Flow Balanced Injectors
Thread Starter
Safety Car
Joined: Jul 2005
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From: Jackson Tn
St. Jude Donor '06-'07-'08-'09
Flow Balanced Injectors
I have seen this term used several times and at what HP does it start to effect the engines performance? Or even worse cause a lean cylinder.
Can you look at the plugs to see which ones are flowing more that the others to use those on the famous #5 & #7 cylinders that fail because they run lean?
Can you look at the plugs to see which ones are flowing more that the others to use those on the famous #5 & #7 cylinders that fail because they run lean?
"AlohaC5" Senior Member
Joined: Jun 2003
Posts: 3,562
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From: Madison, AL
I believe flow matched fuel injectors become a signficant factor while driving at high RPMs vs. high horsepower. A dyno session should tell you what your fuel injector duty cycle is so you know whether or not you're maxing out your current set of injectors and need to go a size bigger. You can lose a cylinder in a relatively low horsepower engine to a "leaned out" condition due to a poor tune - ask me how I know (I lost my original cammed LS1 years ago on a road course due to a poor dyno tune - factor of timing, A/F ratio and other parameters). My current set of injectors are "flow matched" because of how I run my engine - road courses.
Last edited by Gray Ghost GS; Nov 22, 2011 at 10:33 PM.
Team Owner
Joined: Mar 1999
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From: At the beach in little Rhody
On my current setup, I sent the injectors to New Era Performance for cleaning and flow testing. I then put the two highest in the rear two cylinders noting that the flow differences were actually quite small.
As an aside, my old 1990 L98 never started good when hot and it seems most of the L98's had this characteristic. I bought a set of flow matched Lucas disc injectors and the hot start problem went away. Note that I had done both a balance and leak test on the original injectors to ensure that wasn't the issue prior to buying the new set.
As an aside, my old 1990 L98 never started good when hot and it seems most of the L98's had this characteristic. I bought a set of flow matched Lucas disc injectors and the hot start problem went away. Note that I had done both a balance and leak test on the original injectors to ensure that wasn't the issue prior to buying the new set.
Thread Starter
Safety Car
Joined: Jul 2005
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From: Jackson Tn
St. Jude Donor '06-'07-'08-'09
AlohaC5, I can see my inj duty with HPTuners and at WOT I'm at about 80% with mine. But what I don't know is what each cylinder is doing. This might be more of an issue as you push the inj toward 100% and having a cylinder go lean.
Just how much can they vary from each other?
Just how much can they vary from each other?
Melting Slicks
Joined: Jun 2005
Posts: 2,396
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From: Sicamous BC
I had the unlucky 7 syndrome, searching never found answers.....some good theories.
One tuner suggested to me running fatter injectors on 5 & 7 would be corrected by the NB's...then when you tune with WB you are doing the same thing again. Kinda made sense to me.
One tuner suggested to me running fatter injectors on 5 & 7 would be corrected by the NB's...then when you tune with WB you are doing the same thing again. Kinda made sense to me.
Le Mans Master
Joined: Nov 2005
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www.cruzinperformance.com flow tests them, cleans them and flow tests them again and posts the #'s for you online.
Tech Contributor
Joined: Apr 2007
Posts: 10,924
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From: Forney Texas
It is a good idea to learn how to properly read plugs and start doing that. You can not only determine fueling, but timing as well. The guys in the nitrous section of Yellow Bullet are constantly reading and discussing plug reading. That's where I picked up the best information. Using a good tool to read them is highly important too. I use a 10x otoscope to read mine. You must know that you can't simply pull a plug and read it. You need to put a fresh plug in and make a pass and shut it down. Pull the plug and read it.
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Thread Starter
Safety Car
Joined: Jul 2005
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From: Jackson Tn
St. Jude Donor '06-'07-'08-'09
It is a good idea to learn how to properly read plugs and start doing that. You can not only determine fueling, but timing as well. The guys in the nitrous section of Yellow Bullet are constantly reading and discussing plug reading. That's where I picked up the best information. Using a good tool to read them is highly important too. I use a 10x otoscope to read mine. You must know that you can't simply pull a plug and read it. You need to put a fresh plug in and make a pass and shut it down. Pull the plug and read it.
