CSG and RCE tag-team suspension Q&A thread! Ask us anything!

[meeks]

Originally Posted by Racecomp Engineering

Thanks!

And thanks for making me really uncomfortable.

- Andy

Originally Posted by CSG Mike

This goes so well with your avatar...

what can i say? i am a sucker for good suspension porn. haha

in all seriousness, i would like to hear your opinions about mixing and matching springs on konis or the up and coming rce bilsteins.

the reason being is that i would like to see the front a little lower than the back without going the coilover route. i.e. rce gray springs in the front (tarmac? correct me if i am wrong) and rce yellows in the back (maybe a custom spring rate on that to retain balance and match the front spring rate the rce grays have).

budget wise, i do not know how much more or less it would cost (so please, put away your pitchforks and torches, it is a legit question) but i have yet to see somebody do custom spring swaps like a bunch of my friends that have ae86s that do a lot of auto-x/trackdays. they do mix and matches with springs on fixed after-market dampers and as far as i can see, they are pretty effective on that platform. competitive and effective, yet it achieves the look that i am aiming for.


this thread is like brazzers.com in full hd for suspension nuts. thanks again!

[supramkivtt2jz]

Originally Posted by CSG Mike

Springs of your choice, a less expensive set of rims in 17x9, and 235/40/17 tires.

The wheel/tire setup will naturally drop your car without altering suspension geometry, and the springs will slightly drop the car without compromising suspension geometry and ride comfort too much.

two questions:

1) Im not sure I follow the "naturally drop" part. most 235/40/17's are only 0.2-0.5 inches smaller in diameter than the stock 215/45/17

2) does lowering the vehicle beyond 1 inch not alter the geometry with springs? I was under the impression ~0.5 inches lower was where the suspension was designed to operate. source:http://www.ft86club.com/forums/showp...5&postcount=11

[Chee-Hu]

Originally Posted by CSG Mike

Springs of your choice, a less expensive set of rims in 17x9, and 235/40/17 tires.

The wheel/tire setup will naturally drop your car without altering suspension geometry, and the springs will slightly drop the car without compromising suspension geometry and ride comfort too much.

Thanks for the quick response, Mike. That was the route I was heading. Would you suggest upgrading the shocks in the future, or will the stock suffice? In addition, I've read/heard myths about stock shocks with lowering springs. Is it detrimental to the shocks, or is the myth/rumor false? Thanks in advance.

[mike the snake]

I'm lowered 1.5" with ST coilovers (same as KW V1) and I'm looking at getting some aftermarket rear lower control arms.

Some, like the Stance ones, are shaped so they in effect raise the hub, and in reading about them, they say this is good for coilovers like the KW's which adjust height by spring preload.

So, I'm gathering the Stance LCA's offer more droop?

Are they a good match for my ST coilovers?

[CSG Mike]

Originally Posted by supramkivtt2jz

two questions:

1) Im not sure I follow the "naturally drop" part. most 235/40/17's are only 0.2-0.5 inches smaller in diameter than the stock 215/45/17

2) does lowering the vehicle beyond 1 inch not alter the geometry with springs? I was under the impression ~0.5 inches lower was where the suspension was designed to operate. source:http://www.ft86club.com/forums/showp...5&postcount=11

The smaller diameter of the 235, combined with the slight stretch (but still in spec) of the tires being on 17x9 will result in a noticeably lower car. It's enough to make the difference between being easy to drive around town vs scraping everywhere (compared to 225/45/17 on 17x8) on our shop car.

Any lowering alters geometry. The question is, how far are you willing to compromise it? IMO, it was designed to operate at stock height. Any drop is a compromise unless you correct/compensate for the drop.

[CSG Mike]

Originally Posted by Chee-Hu

Thanks for the quick response, Mike. That was the route I was heading. Would you suggest upgrading the shocks in the future, or will the stock suffice? In addition, I've read/heard myths about stock shocks with lowering springs. Is it detrimental to the shocks, or is the myth/rumor false? Thanks in advance.

Try the drop first, and see if you feel like handling is a limitation. If it is, then at that point, explore coilover options.

It's detrimental in that it becomes easier to bottom out and damage the shock. As long as the drop isn't too severe, you should be okay as long as you're careful. You're also slightly out of the optimal range of the shocks, but again, its a small compromise for the drop, especially when you're trying to do it for cheal.

