Slo_crx1

iTrader: (9)

Last week I bottomed my car out pretty good on one of PA's fine roads, and ever since then I have a really nasty vibration that I can't seem to pinpoint. The "ditch" that I hit also knocked my alignment way out, but I took care of that today and that is not part of the issue.

The vibration sounds almost like a wheel bearing going bad, it increases in speed and intensity starting at around 2500 and becoming so overbearing by 4000rpm that you can physically hear it outside the car (at this point almost like a grinding sound) and feel it through the steering wheel, shifter knob, and floorboards. However, it does this vibration no matter what speed and only depending on rpm which to me cancels the idea of wheel bearings. I inspected my motor mounts and they seem to be intact, although I still wouldn't rule them completely out. I inspected the front axles to see if there was anything rubbing or in general out of place, and they seem fine as well. I checked the drive axle to the rear along with the universal joints and bearings and they seem ok, although turning them by hand doesn't show me much. The noise does not decrease by hitting the brakes during the event, it doesn't even seem to make any difference at all. In general it stays pretty quiet up until the 2500rpm mark, starts becoming noticeable, quiets out a little around 3000, becomes obnoxious and overbearing by 4000 and starts to quiet back out over 5000.
I'm honestly stumped at this point, it does have the similarities of a broken motor mount would sound, but spending the money for new mounts would be pointless if it doesn't solve the problem. Has anyone encountered this before? What other things should I look at? I have K-Sport coilovers that I recently put on the car but other than that all the rest of the suspension is stock with 94k miles on it (except for tie rods).

bbyevo8u

iTrader: (14)

i would say its prob your exhaust rubbing somewhere

Slo_crx1

iTrader: (9)

Checked and double checked, there is nothing anywhere even near it. My downpipe is definitely on the custom side due to my top mount setup, so I made sure I went over the whole exhaust system. It's more of a grinding type of sound than a metallic vibration sound.

Slo_crx1

iTrader: (9)

Fixed it today, turns out I shredded every tooth off my Gates Racing balance shaft belt and the balancer slipped off place about 5 teeth. Did a timing belt/balance shaft belt today and the vibration is gone, it kind of sucks too since I only had about 20k miles on those belts.

barneyb

Yeah, anytime vibration peaks at 4000 rpm, think balance shaft.

Slo_crx1

iTrader: (9)

Yeah it ran through my head a couple times but I couldn't think of any logical reason that it would be off from just hitting a dip in the road. Maybe just from the power I'm putting down now? I have been hitting into the 30psi range lately just to see how well the stock bottom end will take it, I guess it's time to look into a B-shaft eliminator.