What is normal fuel pressure with and without a BAP

[NGOT8R]

Can anyone tell me for sure, what fuel pressure is on a FBO 2018+ GT at idle, normal cruising and WOT, with and without a BAP set at 18V?

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[WildHorse]

BAP is designed to maintain factory fuel pressure, not increase it.

 

[NGOT8R]

BAP is designed to maintain factory fuel pressure, not increase it.

Wildhorse, do you by chance know what fuel pressure is on a 2018+ GT? I was wondering if it was higher than a 15-17 GT because of the extra injectors? Scaling my Nitrous Outlet fuel pressure switch to their specs puts FP at 78-79 psi. That seemed high to me, but maybe it could be right; I have no clue. Another thing that seems strange is when I power up the nitrous touch screen in accessory mode, FP is still pretty close to 78 psi, minus a few psi. Shouldn’t the system bleed down over time when the engine is not running?

 

[WildHorse]

Wildhorse, do you by chance know what fuel pressure is on a 2018+ GT?

No idea. I know the DI is stupid high, like 80psi+. The PI side uses much smaller injectors than the 15-17 is all I know. Sorry.

 

[NGOT8R]

No idea. I know the DI is stupid high, like 80psi+. The PI side uses much smaller injectors than the 15-17 is all I know. Sorry.

If it’s around 80+ then perhaps my sensor is tracking properly. Hopefully someone who has confirmed what FP is on DI cars will chime in soon.

 

[BrianH87]

I always thought DI was around 2000 psi. PI around 40-80 psi.

 

[WildHorse]

I always thought DI was around 2000 psi. PI around 40-80 psi.

Yes you are correct Sir. Nominal pressure on the PI side is 45 psi. My apologies to the OP.

 

[cbrtrx]

Lots of incorrect info here, like I already posted in your other thread base rail pressure is around 58psi stock. At wot with an 18v bap it will be around 70. If your bap is on all the time then again it will be around 70psi all the time. Reason is simply because the factory in tank regulator cant bleed off the extra pressure fast enough so there is an increase. DI pressure at wot is 2900psi and has no bearing on what your trying to do. Lastly 47 percent duty cycle logged means the pump is 100 percent on.

 

[NGOT8R]

Lots of incorrect info here, like I already posted in your other thread base rail pressure is around 58psi stock. At wot with an 18v bap it will be around 70. If your bap is on all the time then again it will be around 70psi all the time. Reason is simply because the factory in tank regulator cant bleed off the extra pressure fast enough so there is an increase. DI pressure at wot is 2900psi and has no bearing on what your trying to do. Lastly 47 percent duty cycle logged means the pump is 100 percent on.

From what I’m seeing on my nitrous touch screen which monitors a ton of parameters (fuel pressure being one of them), FP is always reading around 78 psi, whether I put the start button in accessory mode or actually start the car. This is of course with the Nitrous Outlet FP sensor scaled per N/O’s instructions which are 4.5V at 100 psi and 0.5V at 0 psi. The only way I can get a reading of 58 psi is to change the scaling to 4.5V at 51 psi and 0.5 V at 0 psi. My BAP is set to ramp up voltage from normal battery voltage (12-13V), beginning at 50% throttle and reaching 18V at 75% throttle. I haven’t gone WOT on the road yet, only with the engine off, during which the BAP is increasing voltage because the TPS sensor is indicating such on the nitrous touch screen and the throttle blade is completely open at that time. I have also confirmed this voltage increase with a press of the throttle at the fuel pump driver harness with my multimeter.

When I reached out to N/O‘s tech department, I was told that their FP sensor was very accurate. They also asked if I had checked fuel rail pressure with a gauge. I haven’t done this because I don’t have one and don‘t see how it would have changed anything from simply unplugging the fuel feed line to the rails and installing the nitrous fuel rail adapter between the rail and fuel feed line.

 

[cbrtrx]

From what I’m seeing on my nitrous touch screen which monitors a ton of parameters (fuel pressure being one of them), FP is always reading around 78 psi, whether I put the start button in accessory mode or actually start the car. This is of course with the Nitrous Outlet FP sensor scaled per N/O’s instructions which are 4.5V at 100 psi and 0.5V at 0 psi. The only way I can get a reading of 58 psi is to change the scaling to 4.5V at 51 psi and 0.5 V at 0 psi. My BAP is set to ramp up voltage from normal battery voltage (12-13V), beginning at 50% throttle and reaching 18V at 75% throttle. I haven’t gone WOT on the road yet, only with the engine off, during which the BAP is increasing voltage because the TPS sensor is indicating such on the nitrous touch screen and the throttle blade is completely open at that time. I have also confirmed this voltage increase with a press of the throttle at the fuel pump driver harness with my multimeter.

When I reached out to N/O‘s tech department, I was told that their FP sensor was very accurate. They also asked if I had checked fuel rail pressure with a gauge. I haven’t done this because I don’t have one and don‘t see how it would have changed anything from simply unplugging the fuel feed line to the rails and installing the nitrous fuel rail adapter between the rail and fuel feed line.

Gen 3s already have a fuel rail pressure sensor. No guessing needed. On a stock pump at 17.5v I've seen about 70psi. With a dw400 at 17.5v I've seen as much as 78psi at times.

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