PDA

View Full Version : How much can I increase the fuel pressure?


Marahutay
01-28-2017, 08:58 AM
rb25de(t) swapped s13 (10:1comp)
Factory injectors, factory rail, AEM universal fpr, precision 3431 turbo factory ecr33 ECU (afaik)
I'm running in the red at NOT on the wideband. If I blip the throttle afr'a dip down to 16 the back to red. It has a misfire- coil pack harness is on the way.

There's only a 4 lb spring in the gate and I'm just trying to drive this thing to a dyno. How much can I increase my fuel pressure at the rail to hep bring down my afr before I start risking damage to the injectors? They were flow tested and are a healthy consistent set. I also don't plan on using these injectors I have another set of DW's

jr_ss
01-28-2017, 11:11 AM
Your misfire could be a lean misfire and have zero to do with actual wiring.

Increase to 4bar(59psi) on your pressure regulator if your pump can do it.

Marahutay
01-28-2017, 03:26 PM
haha, if you saw the harness it came with you would want it gone regardless. The rest of the harness is brand new and I'm not about to skimp on the coil harness. Got a WS one for 29$ anyway.
The harness showed up today, so on Monday I'm gonna go out and put the AEM universal fpr on with the new harness and I'll crank it no higher than 4 bar. What is the reasoning behind the 4 bar suggestion?

jr_ss
01-28-2017, 03:55 PM
haha, if you saw the harness it came with you would want it gone regardless. The rest of the harness is brand new and I'm not about to skimp on the coil harness. Got a WS one for 29$ anyway.
The harness showed up today, so on Monday I'm gonna go out and put the AEM universal fpr on with the new harness and I'll crank it no higher than 4 bar. What is the reasoning behind the 4 bar suggestion?

Factory is 3bar and you aren't going to gain much head room on 370cc's so no point in going higher. You need larger injectors. However, I'm not entirely convinced having 370cc's is your issue. Have you looked into calibrating or the condition of your wideband?

Marahutay
01-28-2017, 04:33 PM
The wideband has hardly seen any use. Spent a lot of time in the box until it was Installed. I never thought to check its calibration being brand new. It's 12 inches back from the turbine. I have a set of 740cc deatchwerks but I thought that might be overkill. I guess I could always run the pressure lower?

Kingtal0n
01-28-2017, 09:06 PM
you blip the throttle and it goes into the red- and you want to take it to a dyno?

RIP RB

jr_ss
01-29-2017, 12:05 PM
The wideband has hardly seen any use. Spent a lot of time in the box until it was Installed. I never thought to check its calibration being brand new. It's 12 inches back from the turbine. I have a set of 740cc deatchwerks but I thought that might be overkill. I guess I could always run the pressure lower?

It's common sense to ensure calibration or calibrate a new instrument before implementing it into service.

I would bin the redrilled injectors for a better set. DW injectors for the SR/KA do not have the best track record.

Running lower fuel pressure won't compensate for the added increase in fuel flow you'll add by installing the 740's. They are double the size as factory. You'll go from "full lean" to "full rich". Calibrate the wideband and go from there.

Marahutay
01-29-2017, 05:46 PM
It's an AEM UEGO - doesn't need calibration. I'll double check the one in there with one of my others. Hopefully it's actually running fine and that sensor is what's wrong.