Latest thoughts on turbos, pump 93, meth, and compression ?
Eventually, i plan to throw some forged pistons and rods in my LS3 shortblock and im interested in what most people are liking as far as compression on a street pumpgas engine running an air to air and 50/50 water /meth.
right now, im running the SBE with 72cc 317 heads and ricer worthy .098 MLS head gaskets. Static comes in at 9.2 and ive had zero issues at 14psi and 15* .
reason i ask is i really hate killing the quench with those gaskets and the JE pistons that are going in later on have -5cc valve reliefs the stock pistons dont have. With stock LS9 gaskets, my compression would come in around 10.1.
Whats the concensus these days on pump gas, water/meth and moderate boost. How much would the .8-.9 higher compression tighten my tune window ? Id really like to get out of ricer ed with my engine, but since its worked great with the SBE setup, i wont hesitate to run the fat gaskets if the extra compression is gonna cause tuning grief.
what do the turbo ls gurus say ?
right now, im running the SBE with 72cc 317 heads and ricer worthy .098 MLS head gaskets. Static comes in at 9.2 and ive had zero issues at 14psi and 15* .
reason i ask is i really hate killing the quench with those gaskets and the JE pistons that are going in later on have -5cc valve reliefs the stock pistons dont have. With stock LS9 gaskets, my compression would come in around 10.1.
Whats the concensus these days on pump gas, water/meth and moderate boost. How much would the .8-.9 higher compression tighten my tune window ? Id really like to get out of ricer ed with my engine, but since its worked great with the SBE setup, i wont hesitate to run the fat gaskets if the extra compression is gonna cause tuning grief.
what do the turbo ls gurus say ?
I run a 5.3 stock deck and light cleanup on some 862 heads with stock GM LS1 MLS gaskets. Stock everything except springs and pushrods and a custom blower cam. I run 15psi daily via a billet 78/75 on the cheapest 93 pump I get my hands on with wiper fluid at 750cc/min and a eBay A2A. I run about 18* at 15psi and the stock compression is 9.5:1 which is a tad higher than you. I think you could run more timing for sure which will pick u up a bit of power and at 15psi you could easily be 18-20* as the 50/50 really helps with detonation but sucks alittle power as it displaces air and fuel.
most here will tell you that you could bump compression and run straight meth for optimal results. Or you could leave it as is and just bump the timing abit as your compression is alittle lower and safer. You could also rip those 317s off and put on some 862 or 706 heads and pick up a bunch of power. Richard holdender didn’t a test recently
with a 5.3 with 706 and 317 heads and the 317s made a lot less power and made more boost (restriction), 706 heads made like 30hp and 40ftlbs more at .5psi less boost. If boost was increased on the 706 heads to match the 317 the power different would have been even greater.
best option would be stock 5.3 heads, straight meth and bump the timing and boost.
EDIT: forgot I also run the TR6 plugs. I thought about running the bR7 but I’ve heard of issues running them out of boost.
most here will tell you that you could bump compression and run straight meth for optimal results. Or you could leave it as is and just bump the timing abit as your compression is alittle lower and safer. You could also rip those 317s off and put on some 862 or 706 heads and pick up a bunch of power. Richard holdender didn’t a test recently
with a 5.3 with 706 and 317 heads and the 317s made a lot less power and made more boost (restriction), 706 heads made like 30hp and 40ftlbs more at .5psi less boost. If boost was increased on the 706 heads to match the 317 the power different would have been even greater.
best option would be stock 5.3 heads, straight meth and bump the timing and boost.
EDIT: forgot I also run the TR6 plugs. I thought about running the bR7 but I’ve heard of issues running them out of boost.
Heard of the Ohio Boys? Ever seen back to back testing on rear mount turbo's where they went from tubular long tubes to stock manifolds? Zombie on here did it. I don't need a specific link when the physics and info is obvious that cast manifolds simply retain more heat instead of dissipating it.......I thought you didn't do racecar stuff. Everything is a street car 
Racecars also care about weight and not everyone can fit stock manifolds.
Racecars also care about weight and not everyone can fit stock manifolds.
Rear mounts exacerbate the results of good vs. bad manifold heat dissipation, making the results and proof more obvious. I'm not saying stock manifolds perform terribly, they work for tons of people and I started out with them as well. But then I moved on as I don't like to be stagnant, I like to try new things and see what actually works rather then just rely on what others say. That's why my turbo setups change every 6 months!
I'm not saying stock manifolds perform terribly, they work for tons of people and I started out with them as well. But then I moved on as I don't like to be stagnant, I like to try new things and see what actually works rather then just rely on what others say. That's why my turbo setups change every 6 months!
And I'm simply saying that if the primary diameter isn't a limitation due to motor/cfm.....a stock manifold will out perform a tubular manifold all things being equal. Plenty of people spends tons of money on parts that aren't needed. Plenty don't need anything other than a stock manifold for 1000hp.
True as I've seen north of 1200 on stock manifolds but that in itself doesn't define everything about them, also doesn't mean switching to another manifold can't make more power or be more responsive out of boost. Really a mute point as both setups work plenty well enough for most anyone to be happy with and most people wouldn't notice either way.
