I'm going to be setting up my original six as a 98% street car, 1% long trips, 1% track laps.

I actually like street 914-4s with 100 pound rear springs and even 165 tires. Is 100# too soft for a stock 2.0 six?

Maybe I'll get 2.25" coil overs and go for 125# or so. My 3.6 has 300# rear springs and it's perfect for it's use...

-Steve

Hmmm... Scratch that. Looks like the softest 2.25" springs is 150#.

http://www.summitracing.com/search/departm...in/brand/eibach

-Steve

Do not put so much spring rate in the car where the perches and attachment points are being overstressed. I did run adjustable perches with 180# springs and original sway bar in rear. Just too stiff when I stress welded the unibody and put in Tangerine Racing bracing kits.

I went to 140# progress springs (original setup) and it is still too heavy of suspension. I am going to live with my setup and "enjoy" the rough ride. I have complete 911 Carrera 3.2 engine, suspension, brakes, etc. Everything is tied together with brass suspension bushings and grease fittings. I will be increasing the 17 inch rims from 40 series front and 35 sears rear to 55 series and 50 series front and rear respectfully (7 inch front; 9 inch rear). Yes, the front is loaded with heavy suspension torsion and sway bars. Again, to much.

You indicated you are mostly going to do street driving (98%) so I would stick as close to the original suspension as possible. You would be surprised how well the 914 (assuming 4 cylinder since you mentioned 3.6) original stuff is. Just keep it repaired and in good shape

Anyway, have fun in developing your project and continue to do your research well.

Steve

The -6s and -4s had different rear springs when originally delivered to compensate for the heavier weight of the -6 engine.

Running a front swaybar with a heavier rear springs seems to make a nice combination for street and autocross.

the factory six rear springs are 90lbs wire dia. is 10mm 4bangers are 9.5

There are some debates over the original spring rates. Various sources give numbers anywhere from 50 lb/in to 90 lb/in, and usually the Six is noted as having higher rates than the Four.

I have 150s on the back of my 2.0 -4, and the ride is on the harsh side. Part of that is the sport Konis, though.

A decent suspension shop should be able to get you just about any spring rate you want in that size of spring. They might not get them from Eibach at that point, but they should still be available. You may have to talk to non-Porsche places and just give them the spring rate, free length, coil diameter, and the way the ends of the spring are finished.

--DD

Maybe a bit off topic but in the Porsche parts manual rear springs are classified by various color paint marks. Most are red or green
It may be just to make well matched pairs but I seem to remember that yellow paint marks were " 6 " springs

Steve, if you need a pair if oe SIX springs I have a set. PM me if interested .
Marty