eficker

iTrader: (19)

I just had the evo at the track (road course) for the first time today, and driving home, i noticed a motor vibration (pretty obvious too) at 3500 rpm regardless of gear or car speed. It will even do it at a dead stop, if i rev the car to 3500 and hold it there.

It feels as though the crank pulley is out of balance, but it only has 2300 miles on it. I suppose it could also be something in the clutch/flywheel side. It only does at 3500, no higher, no lower.

I have a tbe, mbc (set to 20psi), and thats it for motor mods.

I'm not sure what is causing it, but i dont want to bang out a main bearing before i find out and resolve it.

Just wondering if anyone has heard about or had this problem before. I dont really want to take it in to the dealer, or have to swap my exhaust off so i dont get a voided warranty, but i will if i have to.

kjewer1

iTrader: (4)

On the DSMs if you lost the front balance shaft belt it would vibrate at a specific RPM range and not really above or below that. That would be the first thing I would check. The EVO makes it so easy to get the timing belt cover off too, you can check it in under an hour. The biggest risk if you don't check it is that a broken front bshaft belt has been known to get into the main timing belt on many occassions and make this a much bigger problem.

eficker

iTrader: (19)

kjewer1,

Thanks, i will check that first thing. I wonder if i'm just being paranoid, or not, but it is pretty distinct. Is this a common problem? Is it caused by heat, or hard running? Obviously both were in play today.

PS, how in the heckfire did you pull a 1.59 on snow tires?!?!

Nice work!

kjewer1

iTrader: (4)

I wouldn't say it was a common problem on the DSMs, but it was common enough that you saw it every now and again, and it immediately comes to mind. With EVOs starting to rack up some mileage I'm betting we'll start to see some of the typical DSM problems pop up. Nearly new belts can go to **** too. Very rare I'm sure, but certainly not impossible.

Thanks for the kind words on the short times. Launching the car is one thing I have never had trouble with for some reason. The car typicaly gets low to mid 1.6s. I'm pretty set on running slicks next year for the first time. I'll probably pull 1.8s all year.

smokedmustang

iTrader: (7)

I had that problem when my oilpump balance shaft was 180 degrees out of phase. you havent had the timing belt messed with did you? If not, I am at a loss.

eficker

iTrader: (19)

I literally haven't cracked open any part of the motor, it only has 2300 miles.

Is it possible that there is just some harmonics that come into play at that rpm and i am just being overly paranoid?

The thing that makes me the most nervous is that at that rpm in fifth gear its right at freeway cruising speed, so if it is a serious problem, it could cause some damage pretty quickly.

smokedmustang

iTrader: (7)

Being that new, whatever it is should be covered. Start a "paper trail" on it now, so in the future you can say "Hell, you looked at it". I think you are fine, motor is "seating in", so is the clutch. could be normal. get that confirmation from the dealership though. my 2c.

boscoyo

iTrader: (8)

I had a similar harmonic imbalance at 3500 rpm, but it was letting off the gas and getting back on the gas. My problem was my down pipe was rattling against the under brace and I had a loose bolt in the engine bay. It is probably not the problem, but worth a look. Pop the hood and throttle up by hand.

eficker

iTrader: (19)

Those are both great ideas. I haven't broke out the wrenches yet, just thought i'd formulate a battle plan first.

I worry about taking it to the dealer with a mbc and a tbe. Whats the likelyhood that my warranty will be nixed?

smokedmustang

iTrader: (7)

I think it might be the Downpipe also, check that first. I doubt they would void warranty with the mods you have. is there "clearance" from the DP and the black cross members?

boscoyo

iTrader: (8)

The TBE is not a problem, but the boost controller is. Before you do that, just look at the down pipe to see how much room you have in between it and and the tie bars and throttle up by hand and listen and feel for what you were hearing.

RazorLab

iTrader: (8)

did you happen to spin at the track today and have the car go backwards?

eficker

iTrader: (19)

I forgot about the downpipe. I had to wait on the hardware kit from turboxs (their downpipe) and never spaced out the rear tie bar (the forward one is not installed atm). I will check that out first thing.

No spinning at the track, but the evo does get a little more sideways than my integra ever did. The evo is not too much faster, but the teg was a full race car.

<OT>
One thing i cant believe is that no matter what mistake i made or how hot i came into a corner, the answer to correct the problem was almost always: ADD THROTTLE!!
</OT>

Thanks so much for the suggestions so far. If anyone else has some, pipe up!

sleet

iTrader: (9)

I had the same thing, my exhaust was touching some cross bars under the car making it vibrate.

munoa13

iTrader: (1)

Maybe you need to check the rotory gurter to make sure it is fluxing properly?