I currently have an H-sport Competition rear sway bar. I am going to go back to the JCW 18.5mm rear swaybar. I have to go back to get 100% legal for autocross because I did not and am not installing the JCW front swaybar.

First: Would I be able to get the same net affect of the stiff rear swaybar by going to a stiffer setting on Koni sport shocks but with the smaller stock bar?

Second: Are the Koni Sport shocks a significant improvement over the JCW shocks to justify the time and expense of swapping them out? My JCW is only used for fun driving and autocross.


My other option is to put the JCW front swaybar on and keep the H-sport competition rear swaybar but I have heard the stiff front swaybar reduces traction out of turns, is that true?

 

I'm a little confused by your posting.

Which set of autocross rules are you worrying about? If its the SCCA Stock/Street class (most common), you're allowed to change one bar. So what's the problem?

Its not clear what suspension your JCW originally had. There's the choice of standard, factory sport and JCW (dealer installed, red springs). The 18.5mm rear bar is the factory sport option.

The theory is that softer suspension allows the tires to grip more (but you get body roll with softer suspension). The relative stiffness of the front and rear sway bars transfers grip back to front (or front to back). A stiffer bar transfers grip to the other end. So a softer bar will transfer grip to that end.

I don't know about the shocks.

 

Sorry, this is for SCCA street class. I installed JCW springs and shocks last year. I have the standard front swaybar and an hsport rear swaybar. So right now I am not legal because both bars are different from the JCW suspension. If I put the JCW front bar in I could keep the hsport as my changed bar and be legal.

If I want to keep the h sport then I would have to install the JCW front bar and the rear bar would be my changed bar. Or I have to put the JCW rear bar on and the front standard bar, making the front the changed bar.

Does that make sense? Also, I am pretty sure I measured the swaybar that came with my JCW kit and it was 18.5mm, I'll double check.

 

I think it all really depends on how far you want to go with everything... unless you have someone nationally competitive in DS in your region, the stock JCW should be more than enough to make it a driver's race. If you're aiming for nats, then IDK. I've moved away from Konis to looking at a better valved setup. Optimal valving is always going to be (close to) optimal valving no matter what, without any need to adjust. I'll probably be going the Bilstein route myself - whether or not I'll have them custom valved from the start is my bigger ?

I think as far as sway bars go, if the balance of stock/sport FSB & JCW RSB gives you the rotation you want, it should be "good enough." I think for a fast setup, the car should be pretty loose. JCW FSB & HSport RSB should be quicker since you are essentially getting higher spring rates on both ends, and allow adjustability.

http://farnorthracing.com/autocross_secrets10.html

 

I should have checked my notes before responding. The rear sport bar is 18mm (so the JCW may be 18.5). The difference is pretty tiny so I confused myself, it's only about 12% stiffer.

The common setup is to go with a much stiffer rear bar to balance the car towards oversteer (ie shift the grip to the front). I'd be surprised if the standard front and JCW rear bar would allow for that much change in balance, you'd also get a lot more body roll, which is also in theory a bad thing.

If it we me I'd be keeping the rear bar and changing the front to the JCW. That's similar to the setup Im planning. The only drawback to that is that changing the front bar is supposed to be a much more difficult than changing the rear. So putting the JCW in the back would be the easy solution (but probably not the best solution.)

 

I like the best solution but after looking at the writeups its not a job that I want to get into my self. It looks like a lot of stuff to remove and disconnect to get to the front swaybar. Possibly I can somehow plan on making a trip to Atlanta for Way to do this install.

Do you think any import shop would be competent enough to do this install? There is a local shop that works on BMW, AUDI, porsche and MINI. However I am sure this is not something they have done a lot of.

I guess I could bite the bullet and have the dealer do it. Its only money...

 

Stiffening the rear shocks will not have the same exact effect as stiffer rear swaybar.

Shock adjustments are felt more in transitions for example.

Ideally I'd keep your aftermarket rear bar and go with the JCW front, but the install is a pain in the ***.

- andy

 

FWIW, I'm strongly considering having a local BMW/MINI shop install the FSB.. though, then again, I think I'd prefer to do it myself, hopefully I don't screw it all up

 

One other benefit of the aftermarket rear bar is that you have adjustment. By putting the JCW bar on, you are stuck with what you have.

If you put adjustable shocks on, that is another adjustment.

The way I see it, there are a few adjustments that are available:

1. Tire pressure
2. Alignment
3. Tire size/construction/brand
4. Wheel size/weight
5. Shock rates
6. Sway bar rates
7. Spring rates

On one hand, having too many adjustments can be difficult to optimize.

It also depends on your budget. Understanding what shock brands are legal, and what one brand has over another, is a big challenge.

The good news is that there are others who are doing what you want. Keep getting opinions and keep thinking.

Chances are, if you want to replace the front bar, you can do it. It's only physical work. Not like you are setting cam timing or tuning an ECU. Remove and replace a few Old parts to install one new part.

Have fun,
Mike

 

As far as on the spot adjustability, there are really just the two: tire pressures and the rear sway bar. you need to remove the rear shocks to adjust them, which is why I moved away from the Koni Yellows. I'd rather have my setup critically damped than removing the shock and toying with the adjustment to get it to behave how I'd prefer. On top of having to remove them, it's not like the adjusters on the Konis are all that consistent.

Hence, at least for me, I just have tire pressure and rear sway bar adjustment. I'd rather not use different tires between the front and the rear, wheels will be the same all around, and springs and shocks are fixed to what they will be.

So, as painful as it is, the JCW FSB & using an adjustable rear are really the best option as far as stock/street class goes, IMO

 

When you purchased the car, what suspension was originally on it? JCWs had to have the option checked to either have the sport suspension added or the JCW suspension added, just like Cooper S's. Neither one was standard on JCWs.