were you applying power when the rear-end broke loose? Or did you apply power after the rear-end broke loose?

I learned a lot about how my car handled after driving on snow. Also, I spun my car years ago on damp pavement in Dallas, because I applied power after the rear-end started to get wiggly, in an attempt to correct. In my case (I have a lot less power than your car), lifting off the gas always helped.

Good luck sorting it out! I'm sure that everyone here has their fingers crossed for you... that you will get all the time and enjoyment out of the car that you deserve.

-Kevin

Perry 951

Pavement was concrete.. no rain for the last 4 days. I am running RE-730's, 255, 40, 17's with 4500 miles on them. They were warm when I hit the ramp.

I applied power only when it started to come around. I have done the same in the past and was able to bring it back. I have lifted in this same situation and found myself facing the opposite direction. My personal driving abilities favor a power slide rather than an off power drift. I have only spun this car 1 other time.

Right now, I am pushing about as much power as I was stock, and did this same off ramp 100 times before. This was the 1st time since I rebuilt it that I really pushed it. (I drove it hard on this off ramp many times before, but this time was the edge)

I felt there is a lot more "stick" to the car. It felt unbalanced, hard to explain... other than "DRASTIC OVERSTEER".

89magic98

Well, let me give you some credit for experimenting on a section of road that you have driven many times before. Lots of people get into trouble on unfamiliar roads or with people in the car egging them on.

Are there a lot of deer on the road in Ohio? I remember in summertime, it was always a problem in New York. My brother had a deer run into the side of his car (he was going 35 or so) in his Firebird Formula.

In California, there are always fools resting on the side of the road (usually standing in front of the car on the shoulder), or parking on the offramp (as opposed to the onramp, like the truck drivers know to do). Hopefully there are smarter people in Ohio.

One more question - I assume you didn't have a trunk full of stuff to unbalance the car, right?

More speculation than substance, but bear with me...

-Kevin

SimonK

Welcome to the club of discovering....

Nothing wrong with your car I think you just pushed it a bit harder without realising and we all eventually do it but things go downhill from here without practicing and more practicing and developing your ''*** feel''. You then start thinking you car is crap on the limit... (but you should try others)

I used to drive my car flat out through corners in the UK. Very rough tarmac = safety = tremendous grip all put in place for people who can't drive. You get spoiled driving this way though... I could drive around roundabouts flat out and car would hang on until I would eventually get sick and backed off. Car always felt great - stiff - on the ball - just great - it was far better than my ability to drive.

Then I moved to Slovenia on business.

Roads here are a nightmare. As I arrived from UK I did not take this into account. I have left the road in a left hooker at 60mph backwards. Thank God nothing was in my way of stopping, so Honor was preserved - no dents in the bodywork. My personal pride was shoot to bits though.

Second time I have put my foot down on a straight just after some drizzle of rain and when boost came on - my car swapped ends before I could think what a f**k was this??? Non recoverable. Limited slip - no help - forget it.

My point of this epistle is..

They are great cars but they don't like smooth surface and when they let go - they will let go in a manner mid engine cars do - with vengeance. Yours I believe hasn't got lsd which makes it even more happy in the tail department. You got used to your car and you gave it more of a boot - this is why I say welcome to the club but proceed with caution!

To your q's:

Whatever you do don't stiffen rear konis for street = huge oversteer!

Darting under acceleration 1st and 2nd gear on a non lsd car is normal.

PS: I miss UK roads - fun all of the time. Here in Slovenia - car is on the limit in no time. I also hate the softer feel because of the smooth tarmac.

tifosiman

Brian,

From the photos, it looks like your car could benefit from dropping it with the rear eccentric. Have you done that yet? I know that when I did that, it took away some oversteer from my car.

Tifo

Sami951

How's your alignment? That makes a big difference too.

I don't have any personal experience with the adjustable konis, but from what I've heard, about 70% stiff in the front should work nicely... if yours are externally adjustable I'd definately try it

special tool

You refer to rear end as "squatty" and "soft". Are you sure that you are wording this correctly? Because if you are, we have a contradiction. To decrease oversteer you: soften rear bar settings, spring settings and damper settings - or increase rear tire pressure.
Usually cars with "soft" rears would have some weight transfer and more traction because of it. Do you have 4 dgrees of neg. front camber or something?

ERAU-944

brian, sounds like you made a mistake in trying to correct. when you lose traction in the rear, you're supposed to hold constant throttle setting or make small adjustments, not get on the power. getting on the power (especially in a 951) when the drive wheels have no traction will only make the problem worse, as it did in your case. so here's how i see it - your rear suspension may be a *little* too stiff, causing the oversteer. dave120 suggests adjusting your rear sway to the fullest soft and giving it a try, and when you break traction in the rear, don't get on the gas, that won't save it, you need to modulate the throttle and countersteer.

advice from everyone here (dave, jason, myself)
GO DE!!!
-Michael, Dave, and Jason-

p.s. this almost sounds like a RAD951 post

Porsche8777

I have the identicle set up on a NA and had the same problem on the track. I went to full soft on the rear sway bar and mid settings on the shocks. Now I get a balanced drift and can use the throttle to control under/over steer.

Rich Sandor

I have two sets of wheels, with two very very different tires on either set, and switching wheels makes a tremendous difference in the amount of sway, and rear grip, but not rear end "looseness"

The only way to cure a soft rear end is to use stiffer springs and perhaps to lower the car a bit. More Camber, wider and stickier tires will only increase the cornering speed at which the back breaks loose.

Perry 951

Kevin - there are few deer in the area I live. I am very familiar with deer, having hit 2 when I lived in NJ. Car had nothing in it, 3/4 tank of fuel.

Simon.. my car has LSD.

Tool - What I mean by sqatty is just that. All of our cars squat when under power. I hoped to dial some of that out.. looks like torsion bars or coilovers are about the only solution to that.

Mike - I have powered this car out of trouble many times before. There is a point where you can save it by standing on the gas, or standing on the brakes. I know exactly what you are saying though. This instance, the car drifted under 1/4 throttle on exit (as expected), then became unsettled and started to come around. I did not mash the gas in a violent attempt to save it, but more of a power roll on until there was no return. The Brembos work great!!

My alignment is perfect...For you Ohio guys, Bill Braucksick set up my car, so it was done buy the best. The rear ride hight is slightly lower than the front. I could drop it down to see if that helps, but then my front to rear height will be very different.

I'll try and soften the rear and see what happens. I have put about 1600 miles on it after a 3 year forced vacation... so that may be part of the problem here. Driver may not be as good as he used to be.

My DE sessions can't come soon enough. (much later this year... gotta get the miles on it first)

Steve Lavigne

Sounds like you just needed to give it a bit more throttle on corner exit to get the rear end to stick. You might want to pick up a book on high performance driving. If you don't like it behaving like this, adjust your rear bar to the soft setting.

Also, if your torsion bars are anything like my stock 135,000 mile items, they are WAY too soft. Putting stiffer torsion bars/springs in the rear will, for the most part, reduce rear grip, but give you much better feedback and quicker response.

Of course, the flip side to a soft rear end is large changes in camber and toe with suspension movement. Additionally, if you have too large of a anti roll bar relative to your springs, you can actually lift your inside tire.

Sounds like your alignment is extremely conservative. More negative camber in the rear would definitely increase your rear grip. What is your rear toe set at?

Finally, if your tires are more than 3 years old, they will have nowhere near the stick they originally had. Maybe you should install some Michelin Pilot Sport Cups.