Porsche Group B 930 Project

The Suspension

Torsion Bars

I purchased a set of 22mm/28mm torsion bars off of EBay.  I could not find a 27.5 mm rear torsion bar, so I decided to match as close as possible. I rounded up.

I later purchased a set of 30mm rear torsion bars from my friend and installed the 22mm/30mm combo on the car.  I've been reading the Smart Racing Products Suspension-Tuning Guide and really liked how they have all the suspension suggestions "balanced" to each other.  They recommend No. 23 Bars in both front and back when you look at page 13 for 911/930 87-89.    This is interesting since the factory recommends 23mm bars in the front, but only 19mm in the rear.  This section also recommends the SRP F10 and SRP R10 Valving.  This section in the Guide is for Sport Suspension.  I like the Competition Package recommendations, but I would have to sell my current suspension inventory.  Since I'm trying to recreate the original factory race car, I will use the specs I have found the "The 911 Story" by Paul Frere.

Anti-Sway Bars

The factory Group B cars had 22mm adjustable ASB (18mm stock) in the front and 18mm adjustable ASB (same as stock) for the rear.  By today's standard, this is considered a very soft setup.  I'll probably use 23mm bars in the front and 19mm bars in the rear.  I'm looking a ASB from Smart Racing Products.  Since there is a recommendation to use a softer bar in the back, I'm going to investigate this.  My initial thoughts are to use the 23/23 combo since I stiffened the the rear torsion bar.

Wheels and Tires

I decided to purchase a set of 9X15 and 11X15 BBS RS 3 piece wheels.  I could not found the correct size tires for 16 inch wheels, but I was able to find tires for the 15 inch wheels.  Paul Frere's book "Porsche 911 Story" says the factory used 23 inch high and 9.5 inch wide tires for the front and 25 inch high and 11 inch wide tires in the rear.  The closest tire match that I can find were Goodyear 23X9-15 and 25X11-15 or Hoosier 23X9-15 and 24X11-15.

Rear and Front Wheels - 11 inch Rear Wheel

Strut Tower Solid Mounts

I can't decide to use inserts sold by Smart Racing Products or replace the whole upper strut mount sold by The Racers Group (TRG 6000).  I've been looking hard at the system the WEVO makes that is sold by Smart Racing Products called the Camber King.

Strut Tower Brace

The strut tower brace will be determined by which Strut Tower Solid Mounts I use.

Balance

More to Come...