Compression Ratio?
 

I am building my d16a6 to handle serious boost 10psi daily and 20 psi race. Should i get pistons that put CR @ 8.8.1 or 9.5.1?

Re:Compression Ratio?
 

im doing the same thing as you. mine are 8.8:1

Re:Compression Ratio?
 

9.5.1 I hate low compression. My Civic's at an obnoxiously low 8.0.1 and I hate it.

Re:Compression Ratio?
 

i think i am going 8.8.1 and i am going to port and polish head too so that should raise a little

Re:Compression Ratio?
 

Port and polish raises the compression ratio? :o
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Re:Compression Ratio?
 

new to me ???

Re:Compression Ratio?
 

bahahaha, I think you mean mill the head

Re:Compression Ratio?
 

i p&p my exhaust manifold now i have to run aviation fuel... but at least i can hang with vipers.

Re:Compression Ratio?
 

oops that what i meant

<------ STABS SELF REPEATEDLY THEN BEATS WITH BAT

Re:Compression Ratio?
 

Hey take it easy buddy. Think things through before you go and do crazy things like that. I'd like to be in your will.
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Re:Compression Ratio?
 

8.0:1 is fine, if your car is sluggish with 8:1 your engine management is in a bad state of tune.

Re:Compression Ratio?
 

not necessarily, dropping from mid 9s to 8:1 would definitely make the car feel slower imho

Re:Compression Ratio?
 

no matter how great the tune is; no compression + single cam + no boost = no ------- power down low.

Re:Compression Ratio?
 

no compression and the engine won't run at all, 8:1 is plenty of compression.

Re:Compression Ratio?
 

omg, I didn't mean literally no compression. ::) Look, you can argue all you want but what makes power...compression. Very low compression with no boost down low means no power. I've had experience with 10.1, 9.2.1 and right now I'm at 8.0.1 and all I'm saying is that I hate that low of compression and if I had a choice I wouldn't go lower than 9.5.1. And there's no way you can argue that lower compression will make more power becuase remember, boost is compression and compression makes power. This issue is widely debated and everybody has they're own opinion on it.

Re:Compression Ratio?
 

I agree with whitey, I've drove a few honda single cams with 8.5 c/r and one with 8.1, talk about complete dogs :-\ anything I build nowadays has a comp of around 9.5 minimum. My built ls/vtec is a 10.1c/r engine.

Re:Compression Ratio?
 

My stock Z6 is 9.2:1 compression and it's working out pretty well. I do plan on building my engine over the winter and will more than likely be going with 9:1 compression pistons. I was thinking about going with some endyn 9.6:1, but I figured since it's a daily driver and I will be running off pump gas most of the time I will make the turbo do all the work. I'm not really sure if there is a big difference between 9:1 and 9.6:1, but I'm guessing it will be tad bit safer.

Re:Compression Ratio?
 

coo thanks for all the advice. what numbers should i be running with built bottom w/ 20psi or should i go higher on the psi? with possible evo III 16g?