PaulP

I was told by a expert Porsche mechanic that if I changed to ROW springs, I would only get about 1/2" lower ride height. Said that Euro standards have moved toward US heights. Previous posts keep referring to a 30mm (1.18") lowering of height by changing from US M030 to ROW M030. I would like to go with ROW, but not if I'm only going to reduce by 1/2". What now?

Viken

If you are talking about the 993 Turbo, the ROW springs will lower the US car by 30 mm ± 10 mm regardless of what your mechanic says.

jessejames

I drove a 993tt with Eibach springs. The ride may have been a tad softer than my US sprung car but the ride height was perfect...a little more than 30 mm.

I'm going this way once I figure whether I have to modify the shafts of the rear shocks or change them.

PaulP

Thanks for the feedback. I've read all the posts regarding 993tt suspension changes and not sure exactly what might be my best choice.
Maybe I'll wait till after my first DE with it. Compared to my recent 996 and 993's this thing is kinda scary !!

SundayDriver

When I bought my TT, it had the Eibach springs. Looked great and a very comfy ride, but the springs are WAY too soft for the shocks. The handling was not good. I had a 993 C2 w/ROW M030 that could run circles around the TT. The TT was quicly changed to full coil-over from Mike Schatz.

If any of you guys want the springs to try out, I'll sell them for $50 plus shipping. Drop me a note.

Martin S.

So much good advice above. I would suggest you do a DE with the stock 993TT suspension. This is what I have on my 993 NA coupe with 23mm front bars and 21mm rear bars. You have stiffer rear springs than I do...the 993 NA is a lighter car.

Then if you decide to change the suspension, do with a system rather than simply changing the springs. Consider changing the front struts, rear shocks and get the GT2 adjustable sway bars. All these parts can be yours (If you go with the Bilstein PSS9s, with 9 way adjustable shocks) for about $3,000. FVD sells avery similar 9 way adjustable set up as well. In fact it looks identical to the PSS9 set up. Regardles of whom you go with for springs and shocks, you'll need GT2 sway bars.

In closing, I have spent $thousands on my suspension installing the 993TT suspension, corner balance and alignment, and the car handling hasn't changed that much. This could be an example that the stock is pretty good to start with, and also confirms that I need some more car seat time.

I am off to Willow Springs International Raceway on the 8th for 3 solid days of track time...that should remedy the latter problem.

PaulP

well, I took the tt to a DE event this last weekend and right out of box spun it doing approx 130. Head instructor drove the car after pitting and confirmed that I had a screwed up rear end. slowed down the rest of weekend and adjusted, but car is not right. I've only had this car for a few wks before event, so did not examine alignment, etc. Previous events on same track with stock 996 w/H&R springs I could run 13secs quicker. Came home and looked/talked to several people and have just ordered PSS-9 with RS sway bar from FVD. Will post my opinion after installation and some use.
Many thanks to mdalen and all other's info.

Viken

You need to have a proper alignment performed on your car. Sounds like the rear kinematic toe might be off.

PaulP

Yes, I am going to have The Porsche Store in Dallas perform installation and all alignment. I have also been told to insure kinematic toe is correct. Can someone give me some detail on how corner balancing is achieved and what the kinematic toe is/does? Thanks

PaulP

Got the corner balancing understood from Viken's previous post in 993 board (should have checked first), but still looking for more detail description for kinematic?
Thanks again.

SundayDriver

The 993 rear suspension has geometry that controls toe change as the rear travels up and down. One of the problems with older 911's is that severe toe changes would occur as the rear suspension worked - as I recall you would get toe out as the back end got light, leading to snap oversteer. Toe out, on either end, makes the car darty. This is a good thing, in moderation, on the front of a race car, as it makes a very crisp turn-in. It is generally a very bad thing at the rear.

The 993 has an adjustment that minimizes this. There is a procedure and gauge to set this correctly. If your shop does not understand this, you need a different shop. I don't know the exact process, but it is pretty unique to our cars and requires expertise to get it right.

When you change the camber, you also make pretty drastic changes to the kinematic toe, so that always needs to be reset after the camber. Both the driving behaviour of your car, and the fact tht the rear camber was not correct (at least side to side) makes it hightly likely that kinematic toe is off, as we discussed in our eMails.

Hope this helps you better understand what is going on.