what injectors!!!

[transmaro93]

hopen for 550 crank (give or take)..... going to try and get 450+ to the wheels.... im an m6 so it might be doable...

[S.J.SLEEPER]

keep in mind that if going aftermarket or ford injector, look at what the injector rating is @ **psi. lot of injectors are rated @ 43 psi where the ls1's run 53 psi . so if looking at a 36# injector @ 43psi it is mor like a 39-40# injector @ 53psi

if you go to F.A.S.T. website there is a chart to use for h.p. vrs. injector. that should help you decide your injector size.

[transmaro93]

^^^ thanks ill check that out... not quite following the psi changes though... for some reason the fast 42# are like $300 more than all their other sizes on ws6store..i cant figure that out...

[LTb1ow]

What don't you get?

One will flow a certain amount at pressure X, but if your car rails run at pressure Y, it will be either more/less than that rating.

[transmaro93]

anybody know what pressure stock ltx fuel rails run at with a walboro 255

[LTb1ow]

43 ish?

yeah 42-45, youll be fine with Delphi 37# if itll save you money, i should be putting down around 500 at the crank or a little more and my car runs great

[LTb1ow]

Originally Posted by 86Formula

yeah 42-45, youll be fine with Delphi 37# if itll save you money, i should be putting down around 500 at the crank or a little more and my car runs great

Oh yea? How do you figure?

point proven on AIM

[transmaro93]

your getting crazy numbers for a stock bottom end N/A.... crazzzyyy.... id like to hear your point... just so maybe id learn somthing that i dont know to run the times you do with a car set up like yours...

[LTb1ow]

He thinks his car is fast or something.

[transmaro93]

thats pretty fast for stock bottom end and N/A 500+hp crank tho..... ???

[LTb1ow]

Yea, he thinks its gonna hit tens or some craziness like that.

[transmaro93]

is that car gutted?

[S.J.SLEEPER]

he must have put an LS1 in it !!!!

[Pampered-Z]

If your looking to go 500+HP then I would go with the 42 injectors if your N/A, with boost or NOS then you might want bigger because you'll need extra fuel. You really want to go no higher then 80% DCs or your holding the injectors open too long and you run the chance or shortening the life of the injectors or having a cylinder(s) go lean.

Note that you are also going to need a fuel pump that can feed those injectors at that HP target. A stock pump is most likely not going to be able to feed 500 HP.

You don't need to be too concerned with fuel pressure itself, more with it staying consistent. That is, it matters less if you 40 or 60 PSI of pressure throughut the RPM range, but that you're pump can feed bigger injectors throughout the RPM range.

Your PF is not going to change based on the pump, if you want to change the pressure then you need an adjustable FP regulator. But the need to change it is somewhat of a mute point. Once your tuned, if you change the pressure the ECM will adjust the injector pulse to compensate, you only need to change the pressure if your using it as a tuning aid. But remember the stock ECM is a bit limited, if you go real high with fuel pressure you could have more trouble getting a quality idle, higher RPMs is less of an issue then better the ECM to control a very short injector pulse for idle and tip in.

The LT1s I've built that are near 400RWHP are geting close to maxing out the stock fuel pump. One at 380RW is close to the limits of the stock injectors, another is just over 400 HP running 42# and the next upgrade will have a new FP on the parts list.

My 383 engine ( blower = extra fuel needs ) made just over 500 RW with 9 lbs of boost and the 42's were getting pushed just to the 80% duty cycle. (racetronic pump and wiring harness) So when the time comes to raise the boost level I'll need larger injectors and probably a second fuel pump as well.

[sweetbmxrider]

he has the typical walbro/racetronix pump setup

[transmaro93]

^^^ what he said... also im N/A... and im going to run stock FPR... iv been told i should be find with it as long as the tune is good... thanks for the info though... very helpfull... that goes for everybody

[transmaro93]

ended up going with "pampered-z's" recommendation.... and ordered up a 8pk matched set of racetronix injectors last night... hope they will work becuase they dont give application specific parts they just offer what they do... but i used the link from papered... went with 42#ers.... so hopefully everything will work out good there... orderd those and the hotwire kit strait from racetronix... had no idea they were stationed in canada (yea i know... uhhgg canada)... but they shipped them already today... so thats that for now..

[LTb1ow]

Eh?

[transmaro93]

ehh? .... hey anybody ever order an opti from "thepartsladi" on ebay.... she is sopposed to sell oem stuff... but its not a delco part... rather a delphi part only becuase i dont think delco makes this stuff anymore... just wondering if anybody has used them... i wasnt going to replace my opti becuase i dithink there was nothing wrong with it... but then took matts advice and decided to do it....

[LTb1ow]

Thats the one thats on mine. Although I would go MSD.

[transmaro93]

iv read alot of threads on the subject and alot of people say that the oem is the best unless you want to get into the dynaspark that is like a million dollars... dont forget im only using it for the trigger... not the cap and rotor assem...

[LTb1ow]

Ohhh ok, nice. OEM then.

[transmaro93]

what does the msd offer over the factory part? just for reference