What's the firmest front spring rate I can move to on the S2 with my new Koni Sports while NOT needing to adjust the rear torsion bar AND maintaining neutral to very slightly loose (oversteer) handling?

This is a daily driver which will not see any track or autox duty - just spirited road work.

Thanks!

RK

 

200-220 pounds would be my guess

 

I would agree. Otherwise you'd be underdamped

 

I have the 200# Weltmeister springs in my S (which has an S2 motor so it effectively an S2). What spring rate depends I think on what you use the car for. For driving on the street, I wouldn't go much of any stiffer than my current set-up. In fact, I think it would be ideally a little softer for the street to make it a little more compliant over bumps and reduce the impact harshness--it would be just as fast on the street, and more comfortable. For autocross, I would go stiffer to reduce dive under braking, and I think you can get enough camber to offset the stiffer springs with respect to balancing the understeer/oversteer. I haven't taken that car on the track so I can't say there, but everyone I know who has taken similar such cars on the track seems to invariably go with 300# or more springs in the front initially, say that it is ok with the stock torsion bars, but somehow at some later point always ends up changing the torsion bars. Not sure what to believe there, but I suspect you really need to do the torsion bars when you get to stiffer springs.

 

With the S2 you have a unique spring choice available from H&R - progressive 195-230. Other than this, you are looking at the conversion to 2.5" coils w/adjustable ride height. You cannot use the standard 944 springs from Weltmeister/Eibach.

Ultimately, any increase to the front without other changes to counteract will increase the understeer somewhat. You can add a larger rear sway to the rear to help balance things out a bit more - consider the 968 M030 19mm 3-way bar or the Weltmeister 22mm bar for this.

 

Why can't I use regular aftermarket springs that would fit a Turbo on the S2?

Don't doubt the wisdom - just curious.

THanks,

RK

 

RK-

The S2 has a "special" coil diameter, not shared with the Turbo. I cannot remember if the coil is larger or smaller, I just know they are not swappable.

Cheers,

 

The S2/968 spring is smaller in diameter. Shown here:



Click the pic for more info.

 

Yeah, smaller. Learned that the hard way when installing S2 M474 struts and shocks into my S2 engined 944.

Tried to drop the old 8-valve springs onto the S2 struts and they were too damn big. The cloud of obsceneties is still hovering over the New England region to this day.

I'm guessing someone like Hypercoil could wind you springs in any dimension and rate you want, possibly even in an exotic lightweight material like titanium - reduce unsprung weight. Dunno what it costs. If history is any sort of teacher though, I'd say "a lot".

Bryan

 

If you are just looking for an improvement for the street I would just go with the H&R progressive springs, which are probably very comparable to the Weltmeister springs I have.

I have the Weltmeister bars, which were great for autocross, but since I've stopped autocrossing the car I have taken them off and gone back to the stock S2 swaybars, which I think work a lot better for the street. Also, unless you have an LSD I wouldn't increase the diameter of the rear sway bar as you'll just get a lot of wheelspin. When I was autocrossing with the Weltmeister rear bar, I ended up coming to the conclusion that the car was fastest with the rear bar on its softest setting as otherwise I couldn't get the power down. For the street, the aftermarket bars do bad things for the ride quality and do some peculiar things to the response of the suspension to bumps. I think that with that spring set-up, the springs aren't stiff enough for the suspension to take larger swaybars. If you were autocrossing or tracking the car I'd say you need the bars, but for the street in my view the stock bars are better.

As to addressing the balance of the car, after you do the spring you'll have to get the car realigned. If you give the car a decent amount of negative camber in the front (at least 1.5 degrees) and 0 degrees of toe, that will get rid of the understeer. I would go with a similar amount of camber in the rear, along with a little toe in for stability. The front can adjust to about 2.8 degrees of negative camber, but once you are up to around 2 degrees you will start really noticing tire wear on the inside of the front tires. In sum, a proper alignment of the car will solve the balance issue.

 

Wow - great insight and it makes sense.

My inclination now is to stick with stock springs and just install the Koni Sports - sort out the alingment and see how that works.

Thanks for all the insight!

RK

 

If you are replacing the shocks, my recommendation would be to go with lowering springs like the H&R. They aren't very expensive and they are an improvement over the stock springs, which are definitely too soft and also make the car sit much too high in my opinion (which is aesthetically bothersome and not as good for handling). For a relatively inexpensive, aesthetically pleasing and good handling set-up for the street, I'd just go with the H&R springs (which I'm assuming will lower the rear by about an inch, but do check on this--you want the springs to lower the front by about 1 to 1.25 inches), lower the rear with the eccentric (drops the rear by about .75 to 1 inch) and then get the car four-wheel aligned. Since you'll have to have the car realigned due to the shock replacement and the front springs removed anyway, the only additional things you will be paying for to lower the car vs. just leaving it with stock springs is (1) the cost of the front springs (I'm guessing not more than $120--my Weltmeister ones were about $110) and (2) the labor to lower the rear with the eccentric (this is super-easy and shouldn't be more than an hour of labor for a shop--it will take them 1/2 hour, and they will charge you for an hour (it really is this easy)). Hence, when you are spending $600-700 or so for shocks and another $200-300 for an alignment, the additional cost to lower the car is not very much and it will make the car handle and look better.

 

The H&R springs do lower the car approximately 1". Cost is $195/set (lower production, progressive, different manufacturer, etc). If you want to lower the rear yourself, here are some instructions: http://www.tech-session.com/kb/index...x_v2&id=62&c=4

Good Luck!