MCA Suspension "Traction Mod"

[gpvecchi]

I'm lowered 32 mm on coils, do you think this mod will be too much?

[Xed32]

Should be fine. Received mine and am waiting to put it on. Stock suspension as well. Their site is updated now with international shipping options. I'm doing OEM+, so this and pedders top mounts+bolts.

[StraightOuttaCanadaEh]

Originally Posted by gpvecchi

I'm lowered 32 mm on coils, do you think this mod will be too much?

Isn't the whiteline roll center/bump steer correction kit more for lowered cars?

[Tatsu333]

Originally Posted by strat61caster

What's the rear alignment like?

I haven't had it checked since the install, but it's not supposed to affect the alignment at all, so presumably I'm still at factory original camber and toe in the rear.

Originally Posted by gpvecchi

I'm lowered 32 mm on coils, do you think this mod will be too much?

From what I understand, you'll see comparatively less benefit from it the lower you are, so if you're that low already, it might not be worthwhile.

Originally Posted by Xed32

Should be fine. Received mine and am waiting to put it on. Stock suspension as well. Their site is updated now with international shipping options. I'm doing OEM+, so this and pedders top mounts+bolts.

I have the Pedders top mounts waiting to be installed as well...

Originally Posted by StraightOuttaCanadaEh

Isn't the whiteline roll center/bump steer correction kit more for lowered cars?

That's for the front, if I'm not mistaken, and serves a completely different function.

[strat61caster]

Originally Posted by Tatsu333

I haven't had it checked since the install, but it's not supposed to affect the alignment at all, so presumably I'm still at factory original camber and toe in the rear.

factory alignment isn't very consistent, stability is greatly affected by rear toe, might be the cheaper solution to your problem then the trailing arm bracket.

[Xed32]

Getting a track alignment was one of the first things I did. The factory alignment was dangerous for my driving style. So much over-steer on off camber corners that some off-ramps terrified me. Thought it was something to do with falkens I had on my '16 brz or damage or something and got that stock aligned 3 times by different shops who told me it was fine. When I got the '20 brz and did more research I found it was that terrible factory alignment. Wen to 0 toe in front, slight toe in at rear, slightly less camber in the back and maxed out the 16mm camber bolts at the front. Car drives wonderfully now. Moving to the top hats and the traction mod are just extra enhancements to get it dialed as this car needs lots of front camber and the angle of the trailing arm is too severe for a true rear wheel sports car ( its an impreza part). Sliding the back out all the time isn't fun to me no matter how Toyota & Subaru describe it.

[Tatsu333]

Originally Posted by strat61caster

factory alignment isn't very consistent, stability is greatly affected by rear toe, might be the cheaper solution to your problem then the trailing arm bracket.

To clarify, I did check rear the alignment previously (when I had the front camber adjusted with camber bolts), and it was consistent side to side for both camber and toe, with slight toe-in (all within factory tolerances).

I haven't had it checked since installing the Traction Mod because it isn't supposed to have any effect on alignment.

Originally Posted by Xed32

...So much over-steer on off camber corners that some off-ramps terrified me. Wen to 0 toe in front, slight toe in at rear, slightly less camber in the back and maxed out the 16mm camber bolts at the front. Car drives wonderfully now. Moving to the top hats and the traction mod are just extra enhancements to get it dialed as this car needs lots of front camber and the angle of the trailing arm is too severe for a true rear wheel sports car ( its an impreza part). Sliding the back out all the time isn't fun to me no matter how Toyota & Subaru describe it.

EXACTLY. For me, neutral balance is the goal, not hooning around with the ass end all over the place all the time. I have basically the same alignment (zero toe front, maxed out 16mm camber bolts), but left the rear as-is since camber isn't adjustable stock, and the toe was OK (slightly in). After that, it was definitely better, but still too snappy mid-corner and over bumps so I was not able to put the power down as early as I would like. The Traction Mod sorted that out for me.

[JohnH]

Originally Posted by Xed32

Getting a track alignment was one of the first things I did. The factory alignment was dangerous for my driving style. So much over-steer on off camber corners that some off-ramps terrified me. Thought it was something to do with falkens I had on my '16 brz or damage or something and got that stock aligned 3 times by different shops who told me it was fine. When I got the '20 brz and did more research I found it was that terrible factory alignment. Wen to 0 toe in front, slight toe in at rear, slightly less camber in the back and maxed out the 16mm camber bolts at the front. Car drives wonderfully now. Moving to the top hats and the traction mod are just extra enhancements to get it dialed as this car needs lots of front camber and the angle of the trailing arm is too severe for a true rear wheel sports car ( its an impreza part). Sliding the back out all the time isn't fun to me no matter how Toyota & Subaru describe it.

