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!!!!

 

My guess is motor mount. Do you have just the stock mounts in there?

 

yes, just stock. would a visual inspection clear this up? i mean im trying to put 400whp through the stock 6 year old mounts....

the vibrations occur on the down rev too, ie: if im reving down from say redline, it will vibrate as it passes through 4200-3800rpms

grrrr

pilot bearing? input bearing in the tranny anything?

 

pmd yo monkey ***- but bump anyway

 

bump

 

honda motors seem to have a strange resonance at about that RPM (same RPM i cruise at on the highway, so i notice) and it very well could be a combo of the fact that your manifold was cracked (vibrating a crack will make a noise) and that resonance. OR the crack could have come from the vibration, which is why you've felt it more lately, because the manfold cracked much worse

 

bump for more thoughts

 

wheel bearing?

 

read the thread man...it happens even at a dead stand still.

 

So it happens when you rev it in neutral as well? I dont think the mounts would cause that, maybe if you stab the throttle causing a jerking motion. I would pull the transmission and inspect.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by B6tPoweredMx3 &raquo;</TD></TR><TR><TD CLASS="quote">So it happens when you rev it in neutral as well? I dont think the mounts would cause that, maybe if you stab the throttle causing a jerking motion. I would pull the transmission and inspect.</TD></TR></TABLE>

The engine vibrates a lot even at low load/RPM in neutral. If you have solid motor mounts/polyurethane inserts you can really feel it.

I'd say check all your motor mounts first and put some inserts in there while you're at it. If thats not whats causing it then you may have to check out the clutch/flywheel.

Its kind of funny how everyone in this thread is from Rochester too.

 

the car currently has motor mount inserts in....im not at the car daily, its stored off property of where i reside...ill hopefully have more details this weekend...just looking for more ideas.

im leaning towards a tranny issue