BAP question
Thread Starter
Racer
Joined: Mar 2013
Posts: 392
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BAP question
Noticed today, that my dash logic threw out a "Low Fuel pressure warning".I was on boost and i have that alarm set to go off when ever fuel pressure drops below 55 psi.
First question, shouldn't the BAP kick in and increase the fuel pressure when in boost?
I couldn't see what it actually dropped too since the warning came on, but if it drops to 55, is that ok? Or should I be looking for a more significant drop, lets say to 40 psi?
First question, shouldn't the BAP kick in and increase the fuel pressure when in boost?
I couldn't see what it actually dropped too since the warning came on, but if it drops to 55, is that ok? Or should I be looking for a more significant drop, lets say to 40 psi?
Team Owner
Joined: Nov 2007
Posts: 24,035
Likes: 2,342
From: Gilbert AZ
Hard to say. Tune could take into account dropping fuel pressure, then it isn't an issue. 3-4psi drop isn't uncommon in high HP builds. Most stock pump BAP combos do drop pressure, but you just make up for it in the tune. What you need to monitor is drops from what it was tuned/safe at and go from there.
Thread Starter
Racer
Joined: Mar 2013
Posts: 392
Likes: 0
Well the fuel pressure usually reads between 62 to 64 psi, so its dropping almost 10 psi.
Im only at 617 hp, so its not really a high hp build.
I would imagine when i go into boost, the BAP would kick in, increasing the Fuel Pressure, but I am not seeing that.
Im only at 617 hp, so its not really a high hp build.
I would imagine when i go into boost, the BAP would kick in, increasing the Fuel Pressure, but I am not seeing that.
Team Owner
Joined: Nov 2007
Posts: 24,035
Likes: 2,342
From: Gilbert AZ
No, it doesn't increase pressure. There is still a regulator that regulates pressure so any more flow will just get dumped back into the tank.
Like I said, 10psi drop maybe normal, or it may not be, without AFR and seeing tune/etc it is hard to say.
Like I said, 10psi drop maybe normal, or it may not be, without AFR and seeing tune/etc it is hard to say.
Thread Starter
Racer
Joined: Mar 2013
Posts: 392
Likes: 0
Thanks unreal for clarifying that. I didn't know the fuel pressure would not go up with the BAP. At least thats a relief. I sent out an email to Matt at FSP to see what he thinks.
Last edited by pikkashoe; Nov 24, 2014 at 05:07 PM.
Melting Slicks
Joined: Mar 2007
Posts: 2,391
Likes: 23
From: Santa Barbara CA
Honestly, a wideband is WAY more important than a fuel pressure gauge. That's my opinion at least. I wouldn't do an FI build without one.
And yeah, pressure dropping is "normal". By that, I mean common. BAP or not, once the fuel requirements exceed a certain percentage of the pump's output, pressure will start to drop. It's not ideal, but isn't the end of the world either.
Your car was likely tuned with the fuel system in this condition, so it's being compensated for. The flip side of that is that your fueling won't be as consistent as a car with rock steady pressure. My experience with pressure drop is that it varies based on fuel/ambient temperature. So it might drop more in some conditions than others.
And lastly, I had a stock C6 pump with a BAP and Racetronix harness on my old build. Even with 100% meth helping take a load off the fuel system, I still got noticeable fuel pressure drop at 660 rwhp. Even upgrading to a Z06 pump and a 20 volt BAP didn't stop it when I added a little more power. No surprise you're getting some drop without meth.
And get a wideband. I really like my PLX AFR module & touch gauge combo. I like it better than the AEM failsafe gauge I had before.
And yeah, pressure dropping is "normal". By that, I mean common. BAP or not, once the fuel requirements exceed a certain percentage of the pump's output, pressure will start to drop. It's not ideal, but isn't the end of the world either.
Your car was likely tuned with the fuel system in this condition, so it's being compensated for. The flip side of that is that your fueling won't be as consistent as a car with rock steady pressure. My experience with pressure drop is that it varies based on fuel/ambient temperature. So it might drop more in some conditions than others.
