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Race Gas Or Not


gomer

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i just got some bad news i had emailed a machine shop www.rb-designs.com and ask them what psi they cut banshee heads 2 and he said 165 psi i had plans on running +4 timing with there head mod but he said i needed race gas if i dont run the +4 timing will i still need the race gas this suxs now im all confused

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It depends a lot on what elevation you live at. A head that is cut for 165 psi at sea level should run fine on 91 octance with no timing advance. With a +4 timing advance its getting hard to say, probably ok with 93 octane but getting very close to the limit. When your getting pretty close to the limit of your octane requirements for your compression, all it takes is for you to run lean or too hot and you could still detonate. If you want to play it safe I wouldn't do the timing. Boonman cuts heads for a very inexpensive price that are around 145 - 150 psi (I think) so you could run the +4 timing with that cut. I'd ask him about cutting the head to get 165 psi because if they mill too much off the squish band without recutting the squishband and/or rechambering the dome then the combustion chamber wont have the right geometry and could also have clearance problems with the piston (needs like at least .030 from squish band to piston top).

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