Brake guys - Manual brakes and Alum 7/8" bore MC qun

Hey guys,

Im interested in your thoughts on this one...

My setup has Wilwood Dynapros front calipers and rears are Nissan Skyline single piston alum calipers (a common swap over here)

My setup is manual brakes with an underdash / cantilever arrangement - pedal ratio is around 6.4 and the current setup does'nt give me enough bite on the rotors, so I'm thinking a 7/8" bore MC will up the ante in the line pressure dept.

The pedal is great without excessive travel and there is no air in the system as far as I can tell. MC was bench bled as well.

In the front line I have a line lock and in the rear, and adjustable proportioning valve which is backed right off for full pressure to the rears at present, but I'm not getting enough grab/bite.

I will be checking pressure at the calipers as soon as the gauge kit turns up, but in the meantime, I'm wondering which 7/8" bore MC Pt # is used. This is a 2 bolt MC deal (std Mopar 2 bolt MC spacing.

Would love some input on my setup and suggestions of a source for the MC.

Thanks !

In the cornering forum Feets has a spread sheet that will let you plug in what you have, make changes and see what you will get.


Found the link to teh spread sheet, if you have Excel

http://www.3gduster.com/brakes.html

I have the parts for one in the future. from what I understand the great amt of caliper vol (4 of em) wants a large bore MC to supply that. With a larger bore giving less psi maybe a better pedal ratio would be the plan with a big bore. No actual exp (yet) so I am just thinking out loud as I will be faced with that decision later on. holler how it turns out

I have Strange 4 piston disk on the front and Wilwood 4 pistons on the rear and can say that with the pedal factory set up on my manual braked 69 Dart a 1 1/32" mc sucked. The pedal was like stepping on my concrete shop floor, sure it didn't have much travel but I would have both hands on the wheel and both feet on the pedal to make it stop at the strip. If something had happened on the street and I needed to stop fast I'd been screwed.

I now have a 15/16" mc from Drdiff and it's much better but not as good as the original 7/8" factory mc. When I ran the factory mc I also had 73 disk up front so not an apples to apples comparison.

I've heard guys for years say big brakes need big bore mc's and to a point I agree but I'd like to see how much fluid it actually takes to move the pads the thousandths of an inch required to stop. My guess is that the small bore mc have more than enough capacity.

Noted & when the time comes I might lower the pivot hole to reduce the ratio & see what develops