ACT Streetlight flywheel buzzing/vibrating
 

I had the ACT Streetlight flywheel and clutch kit installed recently. I chose this kit because I liked the feel of it in two other BRZs I drove. This is my daily driver and I don't want to induce extra NVH. I'm told this kit is designed to be used on the street and should not induce extra NVH, which was my experience when I drove it in the other cars.
I'd rather not pay to have a nearly-new clutch and flywheel removed and replace it with a heavier flywheel and clutch. However, if that's what it takes to eliminate the excessive NVH with this kit, that is what I will do.
I'm hoping the cause of the NVH is not the new lightweight flywheel, but instead something else. Maybe a busted motor mount, bushing, or something else. I have the Whiteline rear subframe and diff bushing inserts in the car, which may not be helping things, either.
What do you guys think? Has anyone else experienced this with this kit? What could be some logical explanation other than the flywheel? I'm hoping to find something else wrong with the car that would explain the NVH, but am struggling to imagine what that would be.

Be a man. JK. To be fair, when you drove my car you didn't notice the NVH because I HAVE SO MUCH OF IT! Solid everything :)

Are you talking about chatter? Lwfw cause chatter. I have it but you get used to it and get used to what speeds and gear cause it so you can avoid it if you want to.

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I had the Xtreme Kit with flywheel SB7-XTSS. Not a street friendly kit IMO. The issues with chatter and hang-ups was too much for DD. If it was a track only car I would have tolerated it.


Took it out and had my stock flywheel put back with a South Bend Stage 2 Daily. Much better for a street car. Now I have a practically new ACT kit in my garage in the box. I think I put 5k miles on it.

My kit is the SB7-HDSS, so a bit different. I think yours has a heavier pedal feel than mine, but they use the same flywheel.

I wouldn't call it chatter. Once in a while I hear a tiny bit of chatter at idle but I'm totally fine with that. I'm talking about a buzzing/vibration through the entire car while I drive at nearly any RPM. It is the worst between 2k and 4k RPM, but I can feel it at nearly any RPM. The higher I rev it the less NVH there is. I've tried "driving around it", but it occurs under nearly any conditions, so that's not really a solution.

Hmm well I got a lwfw and act clutch with no noise. Maybe something is loose or installed wrong /shrug, not sure.

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I don't think I ever had that. Tons of chatter taking off in first most of the time, but once I was rolling it was actually nice. Felt like a racing clutch, very stiff with great feedback. That is why I say if it was a track car, it would have been ok, but not for a DD my wife often drives. Just too many issues in stop and go.


Drive shaft ok?

Sapphireho, do you have any other mods like bushings or bushing inserts?

Just a couple:


Anti-Lift/Caster Bushing Kit
Front Control Arm Rear Bushings
Heavy Duty Steering Rack Bushings
STI Upgraded Steering Rack Bolts
Rear Subframe Insert bushings
Rear Differential Inserts
Transmission Bushing Insert
Rear Trailing Arm Bushings,
Front Toe Arm Bushings
Inner Lower Rear Control Arm Bushings
roll center adjuster set


And a CF drive shaft.

Verrrrry interesting. Thank you for sharing. So, just to be clear, while in motion your ACT kit doesn't add any NVH over OEM, right? Thanks again.

Correct. I did not experience what you are describing.

I just did the street lightweight flywheel. Also did the rear end bushing stiffeners from Whiteline. You can hear and feel the gears in the rear diff now. I knew it would have more NVH but did not realize that much. After driving a week or so got use to it and not going back.

I am not feeling the gears. This is something completely different. I know what you're referring to, as I heard that when I changed the bushings too. The buzzing that I am referring to is completely different.