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LS1 Injector Flow Ratings Okay, so I know there has been tons and tons of debating on what the LS1 injectors actually flow... I had purchased a set of them for my new engine, and shortly after I had found a few different flow ratings for them... So I kept searching, and found even more information, and so much of this information was conflicting information. So... I decided to send one out and have it flow tested. The part number of my injector was GM - 12561462, Bosch - 280 155 931. This was one of the set I got from SLP as Take Outs. Rich at Cruzin Performance did the flow testing for me, he also compared it to another LS1 injector, GM #12555894, Bosch #280 155 890. So now, heres the results directly cut from the e-mail Rich sent me: Due to the variations in fuel blends available across the nation, I tested them at two different Specific Gravities (sg). One was 0.685sg and the other was 0.770sg. By doing this, it covers most of the ranges of available fuels. Just for further reference, on the day they were tested, I also measured some fresh 87 Octane regular unleaded fuel and it measured 0.725sg. The common conversion factor of 10.5 was used to convert mL/min into Lb/hr. Following is the test data.... Test date: 8-21-05 Time: 15:30 Fluid Temperature: 69F Barometric Press: 29.99 Relative Humidity: 53% Altitude: 940ft above sea level Injector #280 155 931 GM #12561462 60 Second static flow test @ 0.685sg @ 3Bar = 270mL divided by 10.5 = 25.714 Lb/hr 60 Second static flow test @ 0.685sg @ 4Bar = 315mL divided by 10.5 = 30.00 Lb/hr 60 Second static flow test @ 0.770sg @ 3Bar = 255mL divided by 10.5 = 24.285 Lb/hr 60 Second static flow test @ 0.770sg @ 4Bar = 297mL divided by 10.5 = 28.285 Lb/hr Injector #280 155 890 GM #12555894 60 Second static flow test @ 0.685sg @ 3 Bar = 250mL divided by 10.5 = 23.809 Lb/hr 60 Second static flow test @ 0.685sg @ 4 Bar = 295mL divided by 10.5 = 28.095 Lb/hr 60 Second static flow test @ 0.770sg @ 3Bar = 240mL divided by 10.5 = 22.875 Lb/hr 60 Second static flow test @ 0.770sg @ 4Bar = 275mL divided by 10.5 = 26.190 Lb/hr As you can see from the test results, the flow rate of the injector varies considerably depending on the specific gravity of the fuel and also the pressure they are operating at. Other factors such as the temperature, barometric pressure, humidity, test altitude and the test equipment all have to be taken into consideration when testing injector flow. Given that, I performed these tests twice, on two of my flow benches and the results remained consistent each time. This is not an exact science due to all the variables involved. Because all injectors are manufactured within a range of tolerances, and in this case only one of each part number was tested, the test results would not necessarily represent what a complete set of injectors would flow. I hope however this provides you with data you requested and that you can use it to help dispel some of the "myths" concerning these injectors. I'm sure someone out there in "cyberland" will cry "foul" and say the data is biased or untrue. All I can say to that is that I call it as I see it when testing them. I don't sell injectors so I have no "conflict of interest" in recording or reporting data and I'm not interested in debating what injectors are advertised to flow vs what they actually test at. 1 bar = 14.503 psi 92 Octane tested at 0.745sg. 87 Octane tested at 0.725sg. 3 bar = 43.509 psi 4 bar = 58.012 psi I hope this information helps clarify a lot of things for us... if you need to know the flow rate of other injectors, I believe you can just email Rich at Cruzin Performance, and he may know what they flow if he has recently tested any. After dealing with Rich, I have to say he provided the best service I have ever received from a business, I urge you to have him service your injectors if you need them serviced. He promptly responded to my emails and let me know exactly what was happening. |
Good info, thanks! Also nice to know that GM went back to Bosch injectors. Learn something new every day. RBob. |
I see sticky. And this is why I and numerous others recommend Rich, always steps beyond the call of duty. |
Excellent info -- Thanks for FINALLY putting this issue to rest for us!!!!! |
Good job and excellent data. I want to point out that the LS1 Camaros (I have a '99 SS) came with two different flow rates. The '98, '01, and '02 LS1 Camaros came with the 28.x lb/hr injectors, while the '99 and '00s came with the 26.x injectors. These values are measured at 58psi (4 bars). It appears that you flow tested one of each, one LS1 injector is from a '98 and the other is from a '99, for example. This compares very favorably with the comparison between the L98 and LT1 Camaros, 22 vs 24 measured at 43.5psi (3 bars). BTW: Rich is the MAN when it comes to injector testing! |
Okay I have 2 more bits of info relating to this... I was looking at the injectors and the stock clips... The clips can't be modified to hold the injectors... so I tried to make some clips with little success. I then decided that it might work out if I cut the grove in the top of the injector so it goes all the way around, like an older style injector. So I tried it, works like a charm. Then I tried to seat them in the intake while they were clipped in the fuel rail... looked pretty good, but what about flow? Will the intake block the plume of fuel? I tested that also, no matter how far the injector is in the intake, the plume stayed the same, from all the way seated in the intake, to barely in the intake at all, the intake didn't block the injector. Looks like I'm going to be fine with these injectors in those 2 respects. We'll see about flow once I get this thing up and running, I have a feeling I will need more pressure to get them to satisify the engine. |
Originally posted by TheMysticWizard Okay I have 2 more bits of info relating to this... I was looking at the injectors and the stock clips... The clips can't be modified to hold the injectors... so I tried to make some clips with little success. I then decided that it might work out if I cut the grove in the top of the injector so it goes all the way around, like an older style injector. So I tried it, works like a charm. Then I tried to seat them in the intake while they were clipped in the fuel rail... looked pretty good, but what about flow? Will the intake block the plume of fuel? I tested that also, no matter how far the injector is in the intake, the plume stayed the same, from all the way seated in the intake, to barely in the intake at all, the intake didn't block the injector. Looks like I'm going to be fine with these injectors in those 2 respects. We'll see about flow once I get this thing up and running, I have a feeling I will need more pressure to get them to satisify the engine. |
Next question would be for optimum performance how close in performance should each injector be in a set of eight. I have read where they can vary maybe 6% which is quite abit. If Rich were to test a set of eight and two were off by quite abit how would one go about finding two more that match? Or do some cylinders not draw in quite the same amount of air that others might. Such as the 5-7 cylinders??? Just food for thought. Would this not be a reason why one motor will out perform another with identical parts? The closer the injectors match in performance I would think the better the overall horsepower would be. If two cylinders were slightly rich, another two slightly lean the O2 sensor might read 13.0 but in reality the cylinders were not in fact buring 13.0. They could be 12.5 and 13.5 respectively. Just thinking. |
Your comment about cylinders 5 and 7 drawing more air, is a good reason to put the two highest flowing injectors in those two positions, provided of cource that you flow tested all 8 injectors. Do people have more of a problem with cylinders 5 and 7 running lean? Or having detonation damage? |
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