forged pistons
08-02-2003, 01:54 PM
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forged pistons
I have been doing some research on forged pistons lately. Does anyone here run them? If so, what kind and what kind of sidewall clearence do you run? Stock for my engine is .010 - .030 mm, or .0004 - .0012 inches. I see that there are two common alloys, 2618 and 4032. The 4032 alloy has a higher silicon content (12%), so you can run a tighter sidewall clearance. I am just wondering how tight? I was first turned off by forged pistons because of the large clearences neccesary, which result in increased wear. I need this motor to last for a long time, so anything with a high thermal expansion is out of the question. Btw, since the 4032 is 12%, does that make it eutectic, or is the percentage number of what is hyper/hypo eutectic not set in stone because of the effect of the other elements in the alloy? I am also wondering how strong the 4032 is compared to a 2618 alloy and also a stock cast piston.
Also, I have read of tuning the thermal expansion rate of the cylinder wall with the piston. Anyone have any good info on this? TIA
-Mike
Also, I have read of tuning the thermal expansion rate of the cylinder wall with the piston. Anyone have any good info on this? TIA
-Mike
08-03-2003, 08:09 AM
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I dont really need them, but I would like them. The stock pistons are more then capable of getting me to 300 whp, but I think having forged pistons would be a nice safetly cushoin, especially if I try to do any serious tuning. Also, I could run a 9:1 c/r instead of 8.5:1.
08-04-2003, 08:03 PM
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Re: forged pistons
Originally posted by mpg9999
Btw, since the 4032 is 12%, does that make it eutectic
Btw, since the 4032 is 12%, does that make it eutectic
If you're not doing anything to crazy with your car cast pistons should be fine. One of the main advantages of forged pistons is their resistance to detonation. If your car is properly tuned that really shouldn't be a concern.
It normally goes cast -> 4032 -> 2618 as you go up in either RPMS or HP. When to move from one material to the next is really up to you and your wallet
What a great help that was
Here's some more reading:
http://shop.store.yahoo.com/sr20performance/enin.html
http://www.pcis.net/thehook/may.htm
http://www.hoon.tk/tech_tips/pistons.html
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08-04-2003, 08:39 PM
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I guess my main question is about the thermal expansion of 2618. How much more does it expand over a stock cast piston, and what increase in sidewall clearance will that require me to run.
08-05-2003, 05:00 AM
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Originally posted by mpg9999
I guess my main question is about the thermal expansion of 2618. How much more does it expand over a stock cast piston, and what increase in sidewall clearance will that require me to run.
I guess my main question is about the thermal expansion of 2618. How much more does it expand over a stock cast piston, and what increase in sidewall clearance will that require me to run.
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