Fuel pressure at WOT - Camaro5 Chevy Camaro Forum / Camaro ZL1, SS and V6 Forums

jordan 572 · 06-04-2012, 05:20 PM

So I had the ZL1 pump put in my car, I haven't got a good chance to test it out but id did manage to get fuel psi to around mid high 40's when I was wot. Ted says he doesn't want to see it below 53 psi. My car isn't even putting down much. Max around 520whp. The gauge I am using is monitoring off the obd port is this rail pressure? Is there an issue or are my reading good?

tkrupinski · 06-04-2012, 07:48 PM

what psi are you running? I think you need to add your psi to the preasure reading. Best way is measure off the rail.

thebeast916 · 06-04-2012, 07:51 PM

ObdII reads rail pressure. 48 is a little low. Just watch your air/fuel. That's another good indication.

I think my lean issue is my maxed out zr1 injectors.

Crime2 · 06-04-2012, 07:59 PM

Popcorn

Sent from my iPhone using Tapatalk. If is spelllled wrong deal with it.

jordan 572 · 06-04-2012, 08:22 PM

I drove it again. My pressure is around 52 to 53 Dipping to 51 for just a bit. I was getting those lower readings when I would push the clutch in just for a bit because the reading is so instant.

uniqueskillz · 06-04-2012, 10:06 PM

good info. Keep us updated. I was thinking about getting the zl1 pump for my build as well

tkrupinski · 06-05-2012, 12:48 AM

Quote:

Originally Posted by thebeast916

ObdII reads rail pressure. 48 is a little low. Just watch your air/fuel. That's another good indication.

I think my lean issue is my maxed out zr1 injectors.

I thought OBD read from rear of car near tank?

axis · 06-05-2012, 02:51 AM

Industry standard for baseline FP on FI is 44psi. Some people run it a tad higher. Add your boost pressure to that and you should have your FP under full boost. If you're running 7-8psi, that would put you right round the 53psi that Ted mentioned. Ideally, measurement should be off the fuel rail.

tkrupinski · 06-05-2012, 05:36 AM

I thought that was the way to check it but could not remember for sure.

honeybucket99 · 06-05-2012, 07:25 AM

I think you are measuring delta pressure, but I'm wrong so much that I wouldn't be surprised if you are not. A way to check is to look at reading not in boost--are they reading 53-58 plus 10 (your normal vacuum #) or so?

jordan 572 · 06-05-2012, 02:05 PM

At idle or cruise fuel pressure is almost always at 57 rarely at 58 psi. What does boost have to do with increasing fuel pressure? So the ECM increases fuel pressure 1 psi for every 1 psi of boost?

blake-b · 06-05-2012, 02:26 PM

If your engine is making 10#s of boost at WOT. That means there is 10# of pressure AGAINST the injector flow when at full boost (the engine is trying to push the injectors out of the intake is one way to think of it and that has actually happened in some cases). If your engine is normally at 58psi fuel pressure when not under boost then when it is under full boost of 10#, the fuel pressure will show 48#. You would need a boost referenced fuel pressure regulator in order for the fuel pump controller (generic term) to know when to increase the fuel psi to make up for the lost pressure.

I think that is right from what I have read.

jordan 572 · 06-05-2012, 04:27 PM

Quote:

Originally Posted by blake-b

If your engine is making 10#s of boost at WOT. That means there is 10# of pressure AGAINST the injector flow when at full boost (the engine is trying to push the injectors out of the intake is one way to think of it and that has actually happened in some cases). If your engine is normally at 58psi fuel pressure when not under boost then when it is under full boost of 10#, the fuel pressure will show 48#. You would need a boost referenced fuel pressure regulator in order for the fuel pump controller (generic term) to know when to increase the fuel psi to make up for the lost pressure.

I think that is right from what I have read.

Makes sense, I am not to worried though as Ted has told me what to buy and I trust him.

Zman12 · 06-05-2012, 05:38 PM

Isn't this some of the reason for adding the Zr1 map sensor on boosted applications. That way the computer can see boost and help this.

06-04-2012, 05:20 PM	#1
jordan 572 Drives: none Join Date: Jul 2008 Location: MN Posts: 1,720 View My Garage	Fuel pressure at WOT So I had the ZL1 pump put in my car, I haven't got a good chance to test it out but id did manage to get fuel psi to around mid high 40's when I was wot. Ted says he doesn't want to see it below 53 psi. My car isn't even putting down much. Max around 520whp. The gauge I am using is monitoring off the obd port is this rail pressure? Is there an issue or are my reading good?

