Aeromotive fpr intall and qustion about setting base pressure

[GSTurbo1]

Ok guys I just installed an aeromotive. I set base pressure by removing the vacuum line then set it to 40. When I plug it back in the pressure drops down to about twenty five to thirty psi. Is this normal? Would it hurt to set the base pressure a little higher little higher than 37 psi? What are the bases for setting the fuel pressure?

Thanks jason

 

[dsmpat95]

Unplug your vacuum line from the AFPR and then set it to your desired fuel pressure(yours 37psi) and then place your vacuum line back on. Once the line is on your pressure will drop a little more.

I wouldn't increase your base fuel pressure unless you have a way to tune it.

 

[GSTurbo1]

I have an safc and 550 cc injectors with a Wally 255 pump. I have a wideband all other other good stuff.

I just figured there would be a benefit to bumping the pressure up just a bit

 

[dsmpat95]

There is, it has your injectors flow more.

 

[Tyeler18]

Hope you have a way to compensate for those 550's. If not you're just going to dump even more fuel in there on top of the loads of fuel you already are.

 

[WES_393]

There is, it has your injectors flow more.

It also decreases fuel pump flow.

OP- It's normal for the pressure to drop under vacuum. The fuel pressure changes to maintain flow. If you had 40psi base pressure and ran 30psi of boost, there's actually only 10psi at the injector. The regulator keeps the pressure difference equal. Increasing fuel pressure without tuning will have negative effects. Unless you have a good reason, just set your pressure to stock with the line disconnected.

 

[GSTurbo1]

Ok cool i have a logger on the way I just wanted to turn up the boost to about 15 psi on my big 16 g. I added a 10 percent correction factor with the bigger injectors. I turned my fpr up to 42psi and got a little bit of I burnt fuel pushed out on a wot pull. The bumped it back down. I left it at 40psi it seems to have a little bit stronger pull all the way through. Maybe a little bit better atomization? I might go two steps colder on the plugs to keep from blowing the spark out.

 

[WES_393]

The power increase is likely because your AFR's are leaner and producing more power at 40psi than at 42psi. That's why a wideband is essential for tuning. It could also be due to knock, which can be caused by running too rich. I'm also not sure how spark blowout plays a role here, your likely running into knock or fuel cut instead.

For what it's worth, I've ran nearly 30psi from a small 16g on BPR7 plugs and stock fuel pressure.

 

[gofer]

Your 550cc injectors will flow 500cc @ 37psi base because they're flow tested at 43.5psi. Since you've got an AFPR I suggest setting your base fuel pressure to 43.5psi so those injectors flow 550cc. It's really up to you but just be sure to correct for a 500cc injector with your SAFC and not a 550cc if you keep bfp at 37psi.

Just a recommendation to keep your fuel settings easier to remember.