Suspension Modifications for running non-staggered
 

Hey guys, I am planning to be replacing my hubs and bearings to freshen things up, and am also planning to switch to non-staggered. So far, I have purchased J's S1 front camber joints, and plan to get a Whiteline front sway.

My questions would be:

1) Do the front bumpsteer kits (spacers) help? I noticed RobRob's site shows installation. These are a relatively inexpensive mod.

2) What about rear bumpsteer?

I thought I also saw something on Rob's site about installation of Megan Racing rear toe arms. Are those beneficial, or does anyone else have those? Do they help prevent bumpsteer, or just allow greater toe adjustments? They are also relatively inexpensive.

Does anyone use rear RCAs? Do these correct bumpsteer? I noticed what Spoon calls their "Zero Bumpsteer Kit Rear" looks the same as Js rear RCA.

Spoon
http://www.gtmotoring.com/images/s2k...rear-large.jpg

Js
http://www.gotuning.com/images/produ...0.thumb_medium

3) Do any of you guys disconnect or remove the rear sway when running non-staggered (track, not autocross)?

4) Are there any other modifications/parts I should consider?

The reason I ask is because I would like to just get everything done at one time, and purchase and install parts before it warms up. Pardon my ignorance with some of these. Thanks! :tipwink:

Rear RCAs should not be done without also doing the fronts. It adds the same effect as a stiffer rear sway bar which you aren't going to want with non-staggered. I suppose disconnecting the rear sway might negate things but I'd rather have some little bit of sway bar. I personally wouldn't run rears without fronts.

I'd consider putting slightly stiffer springs up front on the KWs too along with a bigger front sway bar.

Everything will feel fine on the street with the rear stiffened up but on the track/autocross the rear is going to be really happy and you'll end up being slower.

When I first ran non-staggered, I ran a cusco 32mm front sway, no rear sway, and square spring rates on the KWV3s I had. No roll center adjusters, just a good alignment. At that time for my skill level on track, the car was perfect. I tracked it that way for a whole season and never had an issue with it until I added a rear wing. The combination of the wing paired with a big front bar and no rear bar was just understeer central.

I was able to modify my driving for the rest of the day to still have fun, but that was the last track day of the season.

Personally, I'm not a believer in RCA adjusters, but I've always been a run what you brung type of guy. I've always felt my driving can make up for any suspension geometry "issues", so I cannot be an accurate gauge of anything of that kind for you. There are many members here that have used them and can provide you with their feedback though.

^I think there are tons of examples of incredibly fast guys none of which run RCAs. I also agree it's not an absolutely necessary mod. One of the only benefits to them is they will increase bump travel which can be significant.

They are also not an allowable mod for a lot of classes and for classes that do allow them most guys will use their points or money elsewhere.

The lower front camber joints I got came with RCA. I don't notice a difference with or without. I did notice a huge difference with the camber joints

Cool, thanks guys. So it seems a good sway bar and front camber joints should be ok. But in terms of fast cars that use RCAs, I notice that the A&J Racing S2000 a few years ago that set a track record uses them, and so does the Evasive Time Attack car. MaxRev also gave a favorable review of them.

It's not that they aren't a good part it's just that usually the money can be better spent elsewhere. You certainly won't lose performance with them.

It really depends on what you're doing as far as if you're building your car to a certain rule set, points, and/or your other suspension modifications.

There are certain classes that don't allow them for SCCA Auto-X or assign points to them for NASA TT and so on. If this is not the case, then they're beneficial, especially if you plan to lower the car by quite a bit.

Maxrev is using them at all four corners with the Evasive Spec Eibach R2 coilovers, it's extremely beneficial for this shock, especially in the rear since the shocks retain OEM length and lowering the car reduces bump/compression travel length such that you'll more easily contact the bump stops. This is why people spend extra money to have their JRZs and Motons shortened; however, with the RCAs, you can correct the suspension geometry from lowering and return/increase your available bump/compression travel length without having to shorten the shock. That's the main reason to run RCAs, especially if you're planning on lowering the car more than 1".

Your priorities may differ depending on your intended use and if your building the car to a specific class (you'll need to read the rule set).

At least this is my understanding of it.

The RCA's are cool if you're looking for that extra bit of travel. If you do install RCA's, be sure that you take your car to an alignment shop that can measure dynamic toe/aka as bump steer. Also its a good idea to have solid toe links and solid front tie rods so that you can tune out whatever bump steer you make have added by changing the RC.

Thanks for the reply. You do bring up a valid concern, however, I am still a relative rookie to the track + the fact the chassis and drivetrain already have 90+K miles, so by the time I get skilled enough to compete it might be time for a new chassis anyway. I am just looking to build a fun and functional HPDE car with which I can progress with. I do have KW V3s on there right now.

Interesting, I will have to look into that.

So you mean something like these? http://www.evasivemotorsports.com/mm...Code=EVS-AP-TR

And these? http://www.jhpusa.com/store/pc/viewP...idproduct=8626