Forged pistons
01-11-2008, 11:35 AM
#1
Racer
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Forged pistons
I would like to hear from people who have used forged pistons in a lt1 and had any problem with the greater clearance of the forged ones over the hyper. ones being affected by the knock sensors. I am building a 383, and just got to wondering about the piston slap with forged piston when they are cold, and if it might trigger the knock sensors. Any experiences with this would be helpful. Thanks, Tom
01-11-2008, 11:44 AM
#2
Racer
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Well, I don't know how I got this in the C6 section. It's supposed to be in the C4 area, and I don't know how to move it. Sorry, but if any of you could help, I'd be glad to hear from you. Tom
01-11-2008, 02:30 PM
#3
Drifting
I've got a forged 427 in my C6, with diamond forged pitons in at .0055 clearence. If there is any piston noise it's gone soon after start up, and you don't hammer the car when it's cold anyway. At least I don't. So the knock sensor concern isn't really an issue. Don't worry about it no matter what engine your talking about
01-11-2008, 10:27 PM
#4
Racer
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I would like to hear from people who have used forged pistons in a lt1 and had any problem with the greater clearance of the forged ones over the hyper. ones being affected by the knock sensors. I am building a 383, and just got to wondering about the piston slap with forged piston when they are cold, and if it might trigger the knock sensors. Any experiences with this would be helpful. Thanks, Tom
01-12-2008, 08:08 AM
#5
I have an LT4 in my Porsche 944 conversion, and definitely install a LT4 knock sensor. I was using a LT1 sensor and experiencing ignition retard from the noise the aftermarket cam and lifters were making, Swapped the sensor to LT4, and it completely eliminated the problem. Good luck.
01-12-2008, 08:20 AM
#6
Racer
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I have an LT4 in my Porsche 944 conversion, and definitely install a LT4 knock sensor. I was using a LT1 sensor and experiencing ignition retard from the noise the aftermarket cam and lifters were making, Swapped the sensor to LT4, and it completely eliminated the problem. Good luck.
You can also program the computer regarding retard but I own tuning software keeping the stock setting.
The only problem you have is posting in the wrong section.
01-12-2008, 12:18 PM
#7
Melting Slicks
You will never detect the forged piston "slapping". Also, the ECU is not even looking at knock until the engine is up to minimum temp and goes into high gear. It will then advance timing just over the knock point, then retard it just under.
I wouldn't even consider a cast piston in a serious engine build. Some of the newer hyperutectic pistons made be Ok, but you cannot go wrong with a good forged piston.
I wouldn't even consider a cast piston in a serious engine build. Some of the newer hyperutectic pistons made be Ok, but you cannot go wrong with a good forged piston.
01-13-2008, 12:43 AM
#8
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You will never detect the forged piston "slapping". Also, the ECU is not even looking at knock until the engine is up to minimum temp and goes into high gear. It will then advance timing just over the knock point, then retard it just under.
I wouldn't even consider a cast piston in a serious engine build. Some of the newer hyperutectic pistons made be Ok, but you cannot go wrong with a good forged piston.
I wouldn't even consider a cast piston in a serious engine build. Some of the newer hyperutectic pistons made be Ok, but you cannot go wrong with a good forged piston.
No problems with my LPE 403 motor. 
