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I'm putting together an lq4 with a btr stg. 3 truck cam running 799's and long tubes. I have a stock 2001 lq4 intake, rail, and injectors. I've been reading and reading about injectors but seems they all need an adapter or are the wrong height. What would a good plug and play injector be for this set up? Thanks guys
36 lb flex fuel injectors from the newer truck (rock auto says 2010 and newer) 4.8/5.3s fit into the old truck intake like yours as well as into the newer truck intake as that's what they are off of.
12613411 is the part number. No spacers needed regardless of the old truck intake's fuel rail or the newer truck intake's square fuel rail.
I've used these injectors on both old and new truck intake with no issues.
Wiring connectors are different so that needs to be changed.
36 lb flex fuel injectors from the newer truck (rock auto says 2010 and newer) 4.8/5.3s fit into the old truck intake like yours as well as into the newer truck intake as that's what they are off of.
12613411 is the part number. No spacers needed regardless of the old truck intake's fuel rail or the newer truck intake's square fuel rail.
I've used these injectors on both old and new truck intake with no issues.
Wiring connectors are different so that needs to be changed.
You're quite welcome and I am using hp tuners so if you are as well, I can send you the adjusted injector data for those injectors as a bonus. It took a little time to convert the data to a gen 3 style ecu (2011 tune info for those injectors doesn't line up correctly in the 2005/2006 and older Ve style ecus so you can't copy and paste directly from the newer stuff associated with those injectors).
Data for those injectors are in the sticky in the PCM section.
I run them in my car. It's a 50lbs injector @ 4-bar.
I just looked at that 36 lb sticky and that appears to be 39-42 lb injector data not 36 lb. It would also seem to make sense that it's called GTP 36 lb as the GTP injectors are known to be 39-42 lb injectors according to some however I can't confirm that part.
The flow rate versus kPa is the giveaway usually as the sticky 36 lb data starts at 39.8 and goes to 43.7.
36 lbers converted to Ve style ecus have flow rate vs kPa starting at 35 and going to 38. Based on 58 psi fuel pressure.
A stock 2011 5.3 tune with those 36 lbers I mentioned has a minimum injector pulse of 0.750 while the 36 lb sticky has a Min Injector Pulse of 1.27 (04 z06 ls6 injectors are 1.26 and people call those 28 lb injectors)
My data for the 36 lbers is derived from spreadsheets based off of reputable tuners such as Marcin Red hard supra as well as Ed Mowton however I understand there is more than one way to skin a cat in terms of what data to use and how it will effect the tuning/tune.
Of course you can tune around different injector data but big weather fluctuations will show the less accurate data in terms of afrs drifting away from their target more often than not. Accurate data will enable the ecu to keep things a bit more steady as the external environment changes.
Having said all that, if your afrs are happy and all is well at low rpms and high rpms, all is well and the data is fine that you have.
In my case, I'm SD only now and have had nearly the exact same air fuel ratios at 7 degrees Celsius at full throttle compared to a 23 degree Celsius day (temp I originally tuned at) at full throttle. In the end, if it works it works
Edit: some minor confusion as another spreadsheet gives the following info (1st pic) even though I entered in 37.7 lbs and not 36 lbs. I entered in 37.7 because the resulting 58 psi fuel pressure data shows almost identical data to a stock 2011/2012/2013 5.3 tune (2nd picture)
Using the ec tune spreadsheet and entering in 36 lbs with a fuel pressure of 58 psi gives the following info which is less than the factory tune so maybe these 1263411 injectors are 37.7 lbers at 58 psi.
This has me a bit confused now but based on purely factory tune flow rate values and this spreadsheet, my data is a similar amount lower from the factory values as the 36 lb sticky data is higher from factory values.
Using the sticky 36 lb injector data matches up to the ec tune spreadsheet's 39.87 lb/hr @58 psi value as seen below. So maybe gtp injectors are 39 lbers but it seems like the 12613411 injectors are smaller if you compare factory 2011/12/13 5.3 tunes and the injector data.
Jake fusion, I've looked at many of your posts and they helped me when I was searching so please don't take this the wrong way, it just seems like the sticky data is not quite the final set in stone data for a 36 lb injector at 58 psi.
Wph351, I apologize for any confusion here but don't worry as the 12613411 injectors you ordered are a great idea as we know they're at least 36 lbers. You can obviously use whichever data you wish and see what gives you more consistency after tuning. It will probably be fairly close but if you religiously analyze your wideband readings, you may see a contrast between the data. Good luck and good choice on a decent but affordable injector.
I wasn't aware that they made a 36 in the later trucks since they were all flex. They had two variants: 42 and 39. Both are 39mm.
I run the L92 Flex 42lbs. The data for them is accurate.
Ah yes now it makes sense. My mistake was calling the 2011+ 4.8/5.3 injectors flex fuel which they dont appear to be but if you search e85 compatible vehicles, the 2011-2012 4.8 and 5.3 does qualify. Regardless, they are 12613411. I just thought they were forsure flex fuel due to their great flow as a regular gas 2005 6.0 Lq4 has 24-25 lb injectors while these newer 4.8/5.3 injectors are 36 lb and flex fuel needs more flow than regular gasoline.
The 39-42 lb part makes a lot more sense as those are on the newer 6.0 truck intakes from the newer years and they are called 12613412 (2013 6.0 Vin G, flex fuel listed on rock auto), just one digit difference. So if Wph351 purchased 1263411, he has to use 4.8/5.3 data from a 2011-2013 tune.
I wasn't aware that they made a 36 in the later trucks since they were all flex. They had two variants: 42 and 39. Both are 39mm.
I run the L92 Flex 42lbs. The data for them is accurate.
If this spread sheet is accurate, you have 50.4 lb injectors as I guess the 42 lb name comes from their rating at 43 psi. Kind of neat to see GM putting big injectors into naturally aspirated trucks.
I looked up a stock 2011 gmc sierra HD 6.0 tune and the injector data was almost dead on with the spread sheet in the picture. So at full throttle, zero manifold vacuum (0 kPa in the gray column for ls1 style ecus and at 400 delta Map kPa in the newer ecus) it's supposed to flow 50.4 lbs/hr. Wicked for boost and other big mods!
Wph351, if you ordered the 12613411 injectors, the data I have was confirmed after I sent off my injectors for a cleaning. At 58 psi the operator told me it flowed 368 ml/min so 368 cc/min which is 35.04 lb/h. A bit less flow than the newer truck factory tune says (37.7 lbs) but it's still much better than the factory lq4 injectors that are rated at 24.5 lbs (checked the factory tune finally) at 0 kPa manifold pressure and 58 psi fp.
My confusion earlier was because the spreadsheet data I got based on the factory 2011-13 5.3/4.8 didn't match my current tune for the 36 lb injectors (35 lb in my case). I later remembered that I used the injector flow test ratings for my actual injectors in my tune. It seems like that would be the most accurate way to get data catered to your specific set of 8.
The ones I bought are reportedly from an 08 flex fuel motor. What might these be? Lol. There is a lot of confusing/conflicting data out there. Whenever they arrive I'll supply the number off of them.
Hi all, sorry to revive an old post. I'm considering the 36lb injector on my build. Is a SBC 350 with aluminum vortec heads, cam, edelbrock pro flo intake and all the related stuff. I'm using a 0411 pcm and was seeing the flow tables but honestly I don't know where to put that info on the tune. I'm using hp tuners and not to pretend to be a tuner expert. Also regarding that injectors, any suggested brand?
10-25-2017, 10:45 AM
Lq4 injector question 
