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

[Calum]

Originally Posted by wparsons

Question mostly for Andy or Myles, but I'd love to hear from anyone that may have tested this.

What's the effective stock front spring rate when you factor in the bump stop in a typical corner?

The bump stops are designed to be progressive, to help prevent jarring... not that it works perfectly, but I'm sure it's better than if they were designed otherwise.

[wparsons]

I realize that, but the question is about the typical amount of spring rate they add in a typical corner.

I'm trying to guesstimate what the effective spring rate is when the bump stop is taken into account to see what the actual f/r spring rate balance is stock.

[CSG Mike]

Originally Posted by fooddude

Can you please give me a quick (but detailed if possible) overview and summary b/n the differences of V3 vs. RCE Tarmac II's ..(ie: spring rates, valving for use with?, which is better for motorsports, which is better for road/street, etc., etc).

Seeing how they are the same price and same manufacturer, I would love to know the difference. (or, links..if it's been already discussed).

Also, I would like to know other people's preference of the V3/TarmacII coilovers vs. other coilovers in the same price range (which do you think/like more? the V3/TII or the others?). think I read before (when I was researching MonoFlex) that CSG (or some other people?), prefer the V3 over the MonoFlex.

I am getting a bit interested in the V3 and RCE coilovers.. as I am finding out that many competitive racers and highly built 86's are using them (griffen trd, evasive, etc.). I want to know if the are specifically using KW/RCE because they are fantastic, or maybe if it's just because of sponsorship hoopkups.

A list of which famous brz/frs racecars using KW/RCE coilovers would be welcome too


In short:
I want to hear the differences between the V3 vs Tarmac II. And also I want to hear your personal opinions of deciding between the V3/TII's vs. the others I am interested in that are in the same price ($2k'ish). Specifically, vs. the - MonoFlex and Ground Control kit

I prefer 2 way adjustable dampers for their flexibility in changing spring rates, and fine tuning the damping.

For most people, the Monoflex is a great deal because it already includes camber plates, and is valved specific to the rates it comes with. It doesn't offer flexibility to change rates, but it also makes adjusting the damping one dimensional, instead of two.

The KW/RCE is a twin tube, and the Monoflex is a Monotube. I generally prefer monotubes, so it's unusual for me to recommend a twin tube over a mono tube.

You'll need to decide for yourself which is more suited to your needs. The Monoflex is a great value for the price, but offers less flexibility. If you're not going to be playing with adjustments much, you may be better off with the Monoflex.

[fooddude]

Thanks Mike. Yes, that makes perfect sense. The T2's sound fantastic..but like you said, with adding upper mounts it will be much more expensive..making the MonoFlexes attractive pricewise.

Now..how about T2 vs a GC kit setup? GC kit is pretty affordable, offers custom rates, and also comes with quality upper mounts...just unsure if their koni's are up to par with T2's valvings and MonoFlex's valvings though (most likely they aren't, from what I am reading the Koni's aren't as firm/aggressive for motorsports...unless GC custom valves their Konis in their kits per spring rate request and kit ordered ..which I doubt at their same/retail/base price).

[Captain Snooze]

I asked this question here http://www.ft86club.com/forums/showthread.php?t=56678 but I think it is going to get buried.
The motion ratio at the rear is approximately 0.75. I ran the calculation for spring rate "at the wheel" as 0.75 x spring rate but ZDan did the calculation as motion ratio squared x spring rate. Could you please explain why squaring is used?
Thanks.

[Malt]

Originally Posted by normancw

I received my parts from CSG. Thanks to @Racecomp Engineering and @CSG Mike for this great thread and help on selecting components. I can't wait to get them installed and try it on the track.

RCE Tarmac 2




SPL Lower Control Arms


AP Sprint Kit with Ferodo pads and Torque RT700 fluid




Raceseng CasCam plates (sorry Mike, I didn't get plates from CSG - these were just too sexy )

Nice choices! Those bbk's are making me jealous.

[ZDan]

Here's my attempt to physically explain why you have to square the motion ratio to get the wheel rate from the spring rate:

Say you have a simple control arm, inboard end pivots at the unibody, and the wheel/tire is mounted to the outboard end.
Say you are able to vertically mount a 100 lb/in spring all the way out at the wheel/tire end. Motion ratio = 1. Apply a 100 lb. vertical force at the wheel/tire. Resultant vertical deflection is 100 lb./(100 lb/in) = 1 in. Wheel rate is the same as the spring rate, 100 lb/in.

