braking news

[pu911]

howdy all,
I am going to put a set of 930 brakes on a 70 S w/ an rsr body and 3.5 L twin plug motor, car will be primarily used on track but won't be a dedicated race car per se. Do you folks think it makes sence to go a master cylinder set up that allows adjusting the front to rear brake bias, if so how does one proceed on a modest budget if possible.
Thanks as always,
Phil

[Groesbeck Hurricane]

Phil,

I really don't know much, but I do know you will need a master cylinder that allows adjusting the front/rear bias. This will be necessary as you try and maintain control while braking. I was under the impression the stock 911 braking system has this ability, however you are wanting a track car which would require stronger/tougher brakes. I do not know how to do it on a budget and not be called an East Texas White Trash Redneck in the process. I'm sure someone else is already typing that response right now.

David
Certified East Texas White Trash Redneck
7 horses in the backyard
Dog/Cat (very confused pair)
Ford 3/4, Chevy 1/2 (forgot the '48 Farmall B)
'83 Targa

[RoninLB]

Phil.. reads like a great fun 911.. and Bill Verberg is real good on your subject.. he also has a web page.. maybe a PM to attract his attention.. enjoy..............Ron

[Kevin Stewart]

the adjustable pedals are great you can somewhat adjust the pedal hight, and also adjust front to rear biasing, you can also use a brake bias valve, some have screws and some have a lever these work fine, but will not give you more rear brake if you need more rear, i really dont think a rear heavy 911 needs more rear but you never know, i will say to get the brakes set up properly be careful and make sure you take it easy at first be cause if you go on the track and have to much rear brake you will find yourself doing 360's , The stock car guys and road course guys have a adjuster that they run up beside the seat, you will need one of these so you can adjust the brakes while you are on the track, i always forget which gives more rear or more front so I mark it on the dash(arrows left and right with f (front) on one side and r (rear) on the other), Have fun nice upgrade for a track car, Kevin

[ttweed]

Originally posted by Groesbeck Hurricane
I really don't know much, but I do know you will need a master cylinder that allows adjusting the front/rear bias.

I don't agree with this. Porsche designed the F/R bias into the 930 calipers by using different piston sizes. I have the 930 setup on my '73 and it works fine, even with the stock master cylinder. The easiest way to fine tune the bias would be with a proportioning valve, but I don't think it is necessary for what you describe as your goals (not a dedicated track car).

There is no "modest budget" method to go to a dual master setup on a 911. The Tilton setup is $750 and installation requires a lot of work. Check out Smart Racing Brake page for more info.

Good luck on your project, sounds like a neat car,
TT

[Bill Verburg]

Originally posted by pu911
howdy all,
I am going to put a set of 930 brakes on a 70 S w/ an rsr body and 3.5 L twin plug motor, car will be primarily used on track but won't be a dedicated race car per se. Do you folks think it makes sence to go a master cylinder set up that allows adjusting the front to rear brake bias, if so how does one proceed on a modest budget if possible.
Thanks as always,
Phil

No! the dual master cylinder setup w/ adjustable bias bar is very expensive and provides no benefit to you if you use the full f/r 930 setup.

The 930 has very nice native bias due differential piston bores. You can keep your standard 19mm m/c or for better feel at the expense of higher effort get a 23mm ATE replacement.