Sway bar Help!!!!!
10-05-2002, 02:11 AM
#1
Instructor
Thread Starter
Sway bar Help!!!!!
Hi
I've got a suspension problem and could really use some help!!! Iv'e got a 1970 911t that I've been using for autocross events for the past couple of years. The car has always had substantial understeer. Last week I went out to Willow Springs and got my first chance to participate in a real track event. With the increased speed that comes with a closed course track event, I found that the inside front wheel on hard corners would actually come up off the ground as much as 6 inches. The understeering problem was magnified dramatically by having only one fromt tire on the pavement. My times were terrible, and the pucker factor was intense. Now that I'm thoroughly hooked on track events,I have to do something about this, but I don't know where to start.
I spent some time inspecting the underside of the car and determined that the car has a 15mm sway bar on the front, it appears to be original equipment. There is no sway bar on the back. I have done the following mods:
1. "S" Brakes ( this involved changing the Struts and cartridges to Bilstien/ "S" units
2. Turbo Tie rods.
3. 7" Fuchs alloys front and back.
I was thinking that a large diameter Rear Sway bar in the rear could be a good move to counter this problem, but I don't know what size and don't know where else to go with this. The car is primarily used for Weekend Canyon runs, Autocrosses and now that I'm thoroughly addicted to it, Track Events. Any thoughts and ideas to help me cure this problem would be greatly appreciated.
I've got a suspension problem and could really use some help!!! Iv'e got a 1970 911t that I've been using for autocross events for the past couple of years. The car has always had substantial understeer. Last week I went out to Willow Springs and got my first chance to participate in a real track event. With the increased speed that comes with a closed course track event, I found that the inside front wheel on hard corners would actually come up off the ground as much as 6 inches. The understeering problem was magnified dramatically by having only one fromt tire on the pavement. My times were terrible, and the pucker factor was intense. Now that I'm thoroughly hooked on track events,I have to do something about this, but I don't know where to start.
I spent some time inspecting the underside of the car and determined that the car has a 15mm sway bar on the front, it appears to be original equipment. There is no sway bar on the back. I have done the following mods:
1. "S" Brakes ( this involved changing the Struts and cartridges to Bilstien/ "S" units
2. Turbo Tie rods.
3. 7" Fuchs alloys front and back.
I was thinking that a large diameter Rear Sway bar in the rear could be a good move to counter this problem, but I don't know what size and don't know where else to go with this. The car is primarily used for Weekend Canyon runs, Autocrosses and now that I'm thoroughly addicted to it, Track Events. Any thoughts and ideas to help me cure this problem would be greatly appreciated.
10-05-2002, 03:43 AM
#2
RL Technical Advisor
Hi Jim:
For sure, that lack of rear swaybar is causing the majority of your understeer problems. Increasing your rear roll stiffnes with a properly sized rear swaybar will reduce the understeer and fasten down that inside front wheel from lifting.
Personally, I would install a set of larger tubular torsion bars and a pair of larger adjustable swaybars in 20mm diameter. Combined with your Bilstein shocks, this package will make a huge difference. If you do not have a front strut brace, those help reduce understeer and sharpen the steering response, too.
Adjustable bars will allow you to set the understeer/oversteer balance of the car to your skills and preferences.
For sure, that lack of rear swaybar is causing the majority of your understeer problems. Increasing your rear roll stiffnes with a properly sized rear swaybar will reduce the understeer and fasten down that inside front wheel from lifting.
Personally, I would install a set of larger tubular torsion bars and a pair of larger adjustable swaybars in 20mm diameter. Combined with your Bilstein shocks, this package will make a huge difference. If you do not have a front strut brace, those help reduce understeer and sharpen the steering response, too.
Adjustable bars will allow you to set the understeer/oversteer balance of the car to your skills and preferences.
10-08-2002, 10:58 PM
#3
Instructor
Thread Starter
Steve:
Now I know why your opinions are so highly prized among the users of this forum. Your information, especially in responce to my e-mail was very useful. I am scrambling to get the money together for a ZF Style LSD as you requested before my gearbox goes back in the car. as soon as that task is finished I will be ordering the TRG sway bars you suggested. I'll post the info on the car when it is back on the road!!!
Thanks for all your help
Jim
Now I know why your opinions are so highly prized among the users of this forum. Your information, especially in responce to my e-mail was very useful. I am scrambling to get the money together for a ZF Style LSD as you requested before my gearbox goes back in the car. as soon as that task is finished I will be ordering the TRG sway bars you suggested. I'll post the info on the car when it is back on the road!!!
Thanks for all your help
Jim
10-10-2002, 01:53 AM
#4
Race Car
Jim, Steve helped me all last week, via email, get my car aligned for the track...what a job! I was doing home alignment with turn plates, toe plates and a caster/camber gauge. 
I have NO faith in alignment racks whatsoever...long story.
My first day at the track with my new alignment produced the results you stated - BIGTIME inside wheel lift, have the pics.
...just ask the F-40 and 996TT I ran down in the turns.
I loosened up my front swaybar and pretty much eliminated the lift. Had I tightened the rear, that might have provided the same relief, but likely wouldn't cure my understeering problem.
I have a 25.4mm swaybar up front and 22mm on the rear, so I have PLENTY!
Steve's suggestion to go with 20mm is a good one, and DEFINITELY put on on the rear...it's quite a job to get mounts welded up back there, but well worth it in your case, I'm sure.
My "track alignment" settings, via Steve's suggestions worked like a champ...a TOTAL success. I am now convinced that "sportier" alignment settings is the key to getting a car to stick better at the track. <img src="graemlins/r.gif" border="0" alt="[king]" />
I have NO faith in alignment racks whatsoever...long story.
My first day at the track with my new alignment produced the results you stated - BIGTIME inside wheel lift, have the pics.
...just ask the F-40 and 996TT I ran down in the turns.
I loosened up my front swaybar and pretty much eliminated the lift. Had I tightened the rear, that might have provided the same relief, but likely wouldn't cure my understeering problem.
I have a 25.4mm swaybar up front and 22mm on the rear, so I have PLENTY!
Steve's suggestion to go with 20mm is a good one, and DEFINITELY put on on the rear...it's quite a job to get mounts welded up back there, but well worth it in your case, I'm sure.
My "track alignment" settings, via Steve's suggestions worked like a champ...a TOTAL success. I am now convinced that "sportier" alignment settings is the key to getting a car to stick better at the track. <img src="graemlins/r.gif" border="0" alt="[king]" />
