kwigs160966
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Didn't you go with 9.1:1? How long until your build is finished and will you still run pump gas?
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SignUp Now!Compression ratio is something you need to discuss with your engine builder. Stock 10:1 seems to work very well with the URD system. If you reduce CR you will loose power when you are not in boost and can make the engine feel sluggish when you are not hammering down on it. In the end this is something you are your engine builder will have to decide together.
G
Didn't you go with 9.1:1? How long until your build is finished and will you still run pump gas?
Durability.
The stock pistons are made in a way to keep production costs very low. The material uses a high silicone content to keep the expansion rate very low. This helps with cold start emissions by allowing the piston to cylinder wall clearance very tight. The down side is they can be very brittle and when you add boost and get some knock they can crumble like a dirt clod. The common failure point is the ring land that supports the compression ring.
A forged piston uses a different process and stronger material. Production cost is much higher and are not commonly found in production engines except high end stuff and aircraft. Durability is much higher and tend to stand up to boost and knock much better.
Down sides are cost, heavier weight, high expansion rate so they tend to be loose when cold and are prone to piston slap until fully warmed up.
G
Thanks for the explanation
I knew that forged were stronger due to grain alignment, but wasn't aware of expansion rates being different...would that mean you need to warm up an engine with forged internals a little more before beating in it due to larger clearances??
Dave
R u home yet I dont cvthe ticking time clock on the bottom.
Project take engine out and rebuild It is about to start.