SCCA T4 Race Car Build - Suspension
 

Hi all, someone may already bring this up long time ago, but I did not find specific answer. Hope to get some help here.


I have my 2013 FRS since this March and had some track time in Michigan this summer. Since I raced Spec Miata before and really want to build this FRS to a full race car.


SCCA T4 would be good option. My question is what suspension/spring/damper is allowed in this class. Or what suspension do you use for T4 class? I bought my race ready Spec Miata, so I am new to how to build a car for racing. Any help would be appreciated.


What I found so far on SCCA GCR is:
Eibach 4.10582.880 and SPC 67660 allowed. Front strut tower brace allowed. Raceseng, part # raceseng-ft86-r-shock-top permitted.
Non-OEM limited slip differential allowed with +50 lbs. weight
penalty. 55mm flat plate restrictor required. Only 17” wheels permitted.


Eibach 4.10582.880 is Sportline Springs + Sway bar kits.
Does that mean the only spring upgrades to run T4 class is this Eibach Sportline Springs? We have to use OE damper?


Thanks,
Chen

I am building my FRS into a T4 this off season as well so you're not alone. :D



You're correct on the suspension. You have to use that Eibach kit (Spring/sways) on the FRS - different cars get different options and non adjustable shocks that have a P/N stamped on them.



The popular option are Bilstein B8s but MCS and KW both have made non-adj shocks with OTS P/Ns for the cars they are sponsor (Dynasty FRSs in Florida and Oscar Jackson in California). Oscar uses the KWs.

We just built a toyota 86 into a T-4 scca racecar for the runoffs at Sonoma..

Stay tuned for pictures and we will let you know how it runs and what we used...

Phoenix Built Roll cage

Non adjustable shocks suspension

Fire system

Race Seat

Shroth belts

So the Bilstein B8s are the easy button for shocks without going for something like MCS/KW etc. The question I have is how did you go about incorporating height adjustability?

Reminds me of the T2 days when I was building a BMW for club racing.

The Bilsteins are not off the shelf and you would need get it custom valved for the appliction. The good thing is that based on the spring rates, they can match it for you. Believe mine were digressive. You can get new ones from them and have it revalved or send a used one and have it refreshed/custom valved.

MCS is good too (I use their double adjustables.... point is, their service is excellent)

Lutfy

I had planned on a revalve but still curious what adjustable perches are used to adjust ride height.

If it uses Eibach springs (OEM style) then it should work fine with the current perches on Bilsteins? If not, contact Ground Control and they can get you the custom perches (ride height collar etc).

Lutfy

Joe's car won the 2018 SCCA Runoffs in T4 BTW.

https://www.scca.com/articles/201059...unoffs-victory

PSA: That car is currently for sale. For someone wanting to go T4 racing, it might be cheaper to buy a turnkey competitive car rather than build from scratch.

If it was $25k I'd would have already bought it. I believe you can purchase/build one for under $25k and that's what my math is telling me... But in a couple months I'll be starting a build thread for my car. I think it will be a lot of fun and so far I haven't seen one yet for T4. I think it will be a positive thing to illustrate how easy and affordable it is to turn these into race cars and how affordable T4 racing is.

That would be interesting. I hope you do that. I would definitely follow that thread.