Running out of injector or pump
06-17-2018, 04:13 PM
#1
Pro
Thread Starter
Running out of injector or pump
Alright, so I have a walbro 255 in tank with a racetronix harness, and a ecs fuel ring with a -10AN line feeding a magnaflow protuner 750 pump. From the Y, it goes into a -8 to a aeromotive fuel pressure regulator, and a -8an line to the stock fuel rail. On the fpr, I have a -6 return that goes to the factory drain. I’m at 10psi and afr is at .75 lamda on e85 pump. I have a fuel pressure of 59psi, and when my second pump comes on at 2psi, fuel pressure goes up to about 62psi. My injector duty cycle is at 95%. I noticed at wot, my fuel pressure drops from 62psi to 60psi. Am I running out of pump, or am I running out of injector. If I hook up a vacuum line to the fpr, and turn down the base pressure to 55psi or lower, will that give me room to push it to 15psi. btw I’m not sure what should the proper base pressure be at if your using a boost reference regulator, if someone knows, please let me know. Also, I’m running deka 80lb injectors. Thanks in advance.
06-17-2018, 05:51 PM
#2
Melting Slicks
Set your base pressure between 55-58 with the vac line disconnected to keep the factory jet siphon pump happy.
Did you delete the OEM FPR?
Am I reading correct the you have the AFPR in the feed line with the return leaving the outlet of the AFPR? It's always been my understanding that you want the AFPR in the return line not in the feed line. I feel that having it regulate the feed could lead to problems.
Did you delete the OEM FPR?
Am I reading correct the you have the AFPR in the feed line with the return leaving the outlet of the AFPR? It's always been my understanding that you want the AFPR in the return line not in the feed line. I feel that having it regulate the feed could lead to problems.
06-17-2018, 06:26 PM
#3
Pro
Thread Starter
So here is the break down of my fuel system. I deleted the stock fpr/filter. The in tank pump is a racetronix 255 with there pump upgrade harness. ECS ring with a -10 line into a 100 micron filter, and the filter into a magnafuel protuner 750 pump. Then I have both pumps go into a Y and the feed from the Y goes into a 6 micron filter. Btw, coming from the pump, there is a -8 line. That micron filter is attached to a aeromotive fuel pressure regulator, on that fpr, the bottom return goes to the stock return with a -6 line. From the FPR, there is a -8 line that goes all the way to the stock fuel rail where there are 80lb deka injectors
06-18-2018, 01:50 PM
#4
Burning Brakes
I’m having a similar issue with the protuner 750 & a Bosch 044 pump with 127cc injectors on E85. I can’t believe with all that fuel going up front you got away with a -6 return. I had to do a -10 return. I changed out some fittings and I’m waiting to get on the dyno to see if I’ve got it worked out.
My injectors were at 95% around 650 RWHP and 13lbs of boost. My fuel system should support 1000 RWHP all day.
My injectors were at 95% around 650 RWHP and 13lbs of boost. My fuel system should support 1000 RWHP all day.
Last edited by junk c5; 06-18-2018 at 01:53 PM.
06-18-2018, 02:06 PM
#5
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I've got a -6an return on mine and haven't had any issues, twin walbro 450's in the tank, fic 127's, and e85 making about 850 and duty cycle is in the low 90's... I have a set of fic 1650's that will be going on later in the year just to give me some room
06-18-2018, 03:58 PM
#6
Burning Brakes
When I added the magnafuel pump and started the car with -8, the fuel pressure gauge was erratic and wouldn’t hold a constant fuel pressure. I swapped to -10 and the fuel pressure was rock solid. My car has been fighting me since day 1 so me having an issue isn’t out of the ordinary
06-18-2018, 04:50 PM
#7
Pro
Thread Starter
Are any of you guys boost referenced? Cause I'm not. Also, the stock return line for the tank is 5/16, so that's why I have a -6 line going to it. Do any of you guys use a Y that goes into the stock return line and the return on the ecs ring? Also, will ditching the stock rail and going aftermarket, give me better flow?
06-18-2018, 05:01 PM
#8
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When I added the magnafuel pump and started the car with -8, the fuel pressure gauge was erratic and wouldn’t hold a constant fuel pressure. I swapped to -10 and the fuel pressure was rock solid. My car has been fighting me since day 1 so me having an issue isn’t out of the ordinary
Are any of you guys boost referenced? Cause I'm not. Also, the stock return line for the tank is 5/16, so that's why I have a -6 line going to it. Do any of you guys use a Y that goes into the stock return line and the return on the ecs ring? Also, will ditching the stock rail and going aftermarket, give me better flow?
06-18-2018, 05:06 PM
#9
Melting Slicks
Are any of you guys boost referenced? Cause I'm not. Also, the stock return line for the tank is 5/16, so that's why I have a -6 line going to it. Do any of you guys use a Y that goes into the stock return line and the return on the ecs ring? Also, will ditching the stock rail and going aftermarket, give me better flow?
I would think that in theory going to aftermarket rails and putting the regulator after the rails would lead to better flow for multiple reasons. Bigger ID on the rails is the obvious one(dont believe this is your problem) but you’re currently cramming a 3/8”(OEM feed) and 5/8” feed into a single 3/8” line using a tee. You’re also regulating pressure before the rails which, like I’ve said, I always thought was less than ideal. I have no concrete evidence to provide you but I would imagine that regulating pressure pre-rail could create some oscillations/pressure drop in the rails as the regulator bypasses fuel. Putting it after the rails would ensure that the rails are constantly full as the pressure is bled off after the fuel leaves the rails. Again, I have no technical data to support this.
If I were you(not knowing whats strapped to your motor or power goals) I would make a fuel system where both of your pumps share a common path into a y block that splits that to feed each rail, two return lines or even a rail mounted FPR with a crossover line and a -6AN return straight back to the OEM point on the fuel hat.
Last edited by Turpid porpoise; 06-18-2018 at 06:14 PM.
06-18-2018, 05:24 PM
#10
Pro
Thread Starter
Sorry, I have a heads/cam ls6 with a bw s475. I’m at 10psi right now, but I want to turn it up to 15psi. Of course on e85. I’ll try what you said and go from there. I’ll set my base pressure to 55 and hook up the vacuum line also.
06-18-2018, 05:40 PM
#11
Burning Brakes
I’m boost referenced. The supply and return ports on my regulator are -8. Off the top of my head, I believe I’ve go a magnafuel EFI MP 9950-B
Last edited by junk c5; 06-18-2018 at 05:42 PM.