99blancoSS

iTrader: (115)

I have a forged 347 that was setup for a 300 shot of n2o. Is it good for FI?
I wanted to go turbo but knew I couldnt afford to.. but then theres a few kits for sale and so I'm wondering if its even something to think about wiht my current SB. I know the forged are good componants but what about gaps and clearances for heavy n2o vs turbo

anarchy99

iTrader: (7)

What compression is it running now? Thats going to be the biggest limiter to how much boost you can run.

99blancoSS

iTrader: (115)

My current head are shaved and I'm at 11:1 with flat top pistons so I figured I'd have to get different heads and lower my compression. So for me its wether or not the bottom end is ideal for for FI having been built for n2o

HUNTER02SS

iTrader: (24)

You will need to lower your compression alot to run a blower or turbo.Not sure about the ring gap's. I am sure they will be ok though. You might need to get a cam with a wider LSA also?

99blancoSS

iTrader: (115)

yea I figured a cam and head swap, its the blow by on the rings and the tolerances on the bearings that I'm wondering about.
Whats more feasible. Sell my current combo an build a different one for the fi application or convert.

TINKRD

iTrader: (27)

i went from a forged 346ci,, 10.8:1 compression w/ 300 worth of bottle to my current build which is a iron block 408ci, 8.5:1, GT47-88 and the ONLY thing i kept from the old motor is the rods.

everything else is new. i went from 5.3L heads to 317heads, from a Fast90/90 to a victorjr/90 intake. -2cc flat top pistons, to custom dished FI pistons.
From MS3 cam to a custom ground FI cam from LS1 Speed.

It just depends on how much power you want to make. My nitrous setup was making 705/800TQ, so i told myself if i was to ever take the FI plunge i'd want to go BIG.

99blancoSS

iTrader: (115)

thats the whole thing, I dont want to build a whole new setup unless I have to. 6-700hp is good enough for me. I know I can hit that with the n2o but I like the turbo route and know that with a 347 its feasible.

TINKRD

iTrader: (27)

then all you need to do is change pistons and heads and probably the cam

throw some 317 heads on the car and the appropiate dished piston and you'll have 9:1 compression.


you could keep your current setup and put a turbo kit on it, but you wouldnt be able to run much boost b/c of detonation issues.

99blancoSS

iTrader: (115)

So the pistons are wrong as well. I cant lose enough compression with just a head change? bummer, makes it a different story. Bob at Epp said with a meth kit and his s/c setup I could run decent boost with my current setup. But for the price I can get a turbo kit that has potential for more power.

TINKRD

iTrader: (27)

http://www.rbracing-rsr.com/compstaticcalc.html

99blancoSS

iTrader: (115)

whats the chamber size on the 315's? Dont AFR's have a 72 cc head?

mikep2002

iTrader: (10)

If I am correct I think AFR makes a 205 head that has a 76cc chamber. It all depends on how much boost you want to run. I have seen Z06 LS6 10.5:1 compression running 10/12 lbs boost with meth running in the 700 rwhp(without the big head). It all depends how much power you want to make in the future and some risk factor.

I think Texas Speed has the 76cc AFR heads on there site not sure though.

BigJls1

dude ,

I think you answered your own ? " I dont want to build a new motor unless I have to." Dont then: do a head change.
This topic brings an old question from a previos thread
"which is better more boost and low compression or low boost and high compression" If you get your c/r down to 10/1 thats at or below a stock ls1, stock bottoms are taking 8 psi with meth, your forged bottom could easly take 10 with meth and probally lay down 700 hp
IMHO. heres an Idea do the haed change keep the n2o but jet down to a 50 or 75 shot to get out of the hole, and only run 6 psi on your turbo. you will have over 400 hp from 2000 to 6000 rpm traction