C&D comparison of GR86 and BRZ suspensions

[Opie]

Aluminum knuckles are exactly 3.3lbs lighter per side. If any GT86 owner wants a set, I'm selling a set BNIB.

https://www.ft86club.com/forums/showthread.php?t=148513

[Sport-Tech]

Originally Posted by Blighty

When they did the track test was the same as what he essentially said. At the track the two cars behave the same, with the tuning differences seemingly converging when driven at the limit.

Its all opinion though, I'm sure there are a few different opinions out there that suggest that track driving they are different, but perhaps its just not as noticeable as the street stuff.

On the street, TheTopher found in his reviews that the BRZ had noticeably more understeer than the GR86. However he found on the one he personally bought that adding camber bolts at the front to give about 1.1 degree more negative camber dialed most of that out. I wonder if that is something you could trust a dealership service department to do. I also wonder how much that will shorten the life of the tires.

[ZDan]

Originally Posted by Sport-Tech

On the street, TheTopher found in his reviews that the BRZ had noticeably more understeer than the GR86. However he found on the one he personally bought that adding camber bolts at the front to give about 1.1 degree more negative camber dialed most of that out. I wonder if that is something you could trust a dealership service department to do. I also wonder how much that will shorten the life of the tires.

Camber up to -2.5 degrees or more doesn't impact tire life nearly as much as you might think, as long as toe is kept reasonably low. FWIW I'm running -3.5 front -2.7 rear on my daily for street and track.

Dunno if the Pedder's offset top strut mounts fit the '22+, but that's another way to get more front camber, which this car *desperately* needs...

[CSG Mike]

Originally Posted by ZDan

Camber up to -2.5 degrees or more doesn't impact tire life nearly as much as you might think, as long as toe is kept reasonably low. FWIW I'm running -3.5 front -2.7 rear on my daily for street and track.

Dunno if the Pedder's offset top strut mounts fit the '22+, but that's another way to get more front camber, which this car *desperately* needs...

They do fit.

Pedders + camber bolts are a great budget setup!

[mav1178]

Originally Posted by 86-75309

If an aluminum knuckle weighs 8 lbs and is the typical cast aluminum density, then a cast iron part of the same exact volume would weigh 21 lbs, or 13 lbs more than the aluminum one. Iron is typically about 2.67X the density of aluminum.

Originally Posted by mike2100

There is no way the aluminum knuckle saves 13 lbs per side, as said in the video.

Also, it's a little hard to compare ride differences (he says the BRZ is more supple) when one car is on 17" Michelin Primacy and the other is on 18" Michelin Pilot Sport 4.

Originally Posted by mike2100

Engineering to the rescue! Thanks for the scientific explanation. That is a significant weight savings and I'm surprised Toyota didn't want to also incorporate the aluminum knuckle.

Originally Posted by fredzy

The Al knuckles are a lot bulkier, so the weight difference isn't quite so big. User on here measured less than 4 lbs per side, though I saw elsewhere mentions of 6.5lbs which is where the 13 might have come from.

Very late to this but 13lbs total unsprung weight off one axle makes the most sense.

I had Z32 NA rear uprights (aluminum) before on my S13, about 20 years ago. Each side was approx. 7lbs lighter than the cast iron version found on the S13/14/15 rear. This was before the era of CAD and other design variations meant to maximize strength for modern standards.

The difference was night and day running the same wheel/tire/suspension setup before/after.