[CSG Mike]

Originally Posted by mike the snake

I'm lowered 1.5" with ST coilovers (same as KW V1) and I'm looking at getting some aftermarket rear lower control arms.

Some, like the Stance ones, are shaped so they in effect raise the hub, and in reading about them, they say this is good for coilovers like the KW's which adjust height by spring preload.

So, I'm gathering the Stance LCA's offer more droop?

Are they a good match for my ST coilovers?

The Stance LCAs let you lower the car more while preserving stroke on the damper. Basically, they're for cars that are slammed (stanced).

[BRZ NA]

So what's the Max lowering ride height for tarmac 2 without effecting the original handling? or best ride height for tarmac 2 ?I want to lowered the car about 2"from stock height, is there anything I need to replace? thx

[BRZ NA]

Oh and w about -2to -3 camber front and -1.5 to -2 at the rear

[kanundrum]

I am sure this will benefit everyone But list your Ideal Track Setup along with alignment specs using the following supplies. Then List your Ideal AutoX Setup if it differs.

Coil Overs: RCE 0 or Tarmac 2's (Along with KW V3 and Club Sport Equivalents)
LCAs: Choose your Flavor
Other Suspension Components to adjust geometry:
Alignment : Free Range List specs

[CSG Mike]

Originally Posted by kanundrum

I am sure this will benefit everyone But list your Ideal Track Setup along with alignment specs using the following supplies. Then List your Ideal AutoX Setup if it differs.

Coil Overs: RCE 0 or Tarmac 2's (Along with KW V3 and Club Sport Equivalents)
LCAs: Choose your Flavor
Other Suspension Components to adjust geometry:
Alignment : Free Range List specs

Track:

Coilovers: CSG-Spec Tein SRC
LCAs: none
Other suspension components: none
Alignment:

Front
-3 camber
0 toe

Rear
-2.4 camber (natural from ride height drop of -1.4")
0 toe

[Dimman]

Originally Posted by ft_sjo

@Racecomp Engineering @CSG Mike


So I heard someone mention somewhere on this forum the other day about the 'British Approach' (or similar) on springs and anti-roll bars. The statement was around soft sprung damper/spring package and controlling balance with a/r bars.

This is the approach which I have been taught by my mentor (ex-WRC engineer). Our roads here are as you may suspect, very variable. The best roads in England tend to be quite challenging to suspension and overly-stiff tends to perform poorly. I consider the OE damper/spring package on the GT86 pretty good for our 'b roads' (country lanes). Car changes direction quickly, gives reasonable ride quality, not 'crashy' and gives a nice cushion for those rare times I get air.

My car has stock suspension apart from a 16mm rear bar. I found an 18mm bar upset the balance and made it less predictable. Front bar is stock as I don't consider the car has excessive roll. I'm also running AD08 tyres.


So i'm curious what your guys views would be on this style of chassis tuning, versus what I think is your preferred method of stiffer spring and less a/r bar (or even none).

Thanks.

The 'British Approach' is more about picking your springs for a specific frequency ratio front to back. Rear frequency ~10% higher than front.

How high the frequency is would be selected based on tires, track quality and downforce.

The soft spring/hard bar was an older road racing approach, probably having to do with putting power down through shitty tires and on crappier surfaces. But that also sounds like a modern street use scenario.

[solidONE]

What about these guys?



The digressive valving looks pretty decent with really broad range of adjustment, though not quite sure how digressive rebound damping is beneficial to performance. I'm used to seeing just digressive comp damping in some premium grade dampers (penske ohlins). I think AST are going double digress ive with their new 4150 line as well. Fortune seems to offer different valving to match whatever spring rate you order. This is much better than a lot of other brands who only offer the same damping curves for different spring rates. Seems like the components they use to build their dampers are really good quality as well.

What do you guys think?

[ayau]

Originally Posted by Racecomp Engineering

It depends on a lot of factors. You can minimize the effect of overlowering the car by running tons of spring rate and a lot of camber. In general you want to run "just enough" spring rate. Same for camber. However the benefits of a low COG may (and often do) outweigh the negatives from a performance standpoint. Maybe not from a ride standpoint though.

You do start to lose camber in roll when you're too low (i.e. more roll than negative camber gained). CSG brought up the roll center point as well. Both are very long topics.

The rear of the car toes in under compression.

- Andy

Mike said the rear toes out under compression. Which one is it?

What about the front?