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Originally Posted by Xed32
'22 BRZ Question. I see most persons using the Gen1 rear LCA and coilovers. We know the '22 RLCA is around 0.5" different: https://www.ft86club.com/forums/show...54#post3495854
How does that affect the motion ratio? Additionally, the track between Gen 1 and 2 is different (staggered)? It appears most suspension offerings for Gen2 are the Gen1 parts and spring rates. Should this matter?
Additionally, the MCA traction mod ( best mod i've ever put on a car) really tames the rear end step-out and adds comfort. It does not affect alignment, but does changing the anti-squat characteristics affect motion ration at all? I do feel like I can get away with much higher rear spring rates now that the rear end is predictable. I am currently on stock suspension but am looking for performance oriented suspension parts for track and auto-X and most of what I find is looks oriented. |
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Originally Posted by _____That_-_GUY_____
I'm curious about the 1st gen LCA too. I think I'll wait until all this stuff gets ironed out before doing any suspension mods.
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I wrote up this little discussion of the 1st vs 2nd gen differences:
https://www.racecompengineering.com/...ension-changes
Rear motion ratio is a tiny bit higher with the 2nd gen. The example I gave in the article is that a 300 lbs/in rear spring would be about 10 lbs/in stiffer in wheel rate on 2nd gen compared to 1st gen. Not huge, but it's there. Then there's the slightly increased track width in the rear that works against that.
One thing that's interesting is that most 1st gen adjustable rear LCAs actually already have the 2nd gen geometry. This is because the 2nd gen BRZ rear LCAs are the same part number as they are Subaru VA chassis (2015-2021 WRX and STI) and many aftermarket companies have been using the same LCAs for both 1st gen BRZ, VA chassis, and a whole bunch of other Subarus (for better or worse). The act of adjusting the LCAs changes the motion ratio a tiny bit anyway. For me it's not a large concern. I do not expect anyone to make an adjustable 2nd gen specific rear lower control arm, but I'm not in the rear lower control arm business.
The MCA traction mod should not affect motion ratio as far as I'm aware.
- Andrew