what psi?
going to turbo my motorcycle its a 94 suzuki rf900r the motor is based off the 93-98 gixxer 1100w. its stock with 11.3:1 compression. i'm gonna try and find some turbo pistons to lower the compression to liek 9.5:1 or 10:1. if i want to run 93 octane gas how much boost can i run without detonation? i had a guy that builds cuctom motorcycles tell me the motor can hold 15psi before i start breaking internals but i know it'll detonation before that
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Re: what psi?
Depends on dynamic c/r, timing, etc.
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Re: what psi?
Originally Posted by TorganFM
Depends on dynamic c/r, timing, etc.
Check out this link for a little article that explains some things...http://hondaswap.com/turbo-informati...ression-29102/ The article deals with Honda car motors, but the principles are the same for any motor. |
Re: what psi?
But I thought it wasn't that simple, like cam overlap figures into dynamic c/r and not just a formula involving static (in the cylinder as if no valves opening), or will cam specs determine the static compression? I know it's in there somewhere.
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Re: what psi?
wow i was expecting to get flamed instead of getting answers lol but thanks guys
i did the math on that ---- 9.5:1 at 9psi =15.3 effective compression 10:1 at 8 psi = 15.4 11.3 at 5psi = 15.1 i tried to keep them at about the same as what that guy said was ok for that honda motor. how high can you go? or do you want to try and stay around 15.3? it is a daily sriver like the honda. why can you run a turbo at 15.whatever:1 compression on pump gas but not an n/a? is it becuase your only at full boost for a short period of time? |
Re: what psi?
Originally Posted by TorganFM
But I thought it wasn't that simple, like cam overlap figures into dynamic c/r and not just a formula involving static (in the cylinder as if no valves opening), or will cam specs determine the static compression? I know it's in there somewhere.
Originally Posted by zukirf
wow i was expecting to get flamed instead of getting answers lol but thanks guys
i did the math on that ---- 9.5:1 at 9psi =15.3 effective compression 10:1 at 8 psi = 15.4 11.3 at 5psi = 15.1 i tried to keep them at about the same as what that guy said was ok for that honda motor. how high can you go? or do you want to try and stay around 15.3? it is a daily sriver like the honda. why can you run a turbo at 15.whatever:1 compression on pump gas but not an n/a? is it becuase your only at full boost for a short period of time? |
Re: what psi?
AFR's and EGT's ? school me im a noob
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Re: what psi?
Originally Posted by zukirf
AFR's and EGT's ? school me im a noob
EGT=Exhaust Gas Temperature. You can get an egt gauge with a probe and put it in one of the runners on your turbo manifold. Think of it like a temp guage for your exhaust. ;) |
Re: what psi?
Originally Posted by slo_crx1
AFR=Air Fuel Ratio. Stoich is 14.7:1...that is NOT what you want for a turbo motor in boost. Around 12.5:1 is better in boost to give a safety margin.
EGT=Exhaust Gas Temperature. You can get an egt gauge with a probe and put it in one of the runners on your turbo manifold. Think of it like a temp guage for your exhaust. ;) |
Re: what psi?
Originally Posted by zukirf
gotcha thanks teh egt gauge is called a pyrometer by the way my buddy bought one for his diesel
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Re: what psi?
lol tahts what he bought ------- expensive as ---- too
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Re: what psi?
Being a noob, I'd suggest you err on the lower side of compression if you change pistons. The fact is 9:1 vs 11:1 won't get you that much more off-boost power, but will let you run more psi and be more forgiving with ignition timing, etc. DSM guys find 8:1 and sometimes less is best for making a bunch of power, but then again they're ---- is all designed for boost.
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Re: what psi?
Those are all great responses everyone had..
I personally think you should have someone full throttle the bike right into your ------- at 10 psi. :o :o :o :o :o :o :o :o :o I think this answers your question. Next question please! :D |
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