Just bought an LQ4! What I'll do different:
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From: Guelph, Ontario
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Re: Just bought an LQ4! What I'll do different:
Pistons! Sealed Power H1129CT +.75mm, $30 each, hypereutectic flat top (turn an LQ4 into an LQ9) 4.030", 1.325" compression height, with pins offset by 0.030" for reduced "slap"
Even more necessary since I want to run a decent cam and I live at high elevation. And only half the price of forged pistons. I PM'ed Atilla, he says I can run mild boost ( "up to 12 psi absolute max., with intercooling and meth injection, on premuim gas with octane booster, and a proper tune. Polish the tops of the pistons, to keep the extra heat out of them." ) with these if I have the bores honed an extra thousandth, no more, and he will be sending me another PM about rings and gaps.
I don't see running boost at first, but considering how long these engines last, and how horsepower is an addiction for which you eventually need more, then eventually need even more, plus considering the thin air up here, it seems wise to have it honed accordingly. It shouldn't cost any extra. It's just a matter of finding a shop that agrees with Atilla and will do the extra thou.
Even more necessary since I want to run a decent cam and I live at high elevation. And only half the price of forged pistons. I PM'ed Atilla, he says I can run mild boost ( "up to 12 psi absolute max., with intercooling and meth injection, on premuim gas with octane booster, and a proper tune. Polish the tops of the pistons, to keep the extra heat out of them." ) with these if I have the bores honed an extra thousandth, no more, and he will be sending me another PM about rings and gaps.
I don't see running boost at first, but considering how long these engines last, and how horsepower is an addiction for which you eventually need more, then eventually need even more, plus considering the thin air up here, it seems wise to have it honed accordingly. It shouldn't cost any extra. It's just a matter of finding a shop that agrees with Atilla and will do the extra thou.
Your not making a LQ4 a LQ9 unless you buy bushed LQ9 rods & use a floating pin piston.
Build your motor for boost, or dont build it for boost. You need to think about much more then pistons in a boost motor. Hypereutectic pistons came stock in all LS series motors (Mahle makes them) so the pistons your looking at are just oversized stocker pistons, so you can treat the motor the same as you would any other stock short when it comes to boost. Also flat top pistons are not a boost piston, for boost you want more chamber volume to reduce compression ratio to allow you to push more boost.
Ive built 25+ LS series motors that made between 600 & 1300hp, i know what it takes to get power out of these motors. Feel free to shoot me a PM with any questions you've got
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Re: Just bought an LQ4! What I'll do different:
I could tell from Jamie's PM to me that boost wasn't really planned on, but I suggested the slight extra over-hone as a virtually free good idea. It is. Floating pins aren't worth anything in the way of extra power. They're great if you disassemble the engine frequently, but if the engine is expected to go years between tear-downs, they're not worth the hassle.
This build is looking to me to be a naturally aspirated combo, which would give 450-500 crank hp at sea level, depending on the heads. Virgin 241s would get this build to 450, while either out-of-the-box Edelbrock / Lingenfelter, or TEA-ported 241 heads, would push this to 500.
If Jamie wants boost later, a swap to either 317s or large-chamber AFR heads would drop the compression a full ratio without changing pistons.
Way too many enthusiasts are way too quick to jump on the forged-pistond bandwagon. Legit daily drivers do not need them. If you do need them, your engine is too wild for daily driving, regardless of what you might be happy to put up with.
I've seen twin-turbo LQ4s put down over 800 hp with drag radials, pump gas, and stock long blocks, except the cam. Even this is a bit wild for real daily driving, but it's more evidence against "needing" forgings in a build like this one.
This build is looking to me to be a naturally aspirated combo, which would give 450-500 crank hp at sea level, depending on the heads. Virgin 241s would get this build to 450, while either out-of-the-box Edelbrock / Lingenfelter, or TEA-ported 241 heads, would push this to 500.
If Jamie wants boost later, a swap to either 317s or large-chamber AFR heads would drop the compression a full ratio without changing pistons.
Way too many enthusiasts are way too quick to jump on the forged-pistond bandwagon. Legit daily drivers do not need them. If you do need them, your engine is too wild for daily driving, regardless of what you might be happy to put up with.
I've seen twin-turbo LQ4s put down over 800 hp with drag radials, pump gas, and stock long blocks, except the cam. Even this is a bit wild for real daily driving, but it's more evidence against "needing" forgings in a build like this one.
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