The importance of proper installation of high-performance fuel pumps

[Herr-Kuhn]

For those of you who are running high flow fuel pumps in your boosted 928s...you might want to read over this thread.

I run the Bosch 044 pump on the twin turbo car. I looked into going further with an Aeromotive A1000 pump, but truth be told it simply doesn't flow that much more than the 044 does to justify the modification. Remember, on boost these systems will run 65 psig on the rails and the flow lines for the 044 and A1000 cross at about 70 psig, where the 044 actually outflows the A1000. At 35psig, the A1000 will easily outgun the Bosch, but this system doesn't operate there, it operates around 65. At the higher pressures the 044 is only down like 8% below the A1000.

So, long story short I think the 044 is the pump for the car.

I had this unit installed with a power relay dropping right off the battery for max voltage to the pump. This is VERY important as any DC motor's speed is proportional to its voltage and the pumps flow is a function of its speed. I was getting good voltage to the pump, but I wanted more safety on the fuel system.

I noticed that my car didn't run nearly as well on less than 1/4 of a tank of gas as it did when full, especially at the higher boost pressures. I'd be very surprised if others have not had this same experience. This leads me to believe that the factory pickup is just far too restrictive and small for the car. This week, I am fitting an AN -10 line system from the tank to the pump. The fuel pickup will be custom made to allow for lower restriction and will adapt to an AN-10 fitting. Having a small line feeding the pump is no longer an option for me. Remember, the strainer and the line were designed to feed 350 HP or so, not 600-700 HP.

In addition to this modification I have added an electronic device to the system to step up the voltage to the pump as a function of boost pressure. Now, I'll be the first to tell you that I'm not a big fan of bolt on electronic boxes, but this thing just makes sense. The first impression is "just put on a bigger pump". Well, when you do that on a return-line system you are now pumping anything you don't burn back to the tank...bigger pump, more fuel in and out of the engine bay and more heat into the fuel. Cruise on a long trip and the fuel is now quite hot. This is why Aeromotive doesn't recommend their big-gun pumps for street use. The control unit simply steps up the voltage as a function of manifold pressure. It's rather clever..."only on demand" is its motto. The fuel pump control unit is now mounted in the back of the car (behind the tool box). I have to monitor its running temperature but thus far it looks reasonable. You can step to 22 volts, but I'll likely just go to 16-18 volts only.

I will have some pictures later to show all of this stuff. If the pickup system for the fuel pump works as well as I think it will, then I will be offering these for sale to those who are interested. The filter media I have selected is far less restrictive as compared to the plastic strainer unit. Cavitation is a big no-no and tears the pumps up fast. The next time you hear a fuel pump that sounds strained...consider that it may be sucking through a drinking straw to get its fuel.

And always remember...it is easier to pump than to suck!

[Danglerb]

Fuel screen is tall and skinny, so junk clogging the bottom doesn't block all flow is my guess, but I bet as the flow goes up it could suck air. Maybe short and fat or just fat would fix it? Maybe a design that squeezes down to fit through the hole and expands inside the tank?

Some hot rod guys run parallel or series pumps, can't say I like series since one failure and flow is blocked.

What do you think of removing or changing the return line regulation and going to electronic full range pressure control of the pump?

[rhjames]

John---

while I don't profess to know much about Bosch pumps at this point (haven't bothered to do the research....), I can tell you that if you want a pump that will feed anything you're building, Barry Grant is the guy to see.

Grant's fuel pumps are feeding everything from Pro Stock to Pro Mod.....His "mighty sumo" pump will support 750 hp--400pph, and the "king sumo" will support 2000 hp--1000pph. Both of these pumps are fuel cooled, low amp draw, constant flow, made specifically for efi engines. He also markets a regulator matched to these two pumps.

We run one Grant BG-400 pump with #10 AN lines on the quick 16 car, feeding a 572 CI BBC with 14.5:1 CR. No fuel delivery issues---ever. About twice as much HP as your twin hairdryer motor.....This is a tube frame car that regularly runs 5.30's in the eighth, low 8's in the 1/4.

As for fuel delivery, yes John, you're on the right track with going to bigger lines. Not just on the supply side, but also on the return. The larger lines will aid in cooling the fuel (heat due to pump and engine compartment temps). If further cooling is needed, there are coolers out there on the market.

(Grant makes no comment about fuel heat issues in his website at the moment....)

Mine will have the same set up as the Chevy II, with exception the pump will be a "king sumo".-----one of these days....!

--Russ

[AOlson]

One way to verify your theory is to either log fuel pressure if you have a sending unit, or just video your fuel pressure gauge while on the dyno. You'll see if your pump can't keep up.

Just as a data point, I too am running the 044 pump with the stock in-tank pump. With the 42lb injectors at 80% duty cycle, and fuel pressure running at 45psi idle - 65psi max RPM, I have not experienced any drop off on fuel pressure.

[Herr-Kuhn]

Your 2nd pump is probably taking care of any issues. With the earlier cars the fuel is gravity fed to the pump and the feed line is rather small. I had thought about installing a 2nd pump, but I didn't want that complexity. I'm still looking for that extra insurance for my fuel system and I'm sure this will do the trick for me. Also, long term I might want to dial this thing up a little harder and the last thing I want is a fueling issue with it.

