jbrill

Hey guys, I posted this topic a while ago but had no real responses.

My 1990 s2 has a HORRIBLE vibration throughout the whole car when i downshift from 3rd to 2nd, if i dont heel toe or bump the revs up a bit before releasing the clutch.

Now i know u should always heel toe and never downshift, but its stilll a concern to me as to what is causing it. Its definatly not normal, and it never did it before.

Thanks in advance.

Andial951

try checking your exhaust system to make sure its tight and not moving around. I had a similar problem and it turned out to be the exhaust system.

Matt Sheppard

I would advise that you also check your CV joint bolts - as in all of them.

jbrill

about the exhasut, where was yours loose? that definatly coould be a contributing factor as i have recently puut a new exhasut on it.

Andial951

well I left off a hangar so that was a contributing factor. Unsure exactly where it was loose but apparentally it was loose in several areas. My mechanic fixed it while the car was in for somethign else.

There was a thread on here last year about vibration during downshifts.....many different theories but for me and a couple others it was the exhaust system rattling.

Z-man

Well first of all, like you said, downshifting WITHOUT a heel and toe rev-match is a no-no. It just adds unnecessary wear and tear to your drivetrain.

Use the brakes to slow down, not the tranny and clutch. If the vibration is still around under normal driving conditions, then you should look further. To me it sounds like your rubber center on the clutch hub may be going, and your downshifting is just going to make it deteriorate faster.

-Z

jbrill

no rubber center, i replaced it with a spring centered clutch

Z-man

How long ago? The spring centered clutches are more robust, but they can have failures as well...

-Z

jbrill

less than a year ago.

Lumbergs Lackey....MmmmKay

Motor mounts

jbrill

yea?

Mamooguy

Yeah, give the exhaust system a shake to see if it's loose.

Nyx

Clarks-garage has the distance Motor Mounts are supposed to be spread.

ahsan127

I had the exact same problem on my car....traced down every damn thing and then finally gave up. Never really had any problems with the car. Later I got a whole new exhaust from SFR from the headers to the tail pipe and the problem disappeared. I assume it has to do something with the exhaust.
Its been discussed here multiple times if you do a search. No one really has any answers. I would match revs before downshifting and forget about it.

CarbonRevo

I have a spec stage II in my car, and if I don't rev match into 2nd wether it's downshift or upshift, the car shakes BAD. That clutch will NOT slip into 2nd.

Mine also has the exhaust problem, though...