Choosing compression ratio

[sprucegagt]

But I wouldn't use the stock 3400 head gaskets. Leaving .060" quench area will increase KR instead of decreasing it. You really want to keep quench around .040". So when using them your CR raises to 12.3:1.

[silvergtjrad]

Ahh, makes much more sense to me now guys, thanks. The DOHC pistons do give you
12.4:1 then, but that is using the 3400 gaskets. If you use the Ironhead gaskets for better quench, the compression goes up too much to make them useable.

Well, so much for that. Anyone need a set of brand new, stock bore DOHC pistons? $100 shipped in the USA.

[geldartb]

its either making the combustion chamber on the heads bigger to drop the CR a little, with the combo of the .040 head gaskets.

or custom pistons using the .040 headgaskets.

[silvergtjrad]

its either making the combustion chamber on the heads bigger to drop the CR a little, with the combo of the .040 head gaskets.

or custom pistons using the .040 headgaskets.

Im tired of messing around and spending money on things that dont work. Im just going to get my block bored as much as possible, and get some custom 12:1 pistons made. I can still return the DOHC pistons, and easily sell the other forged set for what I payed for them.

[silvergtjrad]

I forgot about this thread, but I ended up going with an 11:1 compression ratio on a set of forged pistons from JE. The shop I used is dicking me around though. Its been about a 4 month wait for them so far. In the last month Ive stopped in once a week to see WTF is taking so damn long. They just keep telling me one more week, two weeks, they should be in by friday, etc..... I wish I could just tell them to fuck off, and go to another shop, but they require a deposit in full for the pistons before they are made. Sigh. The shop has a really good reputation with some pretty high end race cars, but I'll be damned if they gave a shit about me.

[Barry]

Ive got a bottle heater already, and already have a way to retard timing. I have the nitrous spray directly at the IAT sensor, and have it tuned to pull timing when it gets below a certain temp.

Thats creative. My concern is that the time it takes for that sensor to react and to pull the timing. Somewhere I read that that is a very slow sensor, or maybe that was a MAF iat sensor...

[silvergtjrad]

I have my performance enrichment throttle position set low enough that it doesnt give me a problem. At 50% throttle it starts giving it more fuel, and the spray wont come on until 3300 rpms and full throttle

[bob442]

how much did a set of pistons cost from JE?

[i8sum2]

nitrous doesnt effect your cr it just has more oxygen in it then air so u can dump more fuel in and get more hp so its about tuning