Adjusting the fuel pressure regulator, what pressure do I need to set it at?
10-18-2007, 12:16 PM
#1
Adjusting the fuel pressure regulator, what pressure do I need to set it at? Also, there's a small vacuum line on it, do I need to hook it up? What's the purpose of it?
By the way, its an Aeromotive 1000 regulator.
Also, what should the PSI be when you just have the key to on? I assume you need to adjust the pressure while the car is running, then tighten the jam nut?
I've been out of it for so long, I forget the basics. In this case, fuel pressure.
By the way, its an Aeromotive 1000 regulator.
Also, what should the PSI be when you just have the key to on? I assume you need to adjust the pressure while the car is running, then tighten the jam nut?
I've been out of it for so long, I forget the basics. In this case, fuel pressure.
10-18-2007, 01:16 PM
#4
it really depends on your tune. your tuner just needs to tune for the specific injector is all im saying since the flow rating sometimes varies. Sometimes your car won't even start if you put new injectors in on an old or stock tune. But your best bet is to set it to stock pressure unless your tuner tells you otherwise. I'd start out at 58.
10-18-2007, 07:46 PM
#5
Leave the vacuum line open to atmosphere. Start the car, then adjust fuel pressure to what you want it to be. I set mine to 58 and it's giving me rich decel issues with the same injectors. If you're going to be using all of the injector than set it to 58 or higher, if you don't really need 60's, set it lower.
Then set the IFR table to the value in the injectors.xls spreadsheet for 0 kpa all the way across.
Then set the IFR table to the value in the injectors.xls spreadsheet for 0 kpa all the way across.
10-18-2007, 08:05 PM
#7
I'm sorry, I skipped a step. After you set the pressure w/ the regulator open to atmosphere hook the regulator to a vac. source. This will give you lower fuel pressure while you're at part throttle and idle and make tuning big injectors easier.
If you set rail pressure to 58 psi @ atmos, then hook up the reg and draw 15" of vac you'll wind up w/ 43 psi fuel pressure w/ a 1:1 regulator. 58 psi @ 0 psi, and 68 psi @ 10 psi boost pressure.
If you set rail pressure to 58 psi @ atmos, then hook up the reg and draw 15" of vac you'll wind up w/ 43 psi fuel pressure w/ a 1:1 regulator. 58 psi @ 0 psi, and 68 psi @ 10 psi boost pressure.
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10-18-2007, 08:21 PM
#8
Forgot to mention, but this is a drag car, so part throttle doesn't really matter. I set the pressure at 58 psi with the hose connected to the side of the throttle body, but it didn't seem to have any vacuum there.
On a drag car, would it matter to have the vacuum connected? This is a naturally aspirated motor by the way.
On a drag car, would it matter to have the vacuum connected? This is a naturally aspirated motor by the way.
10-18-2007, 09:51 PM
#10
10-19-2007, 06:44 AM
#12
You guys just threw me off. Again, this is a drag car, so part throttle doesn't mean anything to me. Here's what I want to know:
Do I set the fuel pressure with or without the vacuum hose hooked up?
Once I set it, if it's off, do I connect it?
If it's connected, do I disconnect it?
It didn't feel like there was much if any vacuum coming off one of the ports on the throttle body. Do I need to make a port on the intake if a vacuum line is even needed?
Do I set the fuel pressure with or without the vacuum hose hooked up?
Once I set it, if it's off, do I connect it?
If it's connected, do I disconnect it?
It didn't feel like there was much if any vacuum coming off one of the ports on the throttle body. Do I need to make a port on the intake if a vacuum line is even needed?
10-19-2007, 11:03 AM
#13
Your questions have been answered. But I'll answer them again. Set it without a vacuum hose hooked up. IF you hook up a vacuum hose to it, it won't make much of a difference since you have a drag only car, and it will be WOT most of its time running. If you are running forced induction, you definitely need to hook up a vacuum line to it because the injectors operate at pressure differential and you want the fuel pressure to go up with boost.
10-19-2007, 09:26 PM
#14
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For big cams (260+) vacuum lines don't work with FPR NA as you have very little vacuum at idle and when you are cruising it increases a fair bit, leaning off the AFR. For stock sized cams this approach is fine. Change the parameters and its pretty much:
Idle = WOT
Cruise = decent vacuum
WOT = WOT
Hence why ppl. have troubles tuning big injectors on big cammed cars. You have to account for the pressure in the manifold which has turned ***-up. Thus, you need to alter your VE map accordingly.
I would do this:
Leave the vacuum line open to atmo (for NA)
lean off the VE map at idle
richen the VE map at cruise
Idle = WOT
Cruise = decent vacuum
WOT = WOT
Hence why ppl. have troubles tuning big injectors on big cammed cars. You have to account for the pressure in the manifold which has turned ***-up. Thus, you need to alter your VE map accordingly.
I would do this:
Leave the vacuum line open to atmo (for NA)
lean off the VE map at idle
richen the VE map at cruise
