Review: ACT-HD with 11.8lb Flywheel

[ML]

I have had this combo for about 6 months, and I agree with all your points. The rattling with AC on is real though.

[amcp1]

My stock clutch stock flywheel setup do that now so this shouldnt be much of a shock.

[Sriracha]

Originally Posted by ML

I have had this combo for about 6 months, and I agree with all your points. The rattling with AC on is real though.

Glad to hear its working for you too man. Luckily I'm more of a windows down guy anyways so I don't mind too much.

Originally Posted by amcp1

My stock clutch stock flywheel setup do that now so this shouldnt be much of a shock.

Surprisingly enough my stocker made about as much noise as the prolite so its really not that bad. You can just kind of hear it if your in between songs or have a quiet exhaust at low speed.

[akahenry]

Glad to know you enjoy the SB7-HDSS! If anyone's interested in one, I have one for sale!

[007BRZ]

Originally Posted by Sriracha

So finally got around to installing the ACT HD clutch and flywheel combo, took a buddy and I around 8 hours on our backs in the driveway to get it all good and adjusted. Install was pretty straightforward, besides a couple of gummed up dowel pins that made taking the trans off take way harder than it should've been it all went smooth. I documented the whole install with pictures so if anyone wants a DIY guide let me know.

*** DISCLAIMER ***
I have had many aftermarket performance clutches and lightweight flywheels, because of this the difficulty and learning curve I experienced may differ slightly from others experiences.

Now onto the fun part, the first drive ( First 100 or so miles )...

First impression, it drives almost exactly like the stock clutch ( at least until it broke in ). Besides being slightly more temperamental and a little harder to recover stalls it's pretty comparable. Slightly more rev happy and wayyyyy easier to heel-toe/ rev match downshift/ and granny downshift. You can even still slip the clutch to move it slowly without any input on the gas. All of this while being able to hold more than double the stock clutches torque is a good deal to me.

The break-in begins ( 100 - 500 miles in )

This is when the clutch is a little strange, the first half of a trip will feel like a firm stock clutch. Then you'll be sitting at a traffic light and go to move and BAM, car won't even react to dropping the clutch with anything less than 1.5k. This is when the clutch chatter also starts. The more you heat cycle the setup ( heavy stop and go but don't overheat it ) the better both of these will get. The clutch will start to change less violent in its engagement until it starts to just even out. This stage the engagement varies from 1.5k to 3k rpm.

The near end of an era... of break-in ( 500 - 1000 miles )

It is around this time that the setup will start to feel a little bit more grounded and consistent. Shifting you will notice requires a slightly slower release than stock as the setup is pretty grippy. You might still notice the occasional shuddering when taking off from a stop when you haven't engaged first in a while ( going from sitting in 6th on the highway for an hour to stop and go will be a bit rough for the first few engagements ). The more you drive it the more and more it seems to refine itself as it wears in. At this stage the rpm required to get the car moving smoothly is 2k hot - 2.5k when cold.

The new age... of being able to drive above 4k again ( 1000 miles plus )
Congratulations! If you've made it this far reward yourself by allowing yourself to break free of the break-in periods recommended 4k rpm max and let that FA20 sing! If it still feels a little rough at this point head back out to a local neighborhood and put some more stop and go on it to smooth out the rough edges.

Biggest differences between stock and this setup:

1. ( + ) Much more grippy and linear engagement

2. ( + ) Much easier rev matching, even just granny shifting the car feels like you're rev matching it. The lower flywheel weight makes the engine more forgiving if you are a couple hundred rpm above or below what it wanted.

3. ( + ) Heel-toe is more responsive, makes you feel like O'Conner himself banging through gears backward while you stomp the brakes.

4. ( + ) Car feels more responsive to throttle inputs, what little torque we have stock is presented much quicker. The engine feels more willing to be pushed.

5. ( + ) Intake sounds cooler because it can suck air in faster

6. ( + ) The car is now faster due to less rotational mass

7. ( - ) Car is much harder to recover from a stall.

8. ( - ) Using the AC will usually make the flywheel chatter

9. ( - ) You will have to consciously be aware when driving that the car has a lightweight flywheel. This means you cannot just release the clutch to start moving and then give it gas accordingly ( and have a smooth start at least ).

10. ( -/+ ) If you're in the wrong gear ( below 2k trying to plant the petal ), the flywheel sounds like a foghorn letting everyone know you forgot how to drive for a second.

11. ( +/- ) You can hear more transmission noise as the new flywheel has no dampening.


Overall recommendation:
Heck yea I would recommend this clutch and flywheel combo. Although there is a slight learning curve, the benefits in my mind far outweigh the consequences. Give it a week or so of driving once its broken in and you'll feel as confident if not more than you did with the stocker.

Thank You for your Review I just installed the same ACT HD Kit into my 2019 BRZ Saturday It took 4 1/2 hours with my mechanic and a use of a full shop with lifts and all the tools.
I've put on 70 miles and the only chatter that i'm getting is in traffic starting in 1st gear. Your review put me at ease to what to expect during the break-in period. Thank you again.