JNorris

iTrader: (4)

Over the last few months I have done a few suspension mods like a BMR K-member, a Spohn 1” sway bar, and a Spohn adj. torque arm. After I installed the K-member I had the front-end aligned.
On the street the steering feels twitchy and the above 75mph the car does not feel as under control as it did in the past. It also feel loose like it wants to get away from you when you are past ~60mph and at WOT.

At the track the car is loose (some runs are better than others) and I have to fight to keep it straight past the 1/8 mile as the rear seems to be swaying back and forth. At first I thought I was running my slicks too low (14psi) but the car feels only a little better with 17psi in the slicks. The car was not loose in the past. The loose feeling is definitely much worse with you are at WOT than if you were just going fast.

I have checked the installation of the K-member, sway bar, and the torque arm and everything is tight and torque to specs.

Any suggestions?


Thanks

John

kp

iTrader: (34)

I would have the alignment checked again.

Outlaw

Alignment for sure.. sounds like something was not set right OR its settled after the alignment and its thrown the settings off

mongse

iTrader: (2)

Are you running a radial up front w/ a bias tire in the back?

JNorris

iTrader: (4)

Yes I am.

Outlaw

Good call Mongse, that could be it also.. can make the car feel wishie washie at speeds

Dustin Butts

iTrader: (5)

My car was doing the same crapp. I replaced the panhard with a new Spohn adjustable with heim/heim rod ends. All fixed now. The old bar with poly/heim was worn out.

SMOKIN01TA

iTrader: (10)

i have the radial up front and slick out back and goes straight as a arrow, if i slam on the brakes it still eats straight, i think your alignment is off, almost like you have some toe out and its amplified at wot with the additional lift on the front end.

JNorris

iTrader: (4)

Thanks for all the replys.

One thing I noticed after the K-member install is that when I lift the car to put the skinnies on the tires pull in at the bottom much more that it did with the stock K-member. It seems like maybe I have too much camber.

The car transfers weight well and carries a nose-up stance down the track. I think this (front suspension not at full load) is amplifying the problem like SMOKIN01TA suggested.

Maybe I should have the car aligned with the front suspension lifted (unloaded) about 2 inches to simulate race conditions?


Below are the after alignment specs.

------------Left-----------Right
Camber-----(.7)------------(.4)
Toe---------(0)-----------(-.03)

Cross Camber = .03
Total Toe = -.02

John

SMOKIN01TA

iTrader: (10)

i spend 2 hours alignining my car at a friends shop, i checked mine with two guys siting on the radiator to simulate braking, jacked it up 3-4 inches to simulate wot and checked it a normal height. just make sure when its jacked up you still have some toe in, and by looking at your current toe you proably getting toe out on wot which is a baaaaaaaaaaaaaaaaaaad thing unless you like repainting fenders.

JNorris

iTrader: (4)

What alignment specs do you recommend?

SMOKIN01TA

iTrader: (10)

Drag racing you want about -.50 camber, i was somewhere in that area that way your tires are straight up and down during wot, i had about a 5/16 or 7/16 toe in or - 5/16 sayin it propperly sitting normal which gave me a -1/16 toe in at max lift under wot and maxed out my caster to a +4.75 i believe i got out of it, any more than that and the tires start getting to close to the rear part of the outer fender and when you jack it up or launch hard the tire would hit

JNorris

iTrader: (4)

Thanks for the info.

John

Genesis_26317

iTrader: (2)

I hate to sound stupid but don't tubular k-members seriously loosen the car as opposed to a boxed one?

That's what the autocross guys always say, that the aftermarket k-members really weaken front-end handling. Maybe that is making the whole car wobbly....