We Hit A MO30 Problem Today....Suspension Gurus Help!

Gents, I have ROW MO30 suspenion on my car. I ordered H&R springs (-30mm) as I do not like the way the car sits. My Porsche mechanic took out the front strut and we compared the springs before puttin them in. The H&R spring was taller, had more loops and was easier to compress. That did not look right at all. He was also sure that they would not lower the car any further. We did not want to install the springs as we would not be able to return them... Can anyone shed any light on this? If so, what springs can I buy which will lower the car? Many thanks in advance.

The spring rate (lbs per inch compression) is a function of the 4th power of the wire diameter. The new springs may be easier to compress initially, but if they are taller unloaded that doesn't tell you much. You'd have to compress both springs to the same load (that which it will see with the car sitting on it) to see what the resultant length will be.

If the H&R's at rest are taller and have more coils, all it tells you is they are using a softer spring rate. This is very typical of H&R sport springs that have lower ride height, but retain stokc-like ride quality. You won't know the ride height until you put them on, load them up and let them settle.

Thanks. We did consider this, however, I also know from many sources that the H&R's are much stiffer than standard, and possible even the RoW MO30's...

RoW M030 lowers 20mm in front and 10mm in rear versus US stock.

Actually ROW M030 is 20mm +/_ 10 mm in front and 10mm+/-10mm out back. My car lowered exactly 1" in front and .75" in back, which worked out to 25mm and 19mm respectively.

Also depends on which shims you used.

The rates for the H&R are a progressive rate, meaning that it is softer initially then the ROW springs and will get stiffer as the springs compress. I think the rates for the H&R are something like 240-290 and the ROW is about 265 constant for the rear springs.

Excuse my ignorance, but where do the shims fit?

Thanks for the reply. Does this mean that my car will be lower with these springs. I was under the impression that the gap between the loops changes down the spring with progressive rate springs...On the H&R's, the gaps are all even.

The "shims" are probably a reference to the "compensation plates", an issue of much confusion. Lots of info here and at RennTech on that. But basically springs come with a green stripe or a white stripe. Green stripe uses 1 thickness of compensation plate, white uses another. The M030 kit doesn't come with the compensation plates, surprisingly. So this is what you do..... -Know which part # plates go with which color stripe on the spring. -Have the seller open the M030 box that they're going to send you. Not any ol' box, your box. Have them look at the compensation marking (the stripe) on the springs, front and rear. They won't necessarily be the same. -Have the seller sell you the correct compensation plates. Note that you may have to hold the seller's hands on this. I bought my M030 kit from a very well reputed shop that is mentioned here at Rennlist all the time. To my surprise, they didn't know much about the plates. These plates go on the shock mount, not the spring. I've read some posts from some far more experienced Rennlisters then I on how the compensation plates impact ride height. But I have to admit that I still really don't understand it. The compensation plates go on the shock mount, not the spring. And it seems to me that the springs set ride height, not the shock. Putting a rubber spacer on the shock, in my perception, would only move the "band" of shock travel length. The reason for the compensation plates is that the M030 springs come in two different lengths. Green length and White length. Note that there are 3 colored stripes on the M030 springs. A green and white (as I recall) stripe that identify the spring as M030 (or at least I think that's the purpose of the double stripe), and then the compensation marking. The compensation marking is a couple inches away from the double stripe.

The compensation plates sit between the strut mount and the body, thus adjusting the overall length of the whole assembly from body mounting surface to the axle. Bill

Thanks guys. So if the compensation plate is 1mm or so, that won't impact the rige height greatly?

There are two different plates for each front and back. The different between them is 3.5mm (roughly 1/8"). Front: 996 343 511 00 -- 3.0 mm compensation plate or 996 343 511 01 -- 6.5 mm compensation plate Rear 996 333 511 02 -- 0.5 mm compensation plate or 996 333 511 03 -- 4.0 mm compensation plate

The springs on a 996 are not shaped like a typical spring with its conical shape in the front. The rear you'll notice some changes in the gap between the loops, but are less noticible to the eye. The main thing is to double check the part numbers on the springs. I would call H&R if you have any doubt that you have the right springs. I can tell you I had some eibachs before and the car sat about 1/2 inch lower in height compared to the ROW M030. You should see similar results with the H&R.

I have fitted H&R springs. The car does sit lower all round, but is level rather than the rear end up in the air. My initial impressions are that the car is stiffer, but it feels planted to the road and corners much better. Maybe it's me, but it also seems to understeer less... I cannot say to what extent this is due to the MO30 springs being old, but I still think that the upgrade to H&R springs (with RoW MO30 shocks) is a worthwhile one...

I just saw a Boxster (986) on new H&R Springs. The owner was disapointed as the overall drop was very small.