Loose front end
10-04-2016, 02:21 PM
#31
Three Wheelin'
Thread Starter
Current plan:
- Replace rack bushings with PU
- Replace front control arm balljoint
- Lower front ~20mm
Align, drive and see how it feels.
If good, I'll leave the rear alone, otherwise I'll replace all arms in the rear along with sub-frame bushings.
I'll report back as I make each change since it may help others in the future.
- Replace rack bushings with PU
- Replace front control arm balljoint
- Lower front ~20mm
Align, drive and see how it feels.
If good, I'll leave the rear alone, otherwise I'll replace all arms in the rear along with sub-frame bushings.
I'll report back as I make each change since it may help others in the future.
10-04-2016, 02:35 PM
#34
Three Wheelin'
Thread Starter
I have swaybar bushings and drop links on my list for the future, but I don't think that's what's contributing specifically to this problem. Front drop link bushings are definitely soft, so if anyone thinks that could contribute I'll move their replacement up and do it sooner.
Swaybar bushings look ok visually but I figure I'll eventually replace them all based on miles and age alone.
Swaybar bushings look ok visually but I figure I'll eventually replace them all based on miles and age alone.
10-04-2016, 02:36 PM
#35
Three Wheelin'
Thread Starter
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10-04-2016, 02:42 PM
#36
Rennlist Member
Every change needs to be followed up with an alignment check.. Unless you have scales and strings, that approach is going to get expensive pretty quick...
Its really pretty simple though... From what you describe, its a toe issue...
1) Worn bushings - You can check without having to replace. If they are firm (no slop), there is no reason to replace. If you just want to update bushings due to age/preventative go ahead and do them all at once, don't piece-meal it.
2) Front toe - From the specs, it looks good. But you may want to measure yourself just to be sure.. Total toe is all you care about. Measure the distance from tire to tire.. Subtract the front edge distance from the rear.
3) Rear toe - Same as front
4) Rear caster (kinematic toe) - Although it sounds like your shop has the right tools and should know how to use them... This is a very common problem... My money is here... I would talk with the shop owner and make sure he didn't delegate this critical task to one of his lackeys..
Its really pretty simple though... From what you describe, its a toe issue...
1) Worn bushings - You can check without having to replace. If they are firm (no slop), there is no reason to replace. If you just want to update bushings due to age/preventative go ahead and do them all at once, don't piece-meal it.
2) Front toe - From the specs, it looks good. But you may want to measure yourself just to be sure.. Total toe is all you care about. Measure the distance from tire to tire.. Subtract the front edge distance from the rear.
3) Rear toe - Same as front
4) Rear caster (kinematic toe) - Although it sounds like your shop has the right tools and should know how to use them... This is a very common problem... My money is here... I would talk with the shop owner and make sure he didn't delegate this critical task to one of his lackeys..
10-04-2016, 02:49 PM
#37
Three Wheelin'
Thread Starter
I figured I'd put together the rack bushings, front ball joint and height adjust into one alignment check. I don't believe swaybar bushings and drop links require alignment, correct?
1) Regarding bushings, I've done the front of the car already, so that's taken care of. If I do the rear, I'll do them all at once and then do another alignment. Probably in the Spring, so I'll space it out a bit.
2 and 3) Good idea, I'll try that!
4) He definitely did it himself, he's the only one that he trusts to do it right. He's pretty well regarded around here as the guy to go to for 911/993 alignments. He's also the only guy, so I don't have any other options short of driving to Salt Lake, Spokane or Seattle. The good news is that the car felt better overall after the alignment, so I think he did a good job.
1) Regarding bushings, I've done the front of the car already, so that's taken care of. If I do the rear, I'll do them all at once and then do another alignment. Probably in the Spring, so I'll space it out a bit.
2 and 3) Good idea, I'll try that!
4) He definitely did it himself, he's the only one that he trusts to do it right. He's pretty well regarded around here as the guy to go to for 911/993 alignments. He's also the only guy, so I don't have any other options short of driving to Salt Lake, Spokane or Seattle. The good news is that the car felt better overall after the alignment, so I think he did a good job.
10-04-2016, 03:13 PM
#38
Rennlist Member
Rake can be measured on the rocker (door sill) and/or center tunnel with a digital level.
Your KT setting sounds fine.
You actually want a little asymmetry in caster for a street car, largely to allow the car to 'climb' up the crown when driving on the right side of the road. Allows the car to go 'straight' on that surface. Also used to tune the car for ease of turning on specific race tracks (i.e. Limerock).
As others have mentioned, lowering the front is going to require a re-do of at least front alignment, primarily toe.
If your rake really is 0 deg or less then I suspect at high speeds more air is getting under the front of the car and causing float or wander.
Your KT setting sounds fine.
You actually want a little asymmetry in caster for a street car, largely to allow the car to 'climb' up the crown when driving on the right side of the road. Allows the car to go 'straight' on that surface. Also used to tune the car for ease of turning on specific race tracks (i.e. Limerock).
As others have mentioned, lowering the front is going to require a re-do of at least front alignment, primarily toe.
If your rake really is 0 deg or less then I suspect at high speeds more air is getting under the front of the car and causing float or wander.
10-04-2016, 03:19 PM
#39
Three Wheelin'
Thread Starter
Makes sense on the caster, that's what the alignment guy said as well.
Rake adjustment sounds promising. I'll report back after I make my next set of changes (rake, rack bushings, ball joint).
Thanks everyone for your help - what a great group!
Rake adjustment sounds promising. I'll report back after I make my next set of changes (rake, rack bushings, ball joint).
Thanks everyone for your help - what a great group!
10-04-2016, 04:07 PM
#40
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Quote:
Originally Posted by lambotex View Post
my turbo had a similar issue and once I got ride height dead on it fixed it.
What ride height did you end up with? Did you do it yourself?
I'm in Montana so I have to be pretty self-sufficient .
I replaced tie rods, front bushings, ball joints and the car has PSS9 on it. We did three different alignments and the one that worked best was with the ride height is set to RS +5mm.
Originally Posted by lambotex View Post
my turbo had a similar issue and once I got ride height dead on it fixed it.
What ride height did you end up with? Did you do it yourself?
I'm in Montana so I have to be pretty self-sufficient .
I replaced tie rods, front bushings, ball joints and the car has PSS9 on it. We did three different alignments and the one that worked best was with the ride height is set to RS +5mm.
10-04-2016, 05:56 PM
#43
wheel bearings
bent wheel
shocks
ball joints
tire pressures, I use 33/35 cold on the street
possibly other tire issues some just don't track well
your kt should not be maxed and the side to side can't be checked by looking at the eccentrics, the gauge reading tells the story, w/ 0 rear caster the wheels are moved to front of the wheel well, this results in little to no toe change w/ suspension travel( a slow rear), w/ maxed kt the wheels move all the way back close to the mufflers, the more so the more toe change w/ a given amount of wheel travel(a fast rear) the fast rear makes he car twitchey and hard to control
at highway speeds it's doubtful that aero effects are entering the picture
bent wheel
shocks
ball joints
tire pressures, I use 33/35 cold on the street
possibly other tire issues some just don't track well
your kt should not be maxed and the side to side can't be checked by looking at the eccentrics, the gauge reading tells the story, w/ 0 rear caster the wheels are moved to front of the wheel well, this results in little to no toe change w/ suspension travel( a slow rear), w/ maxed kt the wheels move all the way back close to the mufflers, the more so the more toe change w/ a given amount of wheel travel(a fast rear) the fast rear makes he car twitchey and hard to control
at highway speeds it's doubtful that aero effects are entering the picture
10-04-2016, 06:40 PM
#44
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Also remember, factory alignment settings, are not necessarily the best for handling. They're meant to encompass the broadest amount of drivers, with the least amount of surprises (which also, may mean numb response), and reduce tire wear. Determine what your driving level is, use for car, and what you deem as acceptable tire wear (rear). Get all original rubber replaced, then get it set up, and go enjoy.
10-04-2016, 08:03 PM
#45
Three Wheelin'
Thread Starter
wheel bearings
bent wheel
shocks
ball joints
tire pressures, I use 33/35 cold on the street
possibly other tire issues some just don't track well
your kt should not be maxed and the side to side can't be checked by looking at the eccentrics, the gauge reading tells the story, w/ 0 rear caster the wheels are moved to front of the wheel well, this results in little to no toe change w/ suspension travel( a slow rear), w/ maxed kt the wheels move all the way back close to the mufflers, the more so the more toe change w/ a given amount of wheel travel(a fast rear) the fast rear makes he car twitchey and hard to control
at highway speeds it's doubtful that aero effects are entering the picture
bent wheel
shocks
ball joints
tire pressures, I use 33/35 cold on the street
possibly other tire issues some just don't track well
your kt should not be maxed and the side to side can't be checked by looking at the eccentrics, the gauge reading tells the story, w/ 0 rear caster the wheels are moved to front of the wheel well, this results in little to no toe change w/ suspension travel( a slow rear), w/ maxed kt the wheels move all the way back close to the mufflers, the more so the more toe change w/ a given amount of wheel travel(a fast rear) the fast rear makes he car twitchey and hard to control
at highway speeds it's doubtful that aero effects are entering the picture
I'm currently running 34/38 so I'm close to what you are using. I'll try 33/35 next.