MCA Suspension "Traction Mod"

[M0nk3y]

Yay for first Gen2 MCA install photos (at least here)

Cannot stress enough to chase the existing subframe bolt with Kroil or something to clean it out. SUPER easy to cross thread and mess up everything. My existing subframe bolts were not friendly to work with. Needed multiple times of soaking the hole and threads of the existing bolt and running it back and forth to clean up threads.

MCA’s install guide says to bolt first to the existing trailer arm location THEN bolt to subframe. I worked backwards. I don’t see what I’d want to create tension on the subframe bolt and increase chances of cross threading. IMO worked out great. And as you can see, still requires more effort to center that hole. Don’t fully secure down the subframe bolt until you have the other trailing arm bolt located, but yeah, you get the picture


















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[autoracer86]

Did you use factory tq settings for the new bolts supplied or does Mca provide new specs ?

[M0nk3y]

Originally Posted by autoracer86

Did you use factory tq settings for the new bolts supplied or does Mca provide new specs ?

New supplied bolt for the subframe is spec’d at 107 ft-lbs by MCA. Then they recommend the other (2) bolts that go in the existing trailing arm and spacer to be torqued to existing OEM Spec (87 ft-lbs). Make sure you torque the bushing while loaded on the ground


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[RToyo86]

Noted with subframe bolt. I usually hit bolts with the drill brush to clean up junk but blasting subframe hole is a good idea.

[gen3v8]

Originally Posted by M0nk3y

.

Have you tried them. I`m curious.

[M0nk3y]

Originally Posted by gen3v8

Have you tried them. I`m curious.

Yup, it's honestly a night and day difference and truthfully I'm amazed I went this long without any sort of trailing arm correction

FWIW, I have MCS 2Way Remotes, 9k/11k, it's not compromised suspension by any means.

I would say the most immediate impact was the elimination of the "pogo" effect off large bumps or dips in the road. The rear just simply feels more in sync with what the front was doing.

First track even April 25th, I made a ton of changes to the car, but I'm sure I'll be able to see what this is doing to help. FWIW I have STi Trailing Arms on the way as well

[Tatsu333]

FYI for anyone with the first generation (or just wondering what the difference is), I emailed MCA to ask for details on the differences and whether there would be any reason to upgrade, and here was their (very prompt) response:

"There is nothing functionally different, just a few minor design improvements. The main one being a rubber bush assembly that allows for some additional movement between the cross-member and the chassis.

Overall, this is a better and more refined product but we wouldn’t say it is critical to upgrade."

[RToyo86]

Fast shipping!
Mine arrived today, they're very generous with their swag too! 8 stickers and a jet tag. Thanks McA!
Now just waiting on trailing arm to install everything together.

[gen3v8]

Ordered mine on Monday and they arrived Thursday. I fitted them today and test drove it briefly with a full tank. All my whiteline bushes made fitting tight. The car still has easy wheelspin power but it doesn`t snap sideways so aggressively now. I`ll be taking it to the mountain twisties tomorrow for a better shakedown.

[RToyo86]

Parts installed, just getting alignment done now

[autoracer86]

Sweet. Keep us updated

[Ohio Enthusiast]

I'll share my experience with the GP Sport mod on my BRZ. Fairly straightforward to install, both the relocating piece and the solid bushing insert in the rear of the subframe. I did one corner at a time and didn't support the subframe. The biggest pain was the parking brake cable bracket, which just didn't want to align with the cutout when tightening the small bolt holding it.

I had the Whiteline rear subframe inserts (KDT922) already installed on the car. Both the relocating piece and the solid insert have the same shape as the bottom Whiteline insert and they fit the same in the subframe bushing. I left the top part of the subframe inserts in place and didn't notice too much of a difference in that regard.

After installation, it looks like the rear lowered by about 5-8 mm. Sadly I didn't measure before and after, and it's estimated by look and older measurements. My best gauge for the lowering is that a speed bump at my kid's school which used to scrape at the rear only rarely, now scrapes all the time unless I take the opposite lane which is lower.

For driving impressions, I didn't have the chance to go on a track or autocross, but I did drive it in anger on some of the roads I'm very familiar with and continued to lightly oversteer on some specific corners in my daily drives.
First, the rear feels more comfortable over bumps and dips, especially sharp ones.
Second, it's harder to break traction in the dry, in a similar way that moving from the OEM Primacy tires to UHP/Max tires was. I need to be very deliberate in most corners to get oversteer that really requires counter steering to correct. Less deliberate application of throttle causes noticeable rotation but no need for counter steering. I.e. still feel the RWD working. When the car does oversteer, it's mostly gentler and less snappy. Accelerating in a straight line, it's also harder to spin the wheels in 1st or get a chirp in the 1st to 2nd upshift.
Finally, in the wet the car has quite an interesting character - instead of wheel hop the rear tires slide more, causing the rear to step out more easily, and it takes more time for the rear to regain traction. This is mostly the case when accelerating in a straight line, where before the mod being aggressive off the line from a red light (with painted lines and worn intersection asphalt) the rear would hop and spin but letting off the gas would regain traction. Now the rear would slip and slide around and letting off the gas needs to be a second or two longer before I can apply throttle again. When turning it's a similar story, with more grip that turns into even more controllable slides.

Overall I'm happy with this mod, if anything just for the sake of the variety in driving experience after 4 years with the BRZ. I'm still undecided if the daily fun-factor was increased or reduced, and I plan on doing a couple of track days and some back road trips to more fully explore the car with the mod.

[Enigmeerkat]

Sorry for the noob question, but I have a Gen 1 with stock suspension except for Whiteline Swaybars. Would this upgrade still be relevant for my setup? Or does it better suit cars with coilovers?

[autoracer86]

Originally Posted by Enigmeerkat

Sorry for the noob question, but I have a Gen 1 with stock suspension except for Whiteline Swaybars. Would this upgrade still be relevant for my setup? Or does it better suit cars with coilovers?

Stock suspension is even better than coilovers for this mod so you’re good to go.

As you can see in the post above some users have noticed a drop in rear ride height after install so you might have a bit of negative rake which is probably a good thing performance wise but you might not like the look of the rear being lower than the front.