ilikemy944

Pretty sure it is listed as toe in on the sheet, positive should be toe in.

User 52121

Need to confirm this.

Toe OUT will make the rear end feel very loose. Then combined with the stock bushings like Chris mentioned, under load you'll get even MORE toe out....

If it's truly toe OUT then you need to get that addressed.

philstireservice

Keep in mind with everything said above - tire pressure fits in the fine tuning aspect of car set up. Major oversteer or understeer will not be corrected with only a tire pressure adjustment. In addition, every tire basically has a spring rate (think of many tiny little springs pushing out), so different tires react to different initial input. Testing and data recording is very important.

ilikemy944

It is toe in, I specifically requested my alignment specs from the same shop that Shawn went to.

refresh951

I have my alignment sheet and it just says ""toe".

Tonight I might have found some of my issue. A while back before I upgraded my torsion bars, I had set the rear Koni's to near full damping. Thanks to Brad, I now understand this adjustment is for rebound damping only as the compression damping stays unchanged. I am going to do some testing this weekend and will report back on the results.

refresh951

Thanks Pat! Hope things go great this weekend for you and Paul.

Here is a video of a 180 at the last Autocross

SirLapsalot

positive toe is toe in

Droops83

Yup, positive is toe in, negative is toe out.

With my instructor's hat on or not, I do agree with Jim's sentiments about the driver being the most important part of the equation, and this is absolutely true. Consistency is key.

I am not condoning constantly tweaking your settings in pursuit of faster times at this point, but I feel that with your level of power/torque and stock bushings, dialing in a good amount of rear toe while keeping everything else the same would do you a world of good (as long as the bushings aren't so thrashed the static alignment doesn't even make much of a difference). It will lessen the likelihood of oversteer, and make it more controllable when tail-happiness does occur. This comes from personal experience in my own car, as well as in customer cars. Porsche itself calls for more aggressive rear toe-in settings for track use with the street 996/997 GT3 models, despite their sophisticated multilink rear suspension.

Jim also makes a great point about minimizing steering lock; you are much more likely to oversteer when you are all crossed up or dialing in too much lock in an attempt to overcome corner-entry understeer. Your level of power/torque does make things trickier, but it can be used effectively to learn precise control with your right foot. It is just as important as the steering wheel!

Once you get consistent, you can start with subtle setup tweaks. The golden rule is one small change at a time!

mel_t_vin

Shawn, what rear bar are you running? And what is your ride height, ground to fender, front and rear?

refresh951

Rear sway is OEM 19mm

Fender height is 25.3" front, 25.2" rear which gives make the body just slightly lower on the front vs the rear.

refresh951

Brad,

Thanks so much for the info. Did skid pad testing this morning in the local high school parking lot and I now have a fairly neutral car with just a tad of understeer.

I had the rear Koni's set to almost full rebound damping (not realizing the adjustment was rebound only)! Once I backed this off and with tire pressures the same front to back car handles completely different. Amazing improvement!

mel_t_vin

Sounds like re-setting your rear dampers has paid huge dividends and solved your issue.

If your rear dampers were already soft to begin with, I was going to suggest you lower your rear end via the eccentrics another 0.3"-0.4" to counter over-steer.

blown 944

That looked fun. Might want to add that into the course every time

racertomtom

The chart in the OP says to remove weight from the front end to correct understeer. Isn’t that backwards? My car only has 45% on the front and inherently pushes entering turns. Wouldn’t removing more weight from the front make it worse?

JacRyann

The chart is correct. While weight in itself will increase traction, the increase doesn't go up linearly with the weight. So you may only get 70-80% more traction for 100% more weight.

Note that the chart shows the change in weight and the resultant change in handling. With your existing car at 45% front and understeering, if you were to change the weight to 40% front by moving stuff to the back, it would understeer less than it does now.

That's because the 5% extra weight in the back will only be compensated by an extra 4% in rear-traction. Thus the rear-end will be looser and livelier than before, reducing understeer.