9:1 pistons or 10:1???
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From: Fayetteville, NC via Puerto Rico
Why would they would advertise 9.6:1's as being 10:1's? Incidentally, I never heard of anyone running E-85 in conjunction with nitrous. Hardly any Evo peeps still running nitrous nowadays, whereas a few years back it was a bit more popular. Me, I'd stay away from the stuff.
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Joined: Jan 2007
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From: Fayetteville, NC via Puerto Rico
[QUOTE=sparky;8316617][QUOTE]
Why would they would advertise 9.6:1's as being 10:1's? Incidentally, I never heard of anyone running E-85 in conjunction with nitrous. Hardly any Evo peeps still running nitrous nowadays, whereas a few years back it was a bit more popular. Me, I'd stay away from the stuff.
maybe cause is a honda shop
Why would they would advertise 9.6:1's as being 10:1's? Incidentally, I never heard of anyone running E-85 in conjunction with nitrous. Hardly any Evo peeps still running nitrous nowadays, whereas a few years back it was a bit more popular. Me, I'd stay away from the stuff.
My question was actually rhetorical, as I have always wondered if when the advertised C.R of x piston is supposedly, let's say, 10:1, whether or not that C.R. only refers to a stock bore sized piston. That is, for each overbore size would you have to also factor in the increase in swept cylinder volume being compressed into the same size combustion chamber? Or would the advertised number be a final compression ratio which already has the increase in volume factored in.
Most pistons are spec'd by the manufacturer with the cc dish and then the compression ratio on a stock motor. If the head is milled or it is a stroker piston or any other variable then the compression can vary a little.
My question was actually rhetorical, as I have always wondered if when the advertised C.R of x piston is supposedly, let's say, 10:1, whether or not that C.R. only refers to a stock bore sized piston. That is, for each overbore size would you have to also factor in the increase in swept cylinder volume being compressed into the same size combustion chamber? Or would the advertised number be a final compression ratio which already has the increase in volume factored in.
Got me, but most 10:1 pistons are just a flat top with 4cc valve reliefs.
If you use the stock parameters, it comes out as 9.55:1.
I could have some parameters wrong though.
Gasket bore: 85mm
Gasket thickness: 0.051"
Combustion Chamber Volume: 47cc
The combustion chamber volume is the most questionable. Everything else is on the small side and actual compression ratio would be even lower.
Very few EVO builders CC match chambers anyway, so it's not like it really matters.
If you use the stock parameters, it comes out as 9.55:1.
I could have some parameters wrong though.
Gasket bore: 85mm
Gasket thickness: 0.051"
Combustion Chamber Volume: 47cc
The combustion chamber volume is the most questionable. Everything else is on the small side and actual compression ratio would be even lower.
Very few EVO builders CC match chambers anyway, so it's not like it really matters.
[quote=crewdawg130;8316671][quote=sparky;8316617]
maybe cause is a honda shop
whats a honda shop? I never said that national speed advertised anything you must be confused. I happen to be friends with Jordon who works there and is over seeing my build. For you to call it anything other than another shop shows your unprofessionalism. I actaully was going to go with you guys but I didnt feel comfortable leaving my car over a month with someone I dont know that works out of a shop. I also didnt want to make the drive back and forth which would be around a four hour round trip drive. I happen to work next to National Speed and know the owner so I can over see my build and visit my car whenever I like. When my build is complete ill be happy to post up pics and videos. Thanks 
maybe cause is a honda shop
You know anybody running E85 and nitrous?
I know the methanol guys typically use a seperate fuel system with race gasoline on the nitrous system. Methanol tends to freeze the jets when combined with nitrous and bad things happen. I have no idea if ethonal reacts the same.
As for compression, I personally just like a nice flat top piston with ~0.045" clearance to the head surface on a pent roof head. I believe most advertise these pistons as 10:1 on the 4G63 but they are closer to 9.6:1.
I know the methanol guys typically use a seperate fuel system with race gasoline on the nitrous system. Methanol tends to freeze the jets when combined with nitrous and bad things happen. I have no idea if ethonal reacts the same.
As for compression, I personally just like a nice flat top piston with ~0.045" clearance to the head surface on a pent roof head. I believe most advertise these pistons as 10:1 on the 4G63 but they are closer to 9.6:1.
I believe this what someoen was commenting on
Anyway aside from commenting on my tuner and shop of choice I was simply looking for some advice on what pistons to use. National speed org ordered me 9:1's but changed the order for me when I asked. I was just asking to see if my decision was the right one because Iv never had the experience of a motor build. Now if anyone has any more advice for me that would be greatly aprreciated.