Pedal ratio on Manual brake setups

[karolko]

I was wondering if anyone happens to know what the original pedal on the powermater pedals were.

I have heard alot of people saying to swap over to the vacuum style brake pedal and then use the upper mounting hole.

Secondly, from what i know, you want to have the pushrod as parallel to the master cylinder bore as possible so that the piston will not stick inside the master cylinder. Now if you relocate the pin height for added pedal ratio, you will they be throwing off the angel of te pushrod? is that correct?

Help Anyone? Will could you share some light on the subject seeing as you recently went through the swap.

Adrian

 

[Scott Atk]

You may have already read this thread, but lots of good info:
http://www.turbobuick.com/forums/general-turbo-buick-tech/250833-best-manual-brake-setup.html

 

[karolko]

great read thank you very much Scott.

When you moved the pin location for your manual swap, was the rod at some silly inclined angle? That is the only thing i am trying to get my head around. I read on the wilwood site that you would want to have the rod as parallel to the master cylinder piston.

Any thoughts would be nice, and thanks again for the link. I am surprised that i missed it in my seaching.

Adrian

 

[Scott Atk]

Sorry for the delay. I wasn't sure of the answer, i finally got a chance to peek under the dash. The pushrod appears to be parallel to me.
Honestly I experimented with a few different setups and I'm not sure which one I ended up with. I believe it's a PM pedal in there right now. I would definitely start with that. HTH, scott

 

[karolko]

Scott, i ended up going 6:1 ratio simply becausethe difference in height was only 5/8". My pushrod was angled downward slightly so i ended up putting an arc into the rod sor that it would not bind. From the looks of it, the pmaster cylinder will bottom out before my foot reaches the floor which i am happy with. There does not appear to be an excess amount of peddle throw with the 6:1 ratio.

Oh and so you know scott, the PM ratio is 5:1 not 4:1.

mach.80 had a problem with his 6:1 ratio and i do believe it is mainly due to the fact that he was using a 7/8" bore MC, thus he did not have the needed volume.

Thanks for all of your help.

Adrian