Boy from Oz Posted October 4, 2008 Share Posted October 4, 2008 I’m trying to use as many components from my 2005 LS1/t56 donor car as I can and that includes the brake booster (master vac) and master cylinder. I gave away the idea of using the pedals as they were far too long. In sizing up the standard 240Z brake pedal (approx 350 mm long and 50mm from the pivot to the push rod clevis pin) it appears to operate on a 7:1 ratio, i.e. 70mm foot pad travel will move the push rod 10mm. The donor car pedal is 420mm long and 100mm to the push rod clevis pin, giving a ratio of 4.2:1, i.e. 70 mm pedal travel would move the push rod 17mm. This suggests I will require more push rod travel with the donor car booster and master cylinder fitted. To compensate for this I am thinking of moving the push rod clevis about 35mm further down the 240Z pedal shaft towards the foot pad, giving me approximately the same movement ratio at the donor car. This would mean the push rod would be angled at around 15 degrees to the booster. Questions Would the angled push rod create significant functionality and/or wear problems, and would fitting a 15 degree wedge between the firewall and the booster, to align the mechanism by tilting the booster/MC, create functionality issues? Photo shows the abandoned donor pedal lying on top of the 240Z assembly. Any comments appreciated. P.S. I will have the 4 spot Wilwoods all-round. Quote Link to comment Share on other sites More sharing options...
260DET Posted October 5, 2008 Share Posted October 5, 2008 Sounds a bit messy, you may be able to get away with what you are proposing but my experience says do everything right and don't be influenced by convenience. This monster going to be ready for the Nationals next year? Quote Link to comment Share on other sites More sharing options...
Boy from Oz Posted October 6, 2008 Author Share Posted October 6, 2008 To 'do it right' I have to ensure there is adequate push-rod travel. Apart from the new booster being later design technology and in plentiful supply (spares in 20 years time) I'm also keen to show the approving engineer that the rest of the vehicle matches the LS1 - I'm after as little hassle as possible come certification time. I've had another little play around and it looks as though there is enough space to lower the booster 35mm and not foul on anything. Hopefully this will sort the problem out. Next year's Nationals - tell him he's dreamin'. Project's scheduled for a realistic completion date of 2012 - I simply don't get that many opportunities to work on it. Quote Link to comment Share on other sites More sharing options...
evildky Posted March 3, 2009 Share Posted March 3, 2009 did the pedal have as much stroke in the donor chassis? what bore is the master? what brakes are you running? remember it's about moving fluid, so that 10mm stroke wih the 15/16th master might be sufficient but maintaining stroke with a smaller master will move less fluid Quote Link to comment Share on other sites More sharing options...
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