And lastly, I had a stock C6 pump with a BAP and Racetronix harness on my old build. Even with 100% meth helping take a load off the fuel system, I still got noticeable fuel pressure drop at 660 rwhp. Even upgrading to a Z06 pump and a 20 volt BAP didn't stop it when I added a little more power. No surprise you're getting some drop without meth.
And get a wideband. I really like my PLX AFR module & touch gauge combo. I like it better than the AEM failsafe gauge I had before.
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Race Director
Joined: May 2004
Posts: 16,667
Likes: 1,209
From: Raleigh, NC
St. Jude Donor '15
Some can output a simulated narrowband signal.. so you can replace one of your O2's with a wideband, connect wideband to controller, then the controller can output a simulated narrowband O2 signal back to the computer. That's what I'm doing, but getting everything right to make it work was a pain. I wanted to try that before adding another bung and so far it has worked fine.
Probably easier to just add another bung (if necessary) and run a wideband by itself and leave the narrow band ones alone, but there are options I guess is my point
If you do decide to go the route I did let me know and I'll get you the formula I ended up using to make it work
Race Director
Joined: May 2004
Posts: 16,667
Likes: 1,209
From: Raleigh, NC
St. Jude Donor '15
Race Director
Joined: May 2004
Posts: 16,667
Likes: 1,209
From: Raleigh, NC
St. Jude Donor '15
Thread Starter
Racer
Joined: Mar 2013
Posts: 392
Likes: 0
Tuner responded. (love FSP, they are so quick).
Last night the lowest i saw it drop was to 55.4, so it probably just dropped right under 55 when the alert went off. Could have been ambient conditions, yesterday was pretty hot down here (close to 90 degrees) and my car sat idling for a while waiting for someone.
FSP said that is normal what I am seeing, he has seen even bigger drops for fuel pressure.
So for now it seems everything is ok.
I am still going to get the wideband for the car.
Looking at AEM Uego (Tuner recommendation), the pLX and LC-2. Gonna do some research over the next few days and pull the trigger. I think the AEM is a gauge, which I don't really want, having a dash logic.
Last night the lowest i saw it drop was to 55.4, so it probably just dropped right under 55 when the alert went off. Could have been ambient conditions, yesterday was pretty hot down here (close to 90 degrees) and my car sat idling for a while waiting for someone.
FSP said that is normal what I am seeing, he has seen even bigger drops for fuel pressure.
So for now it seems everything is ok.
I am still going to get the wideband for the car.
Looking at AEM Uego (Tuner recommendation), the pLX and LC-2. Gonna do some research over the next few days and pull the trigger. I think the AEM is a gauge, which I don't really want, having a dash logic.
Race Director
Joined: May 2004
Posts: 16,667
Likes: 1,209
From: Raleigh, NC
St. Jude Donor '15
If I was buying again I'd get the PLX. Everyone seems to agree it is as accurate as they get in this price range and don't have a gauge to bother with since you have dashlogic
Thread Starter
Racer
Joined: Mar 2013
Posts: 392
Likes: 0
Just saw this thread:
https://www.corvetteforum.com/forums...endations.html
PLX set up and I could just hook it up to the Dash logic.
Anyone else experience what he mentioned in that thread, about slow response times?
https://www.corvetteforum.com/forums...endations.html
PLX set up and I could just hook it up to the Dash logic.
Anyone else experience what he mentioned in that thread, about slow response times?
Le Mans Master
Joined: Apr 2011
Posts: 7,821
Likes: 412
From: Montreal
St. Jude Donor '13
I use a Zietronix ZT3 which I bought without a gauge and connected it to my aeroforce gauge. It has worked flawlessly for 3 years now and they have a very good reputation. Mine reads almost dead on to what the one on my tuners dyno does.
I suppose the new generation sensor might be better but see no problem with what I have for now.
I suppose the new generation sensor might be better but see no problem with what I have for now.