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HOW'S THIS FOR COMPRESSION


stroking

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If you flat plate cc'ed out that dome and got 21ccs then that is not at all the right dome for a 4mm supercub. You would end up with much less than 21ccs trapped volume and thus you now have 18 or 20-1 compression regardless of what the squish and step is in the dome.

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I agree with radar. Your UCCR is off the charts lol. You should be looking at domes in the 26-28cc range for that motor on alcohol. I can figure it up for you if you want to contact me, and get you set up with a set of domes that will work.

 

-Brandon

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Hot damn that's some cranking compression.

Stroking, is this a known, good working and accurate gauge?

In my experience, a cheap or bad gauge reads low, but it could easily go the other way as well.

 

Just think how hard that thing would leave the line...then implode....:)

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Perfect just make sure you carry a extra crank with you for when it eats the rod bearings out in the first 30 mins lol

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I love me some high compression, but damn! I would guess that when those domes were designed someone forgot about the extra added volume from the larger bore that will be compressed in to the dome.

As for where to bring it in for race fuel, I would say for a drag application 160-170 and no more. I would prefer to bring it in at the 160ish side though to keep cranking losses to a minimum. From my experience the high end motors come out better on compression but really can sacrifice some juice on the big end with to much compression. Not to mention if you keep it on the lower side, you can afford to wick the timing up a little more to make up for it

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I love me some high compression, but damn! I would guess that when those domes were designed someone forgot about the extra added volume from the larger bore that will be compressed in to the dome.

As for where to bring it in for race fuel, I would say for a drag application 160-170 and no more. I would prefer to bring it in at the 160ish side though to keep cranking losses to a minimum. From my experience the high end motors come out better on compression but really can sacrifice some juice on the big end with to much compression. Not to mention if you keep it on the lower side, you can afford to wick the timing up a little more to make up for it

 

sounds like your saying low compresion (150-170) and high timing would be better situated for long distance drag racing

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