Holley fuel injector frustration

[marasjm5]

Hello all; I'm putting together a E38 2011 silverado 5.3 with a single turbo. I'm leaning towards running MAP only. I've relocated my IAT to the intake manifold and adjusted my IAT calibration. I've also installed a 2.5 bar map, determined and adjusted my linear and offset, and I'm almost ready for a first start this weekend. One of the last pieces of my puzzle is to figure out how I can make my Holley 48lb 522-488 injectors work for my application with the lack of information given by Holley. Let me start by explaining that a good friend of mine graciously gave me these injectors which were nearly brand new. He used them for a very short period of time and decided to supercharge his engine, which meant he nolonger needed these ones. These injectors were the whole reason that I decided to turbo this truck, and that was before I understood anything about tuning. Here I am, new frame, rebuilt engine, rebuilt transmission, somewhat educated in the tuning field, topped with a single turbo almost done, and I can't afford new injectors at this point. Trust me, I'd like to buy different ones with proper data if I could. Considering the situation, can anybody shed a little light? Does anybody have or know where I can find solid data on these injectors? Thanks.

[Alvin]

There are GM 50's that people use that people seem to find for $50 on ebay.

Else you can fudge it by trying to use data from a injector that looks physically close to that.. It's a gamble and not correct but might get you going.

[gametech]

There are GM 50's that people use that people seem to find for $50 on ebay.

Else you can fudge it by trying to use data from a injector that looks physically close to that.. It's a gamble and not correct but might get you going.

I looked up that ebay link where people used to get the cheap flex injectors, and it no longer brings up that page. Maybe the guy sold out his stock?

[gtstorey]

I looked up that ebay link where people used to get the cheap flex injectors, and it no longer brings up that page. Maybe the guy sold out his stock?

My saved watch item shows out of stock. Might give it a week or two and see if he resupplies.
https://www.ebay.com/itm/274424906026

[gtstorey]

Hello all; I'm putting together a E38 2011 silverado 5.3 with a single turbo. I'm leaning towards running MAP only. I've relocated my IAT to the intake manifold and adjusted my IAT calibration. I've also installed a 2.5 bar map, determined and adjusted my linear and offset, and I'm almost ready for a first start this weekend. One of the last pieces of my puzzle is to figure out how I can make my Holley 48lb 522-488 injectors work for my application with the lack of information given by Holley. Let me start by explaining that a good friend of mine graciously gave me these injectors which were nearly brand new. He used them for a very short period of time and decided to supercharge his engine, which meant he nolonger needed these ones. These injectors were the whole reason that I decided to turbo this truck, and that was before I understood anything about tuning. Here I am, new frame, rebuilt engine, rebuilt transmission, somewhat educated in the tuning field, topped with a single turbo almost done, and I can't afford new injectors at this point. Trust me, I'd like to buy different ones with proper data if I could. Considering the situation, can anybody shed a little light? Does anybody have or know where I can find solid data on these injectors? Thanks.

It's just not that easy. About all you can hope to for is to get it running "ok" with injectors with that don't have good data.

[Alvin]

I looked up that ebay link where people used to get the cheap flex injectors, and it no longer brings up that page. Maybe the guy sold out his stock?

I have them, but my supplier isn't nearly as cheap and my price isn't as cheap as the ebay ones either.

Search my site for 50 injectors and you should find them.

[blindsquirrel]

Holley 48lb 522-488 injectors

screenshot.24-04-2025 16.06.07.jpg

You wouldn't want to use those even if there was data for them. Heavy, slow, ancient things.

[blindsquirrel]

https://www.gmpartsdirect.com/oem-pa...embly-12613412
https://www.rockauto.com/en/moreinfo.php?pk=1887186

[blindsquirrel]

These right here? https://www.ebay.com/itm/20543132886...e-offer-though
Fake. I am pretty sure Bosch isn't even the supplier on these, they're... Denso, right? Or Delphi? The LSA/LS9 12598646 are Bosch, yes. But not these. The upper o-rings are also wrong. Bosch doesn't use GM 8-digit numbers on their own-brand packaging.

edit: Delphi. Real ones are made by Delphi.

[blindsquirrel]

Used OE parts are often times a safer bet with so many fakes out there...
https://www.ebay.com/itm/15685880141...nope-not-today

[gtstorey]

These right here? https://www.ebay.com/itm/20543132886...e-offer-though
Fake. I am pretty sure Bosch isn't even the supplier on these, they're... Denso, right? Or Delphi? The LSA/LS9 12598646 are Bosch, yes. But not these. The upper o-rings are also wrong. Bosch doesn't use GM 8-digit numbers on their own-brand packaging.

edit: Delphi. Real ones are made by Delphi.

What is it with Hebron, KY? There seems to be a lot of "Straight from China" junk that gets shipped through there on eBay. I understand the west coast stuff but KY?

[blindsquirrel]

What is it with Hebron, KY? There seems to be a lot of "Straight from China" junk that gets shipped through there on eBay. I understand the west coast stuff but KY?

https://www.google.com/maps/@39.0776.../data=!3m1!1e3

screenshot.24-04-2025 16.53.32.jpg

[gtstorey]

https://www.google.com/maps/@39.0776.../data=!3m1!1e3

screenshot.24-04-2025 16.53.32.jpg

I never actually checked it on a map. I didn't realize it's basically the Cincinnati Airport.

[gametech]

I have them, but my supplier isn't nearly as cheap and my price isn't as cheap as the ebay ones either.

Search my site for 50 injectors and you should find them.

I don't need any. I just checked that link when someone on another forum asked about budget injectors, and found that it was no longer good.

[marasjm5]

I appreciate all of the information. I may try to get the truck running for now, but I think different injectors may be in order before I start driving the thing

[Alvin]

There was a time.. that we had to do all this without injector data. I want to say published injector data only became a thing in the 2010's.

But now days.. why?

[marasjm5]

its amazing how Holley sells my injectors for 600$ and they look physically identical to the injectors used in many applications from the late 80s to early 90s. it leads me to wonder if they're actually producing quality components. the fact that I cannot find the patent number for the 522-488 on Holley's own website also leads me to question who actually manufactures these injectors... Your comment led me down a bit of a rabbit hole and I began researching various injectors. All of the injectors that were comparable to mine in flow, shape, resistance, etc. had slower opening rates compared to the newer style GM injectors. heavy, slow, and ancient is a great way to describe them. I would love it if Holley would prove me wrong by being upfront and post proper injector data.

[marasjm5]

I plan to use injector data from another 48lb injector that looks physically similar and has (from what I've gathered) similar specifications. Hopefully it'll be close enough to get the truck running well enough to get it on and off trailers and drive in and out of the alignment shop.

[gametech]

You can easily fudge enough of your airflow data to move the car around the shop with any injector. Having good data is only important once you actually want good idle and drivability. Lots of racecars move on and off trailers and run WOT with nothing more than an approximate IFR.

[blindsquirrel]

Holley makes injectors (and sensors, etc.) to work with Holley EFI systems. In those, you pick which parts you are using from a little drop-down menu. They do not make their parts to be universally compatible with other systems, whether factory or aftermarket. Basically, their parts are proprietary, and used that way, they work OK I guess? It's kinda like going to the GM dealer parts counter and being pissed off the guy can't give you a head gasket for your Mustang.