Notices

Rollover in corner

Thread Tools
 
Search this Thread
 
Old 01-26-2006, 11:43 AM
  #1  
hderr
Rennlist Member
Thread Starter
 
hderr's Avatar
 
Join Date: Sep 2005
Location: Cheyenne, WY
Posts: 169
Received 0 Likes on 0 Posts
Default Rollover in corner

I'm new to auto-x, twice. I really like the way the car runs and it's a hoot to drive, but, I think the suspension has some issues. I know very little about suspensions so any help would be appreciated.

As far a I can tell the suspension on this late 85, 944 is stock with the original springs, shocks, struts,... The car seems to lay way over in a hard corner, it's far worse than this picture shows, especially in a downhill turn. In fact to the point where the tire (correct size by the book) rubs the upper fender wheel well and I have to back way off on the throttle.

So I'd appreciate some advice on this. I'd like to stay in the stock class, ES.

Sorry about the poor quality of the picture as it is a snapshot from the video.

Thanks,
Hank
Attached Images  
Old 01-26-2006, 11:55 AM
  #2  
Z-man
Race Director
 
Z-man's Avatar
 
Join Date: Jan 2002
Location: North NJ, USA
Posts: 10,170
Likes: 0
Received 1 Like on 1 Post
Default

I feel your pain:



By the looks of it, it sounds like you run with SCCA (ES class). Unfortunately, they have very strict rules in terms of what you can and can't upgrade in stock classes. Basically, what you can upgrade won't help you too much with the body lean.

There is one thing you can do - upgrade to a M030 suspension. Unfortunately, that will cost you dearly. AND: per SCCA, you will need to upgrade all of the components that came with M030 - shocks, springs, sway bars...etc. (You can't just slap on an M030 rear swaybar and be dnoe with it!)

My suggestion - leave your car as is. Keep it in sound condition. Learn the drive your car - improve the driver, not the car. Once you get better at it, you can consider upgrades - by then, you'll know what type of upgrade will suit you best.

My plans? I do AX and DE's, and my suspension is in desperate need of an upgrade, as evidenced by the pics as well as the scrapes on the rocker panels of my car! I will be getting a suspension that is more suited for the high speeds attained on the track, but will certainly help me at AX as well. While I typicalyl don't run with SCCA, my upgrades would likely bump me up into ASP. (In my PCA AX program, I will be running I-1 - Improved 4-cyl cars).

Good luck, and welcome to the addiction!
-Z.
Old 01-26-2006, 01:24 PM
  #3  
Z-man
Race Director
 
Z-man's Avatar
 
Join Date: Jan 2002
Location: North NJ, USA
Posts: 10,170
Likes: 0
Received 1 Like on 1 Post
Default

Just one more note: while body lean can't always be eliminated, your driving has a lot to do with it as well - the smoother you on in your weight - transfer in the transitions, but less body lean you will have. Brake a little earlier - get the car to take a 'set' before the corner, and you can eliminate much of the roll.

-Z.
Old 01-26-2006, 02:05 PM
  #4  
hderr
Rennlist Member
Thread Starter
 
hderr's Avatar
 
Join Date: Sep 2005
Location: Cheyenne, WY
Posts: 169
Received 0 Likes on 0 Posts
Default

So, let's say I replace the shocks/struts, which I plan, what change will I see in ax?
Old 01-26-2006, 02:42 PM
  #5  
Z-man
Race Director
 
Z-man's Avatar
 
Join Date: Jan 2002
Location: North NJ, USA
Posts: 10,170
Likes: 0
Received 1 Like on 1 Post
Default

Originally Posted by hderr
So, let's say I replace the shocks/struts, which I plan, what change will I see in ax?
Flatter cornering will be the biggest thing you notice. That translates into crisper turning and handling, and well as quicker transitions.

However, it is possible to go too stiff in AX - while you don't want your car to be wallowing through the corners, a little body lean does translate into more grip. Too stiff and your car can become skiddish on the AX course.
-Z.
Old 01-27-2006, 02:48 AM
  #6  
hderr
Rennlist Member
Thread Starter
 
hderr's Avatar
 
Join Date: Sep 2005
Location: Cheyenne, WY
Posts: 169
Received 0 Likes on 0 Posts
Default

Ok, roger on the driver, and I have a lot to learn on that end.
Maybe this should be a new thread, but what do the bump stops do? Mine are split up the middle???

