Steering angle changes when weighting/un-weighting front end
#26
Well, I checked everything BUT the rack as I have IGN-1As mounted on the frame under it which are a major pain to remove. Kind of kicking myself for that but I didn't have a lot of time and there were other things that needed to get done. Everything else seemed totally fine and tight.
I think in my original post I may have exaggerated the effect on weight/unweight on the turning radius. On smooth pavement the car is very predictable. It's when you get into anything bumpy or uneven that it just feels all over the place.
I wonder if what I am feeling is tire flex, exaggerated by stiff springs, bushings & swaybars + sticky tires? I am running factory wheels.
I think in my original post I may have exaggerated the effect on weight/unweight on the turning radius. On smooth pavement the car is very predictable. It's when you get into anything bumpy or uneven that it just feels all over the place.
I wonder if what I am feeling is tire flex, exaggerated by stiff springs, bushings & swaybars + sticky tires? I am running factory wheels.
#27
Update: I was going through the thread @Sgtblue linked to and realized that I was chasing after the wrong bolts -- I was trying to get to the ones that are on the column that comes down from the steering wheel, not the two straps on the subframe. I did check the bolts on the subframe and they were tight. So either I am too sensitive, these tires just feel weird, or something about my combination of components just doesn't feel quite right. At any rate, I don't think there is anything "wrong."
#28
Racecar - Formula 2000
...On smooth pavement the car is very predictable. It's when you get into anything bumpy or uneven that it just feels all over the place.
I wonder if what I am feeling is tire flex, exaggerated by stiff springs, bushings & swaybars + sticky tires? I am running factory wheels.
I wonder if what I am feeling is tire flex, exaggerated by stiff springs, bushings & swaybars + sticky tires? I am running factory wheels.
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DaveW (07-07-22)
#30
Rotary Enthusiast
iTrader: (25)
Some people have tested bump steer on the factory FD suspension geometry and have found it to be significant.
If I recall correctly, the FD geometry was designed to have toe changes during compression and rebound to add stability in certain situations.
Since my engine is swapped and the steering rack is not in the identical position that it was in from the factory, the tie rod angles created some bad bump steer and I was getting similar symptoms as you. After adjusting my outer tie rod end positions to get closer to zero bump steer, my car now feels significantly more solid and stable.
If I recall correctly, the FD geometry was designed to have toe changes during compression and rebound to add stability in certain situations.
Since my engine is swapped and the steering rack is not in the identical position that it was in from the factory, the tie rod angles created some bad bump steer and I was getting similar symptoms as you. After adjusting my outer tie rod end positions to get closer to zero bump steer, my car now feels significantly more solid and stable.
#31
Rotary Motoring
iTrader: (9)
I just recently read on here someone with a lowered FD was setting up their front end and checking to see of they needed to use bumpsteer spacers and found the stock geometry had zero bumpsteer all the way theough to max compression.
The dynamic toe of the FD is in the front lower arm sliding bushings and the rear upper arm sliding bishings.
If these are shot the car will get wobbly.
One way to kill the bushings is to tighten the mounts with the car in the air and suspension at full droop (like when working on suspension.)
As the factory manual shows, you need to tighten them with the suspension at normal ride height (wheels on the ground or a jack under the tire/axle till that corner is loaded).
Otherwise the bushings tear from over rotation.
The dynamic toe of the FD is in the front lower arm sliding bushings and the rear upper arm sliding bishings.
If these are shot the car will get wobbly.
One way to kill the bushings is to tighten the mounts with the car in the air and suspension at full droop (like when working on suspension.)
As the factory manual shows, you need to tighten them with the suspension at normal ride height (wheels on the ground or a jack under the tire/axle till that corner is loaded).
Otherwise the bushings tear from over rotation.
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scotty305 (08-28-22)
#32
Full Member
I am getting mine done and doing a bit of research online to see what people are setting it at, and for what use.
(For reference, I am super low, previously "stanced" but now going back to more drivable/racey spec. I'm very low, tucking tire, and on basically full adjustable suspension, looking for mostly street/mountain driving, with an occasional drift day. Tentatively looking to go with something in the region of -4/-1 deg camber, which is a big difference from my existing -5.5/-6 deg.)
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SETaylor (12-10-23)
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