Re: Math question

Posted by HH56 On 2011/3/9 12:01:01

I didn't see that much mechanical difference from conventional vs rotary lever either. The BTV put out approx 200 psi with 100 into pedal, no vacuum. The dual is doing about 150. I have several ratios available, current max being the 3.7 and started with less ratio say about 2.5 which by my calculations with that ratio and 1" should have resulted in around 300 out with 100 in (ratio 2.5 x force 100 / diameter or .785 = 318). The numbers with vacuum should also be higher than BTV but are not-- hence the questions about ratio calculation and master cylinder effect.

Another thought: Is there anything in the method or geometry of moving long lever that could change the ratio. I can't see it and am going under the assumption that as long as the lever connect point is at the distance to provide a given ratio, it doesn't matter what the shape of connection piece to pedal is. Currently instead of straight across, I have an "L" shaped piece between pedal and lever. Intent is to lower so all inside is as close as possible to original. With pedal relaxed, long side of "L" starts about halfway up lever and drops down to just above the shaft at full pedal. Height varies depending on ratio selected. All works beautifully with plenty of range--it's just the low numbers that are confusing the issue and making me rethink.

I did have some bleed problems so went to a pressure bleeder --maybe without total success-- so will try your method. It may have to wait until I get someone to help. Crawling in and out and under to pedal and bleed screws doesn't work well anymore.