Almost all Evolution produces some kind of drivetrain noise even with the OEM clutch.

I would like to understand why some Evos make a horrible metallic sound on the road when letting off the throttle at +- 65mph (5th gear).
I test drove an Evo with a performance clutch brand "x" and this sound is simply unacceptable.

If all "performance" clutches produce this noise I will stick with the OEM

 

I have no idea what noise you are talking about

 

It sounds like you are talking about gear noise if I am not mistaken. What this is caused by is torsional vibrations. These vibrations (engine pulses) rattle the gears unless there is adequate dampening between the engine and transmission. This is the main purpose for dampening springs in the clutch disc but a heavier flywheel and good front dampener also help to reduce them as well. Torsional vibrations are worse when the engine has 4 cylinders, a turbo, diesels, hot cams, higher compression and probably a dozen other reasons.

My opinion as to why even the stock EVO makes noise is that the car was meant for performance, at least to a point. The stock flwheel is light, the dampening on the disc is stiff, and of course it's a turbo 4 cylinder. On the MR the clutch disc is Exedy's WAD design which is probably quieter, but not what I would want for performance.

The reason many aftermarket clutches make more noise worse is that they either have no dampening or inadequate dampening. Keep in mind that without disc dampening, the disc is lighter so it potentially will shift faster, but that is not always the case.

ACT's street disc uses good dampening for fairly quiet operation, while our 6 pad race disc is solid center for faster shifting and higher torque capacity than our street set up. I preach all the time that there are always tradeoffs. I hope this information helps.

 

Im having the same problem. your advise helps alot.I was just askin my friend about this the other day.I have act street clutch and a fidenza flywheel at the current time. The noise is not loud in my car at all, but only when i listen to it closely. Other than that i guess ill just keep my radio on and ignore it if you say its normal.

 

Obviously I am only doing an internet diagnosis, but most likely it is normal. I forgot to add that the noise (gear rattle) is normally not harmful to the driveline parts.

 

thanks for your advice.you save me a pointless trip to the dealership.

 

it's normal. i heard it first around 2k miles. i now have 22k and it sounds a little louder ever since i started modding.

 

Thanks ACTman your help is always welcome.

It is difficult to express with words this noise.

This noise is like to grind a metal. It doesn't go away if I let my foot off the throttle, it just goes away when touch the throttle.

BTW, my OEM clutch doesn't produce this noise.

 

Yeah, that makes sense. The gears rattle when not under load, but as soon as you put a load to them they won't rattle. Under heavy engine deceleration, it probably doesn't make the noise too since you are loading the gears in the opposite direction, although in high gear you may not get enough engine braking to notice.

 

Driveline noise is normal in performance cars .... if it is unacceptable may be you should consider an automatic car or a luxury ride ...

k270kmh: Do you really drive an EVO 7?

 

DaWorstPlaya No, I do not drive an Evo 7. I come here to this forum because I drive a chevrolet 68.

 

Under heavy engine deceleration, it probably doesn't make the noise too...
Yes, you are right!!!

 

hahaha

 

LOL! I was just curious because you haven't listed where you live and in the US we only have the EVO 8 ... if you did have an EVO 7 my next question would have been, does it have S-AYC?