I just installed an ACT street light flywheel and Z65-HDG6 clutch. I started my car for the first time today and it feels like I have a little more engine vibrations than before. Is this normal with lighter flywheels?

I have solid motor mounts so my car vibrated more than stock, and I haven't driven it in 3 months so I cann't say for 100% it is worse. It is a mild vibration, nothing crazy.

I had some issues figuring out which counterweight to use. I used an S5 counterweight because my stock N370 flywheel worked with my engine combination.

 

i have solid mounts and a aluminum flywheel.. uh... as far as i cna remember, it didnt vibrate much until acceleration. then the car buzzes a little... thats about it.... sorry its been 2 years, but make sure your counter weight is perfect, i did a 5 spd swap so i used original counter weight.

 

I have a lightweight flywhell (11lb) and polyurethane engine mount. I didn't really notice of vibration @ idle, but if I don't put enough gas during 1st gear acceleration then it vibrates (shake) a bit.
I have to put around 2000rpm to take off smoothly (on 1st gear) from a stop.

 

i also run ACT light fly wheel. one of my greatest errors in judgment on owning the FD. the trade off for performance gain of a light weight is not worth it in my opinion. I also have to engage at a higher rpm or else the whole F**King car feels like it falling apart.

 

get under the car, remove the inspection plate in the bellhousing and use a pry bar ( with good leverage) and pry on your fly wheel, make sure its not loose. I did this on my first rebuild. It would vibrate until I got to higher rpms, and at idle it would vibrate unless I pressed the clutch, and this is what I found. Loose *** fly wheel..no fun but it happens.

 

Make sure you have the correct series counterweight installed on your flywheel

Edit: Re-reading your post sounds like you've got a franken-rotor. Find out from whoever built your engine what series rotors they used, the counterweight needs to match the rotors in series.

 

ttp://www.youtube.com/watch?v=1J5XhlLzh8s

Here's a video, if it works.....

 

So the video works. The sound might be a better indicator than the spray can on the intake.

Now that I got this video think down I'll try to get a better one.

 

I check my flywheel it was good and tight. After I put my exhaust hangers back in and the vibration when down a little.

I finally was able to drive it and the vibration has changed. At 2000 rpm in low gears there a increase in vibration, at idle there is almost no vibration (like stock), and above 2000 rpm in the low gear there is a little extra vibration, and in 4th and 5th gear it almost goes away (more than stock, but not enough to get your attention).

I think I might try to change out my engine and trany mounts and then run it into the ground. I'll balance the whole assembly when I rebuild the engine in a year or so.

 

i have a s5 turbo motor with os giken double plate setup flywheel and correct matching CW and it vibrates at around 4k if im free revving,it makes noise and you can feel the vibration on the shifter,the motor is being apart a couple of times and the bearings showed abnormal wear,this time the whole assembly is getting balanced and i hope that the the issue stops but il still bugs my mind why it does that.

 

Honestly I think that just getting the right series of counterweight might not be enough. I had my rotors (s4TII) lightened to s6(fd) spec then balanced with the front and rear counterweights from an s5 and weight was taken off even though they were supposed to be the same spec. I have a Fidanza aluminum light flywheel and the car is butter smooth at all rpm even with solid mounts. Hell I can't even tell its running when I come to a stop if there is too much noise around me. There is a lot to be said about factory "balance". I don't think your vibration is much to worry about. The sound I heard on the video sounds more like a bad front thrust but I could be hearing it wrong.

 

You might be right I ran a Camden Supercharger for years and they are bad on the front thrust. I'll look into that.

 

So my issue was the counter weight. I put on a different S5 weight and the vibrations went away. I must have had a random counterweight for modified or for a weird engine. I have not yet found it's origin. I marked it permanently with "Bad" to prevent any more headaches.

 

where did you get the Counterweight.the bad one?
If you bought it separately from someone,then my Guess is that it could have been the wrong counterweight.

 

This weight has a long horrible history. I bought it on eBay, was told it was an S4 from a store I have had good luck with. I did not have a clutch yet so my buddy tried it on his S4, caused a horrible vibration. My dumb *** thought, "hey it must be an S5, it has all the right markings" I was wrong.

That's four trany pulls in Michigan winters over a $100 part.

So it not an S4 or S5 and doesn't meet the mazdatrix criteria for any other year.

It's cursed.