Mr. Vapor

Im getting some bad vibrations in my '00 Si.
it vibrates from about 3,800rpms to 4.200 RPMs. after 4200 the vibrations seem to go away.

it will vibrate enough for me to feel it in the shifter and the gas pedal. it also what appears to me anyhow, will change the exhaust note slightly?

the car will vibrate regardless of if im standing stll or in motion. it vibrates if im at a light in neutral and i rev it up to 4k, just the same as if im cruising in 4th gear at 4,000 rpms.


Known instances that may or not be related:

-Did clutch/PP swap within the past 1,000 miles to a 6 puck unsprung
-Raced from a dig an LS1 RX7 and did not pre-load the axles, wheel hopped REAL bad
-No clicking from axles, inspected all CVs, no tears.

My thoughts:

torn motor mount?
flywheel bolts backing out?


ANY help is much appreciated!!!!

Mrs.PengWEN

have you taken a look at your motor mounts??

My car use to do this n I changed out the mounts.

Mr. Vapor

have NOT checked them yet, plan on doing that this weekend. what is a good way to "check them?" i mean just a visual inspection?


Secondly, the vibrations will occur on the down rev as well. Say im in neutral, and i rev it up to 8,000 rpms for example. the car will vibrate as it pass through 3800-4100 and then it will go away. when i let off the throttle, and the rpms come down, as it pass through there again it vibrates grrr

could this be a tranny issue, pilot bearing?

Mrs.PengWEN

lets see... wheres that picture...




thats what a broken mount looks like if your going for visual inspection.

First is the aggravation of increased engine noise and vibration. The second can be binding of linkages--i.e., throttle and some transmission-related controller linkages. These can show themselves in what appears to be increased pedal pressures or slower responses to driver inputs.

With the engine running and parking brake applied, have an assistant behind the wheel apply the brake, then place the transmission in gear and feed the engine some throttle. Stand to the side of the vehicle (never in front of it) and observe the engine's response.

All engines will rotate slightly opposite to the direction of the crankshaft rotation. However, a severely worn or broken mount will cause the engine to show excessive movement, sometimes raising several inches. To check the mounts on the other side of the engine, have the assistant place the transmission in Reverse, and repeat the process. If there is excessive play then, you prolly got a broken mount.

EJ8VTEC

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Mr. Vapor &raquo;</TD></TR><TR><TD CLASS="quote">
-Raced from a dig an LS1 RX7 and did not pre-load the axles, wheel hopped REAL bad
</TD></TR></TABLE>

how do you pre load axles??

Mr. Vapor

bump

Mr. Vapor

highly doubt its rod knock.


more ideas?

Mr. Vapor

bump for more views?

SovXietday

Check those mounts!

If it's vibrating in motion AND not in motion, then your Axles/CV boots/etc have nothing to do with it.

The clutch is a maybe, but most often if they make a vibration it's a chatter during early engagement.

I'd say mounts, especially after severe wheelhop.

Mr. Vapor

clutch chatters engaging and disengaging....this was expected though, its a 6-puck unsprung iron-faced clutch with a pressure plate that holds 500lbs torque.