B&M Regulator / January 1995 Upgraded Fuel Pump

[laser92awd]

I am in the process of upgrading my intake and fuel injectors. While I was at it I got the B&M Commandflo regulator. After hacking off the end of my regulator as per instructions and trying to keep the spring and o-ring in place while screwing it all together I kept thinking "rinky-dink" in my mind. So now that I have it together I'm a little paranoid.

The regulator accepts pressure, not vacuum, right? Or is it the other way around? I attached a hand pump to it and when I pump it I can hear air coming out around where the adjustment screw is threaded in. Is that bad? Should I teflon the screw?

Also I can't remember where I got my upgraded intank fuel pump - it was so long ago. It is an intank pump and is either the 3000GT pump from DSS or the pump Dave Buschur sold back around January 1995. The question I have is what is the maximum pressure I can safely run on whichever pump I have. I understand the base fuel pressure + boost = maximum psi needed from pump. So if I set base at 43psi and a maximum of 22psi on the turbo will my pump handle the 65psi required? (That's only 7psi higher than what I've been running already)

Any suggestions would be appreciated!

 

[DSMu4ia]

That regulator is junk really.

It only allows you to raise pressure.

 

[laser92awd]

I don't understand - why would I want to lower pressure? I've read that the base pressure is 36psi on 1G's but 43psi on 2G's. Aren't injectors flow rated @ 43psi?

 

[DSMu4ia]

Bigger pump overrunning the injectors at idle, and just continually getting worse as boost rises.

We installed a Walbro 255 HP (re-wired) into my friends 2g the other day. Saw WAY above 43psi at idle, and just for shits and giggles, I'll tell you it saw nearly 70psi under boost. He's on stock turbo, so boost isn't that high.

 

[DSMu4ia]

Also, you want to be able to keep stock fuel pressure to keep tuning, etc in check.

If you don't know enough about fuel pressure and how it affects injectors, I'd keep the stock reg, and get a small pump that doesn't overrun anything.

You can make injectors bigger or smaller (flow wise) based on pressure, but then you run into other problems which I don't care to type about.

 

[BatmanGSX]

You need fuel pressure to rise with boost so that the differential across the injector doesn't change. Meaning if you have 43psi (stock 2G) of fuel pressure and 0psi of boost, if boost goes up by 1psi but fuel pressure stays the same you will have less fuel than you should. So what happens when you put a larger pump in with the stock regulator? Well if you have 50psi of base pressure you will stay at 50psi of fuel pressure until you hit 7psi of boost, then it will start to rise. That is totally messed up. Your fuel delivery will be totally nonlinear.

The B&M doesn't allow you lower fuel pressure, true. But that's not the issue. The issue is that it doesn't change the part of the regulator that allows it to be overran by a larger pump.

The bottom line is your car will perform really weird if you use a big pump without a proper AFPR. The B&M Command Flow is not a proper AFPR.

 

[laser92awd]

Why are places like RRE and dsm-performance claiming the B&M is so good? Here's a quote from dsm-performance:

> "About the cheapest adjustable FPR available is the B&M Command Flo. Don't let the price scare you. Several of our cars use them and they WORK. To boot, installation is a snap and requires no modification to the fuel rail.

OK, fine, how do they work? An adjustable FPR does the same basic job that the stock FPR does, but it allows you to manually adjust the base or idle fuel pressure and still maintain the 1/1 increase under boost." <

All I wanted to do is slightly bump up the fuel pressure to get the injectors to flow what they are rated. (I don't want my 550's to run like 500's). I have a VPC, GCC, and Pocketlogger, so tuning shouldn't be a big deal if everything is working like it is supposed to.

 

[DSMu4ia]

Originally posted by laser92awd
Why are places like dsm-performance claiming the B&M is so good? Here's a quote from dsm-performance:

> "About the cheapest adjustable FPR available is the B&M Command Flo. Don't let the price scare you. Several of our cars use them and they WORK. To boot, installation is a snap and requires no modification to the fuel rail.

They also sell Mutt turbos, doesn't that ring a bell? Both don't perform.

You have a VPC, GCC, and other stuff, yet you can't buy a decent AFPR?

Stock 1g fuel systems don't need a afpr as badly as a 2g would, they seem to run better than 2g's do with bigger fuel setups. You can always buy a bolt on, billet adapter, and just bolt an aftermarket AFPR on (paxton, aeromotive, etc), or go with a spoolinup.com unit.

 

[laser92awd]

Originally posted by DSMu4ia

Originally posted by laser92awd
Why are places like dsm-performance claiming the B&M is so good? Here's a quote from dsm-performance:

You have a VPC, GCC, and other stuff, yet you can't buy a decent AFPR?

Stock 1g fuel systems don't need a afpr as badly as a 2g would, they seem to run better than 2g's do with bigger fuel setups. You can always buy a bolt on, billet adapter, and just bolt an aftermarket AFPR on (paxton, aeromotive, etc), or go with a spoolinup.com unit.

I didn't know the B&M wasn't a decent AFPR. RRE has always been reputable and they highly recommend it as well. And I've always heard that the 1G's run leaner than the 2G's and the factory manual specifies a lower fuel pressure on the 1G's than the 2G's. That's why I went with the regulator to begin with.

I guess if it doesn't work then I can always do something different.