Does anybody have a B&M CommandFlo FPR?

[laser92awd]

I am interested in talking to anybody who is running (or has run) a B&M CommandFlo fuel pressure regulator. I just put my car back together after putting on an extrude honed intake, 550cc injectors, VPC Prom, and B&M FPR.

About the only leak I found when doing an air pressure test was around the screw on the B&M. I would like to know if this is normal or not.

Next, when I first started the engine with all my VPC and GCC settings at default (12 o'clock or "0") the engine was running VERY rough. So I looked at the fuel pressure with the vacuum hose off the regulator and was running around 50psi. I tried backing the screw out on the B&M but I couldn't get it to lower the pressure. The screw is almost all the way out (cam cover wouldn't even fit) and it still doesn't seem to have any control.

Deciding it was running rich due to the high fuel pressure I cranked my VPC gain and idle controls to full minimum, then leaned out the 500 and 2500 rpm settings on the GCC. It is idling pretty decent now but I'm concerned about now being able to lower the pressure.

I know some of you don't like the B&M and it may turn out I wind up going back with a stock regulator. But I'd like to talk to anybody who has experience with one.

Thanks!

Jonathan Stanley
1G AWD 16G Laser

 

[nothing stock]

The leak through the screw is probably the cause. Remove it and put some rtv on it. If you can't lower your fuel pressure then chances are your running a pump that is too big. What pump are you using? Is it rewired?

 

[NOSLO2PT0]

You do NOT want the B&M POS on your car. If/When you put a larger pump on the car, it raises your base fuel pressure. You want an adjustable regulator that can LOWER base fuel pressure. The B&M unit only RAISES it. Dump that POS and go buy a true adjustable unit. www.spoolinup.com AFPR is one of the best, and easiest to bolt on, regulator on the market right now.

Mike

 

[laser92awd]

OK, maybe I'm not understanding the point of an FPR. Everywhere I have read that the 1G's start at a stock base fuel pressure of 36 psi and then it raises on a 1:1 ratio with your boost.

So to me it would seem logical that if I raised base fuel pressure to 43 psi and kept the 1:1 ratio that it would help the injectors deliver more fuel. Is my thinking screwed up? Since I have both a VPC and GCC shouldn't I be able to compensate for the extra fuel? I think I have up to a 24% leaning capability using both units so that would give me a wide range to work with.

Also to the person who suggested putting RTV on the screw - do you actually have a B&M FPR? I don't want to put RTV on the screw if you're not supposed to - maybe the design of it is to bleed out some air through the screw hole.

If you guys do a search for B&M Command Flo Fuel Pressure Regulator you will find basically nothing but positive comments about it and people with many different kinds of cars seem to use it.

I'm looking at the Spoolinup unit. So are you guys trying to tell me that with this unit I can set the stock FPR at 36psi to maintain stock idle, but then have the pressure jump up higher under boost?

 

[NOSLO2PT0]

So I looked at the fuel pressure with the vacuum hose off the regulator and was running around 50psi.

So to me it would seem logical that if I raised base fuel pressure to 43 psi and kept the 1:1 ratio that it would help the injectors deliver more fuel

I took both of these statements from your posts. YOu didn't mention which pump you are running. If you are using the Walbro 255lph, your base fuel pressure will be around 50psi. If you are running race gas and 20+psi, your car won't very well on the top end. See this post for explanation http://dsmtuners.com/forums/showthread.php?s=&postid=77540#post77540

Basically, the bigger pump raises fuel pressure so much, when you run high boost you are overrunning your FPR. The B&M unit only RAISES fuel psi, and you want to LOWER it. Junk that thing and buy one that allows you to lower fuel psi.

Mike

 

[laser92awd]

OK I worked with the regulator and got it down to 43psi. To do it I had to remove the timing belt cover, adjust the screw, then put the cover back on. The screw is basically out to the point where it is completely up against the cover but it seems OK. The screw IS adjusting my pressure up and down, but only down to 43psi which is what I wanted to start at anyway.

I don't know what kind of pump I have. I bought it in January 1995 from either Buschur Racing or Diamond Star Specialties. It was back when there weren't a whole lot of choices.

I just made a log with the new setup. Here are my initial results:

20psi - rock solid no spikes or creep.

VPC: RESPONSE at full (6 o'clock), IDLE at minimum (7 o'clock), GAIN 3 clicks above minimum (9 o'clock), OUTPUT at 12 o'clock.

GCC at default except 500 on EGC set to full lean.

(Idle goes to crap if I don't totally lean it out on the VPC and GCC)

Base fuel pressure set to 43psi.

Full run up to redline in 3rd gear.

O2 at .88 most of the run, lowest .86

0 Knock until 6937 rpm in 3rd gear, then 7 knock decreasing to 1 knock at 7104rpm.

Timing average of 21, no big ups or downs.

Injector P/W: Starts at 20.000mS, ends at redline 15.897mS.

EGT hit a max of 780F with ambient temperature of 86F.

Coolant 201F solid through run.

Note that those are the highest O2 readings and lowest EGT readings I've ever had. Before I did this upgrade (550cc injectors) I was getting knock in 3rd gear, .82 O2 readings, and 880F EGT readings at 15psi. Now I'm running 20psi and it looks like I have lots more room. I also compression checked my engine and all 4 cylinders are within 1psi of each other and are well within spec (155psi). Not bad for an 11 year old car that's been boosted its entire life...

http://drive.to/92laser

 

[laser92awd]

I just figured out that I have the Buschur Racing upgraded fuel pump from January 1995. I have no idea what pump he was using back then as it was just sold as a Buschur Racing fuel pump. Any ideas?

 

[NOSLO2PT0]

What turbo and gas was this 20psi run with? All the #'s sound pretty good. I'm guessing you have a 20G or bigger. It's damn near impossible to run 20psi on pump gas with a 14b or 16G, even with a FMIC.

Either way, I don't know how you were able to LOWER fuel pressure with that B&M unit, you could only RAISE fuel pressure. Oh well, learn something new every day.

Mike

 

[laser92awd]

I have a 16G ported and clipped and an Alamo sidemount. I run 93 octane pump gas. I went out tonight and ran 3 more 20psi runs and they were all like the one I mentioned earlier. I did not run them back to back - there was lots of cooling time between each run.

When I said the FPR was at 50psi, at that point I had the adjustment screw screwed in some. So it isn't really that I was lowering pressure, I was just backing down the FPR to the beginning of its range. For all I know with my fuel pump I may have already been running 43psi without the FPR. Unfortunately I installed the gauge and the FPR at the same time so I don't know. At least I know I have an easy way to raise pressure if I need to in the future.

And I'll keep in mind that if I go with a Walbro pump someday that I'll likely have to get an FPR that can lower pressure.

 

[RocketDSM]

I'm running a stock pump and a B&M and the lowest I can get it to go is 41-42psi. So your 43psi sounds about right the bottom of the range.