Seems like you drive like me. I'm curious as to what your actual camber and toe specs are at the rear? I am able to do my own alignments, so its free, but I am new to rwd sports cars. I can setup other stuff well, and did basically as you speak about, but I don't have actual numbers to go with.

[JohnH]

Originally Posted by Tatsu333

Latest mod installed today - MCA Traction Mod:



Installing on jack stands in my garage was not super fun...LOL.

Also, if you ever do this mod, do yourself a favour and do ONE SIDE AT A TIME. I.E. do EVERYTHING on the one side, then start the other. Trust me.

Haven't had a chance to really push it in the twisties yet (my favourite roads are currently cut off by flooding due to heavy rains over the last few days), but I took it through some of the spots around town where I've had some code brown moments with the back snapping out mid-corner and my first impressions are that it does what it says on the tin - puts the power down much better through corners and particularly bumpy corners.

Before, it felt twitchy and would snap into oversteer when the outside rear loaded up suddenly and the diff would shunt the power to that wheel, but now it's WAY more planted.

Helical diffs on FWD are friggin magic - when the outside wheel loads up, it just shunts torque to that wheel, tucks in and drives the front end around the corner. I installed a Quaife diff in my Tiburon, and it was insane how well it could put power down in corners.

With the BRZ's stock behaviour, I was having my doubts whether the same type of diff made sense in a RWD car. With this mod, I feel like it more progressively loads the outside wheel, making the diff behave better. The car feels like it has more of the balance it should have had from the factory as a proper sports car.

HIGHLY RECOMMENDED MOD, for sure!

with the timing of your post re: roads cut off due to flooding, you must live near me. Hope everything came out ok for you. some had it bad

[Tatsu333]

Originally Posted by JohnH

with the timing of your post re: roads cut off due to flooding, you must live near me. Hope everything came out ok for you. some had it bad

We're in Abbotsford, but thankfully high enough up that we weren't directly affected by the flooding!

[Tatsu333]

Originally Posted by JohnH

Seems like you drive like me. I'm curious as to what your actual camber and toe specs are at the rear? I am able to do my own alignments, so its free, but I am new to rwd sports cars. I can setup other stuff well, and did basically as you speak about, but I don't have actual numbers to go with.

For what it's worth, I was on stock camber (since it's non-adjustable) and as close to zero toe in the rear as the local shop could get it (just slightly toed-in).

I just installed my H&R Sport springs today, so expect that I've gained some negative camber in the rear now, and I think it also dynamically gains some toe when lowered. Will get a new alignment done in a couple of weeks' time, again, aiming for zero toe or just slightly toed in at the rear (in theory, a *tiny* bit of static toe-in should result in zero toe while in motion because the wheels will dynamically toe-out a tiny bit).

I also installed the Pedders caster / camber top mounts and DEFINITELY gained some negative camber there! Will aim to have my front camber about the same as the rear, and again, aiming for zero toe.

Like with the rear, on a RWD car the wheels *should* toe out a bit dynamically vs. the static setting when moving. In this case, I should end up with a net bit of toe out, which should help turn-in.

Some folks like a bit of static toe-in on the front AND rear on a RWD car to make the front end a bit less nervous because it then zeroes-out dynamically. Can also help with tire wear.

This behaviour in the front is the opposite of what happens on a FWD or AWD car, because in those cases the drive through the front wheels will just exaggerate the static toe (I.E. it tries to pull in whichever direction the static toe faces - in or out). EDIT: actually, thinking about it, under power driving straight, the front wheels on a FWD or AWD car will slightly dynamically toe-in because the drive pulls them forward around the steering axis...I think...

The rear behaves the same dynamically on FWD/AWD/RWD - will always tend to slightly toe-out due to drag.

At least, that's my understanding of how it all works!

[Compelica]

Just got it installed.

Initial impressions off the workshop - the rear is much softer and comfortable over rough roads, akin to softening the shocks. It is not as jumpy, or startling as before.

On corners, it feels as if the rear suspension now absorbs more of the body roll. I understand what the others have said when the car is twitchy to oversteer on high speed long corners but I have yet to test if the Traction Mod eliminates that issue.

[jeepmor]

Just ordered a set from the UK. I'm still on stock suspension.

Any comments on how it affects the balance? Does the rear still slip out first when pushing a corner too hard and passing the grip limit? MCA's rep looks pretty good in Aus, and the feedback on here made me pull the trigger.

[PulsarBeeerz]

Originally Posted by jeepmor

Just ordered a set from the UK. I'm still on stock suspension.

Any comments on how it affects the balance? Does the rear still slip out first when pushing a corner too hard and passing the grip limit? MCA's rep looks pretty good in Aus, and the feedback on here made me pull the trigger.

It feels as if you are running a slightly staggered setup. The rear will step out if you really want it to, otherwise it is much more planted on acceleration out of corners. No change in balance entering a corner. Ride is slightly softer overall in the rear as well.