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Discussion Starter · #1 · (Edited)
I was wondering if anybody on here with an M90 was running high compression such as 10:1 ratio, that is the ratio I will be running once my motor is back together. What has your experience been if you have ran a motor like this?
 

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I would think you might have a prob w/ KR running that much. I've heard people get away w/ a stock pulley on 9.5 comp, but I dunno about 10:1, that will make even more heat and detonation will be more of a concern, are you planning on doing any mods to reduce KR?
 

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It'll be fine on a well tuned combo, as long as you don't go nuts with the boost. You'll of course need to run good gas, but with a good IC system, regular premium should be ok. Without an IC on race gas, 3.0 pulley would prolly be as small as you can go, but with IC, you can prolly get away with 2.8 and some timing. The 1X cam is a little small for that compression, unless you're going for a sleeper. You need something a little stouter like a stage 3, or XPZ to get the most out of that compression.
 

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Discussion Starter · #4 · (Edited)
Im going for a sleeper, was planning on running 3.4 pulley for daily driving. I wont have an I/c so what do expect this thing should run at the strip with race gas and smaller pulley, what are your guesses? Its my daily driver and i wanted to keep ok gas mileage since I drive it like 30-50 miles a day.
 

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All things being equal, I THINK more boost on 8.5 to 1 will net more power than raising compression... provided you do both to the point of KR...

I could be wrong.. however, if you can get a good IC/head/cam combo going I think you could pickup some good power out of the 10 to 1. :confused:

Hopefully some of the big guys chime in. :D
 

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With my new engine build up, 9.5:1 compression with a standard bore. Stage 3 cam with heads...and a long list of other go fast parts. Pluss I still want to be able to use my nitrous (DRY), only a 50 to no more than a 75 shot. Considered running stock or lower compression, but with no boost...no power.

I have a D.U.B. installed so I will just play with the pulley sizes to see what works well. I have the sizes 3.4 to 3.0 but I have been told I can go smaller with an IC. But I'm trying to avoid buying one.

~Farnsworth~
 
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