steves86ta

iTrader: (5)

Hi All

I am personally carb-retarded. I do not understand them i do not like them and am not good at tuning them.

Here's the deal, im building a Jet Boat with an LS in it. Engine specs are as follow

LS2
Milled 243 heads (11.5:1 static compression, 10.19:1 dynamic compression)
BTR Stage 4 NA cam (235/242 .621/.592" 111+3)
Victor JR Intake
MSD 6012
Open Large tube headers (1 7/8 primaries)

I have a Holley 4150 750 CFM carb with mechanical secondaries and no choke.

Stock jetting is supposed to be 71/80 and a PV of 6.5

I will be running a mix of 100 leaded and 91 octane.

Anybody know carbs enough to get me a close baseline to get started with?

what should i look at changing/setting up?

Thanks

TXsilverado

iTrader: (18)

run the carb stock with a wideband and go from there.

steves86ta

iTrader: (5)

any recommendations for a wideband setup? something inexpensive would be nice.

Also, my exhaust is "wet" meaning water is injected into it. Will this matter?

TXsilverado

iTrader: (18)

never done a boat, but that sounds like a combo I would want tuned on an engine dyno for peace of mind. it's hard to get accurate wideband values on a open longtube much less with water getting pumped through the exhaust. how exactly is water pumped through the exhaust on this thing?

steves86ta

iTrader: (5)

Yeah thats what its sounding like. Gonna try a few things and go from there. Maybe check the plugs out

Water is injected into the primary tubes above approx 2k rpm. For a few reasons;
1. At idle if the cam is to radical (this one is) its possible for the engine to suck in water
2. Noise suppression
3. Cool off the headers
4. Legal obligations

OkieDave

Turn off the water. Get a wideband. Look for 12 or so AFR. Tune up or down with jetting. Timing is also critical. Ask around. Someone will help.