Toyota GR86, 86, FR-S and Subaru BRZ Forum & Owners Community - FT86CLUB

Toyota GR86, 86, FR-S and Subaru BRZ Forum & Owners Community - FT86CLUB (https://www.ft86club.com/forums/index.php)
-   Tracking / Autocross / HPDE / Drifting (https://www.ft86club.com/forums/forumdisplay.php?f=39)
-   -   I :heart: double A-Arms. :) (https://www.ft86club.com/forums/showthread.php?t=68492)

rice_classic 06-21-2014 03:49 AM

I :heart: double A-Arms. :)
 
So I was swapping the front springs on the race car and while I had the shock/spring out but the rest still in place I decided to fire up the camera with my camber gauge attached.

Very cool. Ignore the caster setting on the gauge.. I neither adjust nor measure caster on this car. That setting is OEM.

[ame="http://vimeo.com/98792402"]suspension travel on Vimeo[/ame]

ayau 06-21-2014 07:41 PM

IMO, front double wishbone suspension plays an important role for FWD cars because it's what drives the wheels. If your CRX was RWD and had MacPherson front struts, I wonder if it would still set similar lap times.

rice_classic 06-21-2014 10:41 PM

Quote:

Originally Posted by ayau (Post 1809031)
IMO, front double wishbone suspension plays an important role for FWD cars because it's what drives the wheels. If your CRX was RWD and had MacPherson front struts, I wonder if it would still set similar lap times.

That sentence right there is TRUTH! It's also why I won't buy a modern Honda.

I don't know on the 2nd part because I tend to think I'll be fast regardless of what you put me in. :happyanim:

ayau 06-22-2014 12:31 AM

Quote:

Originally Posted by rice_classic (Post 1809196)
That sentence right there is TRUTH! It's also why I won't buy a modern Honda.

I don't know on the 2nd part because I tend to think I'll be fast regardless of what you put me in. :happyanim:

Similarly, I think that's why Porsche and BMW can produce fast cars because they have multi-link RWD (increase in negative camber under compression).

Makes me wonder what the compression camber rate is on my ITR.

Btw, are you using adjustable upper A-arm to set your negative camber? If so, which brand/model?

fooddude 06-22-2014 03:31 PM

Going from working on many EGs/EFs to an S13 back in the day boggled my mind when I replaced the S13's springs/shocks for the first time. I thought to myself, "hmmm..interesting. Why does this S13 have such an archaic looking suspension? I thought it was going to be awesome, from all the hype about it. Is this what domestic cars(that are known/rumored to not handle well) have too? I think so. I miss my Honda."

neurokinetik 06-23-2014 08:01 AM

Most of the later domestics do, with the exception of the Corvette which has been SLA for a long time. Mustangs have been struts up front since at least the fox body days.

Too bad we got the McSuspension on this car. I miss my Miata.

DarkSunrise 06-23-2014 08:59 AM

Quote:

Originally Posted by ayau (Post 1809332)
Similarly, I think that's why Porsche and BMW can produce fast cars because they have multi-link RWD (increase in negative camber under compression).

The Porsche Cayman actually has macpherson struts at the front AND rear.

But I agree with your overall point. BMW and Porsche have proven through racing that you can be fast in a RWD car with macpherson struts at the front (and loads of static negative camber to compensate).

DarkSunrise 06-23-2014 09:22 AM

Haha isn't that just splitting hairs at that point?

Porsche refers to them as macpherson struts btw:

Quote:

Rear Suspension: Wheels independently guided on transverse control arms with longitudinal control arms, tie rods and suspension struts (McPherson type, optimized to Porsche requirements); cylindrical coil springs with internal dampers; anti-roll bar

http://press.porsche.com/vehicles/20...ifications.pdf

EDIT: That's odd, the post I replied to (saying they were chapman struts at the rear) disappeared.

rice_classic 06-23-2014 02:36 PM

Quote:

Originally Posted by ayau (Post 1809332)
Similarly, I think that's why Porsche and BMW can produce fast cars because they have multi-link RWD (increase in negative camber under compression).

Makes me wonder what the compression camber rate is on my ITR.

Btw, are you using adjustable upper A-arm to set your negative camber? If so, which brand/model?

With the right design a Mac setup can have a dynamic curve. Transversely, a double arm suspension (of equal length arms) can have no dynamic curve.

The dynamic camber curve of a double arms isn't inherent to the fact there's 2 arms but to fact that they are of unequal length.

On a Mac setup, if the angle of mounting to the body is very steep then a mac setup will have a dynamic camber curve. Not highly aggressive like that of a CRX but a dynamic curve nonethless. However, on the vast majority of road-going cars, the macs are mounting quite upright as the design restriction of a chassis doesn't allow a steep angle.

Last time I looked at the rear of a Cayman, the angle looked pretty steep... Same with the Alfa 4C but I don't know what kind of curve is represented through the motion with their specific geometries.

In the video I was baselining 4degrees because my car was in the air and on my slightly uneven garage floor. On a flat pavement with my car on he ground I run ~3 degrees up front. I would like about 3.5 or 3.75 but I can't achieve that legally because of ITA rules.

I use OFFSET bushings in my anchor bolts (what my OEM UCA uses to mount to the body)

markw 06-24-2014 04:12 AM

Honda screwed it up in 2001 when they went to struts up front. Love my EF. :)


All times are GMT -4. The time now is 11:42 PM.

Powered by vBulletin® Version 3.8.11
Copyright ©2000 - 2026, vBulletin Solutions Inc.
User Alert System provided by Advanced User Tagging v3.3.0 (Lite) - vBulletin Mods & Addons Copyright © 2026 DragonByte Technologies Ltd.


Garage vBulletin Plugins by Drive Thru Online, Inc.