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what compression to do


qboronyrican

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ok i dont know if i ever asked this before but here goes....i have a 4 mil stroked shee, aggressive trail port, case port matched, 35mm air strikers v forces, and curently running about 175psi in 60-80 degree weather @ sea level-800 above.....my questions are 1. what comression would i need to go down to to run straight 93 octane pump gas? 2. what will i be losing going down to that compression? 3. also what would i gain if i went up in compression and how much is the max i should go if i went that route? ..... race gas is getting to dam expensive for me to go ridding for 6 hrs at a time but if its going to cost me major power ill deal with it.......thanks for the info guys

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ok i dont know if i ever asked this before but here goes....i have a 4 mil stroked shee, aggressive trail port, case port matched, 35mm air strikers v forces, and curently running about 175psi in 60-80 degree weather @ sea level-800 above.....my questions are 1. what comression would i need to go down to to run straight 93 octane pump gas? 2. what will i be losing going down to that compression? 3. also what would i gain if i went up in compression and how much is the max i should go if i went that route? ..... race gas is getting to dam expensive for me to go ridding for 6 hrs at a time but if its going to cost me major power ill deal with it.......thanks for the info guys

 

 

 

someone has to have some insight, thoughts. acual knowledge on this

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ok i dont know if i ever asked this before but here goes....i have a 4 mil stroked shee, aggressive trail port, case port matched, 35mm air strikers v forces, and curently running about 175psi in 60-80 degree weather @ sea level-800 above.....my questions are 1. what comression would i need to go down to to run straight 93 octane pump gas? 2. what will i be losing going down to that compression? 3. also what would i gain if i went up in compression and how much is the max i should go if i went that route? ..... race gas is getting to dam expensive for me to go ridding for 6 hrs at a time but if its going to cost me major power ill deal with it.......thanks for the info guys

You would need to go down to 160 or below to run 93 octane. You would lose some bottom end grunt on your motor(torque).If you went up from were you are in compression you would lose over-rev on your top end. I like having around 180 compression, think that is right around the sweet spot if you run the fuel that supports that kind of compression. What dome size are you running now? B)

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im not to sure what domes are in there now ...they are dimes made by hjr for the 4 mill but i do know im right around 175 psi on each side....would i really be able to feel the difference between 173 and 160 on the bottom end? is it a big difference?

I don't think you would feel that much difference since you have a 4mil crank. It does not sound like you are a drag racer so i would give it a try and see if you like it. It is not that hard to swap out domes.

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no im not a dreg racer and thats why i thought of going down and saving some money ....all i do is alot of open trails with a bunch of coal hill climbs and some tight trails so do think i need that little extra down low

I would try it and see if it works for you. I have a t-5 bike that runs on pump gas and it is not a stroker, it works good for that kind of riding, a t-5 is a mid to topend pipe.

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