Going FI and will be pushing 6lbs. The car is going to use a small cam and ported heads. It will probably produce a little over 460rwhp. Would 36lbs be enough or will I need the 42lbs ones? Thanks for your help!

 

I would go with the 42's which will leave you a little room to breathe. If you have any thoughts of pumping up the boost in the near future, which usually happens with us power hungry folk, then i'd consider 60's. You'd be good with them for quite some time and the'll support a lot of power. You'd probably run out of fuel system in that case before you run out of injector. Even with the 42's though, make sure your fuel system is up to par. A safe bet is at least one 255hv pump in the tank like the Racetronix setup.

Ken R.

 

My 36#s were at 76% dutie cycle on my 383 making 411RWHP thru a 12bolt auto. I think 42s should be fine for you.

Jay

 

60# mototrons and never have to worry

 

Ya I have a 255lph in tank pump. If I'm going to do a dyno tune do I need the FMU or an inline pump? I figure with the right injectors and in tank pump I should be able to tune the car for the SC on the dyno. AF ratio is everything.... right?

 

It's not everything. Make sure you don't have too much timing in it also. The single in tank 255 should support 6psi. You talking with 36'ers or 42's? I would guess the 36'ers would hang but i'd be more comfortable with at least 42's in there. Do you have a boost referenced regulator along with a fuel pressure gauge? If so, watch it closely. If your building boost but your fuel pressure isn't rising with it, that could be a sign of not enough fuel volume from your pump. If your fuel pump is up to par but your not richening up your A/F as you add fuel in your tune, then that could be a sign of too small of an injector. I would try and stay away from the FMU route if you can help it and add fuel in your tune at WOT if you have that capability. It's the better way to go IMHO. Let us know how it goes...

Ken R.

 

since an intank 255 is good till 500-550rwhp i think you should get the bigger 42's so you dont have to touch the fuel system for a little while. Its only a matter of time til your going to up the boost.

 

Ya I will get the 42 pound injectors. I'll be running a boost referenced regulator, boost gauge, and fuel pressure gauge. I'm also considering a A/F ratio gauge.

 

i would just get some siemen deka 60#'s
PM me for a place to get em pretty cheap, i paid like 350 for the set of mine i believe

 

Go big or go home I'm in the 460 range on 48's and I'm running out of injector. Just get the 60's buying injectors once are cheaper than buying twice.