In one stroke, BIRA member, Alexander van Gerbig, has created a braking solution for 4-Bolt Audis and a two-piece rotor option for System 1. Here are some pictures of Andrew's Audi 80 with his new brakes, and the story behind his 4-bolt, two-piece rotor project.
I
wanted bigger brakes. I bought a set of use G60 calipers and planned to fit
those to my 80, but it became apparent that finding the right rotor would be
a pain and the G60 setup was exceedingly heavy compared to my
stock single piston system. I started researching the
various "big" brake kits. The barriers to my
purchase of most of these kits were the need for 17" rims, a useless
amount of braking for my application, split calipers, and a high price.
I had heard of BIRA, but I knew they only provided solutions for 5-bolt Audis. BIRA's System 1 was enticing - the perfect amount braking; monobloc calipers; it fits most 16" rims; and the price was right. I eventually decided I wanted BIRA's System 1 on my Audi 80 and I also decided that I'd figure out how to do a 4-bolt solution.
At first, designing custom rotors seemed a little above my above grasp. However, after I consulted a few shops, and talked to a few folks, I decided to give it a shot. I asked several Audi shops to help me obtain two piece rotors that had the same dimensions as Audi's 312mm x 25mm A8 rotor, but they were not interested. Other shops were interested, but they also wanted rather large sums of money. I decided to go around these shops and went straight to the source of big rotors, Coleman Machining.
I
contacted Coleman via fax with some designs I had created in Photoshop. A
call back confirmed that Coleman could do the rotors for me,
however they wanted a sample rotor to work with. Before
proceeding, it was necessary to confirm that
the hub offset of my Audi 80 was the same as the cars that were using System
1. I measured the hub offset and it was the same. I bought an A8 rotor, a
Boxster caliper, and obtained a set of test brackets from Greg Johnson. I
test fit System 1 with an A8 rotor and checked my wheel clearance
as well.
Everything
lined up except for the wheel bolts, of course, and I had just enough clearance
with my 16in Borbet Type T rims. I
shipped the A8 rotor to Coleman. They made some designs that suited them a
bit better. I checked their designs to make sure all the
dimensions were the same as a stock A8 rotor, but
things were not perfect. I consulted with Greg Amy and he
got everything straightened out for me. After two more minor changes,
I signed off on Coleman's design and waited. When the rotors arrived all
the dimensions measured up correctly! I test fit again and
everything was correct, but I needed the bolts and nuts to
attach the hats to the rotors.
Coleman
was able to provide this hardware. Bolting-up System 1 went without a hitch.
At first, it seemed as though there might be an interference problem with
the bracket and the strut, but my fears were alleviated once the car was back
on the ground. The 15" brake lines work perfectly on my lowered car, but I
would recommend 16" lines for other TYP89 owners.
At the same time, I installed new factory rotors and Kerr Friction race pads in the rear. The pedal feel and travel instantly became better, almost nicer than stock. Each time I fiddle with the brakes (new pads, bleeding) the pedal feel gets even better. I am very impressed with it, particularly when you consider how much bigger these brakes are than my stock single-piston setup. I can't comment on extreme braking as of yet, but I know it's going to be good considering all the raves from other members so far. I can't wait to try it out more!
I must thank the whole BIRA community for their help and support while I worked on the two piece rotors. I must especially thank "the Gregs" for all their help and for creating BIRA. To those of you considering BIRA for your car I must say this, just do it.
Alexander van Gerbig - 1988 Audi 80 (FWD) (HOR Technologies Sport Hydro Camshaft, K&N Filter, Automatic to Manual Transmission Swap, 2Bennett Coilover Program with Eibach 380/340 Progressive Springs, Koni Sport Shocks, BIRA System 1 with Coleman Two-Piece Slotted Rotors, Borbet Type T 16x7.5" Rims, Dunlop SP9000 Tires, and RS2 Headlights).
BIRA says Thank You, Alexander! You reflect what we're all about - an association of enthusiasts who are interested in co-creating better braking systems for their cars. Several of you have no doubt thought: with the right hat, System 1/Coleman will also fit five-bolt Audis. You're correct! With an appropriate hat, it may also fit UFO-based Audis. We're looking into it.