camber and sway bars

[FPerron]

I road race my 05 LGT and last year experienced neutral handing with Megan coilovers, and Perrin front and rear 22 mm sway bars. I had -2 degrees camber front and about - 1.5 rear.

 

This Winter, I added adjustable rear lower control arms and adjusted the camber to - 2.5 degrees front and rear. The result was a huge increase in understeer on slow corners (although fast corners seemed much safer than before). I should also mention that I added a large APR wing to the rear which I doubt affects low speed handling.

 

I'm hoping that I can correct the slow corner understeer by replacing the 22 mm rear bar with a 25 mm bar. The wing should keep the rear end planted in fast corners.

 

BTW, the car looks alot better with it's race wheels and tires installed.

 

Thoughts?

 

 

http://www.henstoothdiscs.com/images/Picture1.jpg

 

http://www.henstoothdiscs.com/images/Picture2.jpg

[meier motor sports]

[FPerron]

 

Understeer is something you feel, not something you see:p

[meier motor sports]

i wana see the car fool

 

http://plaza.ufl.edu/mujahid/hand/hm-understeer.jpg

[FPerron]

I know. Just couldn't resist:lol:

 

If I send you a pic, will you post it for me????

[Drew888]

Only a bench racer here but... you incresed the front an additional -.5 and the rear by -1* and would like to control the understeer w/ the sways?

 

Sounds like the additional rear bar should do the trick but you'll never know by how much until it's put on and tested. I'm betting that it won't quite be enough then you'll have to back the rear camber off a bit and test again.

 

When you do get it dialed in, chime back in here and let us know how it went.

 

BTW, what camber plates are you using? Sorry haven't searched yet.

[DiscoWagon]

The correct way to reduce understeer is to increase front end grip. Although you may have slightly increased front end grip, you also increased rear end grip significantly. My general rule of thumb on Subarus is at least 1 degree difference between front and rear (front always more). Try backing off of the camber in the rear and your car should handle like it did, in fact it should be better. (F) -2.5 ® -1.5

[Saul_Good]

The correct way to reduce understeer is to increase front end grip. Although you may have slightly increased front end grip, you also increased rear end grip significantly. My general rule of thumb on Subarus is at least 1 degree difference between front and rear (front always more). Try backing off of the camber in the rear and your car should handle like it did, in fact it should be better. (F) -2.5 ® -1.5

 

You beat me to it. +1 on what disco said.

[FPerron]

You raise an interesting point, but it seems self-defeating to sacrifice grip at either end of the car. I'm running Toyo R888 tires for which the minimum camber setting is -2.5 degrees. I'm hoping the bigger rear sway bar will help on initial turn in. Once that's accomplished I'm all the way on the power through the apex and getting better grip from the rear on the way out.

 

From a theoretical perspective, I can't remember if increasing roll resistance at one end reduces grip at that end or increases grip at the other.

[q2slinger]

I would try setting the front sway to the soft position and set the rear to stiff. Should definitely help and its free.

[Drew888]

FPerron,

 

It looks like you know what to do so now not clear to what it is you are looking for.

 

It does seem self defeating only in that I don't yet understand what the Max neg. camber is in the front of an LGT. In keeping your neutral handling you'll need to do as Disco and I have said.

So what can we get out of the LGT? If you can get another full degree or at least 3.0, stiffen the rear bar, and maybe loosen the front then you have done all you can. Micro adjustments will come with seat time. This is just where I'd start.

[RaceComp Engineering]

From a theoretical perspective, I can't remember if increasing roll resistance at one end reduces grip at that end or increases grip at the other.

 

Did someone say theoretical?

 

So a bigger rear swaybar will increase weight transfer at that end of the car and reduce it at the other end of the car since total weight transfer for a given car and turn will remain the same. The increased rear weight transfer will reduce rear grip, the decreased front weight transfer will increase front grip (due to more evenly loaded front tires).

 

BUT at the same time, the bigger rear sway will reduce body roll, and you won't be losing camber as much, and rear grip will increase.

 

The net change in rear grip may increase, maybe slightly decrease. But the front definitely gets more grip, and these cars especially have a need for it up front, so your overall grip increases.

 

So the correct answer is, as usual, it depends.

 

 

- Andrew

[RaceComp Engineering]

Other then that nonsense i just posted, I think you might be running too much rear camber. I'd drop it down to maybe -1.5-1.9 before buying new parts.

 

- Andrew

[FPerron]

Added pics

[DiscoWagon]

You should have spent the money on a front splitter instead of a rear wing.

[FPerron]

I have a front splitter. the wing is for rear downforce in fast corners. This is not related to the mechanical grip problem I originally posted about.

[RaceComp Engineering]

What are your ride heights?

 

 

- Andrew

[FPerron]

I don't have the exact ride hight numbers, but it's about the same as it was with STI Pinks - slightly adjusted for corner weighting. I've got the Megan coilover rebound settings at 5 clicks off full hard. I tried backing off the fronts 5 more clicks, but it made no difference. I just installed the 25 mm rear bar, but I won't get to test it until the practice session befor my next event in early July.

 

BTW, I posted the pics on the Exterior forum and got flamed like you read about:lol: - as expected:lol: