U know what... U might be right. I have BC coilovers and i just lowered them. Before was a 2 finger gap now... 1 finger and I added 18x9.75 +20 wheels. So how do I fix this??? Do all lowered X's have this problem. I doubt it.

 

It seems that some have it and some don't. Try raising it up 5mm at a time and see if it stops. I bet it does. As far as fixing the problem if you want to stay lowered....i have know idea.

 

Any suspension guru's out there want to shed some light on our problem.

 

Ok, cant say i have that issue then, im also on BC coilovers if thats makes a difference atal

 

I have this very same problem after having coilovers fitted which lowered the ride height.

3rd & 4th gear full boost you feel a vibration like driving over textured paint on the edge of a motorway. Feels to be more at the rear to me

Any answers to this other than lift it up? Seems to be a drive train issue?

 

may be its due to old engine or due to broken steering and suspension components .

 

I would hope not as my car has 10k miles on the clock, it was fine then had Exe-TC fast road coilovers fitted along with Eibach rear roll bar and a whiteline roll centre correction kit. First time I booted it (3rd gear) on the way home after fitting I felt the vibration.

something aint right but was surprised to find others with same issue after going lower / fitting rear or both roll bars.

any help greatly appreciated I tried PM'ing the OP but no answer his psot was a long time ago now...

 

Responses like this really make me think twice about posting on this site. Unreal.

I'll try to add something constructive to this thread. This problem is common on many cars. Google it. After a lot of reading I found this little thread on the S2000 forums. It is a very common problem to have vibration under acceleration after lowering those cars. This thread indicates why, and how to fix it. What I don't know, is that if this is the cause of our problem. It sure seems like it might be. As I said earlier, I had the problem with Eibachs, then switched to Swift Sports, and the problem is all but gone. It DOES have something to do with ride height.

http://www.s2ki.com/s2000/topic/6931...r-lowered-car/

 

Thanks for a useful reply my car only has 10k on the clock is it still likely to be the CV buckets that have worn to the old ride height? I guess its possible? Any thoughts of a diff bush letting things get out of line and feeling a prop UJ vibration?

Cheers again black 95tt (agreed on the earlier post WTF)

 

If it makes you feel any better, it's not just you. When I suggested that someone check their drivetrain after getting new noises after lowering a car, I was told "but I only changed the suspension" and was pretty much ignored. I'm not saying that either of us are correct in these cases, but people do seem to underestimate the effects of changing the angle of their axles.

 

Agreed. But why does it affect some cars and others not? Some guys on here are slammed and you never hear a word about vibration. Others like myself, had the problem with a mild spring drop. When putting my swifts on a couple weekends ago, I was very careful when installing them and also took the time to closely inspect all of my axles, ball joints, tie rods, etc. Everything looked fine. The car is much smoother now and I did nothing other than raise it up by about a 1/4-1/2". It very well could have been a previous install error, but I have my doubts.

I've also read quite a bit about harmonics in the cv axles when the angle is too straight, which would be the case when you are lowered. I noticed our cars don't have a weight in the center of the axle like some cars do to combat this problem. Maybe adding one would help?

 

A whole bunch of things contribute to the wearing of divots in the CV cups which can later turn into a drivetrain vibration. The amount of grease in the cup; the usual temp when you're driving hard; whether you only drive hard in a straight line (putting all of the stress in the same place every time) or often are powering out of corners (which spreads the wear around). There's probably variation in the quality of cups, too. The key point is that this is another place to check when tracking down a vibration, as are the prop-shaft mounts, hydraulic pumps on the diffs (which only lock under power, so they only need pressure under power), etc, etc. Most of all, it would be great if people started thinking about their cars as interacting systems, as opposed to separate units. Yes, the most recent change that was made to the car was suspension-related, but that doesn't guarantee that some new problem that just emerged is also suspension-related.

 

trouble holding boost?

 

UPDATE:

Ok so had the car up on a ramp and I had a look around. I have a Milltek turbo back decat exhaust fitted which has a resonator box before the rear box. For some reason now the car is lower the corner of this resonator box had been rubbing on the prop shaft under full load! On the ramp there was about 1/2inch clearance but obviously under full power they were touching. We adjusted the distance as much as possible giving about 3/4inch clearance with the car sat on the ramp. This has almost cured my problem but its still touching a little so I need to make an adjustment to the corner of the resonator box once I can get it back on a ramp (hammer time).

I dont know if I have another problem (engine mount or prop guide) thats allowing these to touch or why lowering the car suddenly caused the two to touch as they didnt before, good few thousand miles with the Milltek fitted b4 lowering...

Thought I'd post as I found my answer to this problem, it could be the same for you.

 

^ Good to hear. Did that definitely fix the problem though? You didn't you hear any scraping sound from that rubbing? I'll check again tonight but I'm certain that my Perrin DP is nowhere near the prop shaft.