Remove that spring and place a spring vertically at the point halfway between the control arm pivot and the wheel/tire end. Motion ratio is now 0.5.
What spring rate is required to give the same 100 lb/in wheel rate?
If you just double the spring rate to 200 lb/in, here's what happens:
Apply 100 lb. at the wheel/tire. To resist this, the spring has to apply 200 lb. at the midpoint because it has 1/2 the leverage. To resist with 200 lb, the 200 lb/in spring must deflect 1 in. If the deflection is 1" at the spring, which is only halfway along the control arm, then the deflection at the wheel/tire is 2". So the wheel rate is now 50 lb/in, not 100 lb/in
You need a 400 lb/in spring to achieve the same 100 lb/in wheel rate as before.
400 lb/in * (0.5)^2 = 400 lb/in * 0.25 = 100 lb/in, the correct wheel rate.

Basically, with 1/2 the motion ratio, you have to double the spring rate TWICE.
Once to get 2x the force (needed because of reduced leverage).
And again to account for having to apply this greater force with only HALF the spring deflection (so that the deflection at the wheel is the same and not 2x).

OK, that was kind of wordy but hopefully makes the point...

Originally Posted by Captain Snooze

I asked this question here http://www.ft86club.com/forums/showthread.php?t=56678 but I think it is going to get buried.
The motion ratio at the rear is approximately 0.75. I ran the calculation for spring rate "at the wheel" as 0.75 x spring rate but ZDan did the calculation as motion ratio squared x spring rate. Could you please explain why squaring is used?
Thanks.

[CSG Mike]

Originally Posted by fooddude

Thanks Mike. Yes, that makes perfect sense. The T2's sound fantastic..but like you said, with adding upper mounts it will be much more expensive..making the MonoFlexes attractive pricewise.

Now..how about T2 vs a GC kit setup? GC kit is pretty affordable, offers custom rates, and also comes with quality upper mounts...just unsure if their koni's are up to par with T2's valvings and MonoFlex's valvings though (most likely they aren't, from what I am reading the Koni's aren't as firm/aggressive for motorsports...unless GC custom valves their Konis in their kits per spring rate request and kit ordered ..which I doubt at their same/retail/base price).

I'd lean toward the T2 or Monoflex.

[fooddude]

I think the T0 would prolly be a better comparison vs the GC kit ..as both of these are fixed valving...but then, the GC kit would have the upper mounts included... so, it would come down to which has firmer or better valving for higher rates... which I would guess the T0 too would be the better choice over the GC kit again.

[FR-S Matt]

Thinking of going to the KW V3's over the T0's for a softer street ride. I don't see the track, and if anything a few HPDE's here and there. The T0's seem firmer, but I've heard from others the V3's are one of the most comfortable street coilovers out there with lots of flexibility.

[Malt]

This could just be me but the fact that the T2's didn't come with mounts was a plus because it allowed me to get the ones I wanted instead of wasting money with the typically crappy mounts that come prepackaged. Of course not everyone is willing to spend close to a $1000 on raceseng front and rear mounts.

[wparsons]

Originally Posted by FR-S Matt

Thinking of going to the KW V3's over the T0's for a softer street ride. I don't see the track, and if anything a few HPDE's here and there. The T0's seem firmer, but I've heard from others the V3's are one of the most comfortable street coilovers out there with lots of flexibility.

If you want more comfy than the T0's, look at the V1's. The T0's are V1's with stiffer springs and valved to match, the TII's are V3's with stiffer springs and valved to match.

Unless you need all the adjustability, the V1's will be a great option.

[FR-S Matt]

Originally Posted by wparsons

If you want more comfy than the T0's, look at the V1's. The T0's are V1's with stiffer springs and valved to match, the TII's are V3's with stiffer springs and valved to match.

Unless you need all the adjustability, the V1's will be a great option.

Yeah, I don't need all the adjustability of the V3's. Are they awesome? Yes. I'm more of the set the height, forget it, and drive type. There are things I do like about the Tarmac 0's on the road though. It does feel like a more sport-like suspension over bumps and feels great around corners.

[Racecomp Engineering]

Originally Posted by FR-S Matt

Yeah, I don't need all the adjustability of the V3's. Are they awesome? Yes. I'm more of the set the height, forget it, and drive type. There are things I do like about the Tarmac 0's on the road though. It does feel like a more sport-like suspension over bumps and feels great around corners.

Raising your car, even just a little bit, might be all you need.

- Andy