Blackroc86

What are you guys setting your pressure at on your carbed engines?

10.90streetcar

7 - 9 lbs

AlkyIROC

Most carbed engines like 7 psi. 9 is the outside limit. Above that and the pressure starts to lift the needle off the seat.

I run mine at 8 psi but I also flow a huge amount of alcohol into the float bowls.

five7kid

iTrader: (14)

6 is good for the typical car/engine. All you need is to keep the bowls full. If the pressure doesn't droop, that indicates it's doing that. 1 psi is enough if the bowls stay full.

muggsyjack

Running 6.5 with no drop at end of 1/8th mile.

Blackroc86

Thanks for the replies guys. I am running 7 at the start and down to 4 at the finish. The car is running strong right through. Not sure why the pressure is dropping. Running a Holley Blue and a Mallory 3 port regulator with 3/8 line the whole way. Maybe it is the guage acting up. I want to do a couple of runs with a 100 shot and don't want to go lean at the top end.

five7kid

iTrader: (14)

Whoa, nobody said anything about spray!

Whole different ball game.

You may have a restrictive fitting somewhere in the system or filter that's causing your pressure drop with demand. I'd sure resolve that b/4 spraying.

Blackroc86

Just recently removed the in tank TPI pump and put on the Holley blue. A fresh fuel filter was put on at the same time. I was getting a similar pressure drop when using the TPI pump with the Mallory regulator.

AlkyIROC

It's not just pressure the the amount of fuel that needs to get pushed. The faster a car goes, the harder it launches. The fuel pump has to push fuel to the front of the car during accelleration. This takes a lot of effort. The cure is to install the fuel system up front hoever a street car can't really do this.

A couple of other options. Run a second blue pump. Hook it in parallel so they both pull from the tank using seperate lines but just after the pump, the 2 lines become one. The blue pump isn't really very big but for most street cars, it's all they need. Compare the blue pump to a BG220 or BG280 and you'll see just how small it is.

Second option is to install a bigger pump. See above.

Third option is to step up to a larger fuel line. A 1/2" line from the fuel tank/pump to the regulator at the front will help the fuel demand.

If you're dropping for 7 to 4 psi during a run, the fuel system can't handle the demand of the engine. Any of the above should be tried to fix the problem.

I went and rechecked my system and it is set at 8 psi. My fuel cell and BG280 pump are mounted up front and I run 5/8" fuel line from the fuel cell right to both float bowls. My pressure doesn't move during the entire run.

IHI

iTrader: (1)

I've been having fuel pump problems lately myself, long story but resolved.

MY experiences, and judging by your sig under the avitar your motor is pretty stout. I had a Holley red as a temporary replacement when my A2000 fell victim to welding wire from the guy that sumped it. Anyways, I kept getting a stumble/surge at the top of 1 st and 2nd gear. Finally mounted a gauge-autometer under my cowl to monitor pressure. At WOT the gauge instantly went to 3psi. I have 5/8" fuel line from the tank to the carb so expected a pressure problem with this small pump, but not that bad.

So, took the spring out of the Holley black pump in the S-10 and installed it in my temporary Red pump, pressure immediately went up and I had to readjust the regulator to 8psi. Going down the track it carried 7 psi at WOT, no more surging stumbling at the top of the gears and picked up a soild .175 in the 1/4 and went back to running what it did before my first big pump died.

If your dropping down to 4psi, be very leary of lean out condition. I was lucky, no, very lucky I did'nt swiss cheese a piston. At first we were chaulking it up to the new aluminum spacer getting hot and changing the signal to the carb along with possible vapor lock since I was also in round robin racing too.

Try to scrounge up a buddy with an old black pump and switch the pressure reilef spring, this should help a bunch if not cure the pressure drop problem. Even with just a blue pump, I'd be very leary of shooting spray, there just is'nt enough volume or pressure from that one little pump to keep up with the double duty. Alomst all the guys I know with their street cars run 2 blues, one for motor and the other when the spray kicks in., or just buy the monster pump like mine and it's all the pump you'll ever need My Brother in law is running the same pump and he called aeromotive to see what pump to use with his 500hp fogger system. They said this A2000 is plenty of pump for his motor AND the spray!!

Just like the rest of go fast parts, pay alot now, or buy twice later

AlkyIROC

I bought a BG400 to replace my BG280 (not installed yet). Even with the new engine, I'll never have a lack of fuel problem.

IHI

iTrader: (1)

That'll flow PLENTY of Alchol to get a whole town of irish rugby players drunk!!!!

Just hope in the future the BG customer service gets better, my only reason for picking Aeromotive. Waay to many racers getting the shaft. But that's not from personal experience, just from what I've read on the racing forums I go to.

AlkyIROC

I've heard the same thing. I've never had a problem with the 280 and I bought it used. I picked up the 400 used also. If the 400 works out, I can sell the 280 for what I paid for the 400.

I bought a new Aeromotive bypass 4 port regulator because it was cheaper than the BG one. Gotta feed those 4 float bowls somehow.

Blackroc86

This morning we tried a flow test. We tried it both before and after the regulator and both times it pumped 3 litres in 30 seconds. Does that sound right?

IHI

iTrader: (1)

Dont know how liters change over to gallons, but click on this link. I assume it has a "safety factor" figured in just to be sure, but it gives you something to look at and shoot for.


http://www.barrygrant.com/bgfuel/def...age=81#FUELCAN

Trevor86TA

1 liter = 3.78 gallons so if it was exactly 30s, he could do 1 gallon in 37.97s.

Blackroc86

Thanks for doing the calculations Trevor.

IHI

iTrader: (1)

If that's the case I would most definately fix/upgrade the fuel pump!!!! WOW, almost as pitifull as the Holley Red pump in stock trim.

AlkyIROC

I think the last time I checked, my BG280 pump fills a 4 liter jug in about 15 seconds.

five7kid

iTrader: (14)

Make that 3.78 liters per gallon (1 gallon = 3.78 liters) and I'll agree with you. 95 gallons per hour at 6 liters per minute.

Trevor86TA

Typed it wrong...

The math was right though.

SS CAM

Blackroc86, I had a similar problem with fuel pressure drop. I was using a moroso inline fuel filter before the pump, turn out even though it was new and clean it just couldn't flow enough to keep up with the pump and demand put on it. Problem solved by matching up the flow of the filter to the fuel pump, hence problem was solved and no more drop. I have a Mallory Comp 140 pump and matching Comp 140 fuel filter now.

IHI

iTrader: (1)

Again, from experience get a high flow PAPER element to put between the tank and the pump. I have 2 reusable high flow mesh filters and while they allow max flow, the micron rating is rather high and they allow the tiny stuff through.

Before I reinstalled my A2000 I bought the Aeromotive inlince filter, paper filter that flows 390gph so it can outflow my pump at 350gph which i can live with

FWIW the A2000 in my car flows 1 gallon in 12 seconds, so whatever that equates too in canadian terms The pump is noisey though, once the car is started it blends in with the muffler tone, but when setting floats or pressure it makes a Hooley blue almost sound like a stealth pump!!!