Quote:
Originally Posted by charlie66
Measure twice cut once! lol.
Just to throw it out there, I had my motor set up for 8.75 to 1 and later found out that it was really 8.4 to 1. It always ran great and made real good power. Then further down the line I changed the pistons to flat tops to raise the ratio up . Got it to 9.5 to 1 and it didn't give any better response down low. It did make more power with less boost for sure though.. I myself like the lower ratio 100%.. Just throwing out my real world experience because I know how these kind of things really make for sleepless nights trying to make the right move on things.. And also , the higher I had the ratio the more tuning challenges I had .. I'm building a new twin build and im shooting for 8.75 to1. If it goes lower I wont even care..
Good luck ....
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Yeah, this is going to be regularly street driven on pump gas(Street) / e-85 (Track). I initially chose 9:1cr as the target, however to achieve the 9:1cr part of that equation was to sit the pistons .020 in the hole. The new head gaskets change all that.
My fear is having to much quench. With the 72cc heads, 40cc dish, .041 head gasket that was going to land me around 9:1cr... but with a .061 quench.
By stepping up to the thicker head gasket (.060 - just measured them) , that would have put my quench in the .080... making 8.8cr. The high quench being the bigger issue for me.
So, I was going to have to deck the block anyway to bring things down to a more efficient quench. So now our target is .005 in the hole which still puts it at .065 quench (Still high) and right at 9.01cr.
I'm not really sure how this is going to effect the engine... Some say the quench is not so important with boosted engines... Some say any more than .060 can lead to slow combustion and ultimately detonation. All of which I would like to avoid.
However, with a 40cc dish pistons... the whole "quench" thought may be irrelevant.
So it really is a pleasant surprise that the block was already .010 +/- .005 shorter than advertised. Just need to remove .005 to clean it up.
Good times.
SPEED SAFE, NICK