My setup:
383 gen 1 sbc, forged everything
8:1 comp.
TFS 195 cnc chamber heads,72cc-as cast
224/236, .573/.593 116* lsa hyd roller (xe high lift)
motown single plane intake converted to efi
90* elbow w/75mm tb
Electromotive Tec2 ecu
Aeromotive A1000 pump, reg., filters etc. -10 feed line, -8 return
D1SC 18+ psi boost
custom air/water intercooler
1-3/4 long tube header, 3" exhaust, x-pipe, borla mufflers and dumps
TH400, 3000 stall PI converter
9", detroit locker and 3:73 gears
I have 55lb injectors and when I ran the car on the dyno it fell flat at 5400-5500 rpm, 14+ afr! It did make 520rwhp, but should still have plenty more in it.
I talked to an Electromotive dealer today and he said 55lb injectors should be plenty for my setup, what do you guys think?
I would think this setup should be good for 650+ rwhp (out of line?)
By the way, this is in a 69 Nova (no kidding dude, that's your member name!). The reason I am asking you guys is because I can't find a forum like this that caters to old stuff with modern efi., etc. Also, LT1's and gen 1's are enough alike that the same stuff works. Thanks for letting me hang out, I would appreciate any help.
Steve

 

As long as you are using an Electromotive, why don't you get some big low impedance injectors and run them? At least the TEC3 will run low impedance injectors, so I am assuming the TEC2 will as well. BTW: I run a TEC3r in my race car and really like it. I am surprised you don't hear more about Electromotive here.

Rich

 

i had 75's in a similar setup. they were holding thier own but running up on the duty cycles (85+). switched to 160's and the car picked up immediately. as a side note though the 75's were more streetable although i haven't really played with the 160's a whole bunch for that purpose.

 

To be specific, ~90# ought to be enough for just about anything.

Rich

 

I did try some 72's, but they were too rich at Idle/cruise and I do like to drive it on the street.
I am switching to a Tec3 soon, a friend has a spare one off his bike and I'm getting a good deal. I might run it staged, said friend is doing this in his twin turbo 470ci Mopar Wedge Cutlass. His car works very well this way.
I will probably keep the 55's for my primaries and maybe 4- 72's on the secondaries- my intake is already plumbed for the 4 extra in the base of the 90* elbow.
I also have some 30lb'ers I could use, what do you think?
Steve

 

*shameless plug*

Well if you change your mind about the 72lb injectors I have some for sale.

 

I have similar combo, stock ecm, fuel lines, with a six speed so not sure extra loss from auto would be. with 55 pound siemen injectors I made 657 to the wheels.

I even had room to pull fuel from tune that was in the car from previous combo.

John

 

using a basic injector formula your engine should be able to push 700 hp x .6 brake specific fuel consumption = 420 lbs per hour. divide that number by 8 cylinders = 52.5 lbs per cylinder. take that number and divide by max duty cycle of an injector of 80% = 65.63lb injectors.
the formula is hp x bsfc=lbs per hour of fuel. then,

lbs of fuel per hour / number of injectors= fuel requirements

lbs per hour injectors / .8 = injectors safe point without going over 80% duty cycle

bsfc of a naturally aspirated engine is normally .45-.50, most supercharged and turbocharged cars is .60-.65

max duty cyle is 80%= most injectors do not run efficient at under 1.7 milliseconds. these are general guidelines and every engine is different

 

Changing to a Tec3 ecu so now I can go full sequential. I should be able to run a 72 and idle fine.
Steve

 

We run a TEC3 in my buddies Mustang. It idles fine, though a bit rich at ~12.5:1 with 160lb injectors.

Rich

 

when I ordered my DFI system I had them get me the fuel injectors at the same time and pre program my system for them, they told me 48s would be the smallest it would be maxing them out but would work, after talking with them and deciding I went with F.A.S.T 65s for in there then.

 

rskrause, should I run the Tec3 in sequential, or should I go with a staged setup?

 

Frankly, we haven't seen much difference between running batch fire and sequential. And sequential can be a PITA to setup. We use batch fire.

Rich

 

The guy I'm buying the Tec3 from is running in "phased" sequential for the 8primary injectors (83's), and has 8, 160lb injectors staged for secondaries with his Tec3.
My intake and plumbing are set up for 8 primary injectors and 4 more for secondaries. I am thinking about using my 55's for pri. and 72's for sec., what do you think?
Steve

 

are 96#s too big for idle? will 78s high Z work just fine???

My big puzzle is we have an ls7 pushing close to 800rwhp with a YSi with 60# injectors!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!