Raising allowable fuel pressure on HP Tuners - Camaro5 Chevy Camaro Forum / Camaro ZL1, SS and V6 Forums

Valkyrie14 · 09-18-2021, 06:03 PM

I installed a dual pump and 100# injectors last March. I had it tuned and the tune is good. I was looking at my parameters the other day and I saw that my max fuel pressure was set at 58. So…why?

Can’t I take it up to 100 theoretically? And if so, can I just change that part of my tune without throwing everything else off?

I am not a tuner, I have had three tuners and spent about 1200 on them combined. I don’t want to drop another 300-400 to make what seems like a minor adjustment.

larry_g · 09-18-2021, 06:51 PM

58 is stock psi and seems to work well with most injectors. I think it just puts them in the sweet spot for injector duty cycles and pump output.

Even my system that doesn't use the FPCM to control pressure still has a a base setting of 60 psi. It then uses a 1:1 fuel pressure regulator to increase pressure as boost increases so that the pressure differential across the injectors remains constant. A change in pressure settings would require a new tune.

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Valkyrie14 · 09-18-2021, 07:06 PM

Quote:

Originally Posted by larry_g

58 is stock psi and seems to work well with most injectors. I think it just puts them in the sweet spot for injector duty cycles and pump output.

Even my system that doesn't use the FPCM to control pressure still has a a base setting of 60 psi. It then uses a 1:1 fuel pressure regulator to increase pressure as boost increases so that the pressure differential across the injectors remains constant. A change in pressure settings would require a new tune.

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So the setting isn’t actually limiting the fuel pump?

larry_g · 09-18-2021, 07:28 PM

Quote:

Originally Posted by Valkyrie14

So the setting isn’t actually limiting the fuel pump?

It depends on how your system is set up, on mine that setting has no impact. I only use the FPCM to monitor fuel pressure for logging and the safeties that will kill power to the pumps in case of an accident.

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Valkyrie14 · 09-18-2021, 07:38 PM

Quote:

Originally Posted by larry_g

It depends on how your system is set up, on mine that setting has no impact. I only use the FPCM to monitor fuel pressure for logging and the safeties that will kill power to the pumps in case of an accident.

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I moved my FP sensor to the FP regulator and ran wires back to the original location of the FP sensor. So I believe the FPCM is still engaged. I just want to make sure I am getting most out of my system.

larry_g · 09-18-2021, 07:49 PM

Quote:

Originally Posted by Valkyrie14

I moved my FP sensor to the FP regulator and ran wires back to the original location of the FP sensor. So I believe the FPCM is still engaged. I just want to make sure I am getting most out of my system.

Unless you are running out of fuel or maxing out injector duty cycle, there really isn't an advantage to increasing pressure.

For example, before I upgraded my fuel system, my tuner had to increase the injector duty cycle to compensate for running out of pump. Fortunately I had big enough injectors to handle it but it was a bandaid fix at best. That's why I upgraded. I now have a fuel system that can handle more than twice my current power level.

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G8One2 · 09-18-2021, 08:39 PM

The fuel pump itself has an internal regulator that won't let it go past 58 psi. You'd need a ZL1 pump or better to run higher pressures. I currently have a ZL1 pump installed and running 60 psi at the rail. I could run up to 65 psi if I wanted.

Valkyrie14 · 09-18-2021, 09:28 PM

Quote:

Originally Posted by G8One2

The fuel pump itself has an internal regulator that won't let it go past 58 psi. You'd need a ZL1 pump or better to run higher pressures. I currently have a ZL1 pump installed and running 60 psi at the rail. I could run up to 65 psi if I wanted.

I have a AGP dual pump.

G8One2 · 09-18-2021, 10:08 PM

You may need to copy over the ZL1 parameters in the FPCM. Then make changes to desired pressure, low flow, high flow and default pressures under the fuel tab.

Valkyrie14 · 09-18-2021, 10:19 PM

Quote:

Originally Posted by G8One2

You may need to copy over the ZL1 parameters in the FPCM. Then make changes to desired pressure, low flow, high flow and default pressures under the fuel tab.

Thanks, I will check that out.

gtstorey · 09-20-2021, 10:22 AM

The pump curve won't necessarily let you change it to any psi. A major change like 100 psi probably wouldn't be possible and at least would put the pump way off it's best efficiency point.

This is for pumps in general, so more of a warning to be careful. I haven't seen the pump curves for any of the fuel pumps available.

eLeSthree · 09-23-2021, 09:57 AM

Quote:

Originally Posted by Valkyrie14

I have a AGP dual pump.

The FSCM (fpcm) isn't controlling fuel pressure if you have a mechanical fuel pressure regulator.

prod · 09-24-2021, 05:15 PM

Why are you wanting higher pressure? I would be looking at correct fuel volume, which is what tuners determine using AF ratio. Not enough volume makes it go lean assuming the injector duty cycle is reasonable.

