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Flow Matched Injectors

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Old Dec 17, 2025 | 03:52 PM
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Default Flow Matched Injectors

Are flow matched injectors necessary for milder builds? I'm about to pull the trigger on a set of new injectors and I can get brand new x8 set of Bosch L77 injectors for $220 shipped to my door. I'm looking at pretty much double that (a bit over $400) for a set of the same injectors that have been flow matched...

Is this money worth spending now? Could I get them flow matched at a later date?
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Old Dec 17, 2025 | 06:38 PM
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Not a big problem with new injectors. It’s the older that can have wear or deposits. Weakened coils. I’m going to match mine with a DW65c pump to match their needed flow. Adequate flow, no overkill. Will you have any wide band testing when your build is complete? If the wide band is good, flow matching can be a later option. Misfires or lean plugs would mean testing in needed.
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Old Dec 17, 2025 | 07:35 PM
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Originally Posted by G8 Drew
Will you have any wide band testing when your build is complete?
As in will I have wideband sensors on the exhaust? Yes, probably one per bank. Doubt I’ll bother with one per primary.
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Old Dec 18, 2025 | 08:28 AM
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if you are buying new injectors from a reputable source it is unnecessary most likely, what are you considering as a "mild" build?

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Old Dec 18, 2025 | 09:27 AM
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Originally Posted by 1988montecarloss
if you are buying new injectors from a reputable source it is unnecessary most likely, what are you considering as a "mild" build?
L92 with BTR Trinity intake, 102mm TB, VVTI delete, decent cam, valve springs, injectors and I think that’s about it.
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Old Dec 18, 2025 | 12:17 PM
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IF the highest manifold pressure you run is "ZERO" you don't need to pay extra for flow-matched injectors.
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Old Dec 18, 2025 | 03:09 PM
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Thanks for the advice all, I've ordered a set of 8 new but unmatched Genuine GM Bosch 12639221 injectors from an L77.
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Old Dec 19, 2025 | 02:53 AM
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Originally Posted by MattFatPanda
Thanks for the advice all, I've ordered a set of 8 new but unmatched Genuine GM Bosch 12639221 injectors from an L77.
Spoiler!
From where you ordered?

Last edited by AmbroseWinthrop; Dec 29, 2025 at 12:52 AM.
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Old Dec 19, 2025 | 05:41 AM
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Originally Posted by AmbroseWinthrop
From where you ordered?
A company in Australia. 290AUD for 8.
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Old Dec 21, 2025 | 01:07 PM
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RC Engineering in California used to do this. I know Russ passed away several years ago, so not sure if they're still around, or not.....
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Old Dec 21, 2025 | 03:14 PM
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Interesting timing on this topic. A guy down the street from me is doing a budget low boost turbo build, and I am selling him my 20 year old siemens deka 60lb injectors that I replaced a couple of years ago with 1050cc FICs when I added a flex fuel sensor to my car. The set was never flow matched to start with, and I decided to clean and test them before selling them. The spread between highest and lowest flow was about 6.5%. I believe the factory acceptable tolerance is around + or - 6%.
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Old Dec 23, 2025 | 11:40 AM
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RC Engineering is still around. They now are known as RC Fuel Injection.
Phone#: (310) 320-2277. Hope this helps.....
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