Best way to go FI from current set up.
Best way to go FI from current set up. Current set up is more of a N20 build but wanting to change it to FI.
Plan is to make right around 1000rwhp
Current set up
418ci at 12.8cr (4" stroke "4.083" Bore)
PRC 237 heads milled 58cc
Flat top piston with -4cc reliefs
254/260 .630/.625
Fuel system is:
Weldon 2035B
60lb injectors (aprox 90% duty NA)
E85
Weighing options:
Swap the piston to a dish piston and rebalance bottom end (-14cc with .06 gasket = 11.3ish)
Swap the piston to a custom dish piston and rebalance bottom end (-18cc with .06 gasket = 10.9ish)
Swap to a larger CC head (72cc with .06 gasket = 10.9ish)
Obviously lower compression would be better, but is 11.3 too high for E85 and 1000rwhp?
The other question is, is it more of a static compression issue or a dynamic/cranking psi?
I know my buddies little Honda is making 960rwhp on E85 with 40ish lbs of boost trapping 163mph, just not sure what static compression is.
Plan is to make right around 1000rwhp
Current set up
418ci at 12.8cr (4" stroke "4.083" Bore)
PRC 237 heads milled 58cc
Flat top piston with -4cc reliefs
254/260 .630/.625
Fuel system is:
Weldon 2035B
60lb injectors (aprox 90% duty NA)
E85
Weighing options:
Swap the piston to a dish piston and rebalance bottom end (-14cc with .06 gasket = 11.3ish)
Swap the piston to a custom dish piston and rebalance bottom end (-18cc with .06 gasket = 10.9ish)
Swap to a larger CC head (72cc with .06 gasket = 10.9ish)
Obviously lower compression would be better, but is 11.3 too high for E85 and 1000rwhp?
The other question is, is it more of a static compression issue or a dynamic/cranking psi?
I know my buddies little Honda is making 960rwhp on E85 with 40ish lbs of boost trapping 163mph, just not sure what static compression is.
I think the cheapest option would be to switch out the heads. 10.9 ish compression would be great for a FI build. You would probably want to change out the cam too so it's more FI friendly.
Teching In
Joined: Sep 2007
Posts: 24
Likes: 0
I'd rather see a 64cc head with 0.030 gasket just to bump you down a few tenths. I wouldn't want 0.060 thick gaskets as to keep quench tight. I built the motor as 12:1 CR but after I had the valves changed out to an LS3 intake and Ferrea exhaust it bumped it down a bit. Like Josh said, I've seen 26 degrees from 4k up at 940rwhp. It made 920rwhp on 24 degrees and I haven't tried any more. Mine's also an aluminum LS2 block which I think helps a small amount.
Cam specs are below to give you an idea of dynamic CR.
Cam specs are below to give you an idea of dynamic CR.
Couldn't you sell your heads to offset the cost of a new set of LS3 heads??
Change out the springs 2 match a boost friendly cam and use an LS3 intake.
A single 88 on E85 and you have your quad digit RW
Change out the springs 2 match a boost friendly cam and use an LS3 intake.
A single 88 on E85 and you have your quad digit RW
