Hi, folks. Most of the regulars know that I've been fairly happy with my setup - factory Bilstein suspension, Whiteline F/R anti-swaybars, GTSpec trunk cage. The car is killer at 8/10. At 9.5/10 there are some issues. Namely, understeer. Understeer on entry, understeer mid-corner, understeer on exit. This is most noticeable on sweepers.

This being said, 99% of my driving is on the street where the car sees 8/10 each and every time it hits the pavement. It feels great. No complaints. The hint of understeer offers a nice margin of safety. While I would like to improve the car's on-track behavior, my primary goal is daily fun. That's it. It's the only thing I care about - ie. how much fun am I having driving the car. Again, those who hang out here know where I stand on most issues, so there's no need to repeat it.

I'm debating between a set of GTWorx springs with a RCK, or a locking rear diff. Which option would you suggest for my needs? Maybe nothing. That's an option, too. What do you think?

 

Well, GTWorx springs are the cheaper route. BUT, I don't know of anyone that has done the diff upgrade on your setup. I would be very interested in your feedback if you did it with the current mods.

Honestly, for your use and wants, I would go diff first. If that does not put a grin on your face with RWD like characteristics, then change the spring rates to decrease the understeer.

 

I have solid tops on my rear struts, I think they are called pillowball mounts made by tein.
On the track my car feels great very little understeer unless I screw something up
With AX the car rotates great for the most part. (depending on traction, air pressure)
I think I am usually the cause of my understeer, when I get things right or let an instructor drive my car I always get good feedback on how my car handles.

So anyway it might be worth a try before sending out your diff

BTW im on bilsteins, gtworx springs, with tein camber plates and the rear mounts. Everything else is stock suspension wise.

 

I'd also try the rear diff first. Maybe not the full 12plate since you're not on hoosiers, the 8 plate should work perfect and is $100 cheaper. Then just really cement the idea of slow in fast out. That will reduce understeer and give you throttle oversteer coming out.

Ill also throw in that the GTworx springs are amazing. Not to low and about perfect stiffness for a DD. This is what the car should have come with in the first place IMO.

 

I would start with an upgraded rear diff, that has made the biggest difference in my car's setup - both with stock springs and now with Swift Spec-R springs.

I would also look into replacing the rear trailing arm bushings with poly bushings and add a WL rear bumpsteer correction kit. I did both of these prior to the rear diff, and it did help braking stability and helped cure a _small_ amount of understeer - not nearly as effective as the rear diff, though.

l8r)

 

I have been wondering about this as well, I DD and hate the understeer. Thanks for the thread. Would love to hear more feedback.

From what I have read, the rear dif is the way to go. This is just from reading though so take it for what its worth.

 

Along with the rear diff, I'd replace the Hotchkis springs as well. Those can't be helping your understeering issues.

l8r)

 

I really appreciate the thoughtful comments, guys. Thank you.

 

Yeha they were on there when I bought the car. There on the mod list haha, would really like a half decent set of coilover.Im thinking a rear swaybar would really help out, so thats propably my next purchase.

Thanks for the advice. sorry to thread jack.

 

Look up my hotchkis vs gtworx springs. My car came with the Hotchkis kit also and the end result is its downright awful. I couldnt get anything other than understeer with them. With GTworx I do have understeer at the limit but that limit is significantly higher, and with a slow in - fast out driving style I can get a little throttle oversteer.

 

For you usage, I would agree that a better spring would be very helpful. THe advice on the GT Worx srpings are dead on. I've riden in a few cars with them, and the handling and ride quality is very nice. The pillows also help. At least ge tthe fronts for more camber adjustment!

 

springs are gonna help with boat like swaying the stock springs have. The rear diff will help with mid corner and corner exit understeer. Since you already have whiteline swaybars fr and rear I assume you have some of that swaying under control.

My .02 is to go for the rear diff upgrade. TRE and Shep both offer a great service. On another wise stock setup, I installed a set of Robispec springs and found that the floaty feeling during slaloms was greatly reduced along with better steering input. The TRE rear diff though made mid corner and exit understeer almost non existent.

 

I would go with the diff first like all said above. Not sure what your plan is but springs realistically don't help THAT much. Although your stock springs are most of the problem. I went from stock Bilsteins and Swifts to custom Ohlins and it was like driving a different type of car. Albeit a lot of money to spend but I believe it's worth it if you have any desire to track the car. Even the swifts left alot to be desired at the track and I could never totally tune out the understeer with swaybars, tire pressures, etc.