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-   -   Those running stock fuel pumps... (https://www.camaro5.com/forums/showthread.php?t=317533)

11syn3rgy 09-10-2013 03:40 PM

Those running stock fuel pumps...
 
Hey guys, just thought I'd let you know about my recent "holy crap" moment! I am running the Maggie TVS 2300 (3.8 pulley) with LT headers, high-flow cats, CAI Inc intake and Borla S-Type exhaust. THANK GOD I have the master (Mr Jannetty) tuning my car. I noticed some slight "surging" the other day at very light throttle. While I didn't think too much about it, I contacted Ted and he asked me to send him a data log so he could fix whatever was going on. I took my lap top, went for a cruise and sent him a low speed and a high speed data log (SCT) so he could take a look. I am only running around 6.5 lbs of boost with this 3.8 pulley and I am (as the title says) running the stock fuel pump. Ted immediately noticed that I am running dangerously LEAN once I get above 4500 rpm!!! NOT GOOD. This is nothing that he can tune for since my stock pump is simply NOT keeping up. Also keep in mind that my AFR is right where it is supposed to be (11.5:1). This is where I was missing it! I assumed that just because my AFR was dead on that my fuel pressure must be good? UMMMM, NOPE!! My poor LS9 injectors had to work near their peak (duty cycle) just to keep up. Thank God I didn't hurt anything! Needless to say, my ZL1 fuel pump and ADM controller are already on the way. I just thought that I'd share in case anyone else out there is in my situation. This is still a learning experience for me, but between this forum and Ted, I feel like I'll get 'er dialed in.

Thanks guys!

Nitroman28 09-10-2013 04:42 PM

If your AFR is 11.5 how are you running lean?

11syn3rgy 09-10-2013 06:41 PM

Quote:

Originally Posted by Nitroman28 (Post 6992667)
If your AFR is 11.5 how are you running lean?

My fuel pump was not keeping up with the proper pressure, so it forced my LS9 injectors to work overtime! I'm far from an expert on the topic, but when Ted tells me that I'm running "dangerously low fuel pressure", I gotta listen! ;)

Iam Broke 09-10-2013 06:58 PM

What was the fuel pressure and injector duty cycle?

11syn3rgy 09-10-2013 07:10 PM

I can only tell you the fuel pressure that the SCT data log showed. I'm not sure what the unit of measure is but according to Ted, its supposed to be holding steady at around 130. I was falling into the 70's at rpm's above 4500!!! He said that my duty cycle was close to maxed out but I didn't ask the exact percentage? To be honest, it really didn't matter to me at this point. I quickly ordered my new ZL1 pump and ADM controller.

11syn3rgy 09-10-2013 08:02 PM

Ted just told me to multiply my 133 number by 3 to get my kpa reading. 400 kpa equals approx 43.5 psi. When my numbers fell off to 77. That was around 19.5 psi. Not good!!

05SilverStreak 09-11-2013 02:55 AM

I am also trying to grasp the concept of a good AFR and being able to maintain a good AFR with low pressure. I run nitrous on a stock fuel pump so I need to know this. OP can you post more info if you get it on how this is possible?

11syn3rgy 09-11-2013 08:27 AM

Quote:

Originally Posted by 05SilverStreak (Post 6994126)
I am also trying to grasp the concept of a good AFR and being able to maintain a good AFR with low pressure. I run nitrous on a stock fuel pump so I need to know this. OP can you post more info if you get it on how this is possible?

The only thing that I have found out about my situation is that my low fuel pressure was forcing my injectors to work near their peak duty cycle. Once I install my ZL1 fuel pump and ADM controller, my injector duty cycle will come back down. You might want to contact Jannetty directly for your situation. I don't pretend to be an expert guys, I just wanted to make you aware of the potential dangers of our stock fuel pump on FI cars. I was under the impression that my stock fuel pump would easily be able to keep up at my HP level. That was not the case!

BooSSted 09-11-2013 08:39 AM

Didn't need the ADM component, but you have it already... Swap out injectors now and turn up the boost haha!

11syn3rgy 09-11-2013 09:47 AM

Quote:

Originally Posted by BooSSted (Post 6994503)
Didn't need the ADM component, but you have it already... Swap out injectors now and turn up the boost haha!

The ADM controller gives Ted more freedom to 'play' and after what just happened, seems like cheap insurance? Oh, and I am installing my 3.6 pulley. Gotta make the most of the situation, right? Hopefully I can manage a mid 11's in a few weeks at the track. That would make me very happy. Simple pleasures. ;)

Craig B 09-12-2013 06:26 AM

Quote:

Originally Posted by BooSSted (Post 6994503)
Didn't need the ADM component, but you have it already... Swap out injectors now and turn up the boost haha!

How much HP can the ZL1 pump handle?

bct10985 09-12-2013 06:47 AM

Im at 600rwhp on a mustang dyno probably around 650 on a dynojet, with zl1 pump and adm fpcm

Badbubba 09-12-2013 07:41 AM

Confused, if afr is 11.5 throughout the run, how can that be lean? I understand if the fuel pressure drops, the injector duty cycle would need to increase. Why wasn't this seen when you 1st had the car tuned? Or did you load a canned tune or have a different shop tune it? Surging at only light throttle sounds like something else since, I would think, the stock fuel pump should be able to keep up under light load. So, not sure if the surging would be due to fuel pressure. Quite possible surging is a tune problem and that the fuel pressure was observed to be dropping as well. 133kpa should be at idle on sct livelink2, multiply by 3 and then convert to psi. 400kpa=58psi. So 70kpa, 210kpa=30psi.

Ron_Robinson1 09-12-2013 08:50 AM

Quote:

Originally Posted by Criag B (Post 6995777)
How much HP can the ZL1 pump handle?


I have been over 600 rwhp for 7,000 hard miles without any issues this summer, and I don't use a ADM controller with my ZL1 pump. Car runs great.


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