Lightening the rotating mass?

[pointless]

Well it's getting close to a clutch replacement and I was thinking about getting a lightened flywheel while I was at it. then I got thinking what about lightening up everything lighter pulleys, fly wheel, clutch, and driveshaft? I've heard people getting check engine lights from some of this stuff anybody see any problems or have any suggestions on this? Thanks

[AmsOil]

I have heard of the same problems, but my CEL is permanately turned off throgh my utec because of having no cats anyways. When I replaced my clutch and flywheel a few months ago, I replaced it with a SPEC stage 1 clutch, and a 9.5 lb Fidanza flywheel, and have not thrown the misfire code. (I check it fairly regurlarly since I have the light turned off). I do not know if this is because i just got lucky, or it is a hit and miss, I do not know. Maybe if I had done the pulleys it might have done it. I dont know if this helps, Kyle

[Jard]

You may get a misfire code if you go too light. I know that the WRX guys were getting them all the time with a lightweight pulley and lightweight flywheel.

I think if you did something like an ACT StreetLite (15.0 lbs.) flywheel only, you would be okay.

If you do something like an ACT ProLite (11.1 lbs.) AND a lightweight pulley...then all bets are off...

[Usher]

I have the ACT Prolite (9.6 lbs.) and I've only gotten the check engine once at the last rallycross. I've never seen it during the other 2-3 months I've had the flywheel on the car. The main theory I've heard is that the light comes on due to the engine revving too fast. If that's the case, it probably happened due to staying on the gas for the little jump in that event.

[pointless]

Maybe I will just go for it and see what happenes and possible just turn off my CEL if it keeps throwing it.

Other question so even though its throwing the check engine light it's not causing any harm to the car at all?

[conorpeterson85]

i have an agency lightweight pulley, and it threw a cel, disconnected my battery for 15 mins, no problems since then.

[indytruckboy]

The EM might have problems controlling your timing/fueling as they now the engine's position by the crank sensor. I am not 100% on this, but it seems to make sense.

[Usher]

Now that I've had the lightweight flywheel on my for about a year, I thought I'd follow up a little on the check engine light thing. I've noticed that about every 3-4 months I get a check engine light (misfire on cylinders 1 and 3) then about a week later I'll get another check engine light (misfire on cylinders 2 and 4). There seems to be some sort of long term accumulator in the ECU that is not cleared when clearing the codes and when it gets high enough, you get the check engine light.

Most recently, I had misfire cylinders 1 and 3 show up last week, and the check engine light came on again on the way to work this morning. I'm willing to bet it says misfire cylinders 2 and 4. Both times, the light came on while gently accelerating away from a stop light.