LT5 Injectoes

[Ghostnotes]

Cirious as to how much HP you can squeeze out of LT5 injectors? My engine is built for big numbers and im wondering how much can be produced without meth/water etc. Im just restricted for the time being from going with a complete 30%+ injection system.

[TriPinTaZ]

I thought LT5 injectors were the same as LT4 and the extra fuel flow needed came from the port injectors? Or are you talking about the LT4.5 that comes in the new Escalade V?

[Ghostnotes]

I got the numbers screwed up.
I ment the injectors that come with the ZO6/ZL1. I always thought they flowed more.
Im stuck for now with budget constraints, but I am tired of just running 6-7psi. Im good with budgeting for what I thought was upgrading to LPFP/HPFP and ZO6 injectors, but going with the 30%+ setup right now is too expensive.

[TriPinTaZ]

Used LT4 HPFP, used LT4 injectors, and used JMS low side booster would be the cheapest way to bump your fuel delivery. Turn up the high side pressure to 3000-3200 if it will hold.


I actually have a JMS for sale as I went DSX low side when my fuel demands went beyond the LT4 stuff.

[Ghostnotes]

New clutch, torque tube and axles (future proofing) ate some of my fuel budget for now. Might take you up on that booster, but the injectors and HPFP I plan on new. My cam already has a 30% lobe. Im just wondering what kind of max HP i can squeeze out of an LT4 setup and be safe.

[TriPinTaZ]

With the cam lobe you can turn up the high side fuel pressure to 3300-3400 PSI and gain some headroom over what you would normally get at 2900psi. The stock LT4 injectors seem to be ok up there. They definitely handle 3200 psi without an issue as that is my standard go to on that setup.

[Estep40511]

There are three different injectors for the Z06 also....if you can get the high flow, you might get more out of it. I know on the factory side of things, anytime Im looking at a Z06 with the high flow injectors(doesnt happen often), the ECM is always pulling fuel. Kind of silly to even have them in from the factory, but thats what they do.

[TriPinTaZ]

I agree, if you're going to buy all new LT4 injectors, get the high flow part numbers. They will be SLIGHTLY better but you might squeak out 1 or 2 % more E lol. I know that isn't a lot but the flow variances in LT4 injectors isn't that much.

[Estep40511]

I agree, if you're going to buy all new LT4 injectors, get the high flow part numbers. They will be SLIGHTLY better but you might squeak out 1 or 2 % more E lol. I know that isn't a lot but the flow variances in LT4 injectors isn't that much.

On a stock LT4, the ECM doesnt really care which injector is in it. Ive put high flow replacements in a car that had nominal flow, just to get it back on the road. (backorder is a bad word at GM)

[TriPinTaZ]

On a stock LT4, the ECM doesnt really care which injector is in it. Ive put high flow replacements in a car that had nominal flow, just to get it back on the road. (backorder is a bad word at GM)

I'm referencing target lambda vs the wideband compared to ho much E you can run before you're out of injection time.

[Ghostnotes]

At this point I have no intention of running ethanol....straight pump gas.
From my understanding, I only had 4 choices when it comes to injectors. One was the standard OEM replacements. Two was the stock replacements for the LT4. Three a 30% LT4 variant and another I had just learned of recently which are huge. I am looking to see what kind of gains I can get with the stock replacement LT4's. The 30% are damn near 5k for a set, not to mention the HPFP upgrade....etc as well. I had a choice to either do the drivetrain or the 30% injector upgrade. To me it makes sense to upgrade the drivetrain first, but I have enough in the budget to go with the stock size replacements if I can get a decent gain from them for a year or so.

[TriPinTaZ]

$5000 for 30% injectors?! The XDI 30%+ (over LLT4 oem size) is around $2000, unless they raised their prices? I know LPE just jacked up the price of their HPFP by $1000. Fortunately I bought both the XDI and the LPE pump before any price bumps. I did have to wait 6 months for the pump and 6 weeks for the injectors though.

If you're not doing ethanol, then I would go with the LT4 stuff. You can find some used LT4 pump and injectors for about $1000 on the forums. I just sold my stock stuff for $1000 and it only had 10K miles on it. It's already in the guys car running perfectly. If you're concerned about budget, used is the way to go as long as you can trust the seller.

[Estep40511]

Ive got a brand new LT4 pump and nominal flow injectors for sale if interested.

[Ghostnotes]

I was referring to Lingenfelters, but I know for a fact a year or so ago a set of FIC or anybody else were 4000+. This might change a few things.

So I'm sure this has been brought up but who is most reliable and provides the most accurate injector data??

[TriPinTaZ]

i was referring to lingenfelters, but i know for a fact a year or so ago a set of fic or anybody else were 4000+. This might change a few things.

So i'm sure this has been brought up but who is most reliable and provides the most accurate injector data??

xdi