Master Cyl?

[Blind Mule]

Roo what type M/Cyl do I need for my build not sure if it will have drum or disc? The smaller bore M/Cyl seemed to work better when I had a Rear eng car it had drum brakes and it would stop as good as most of the disc cars!  Not saying drum is better I already have the stuff 

   Thanks!

[rooman]

Master cylinder size is based on volume needed to move the pistons at the wheels and available leverage to move the piston in the master cylinder.  Disc brake pistons don't move far but they are usually quite large in diameter vs the wheel cylinders in drum brakes. In most cases a 3/4" bore master cylinder will do the job provided that the pedal/lever ratio is correct.

Roo

[Blind Mule]

Thanks

[BK]

Can I expand on this question? Is there any advantage to using a remote reservoir as opossed to the 1 piece master cylinder/reservoir combo. If I,m right you use the weight of the fluid in the remote style to keep the pucks where you want them. I was thinking the residuel pressure valve you use with the 1 peice unit may create more brake drag than the other.

[janjon]

For what it's worth my low-mounted integral Wilwood master cylinder with RPV, and Wilwood calipers, seems to show no drag associated with it. The brakes work fine and the wheels spin freely when the pedal is up.

[tylercrawford]

Can I expand on this question? Is there any advantage to using a remote reservoir as opossed to the 1 piece master cylinder/reservoir combo. If I,m right you use the weight of the fluid in the remote style to keep the pucks where you want them. I was thinking the residuel pressure valve you use with the 1 peice unit may create more brake drag than the other.

Could be to eliminate having to use a residual valve . . . I know pretty much every modern fuel car uses a remote reservoir up mounted on the upper frame rail

[janjon]

True that, but I would think that most modern fuel teams would be able to afford an RPV, would even have space in the trailer to store a spare, and could afford the weight of the unit. Probably, the weight of an RPV is about equal to the weight of the line running upward to a remote reservoir. Surely there's a good reason why they do it that way.

[tylercrawford]

True that, but I would think that most modern fuel teams would be able to afford an RPV, would even have space in the trailer to store a spare, and could afford the weight of the unit. Probably, the weight of an RPV is about equal to the weight of the line running upward to a remote reservoir. Surely there's a good reason why they do it that way.

I don't really know . . . I can ask the next time I see someone I know at a nationals event for the "real" answer.

From my own dragster, adding a RPV is 4 more chances for the brake system to leak.  And not that the tapered flange design is terrible but the body of the valve uses 2 pipe threads so you need 2 more fittings for a flange adapter for the line.

I would think its more of a KISS principle thing

[janjon]

I, too, have an overdeveloped appreciation of the elegance of simplicity and minimalism in the design and construction of rolling stock in general, race vehicles in particular. Space constraints and fabrication limitations drove my RPV choice. Flare and NPT connections are very well established as reliable. I wouldn't worry about a few extra of them. And if I can't afford a few more fittings, I can't afford a few fittings in the first place. But it is cool to see installations where the necessary parts and attachments are there, and unnecessary ones are not.