H
Old 01-27-2006, 11:39 AM
  #7  
jim944s2
Racer
 
jim944s2's Avatar
 
Join Date: May 2003
Location: Tacoma WA
Posts: 456
Likes: 0
Received 0 Likes on 0 Posts
Default

Last fall I drove my friends 944S w/ 450# Ground control coilovers and 31mm torsion bars (I had stock M030 951 struts/springs t-bars). I almost couldn't believe the difference, it was really surprising how much less effort it took to get his car through the slaloms, -like I could just use the tips of my fingers on the steering wheel.
So I just finished installing GC coilovers (350#), and I'm putting on a 968 M030 rear sway bar, I already have m030/25.5 torsion bars. I'm told that should be a good compromise (if there is such a thing!) without going to really large torsion bars. Keep in mind it will cost about 2 to 3 times what you initially think it should.
Old 01-27-2006, 01:11 PM
  #8  
Techno Duck
Nordschleife Master
 
Techno Duck's Avatar
 
Join Date: Jun 2003
Location: San Diego, CA
Posts: 9,980
Likes: 0
Received 8 Likes on 5 Posts
Default

Regarding what Z-man was saying about to stiff a suspension for autocross. I spent one entire autocross day trying to get my suspension settings just right. I had started out with the front struts set to medium stiffness. It felt great on offramps, backroads and driving on the street, but in autocross it did terrible. The front end pushed in low speed corners very badly, to the point one might have thought i was driving a frontwheel drive car.

I tweaked my tire pressures in the front to 34 and kept the rear at 36. I softened the front struts to about 1/4 stiff (a little less than that actually) and it still understeers a bit in low speed tight turns, but not nearly as bad as before. I think it has something partially to do with the 205 width tires in the front and 225 in the rear. My next set of tires i am going to do 215 or 225 all around to try and stop that.

I also plan on doing the M030 19mm rear bar, but will probably do that mid-season depending on whether i feel i really need it or not.

I have learned that weight transfer really helps and im going to work on smoothing out my runs this season. One trick im trying to learn is to brake into a turn slightly to try and shift the weight onto the front wheels, hoping to get a better contact patch....dont know how much its actually helping though.

Regarding the bump stops. Correct me if im wrong, but they prevent the suspension from bottoming out completley. They are split in the middle i believe so you can slip them onto the strut shaft without having to take the strut mounts off.

Z-Man, that last picture is awsome seeing how much the suspension is compressed. Im suprised you havent ripped off the front bumper cover yet! I might be seeing you if you are autocrossing this season again...i plan to start going to the NNJ events also. Its only about an 1.5 hour drive for me.
Old 01-30-2006, 12:36 AM
  #9  
racerjsz06
Track Day
 
racerjsz06's Avatar
 
Join Date: Jan 2006
Location: Maryland
Posts: 17
Likes: 0
Received 0 Likes on 0 Posts
Default

See if the guys running 944cup cars have any ideas or old parts - www.944cup.com

I had Leda's ASA Gas Coilovers all the way around on my 944T and they were great but expensive. You can find the m030 on ebay. I'm not sure if a Trubo setup would work, but if it did, with the addition on upgrade springs it would be an improvement. Try to get a better set of swaybars too.

Or if you want to go really cheap just upgrade your springs. This won't help on the rear with the torsion bars.
Old 01-31-2006, 12:46 AM
  #10  
sbyrne
Racer
 
sbyrne's Avatar
 
Join Date: Oct 2005
Posts: 273
Likes: 0
Received 0 Likes on 0 Posts
Default

Look for the book "Secrets of Solo Racing" (can't recall the author's name) for some additional info. You might also want to try an Evolution Driving School - they are dedicated to autocross training.
Old 02-12-2006, 01:15 AM
  #11  
Z-man
Race Director
 
Z-man's Avatar
 
Join Date: Jan 2002
Location: North NJ, USA
Posts: 10,170
Likes: 0
Received 1 Like on 1 Post
Default

Originally Posted by sbyrne
Look for the book "Secrets of Solo Racing" (can't recall the author's name) for some additional info...
Henry Watts is the author. Though a bit of a dry read, it is the Autocross Bible.

-Z
Old 04-26-2006, 10:55 PM
  #12  
hderr
Rennlist Member
Thread Starter
 
hderr's Avatar
 
Join Date: Sep 2005
Location: Cheyenne, WY
Posts: 169
Received 0 Likes on 0 Posts
Default

I had the alignment guys put some negative camber in both the front and rear of the car. Man, what a difference that made. I could actually carry some speed into a corner without worrying about tearing out the fender. I'm also running lower tire pressures, 32/34 (street tires), and that seemed to help. I don't have the book in front of me, but I think we put -1.1 in the front and -1.5 in the rear.

Anyone else using numbers like these?

Hank
Old 04-26-2006, 11:23 PM
  #13  
Z-man
Race Director
 
Z-man's Avatar
 
Join Date: Jan 2002
Location: North NJ, USA
Posts: 10,170
Likes: 0
Received 1 Like on 1 Post
Default

Hank -
I had about the same amount of negative camber when my suspension was stock. Works well for a street/AX car.

-Z



Quick Reply: Rollover in corner



All times are GMT -3. The time now is 10:57 PM.