06-05-2012, 02:51 AM	#8
axis Search Ninja Drives: 2010 Black 2SS/RS A6 Join Date: Oct 2009 Location: Central Ark Posts: 7,183	Industry standard for baseline FP on FI is 44psi. Some people run it a tad higher. Add your boost pressure to that and you should have your FP under full boost. If you're running 7-8psi, that would put you right round the 53psi that Ted mentioned. Ideally, measurement should be off the fuel rail. __________________ 2010 Black 2SS/RS A6 Halltech CF 102 fed GPI modded intake manifold Bo (knows) White ported TB Kooks LT's/ Dynomax VT Pfadted (springs/sways) Dyno tuned by Rhino and GPI I once parallel parked a train.

06-05-2012, 07:25 AM	#10
honeybucket99 Drives: 2SS/RS CGM CAMARO BEAST Join Date: Jul 2009 Location: carrollton, ga Posts: 425	I think you are measuring delta pressure, but I'm wrong so much that I wouldn't be surprised if you are not. A way to check is to look at reading not in boost--are they reading 53-58 plus 10 (your normal vacuum #) or so? __________________ 2010 CGM 2SS/RS; 418 stroker; JE Forged Pistons (offset wrist pin); Forged Crank; upgraded valvetrain; Custom Comp Cams Cam; Kenne Bell 2.8; ID 1000s; Aeromotive Fuel pump with return; ARH Long Tubes; Spec heavy duty clutch; 3" Magnaflow Cat Back; Nick Williams 102 mm Throttle Body; Tune fixed by Dave Steck; 815 HP and 14 mpg Upcoming-- Disintegrated drivetrain; Divorce if/when my wife catches on to my addiction

06-05-2012, 05:38 PM	#14
Zman12 Drives: 2010 Camaro 2SS Join Date: May 2011 Location: Gardner,Ks Posts: 490	Isn't this some of the reason for adding the Zr1 map sensor on boosted applications. That way the computer can see boost and help this. __________________ Whipple,custom cam,CAI,Kooks,Pedders and PFADT 626RWHP 549TQ ..

06-04-2012, 07:48 PM	#2
tkrupinski Hugger Orange Drives: 2010 Hugger Orange 2SS/ RS YSI/4l80 Join Date: May 2010 Location: Marysville Ohio Posts: 535	what psi are you running? I think you need to add your psi to the preasure reading. Best way is measure off the rail.

06-04-2012, 07:51 PM	#3
thebeast916 Drives: Blown G8 GT Join Date: Apr 2010 Location: Orlando, FL Posts: 782	ObdII reads rail pressure. 48 is a little low. Just watch your air/fuel. That's another good indication. I think my lean issue is my maxed out zr1 injectors.

06-04-2012, 07:59 PM	#4
Crime2 Got Boost? Drives: 2010 1SS RS Join Date: Aug 2011 Location: Clearwater, FL Posts: 606	Popcorn Sent from my iPhone using Tapatalk. If is spelllled wrong deal with it.

06-04-2012, 08:22 PM	#5
jordan 572 Drives: none Join Date: Jul 2008 Location: MN Posts: 1,720 View My Garage	I drove it again. My pressure is around 52 to 53 Dipping to 51 for just a bit. I was getting those lower readings when I would push the clutch in just for a bit because the reading is so instant.

06-04-2012, 10:06 PM	#6
uniqueskillz Drives: ETMC built 700+hp Twin Turbo LS3 Join Date: Apr 2010 Location: Killeen, TX Posts: 682	good info. Keep us updated. I was thinking about getting the zl1 pump for my build as well

06-05-2012, 05:36 AM	#9
tkrupinski Hugger Orange Drives: 2010 Hugger Orange 2SS/ RS YSI/4l80 Join Date: May 2010 Location: Marysville Ohio Posts: 535	I thought that was the way to check it but could not remember for sure.

06-05-2012, 02:05 PM	#11
jordan 572 Drives: none Join Date: Jul 2008 Location: MN Posts: 1,720 View My Garage	At idle or cruise fuel pressure is almost always at 57 rarely at 58 psi. What does boost have to do with increasing fuel pressure? So the ECM increases fuel pressure 1 psi for every 1 psi of boost?

06-05-2012, 02:26 PM	#12
blake-b Drives: 2009 ZR1 Join Date: May 2010 Location: KCMO Posts: 3,205	If your engine is making 10#s of boost at WOT. That means there is 10# of pressure AGAINST the injector flow when at full boost (the engine is trying to push the injectors out of the intake is one way to think of it and that has actually happened in some cases). If your engine is normally at 58psi fuel pressure when not under boost then when it is under full boost of 10#, the fuel pressure will show 48#. You would need a boost referenced fuel pressure regulator in order for the fuel pump controller (generic term) to know when to increase the fuel psi to make up for the lost pressure. I think that is right from what I have read.