I have a Walbro 255lph fuel pump, bosch 36# injectors (I believe they are LS1 style).

My friend told me something about the ls1 injectors needing a different fuel pressure than lt1 injectors. Should I be running stock suggested fuel pressure right now. I've got the mods in sig.

 

You should run stock FP. The injectors are 36#'s @ a specific pressure which should be around 42psi. If you start messing with the FP your tune will not be correct.

 

I understand that I should run stock fuel pressure with 36# injectors, but I am saying that I think they are ls1 injectors.

If they are LS1 injectors, do I need to run a different fuel pressure?

 

Well, IMO if you don't know what kind of FP the were rated for I think you need to find that out FIRST. Then figure out what FP you're running at and adjust FP or find the diferance so you know what pressure you're actually putting out. I ran in circles saying that so I hope you understand what I mean.

 

Doesn't matter what they "fit" they are 36#. Figure your HP and adjust the FP to support THAT HP level. If ya went by "fit" the people who are running Motorsport injectors would be in a world of hurt.

 

what is stock fuel pressure? cause i messed with mine a lil bit too so maybe i need to set it back

 

46-47 with vacuum hose off. 38-39 with it on.

 

one more time...

If I run ls1 style 36# injectors on an lt1, would they require different fuel pressure than lt1 style 36# injectors on an lt1?

I am currently running at 43psi. I don't what vaccum hose you guys are referring to.

 

The hose to the fuel pressure regulator. Taking the vacuum hose of simulates WOT for the regulator. As already said you need to find out what pressure those injectors are rated at. Probably would get a better answer in the LS1 section.

 

Kurt, YOU ARE NOT LISTENING. What the guys are saying is that first you need to know is what pressure the 36lbs flow was at. IF that wqas at the LS1s 58psi they will still work just fine on an LT1 just at our 43.5psi will flow closer to 30lbs. No offense but just from this thread I am going to say you do not have enough knowledge yet to be playing with an adjustable regulator all you would accomplish is spending more money and making your tuners job harder.
If that 36lbs rating is at 43.5psi then they will flow more like the 42lbs mentioned aerlier if run with LS1 58psi, someone eluded to the fact the SVO injectors so popular for upgrades on the LT1 are rated at 39psi so on an LT1 a 30lbs SVO flows a little more than 30lbs which the tuner compensates for when setting up the injector ratings in the tuning no adjustable regulator needed.

Adjustable regulators are best left to the guys like Injuneer who know what they are doing and have a specific goal in mind for using one. IMO using one to tuner or to make small injectors act arger is foolishness unless you are at a point where larger injectors are going to require MAJOR rework of the setup but that isn't the case till I think over 50lbs. injectors so VERY FEW of us will ever be there. Yes a regulator costs less than new injectors BUT figure on selling your current injectors when upgrading and all of a sudden an injector swap is brought down to the cost of a regulator and some of the aftermarket regulators have had MAJOR quality issues and as noted playing with them greatly complicates your tuners job.

 

I am currently at 43psi. I have not adjusted the fuel pressure at all. I was just curious to know if I needed to. But now I know that I cannot adjust my fuel pressure unless I was informed to by my tuner.

So, even if these injectors were rated at the ls1's fuel pressure at 36#, then 30# for me would do just fine for a </=500hp setup. Right?

 

Ran the actual math rather than the guesitmates and 36LBS at LS1s 58psi is 31.2 at the LT1s 43.5
At a BSFC of .45 which is a good number for NA they would support 500FWHP at about a 91% duty cycle for forced induction they would be too small though. This is asuming the 36lbs rating is indeed at the LS1s pressure which you really need to verify as goss injector size missprogramming can do serious damage very fast be it too small or too large.
Should be a PN on the side post it up and we will see whatwe find.

 

I will post up the part number as soon as I get back to NC. I do know that they look like ls1 injectors, not lt1 injectors.

 

A 30# Motorsports injector will make 500FWHP with 53#PSI of fuel pressure.A36# Motorsport injector WILL make it at 40PSI. This is keeping them below 90% duty cycle@.5 BSFC
If your injectors are rated 36#@58PSI then to make 500FWHP they will have to be at 55PSI

 

So if they are rated at ls1 fuel pressure, I need different injectors. If they are rated at lt1 fuel pressure, I am fine. Right?