kwv3 too little spring rate for time attack /w aero, solution???
 

Hey guys! I'm looking for some advice to fix the lack of spring in my '13 FRS that I use for time attack at my local track.

The car has ~ 300 whp, r compound 255 width tires, and full aero (verus race front splitter with end plates, verus rear diffuser and underpanel kit, and 9lives 69" aerofoil). I have the later kwv3s that have the front 40 N/mm and rear 50 N/mm (40-200/50-200) springs. These are 230/285 f/r.

I'm thinking the likes of kwv3 clubsports @ 400/400 would still be too soft for the setup I'm running, is that correct? I would think I'd need something in the 500-550 range, but I figured I would come here for some advice!

Is there anything I can do in terms of having my v3s revalved and have new springs put on or the like?

I want the car to corner more flat. I already have a big front swaybar (whiteline), and I just took the whiteline rear bar off in favor of the oem one. The car was too prone to oversteer with the larger whiteline rear bar.

They can definitely be re-valved, but by the time you have them re-valved and buy higher rate springs it'll probably be cheaper to just buy something else and sell the V3's.


Are you bottoming out under aero load at higher speeds in a straight line, or just concerned about the body roll? Are you bottoming out the loaded side under cornering forces?

IIRC, the KW 2way clubsports are 340/400, not 400 square.


I would go for RCE T2's with the 500lb spring option personally.

When I asked KW about custom valving they said that there was no custom valving available for my V3's. Rebuild to factory spec only. That said, plenty of people run upwards of 500 lbs on the V3's with no problem. They are usually adjusted very low in the adjustment range with the lighter springs and the adjustment range is good enough to handle heavier springs fairly well. Of course you'd likely prefer to have more high speed damping too but you may be fine. Maybe someone else who runs springs like that on the V3 can chime in.

If there's revalves for KW it's a black market or an overly eager customer rep who will likely disappoint you. Or maybe I'm wrong and they're offering the service again.

If you want to keep the budget in check buy the springs and slap them on and go test and tune the setup, the next level of dampers up from where you're at frequently come without springs so you can reuse them if you decide move on from the kw, brands like JRZ and MCS etc. If budget is no concern I'd call up people running in your series and ask for advice and help upgrading and ditch the kws but that's just me.

What tires are you running? 500# would be high but workable for 200tw tires Imho but in the ballpark for the fastest 'streetable' tires, might even be too low if it's true racecar. Tein src are 9k/10k iirc so 500/550 ish off the top of my head.

Depends on how massive your aero setup is, what tire you plan to continue to use, what courses you're running on, and what classing you're planning to be in. You can have the best suspension setup in the world but can be dialed incorrectly if the user is not experienced enough in fine tuning or if the damper spec is built incorrectly. Application is key. :thumbup:

I'm going to try some swift 60mm 7 inch 505 in front/rear springs. Hopefully the dampening can keep up. We will see.

The car was having issues hitting the bumpstops last year without aero. It would also load up quite a bit on one side in corners and in situations where there was an s, or direction change, the suspension movement would approach the point of upsetting the car (it was manageable, but it really felt too soft, both from the side to side lean and the dive on braking/accel).

I haven't tracked the car with the wing and other downforce adders yet, but I wanted to get the springs firmed up before heading out this spring.

The tires are Nitto NT01s, but I may try R7s this season for a bit more grip. 255s square. The car is rarely used on the street and is mainly used for lapping and time attack. No wheel to wheel proper racing though.

Imo, you'll likely still be undersprung given those tires and aero.

You're likely right. This is the compromise to run the same dampers and avoid a full upgrade vs just swapping out springs. It should be much better than the 230/285s though.

May need to further dial this in and eventually move to a different damper.

I was running a similar setup to you last year, except maybe that I think Im producing a tiny bit more front aero than you. The car would ride the bumpstops during braking and very high speed cornering (turn 1-2 at Tremblant for example, which is a flat-out 160-170km/h uphill turn). I was on 6k/8k springs (335/450 lbs) and it was clearly still too little. I upgraded to 12k square (670lbs) because I will be improving the aero even more this year.

I honestly think you would be better off selling your KWs and getting something with custom spring rates. As an exemple, you can probably sell yours for $1500 (easy quick sell at that price) and put forward another $1000 and you could have Fortune Autos 510 with whatever spring rates you want. Its less money probably then revalving your KWs (price of labor + new springs). There's probably a few brands around that can offer you custom spring rates on demand, I used the FA as an example, not the deal breaker kind of thing.

As others have mentioned, you can have the V3s rebuilt but not revalved.

For a car with r-comps and full aero, regular V3s are not ideal if you're competing. You would want to go further than V3 clubsports, too.

Sticking with KW, the 3 way clubsports would be a great choice that can easily support the spring. We have our RCE T3 which is a custom version built by KW (with a warranty unlike the KWs!). They're very good.

The 500s on the V3s will definitely be pushing the valving pretty far beyond what they're designed to handle. But, you won't be bottoming out as much as before...

- Andrew

NT01's are slower than the current best 200tw tires, 500lbs/in (9kg/mm) should be enough for that.


I don't know that he'll get a happy setup that works well on both NT01's and R7's though. That's a pretty big difference in grip levels.