Silver Surfer

Thanks Bill, you are very generous with your knowledge!

mhm993

Sunset has the longer bolts in stock. (For some reason, the stock black caliper bolts always arrived in green coating but the tt bolts arrive w a red coating. )

I've been running TT/RS calipers for a number of years, for the benefit of larger rotors to help disapate heat, but w/ no changes to proportioning valve or any other changes. The car weighs 2975 and I run hancook dot slicks and pfc brakes. I'm extremely satified with the outcome.

cobalt

I am using the 322/28 with RS calipers rear. Any rotor we were able to make work at all required a custom hat and would not allow me to retain the handbrake on a 964 trailing arm. The bolts holding the hat to the rotor interfere with the handbrake and there is not enough clearance no matter how we approached it.

If you have a solution using these sizes on a 964 trailing arm I would be very interested in it.

964TT

It seems I do, lets see if it all works out as planned. What p/v are you using with the 993RS rear setup?

MarinS4

Has anyone considered just machining the TT rear calipers for larger pistons? It would be a great way to increase rear bias without the costs. I would opt for even smaller sizes than RS. Maybe a 28/32 split would be in between the two and offer a good compromise.

drb930

+ 1,000,000
Just what I was thinking...

drb930

If you are running a 965 rear arm there is a Cayenne 300 X 28 rotor that works, & has the parking brake drum.

Bill Verburg

Geoffry Ring and I talked about doing this years ago but never went forward w/ it. If you wanted an intermediate bias between tt and RS you'd want to use the normal 993 rear 30/34 pistons.

The 993RS bias is only slightly more rear ward than that of pre '84 911.

As I said I have it on both my cars, on the '76 C3 there isn't even a p/v. This setup works great on the street and on the track. for track use the more rear bias that you can use the more of the load is taken off the front, that's a good thing.

lower car, stiffer suspension and effective lsd are all pluses to take advantage of more rear bias.

the issue w/ this setup on 964 is the parking brake not bias.

trophy

Thtas a great idea, Doing that would not be that expensive overall, as you would only machine one bore from 28 to 32. 4 Pistons and a set of seals and you would be off...

MarinS4

That's kinda where I was going with it. The differential bore would also help pad taper. Adjust pad compound to taste from there.

Bill does make a compelling argument when comparing front to rear splits in the earlier cars though. I almost think the TT bias was another way Porsche tried to tame the widow maker reputation.