G8One2 · 09-25-2021, 09:07 AM

Higher pressures make your injectors flow more, if your fuel pump can keep up. I've got mine running 60psi at the rail. My injectors are 65lb/hr at 38psi and 80lb/hr at 60psi. No, I dont really need that much flow, but I needed more flow for E85 and I want to eventually do more mods. Wanted to make sure I never max out my duty cycle on the injectors.

09-18-2021, 06:03 PM	#1
Valkyrie14 Valkyrie14 Drives: Chevrolet Camaro SS Join Date: Mar 2020 Location: Eau Claire, Wisconsin Posts: 962	Raising allowable fuel pressure on HP Tuners I installed a dual pump and 100# injectors last March. I had it tuned and the tune is good. I was looking at my parameters the other day and I saw that my max fuel pressure was set at 58. So…why? Can’t I take it up to 100 theoretically? And if so, can I just change that part of my tune without throwing everything else off? I am not a tuner, I have had three tuners and spent about 1200 on them combined. I don’t want to drop another 300-400 to make what seems like a minor adjustment. __________________ 2014 SS LS3/LSA Supercharger, 10% Super Damper, 2.55 upper, AGP Dual Pump, ID 1050 injectors, Pegasus solid rear cradle bushings, LT Headers, Roto-Fab CAI, Elite E2 catch can, E85 corn fed, 160 Thermostat, Monster Twin Disk, MGW Short Throw shifter, Tick Clutch Master Cylinder, HP Tuners, JL Audio system.

09-18-2021, 06:51 PM	#2
larry_g Drives: 2014 1SS/1LE Join Date: Nov 2015 Location: Louisville, KY Posts: 826	58 is stock psi and seems to work well with most injectors. I think it just puts them in the sweet spot for injector duty cycles and pump output. Even my system that doesn't use the FPCM to control pressure still has a a base setting of 60 psi. It then uses a 1:1 fuel pressure regulator to increase pressure as boost increases so that the pressure differential across the injectors remains constant. A change in pressure settings would require a new tune. Sent from my Pixel 5 using Tapatalk __________________ 830 WHP 700 WTQ, Whipple 2.9 @ 13lbs Boost, Flex Fuel Tune by Blevins Tuning, LSA SBE, 3.5 GripTec, ATI LS3 Damper, AFR 260cc Mongoose, ARP Studs, Yella Terra Ultralites, Johnson 2110R, BTR PDS Stage 3, Melling 10355, Improved Racing Baffle, ID1050X, DSX Triple Fuel Pump, RotoFab CAI, NW 103mm TB, Stainless Works 1-7/8" LTH to 3" Speed Eng w/ X-pipe to NPP, Powermaster 9509 XS, Detroit Speed Motor Mounts, MGW, Monster LT1-S, ZL1 Calipers, DBA Rotors & Pads, Bilstein B6 Struts & Shocks, BMR 1.25" Drop Springs & Adj Rear Bar, Pegasus Solid Bushings, Z/28 Wheels, other misc parts.

09-18-2021, 08:39 PM	#7
G8One2 Drives: 2014 Camaro 2SS Join Date: Feb 2015 Location: Metro Detroit Posts: 492	The fuel pump itself has an internal regulator that won't let it go past 58 psi. You'd need a ZL1 pump or better to run higher pressures. I currently have a ZL1 pump installed and running 60 psi at the rail. I could run up to 65 psi if I wanted.

09-18-2021, 10:08 PM	#9
G8One2 Drives: 2014 Camaro 2SS Join Date: Feb 2015 Location: Metro Detroit Posts: 492	You may need to copy over the ZL1 parameters in the FPCM. Then make changes to desired pressure, low flow, high flow and default pressures under the fuel tab.

09-20-2021, 10:22 AM	#11
gtstorey Drives: 2010 Camaro SS2,L99, LSA SC Join Date: Aug 2017 Location: Huntsville, AL Posts: 2,154	The pump curve won't necessarily let you change it to any psi. A major change like 100 psi probably wouldn't be possible and at least would put the pump way off it's best efficiency point. This is for pumps in general, so more of a warning to be careful. I haven't seen the pump curves for any of the fuel pumps available.

09-24-2021, 05:15 PM	#13
prod Drives: HHR Join Date: Dec 2015 Location: GTA ON CA Posts: 451	Why are you wanting higher pressure? I would be looking at correct fuel volume, which is what tuners determine using AF ratio. Not enough volume makes it go lean assuming the injector duty cycle is reasonable.

09-25-2021, 09:07 AM	#14
G8One2 Drives: 2014 Camaro 2SS Join Date: Feb 2015 Location: Metro Detroit Posts: 492	Higher pressures make your injectors flow more, if your fuel pump can keep up. I've got mine running 60psi at the rail. My injectors are 65lb/hr at 38psi and 80lb/hr at 60psi. No, I dont really need that much flow, but I needed more flow for E85 and I want to eventually do more mods. Wanted to make sure I never max out my duty cycle on the injectors.