[rhjames]

Originally Posted by AOlson

One way to verify your theory is to either log fuel pressure if you have a sending unit, or just video your fuel pressure gauge while on the dyno. You'll see if your pump can't keep up.

Just as a data point, I too am running the 044 pump with the stock in-tank pump. With the 42lb injectors at 80% duty cycle, and fuel pressure running at 45psi idle - 65psi max RPM, I have not experienced any drop off on fuel pressure.

(please excuse my drag race car comparison, but I think it is fairly relevant)

you can also use the Barry Grant 1 gallon fuel can test:

on his website, in the technical discussions, you will find the fuel can test. he describes the test as the time it takes for your pump to fill a one gallon gas can. there are several time/fill targets listed on a chart, so there should be a way to compare to what you are trying to achieve here (preventing fuel starvation under hard acceleration).

ex: a 10 second 1/4 mile car needs to fill a 1 gallon can in 25 seconds.

this corresponds to approximately 600 hp to make a 3500lbs car run in the tens, necessitating a fuel rate of 300 lbs of fuel per hour.


this is a cheap test to perform without getting into some really expensive equipment, and the results should show if your fuel delivery system is up to the task.

with this in mind, you can eliminate the in-tank pump, use AN #10 line from the tank to filter to BG "King Sumo" pump, then AN #10 line to the regulator and then even just AN #8 line for return to tank. from the regulator you could use the standard lines to the injector rails/lines.

If this set up will faithfully feed a 1500hp Pro Stock engine, with all of the G-forces involved in zero to over 200mph in less than 7 seconds, there's plenty enough to feed a 600hp 928 motor......

It's not all about pressure, it's about volume as well.

here's the link for you to reference:

http://www.barrygrant.com/bgfuel/default.aspx?page=81


--Russ

[Herr-Kuhn]

That's a clever way to measure fuel flow...set it at the pressure you want to run and then remove the return line and see what you get.

One of my main goals with this system was to have the fuel system as stock as possible. Putting a monster sized pump is possible but comes with many headaches. There is just so little room under the car back there, and to run new lines is a royal pain due to the space constraints.

I'm confident these mods will give me sufficient overhead for where the car is headed. I've talked with some guys at Kenne Belle that claim to have fed 800 HP through a 5/16" line bu increasing fuel pump voltage. I'm going conservative on my spike...maybe 16-17 volts only to have some respect for pump life.

I'll try and get some photos of the mods up soon for those who are interested. My PEMs will be here newt week and I'm looking forward to fully buttoning up the inside of my car. I think that all aftermarket alarm and stereo installation people should be forced to fix the problems they cause.

[AOlson]

What fuel pressure are you running?
What kind of duty cycle are you getting on the injectors?

[Herr-Kuhn]

I'm running stock lines and regulators withe the 42 lbs injectors. On boost it runs around 65 or so psig. Last I logged duty cycle I was into the 80s, but it's been quite some time since I've done this so my memory is fuzzy right now.

I'm hoping to be able to run just to one bar with the car...maybe slightly less.

I hooked up the boost line to the pump booster last night (but a tear in my bloody rear seat side panel doing this). It pulls the voltage down to about battery voltage when in deep vacuum (20" or less)...when you go to atmospheric the voltage steps up and then further steps up into boost. It's a rather clever little box.

I'll try and get some pictures for you guys tonight or tomorrow. The box does generate some heat, but I think it will be maneagable...afterall nothing is 100% efficient...except for TURBOS

[rhjames]

Originally Posted by Herr-Kuhn

Putting a monster sized pump is possible but comes with many headaches. There is just so little room under the car back there, and to run new lines is a royal pain due to the space constraints.

After all you've engineered (plumbing-wise), I would think that running new fuel lines would be a piece of cake for ya----


Did you do the gas can test?


--R

[rhjames]

got an e-mail from Professor Ott, he too, is running an 044 on his monster car.....no issues for him on supply.

sent him the BG link as well for future reference......

[928sg]

I have the stock in tank pump feeding my 044 pump... maybe its overkill.. but it gets really hot here in the summer time.... I look at it like insurance......


John,
Is your 044 pump noisy as well? I've heard a few of them and they are always noisy....

[Danglerb]

Some of these fancy pumps look a bit cobbled together to me, some new generic motor assembly that is being used by many brands with their pump parts. Doesn't make me too ready to leave brands like Bosch or Walbro behind. Gotta figure those making millions of pumps have to learn a bit about how to do it.

Magnafuel


Barry Grant

[rhjames]

Originally Posted by Danglerb

Some of these fancy pumps look a bit cobbled together to me, some new generic motor assembly that is being used by many brands with their pump parts. Doesn't make me too ready to leave brands like Bosch or Walbro behind. Gotta figure those making millions of pumps have to learn a bit about how to do it.

Magnafuel


Barry Grant

while you may not be ready to leave to another manufacturer, the discussion here is the elimination of fuel starvation of high fuel consumption engines.....

we have used the BG 400 on the quick 16 car for several years without issue.

your opinion of what looks cobbled up is just that, opinion. in reality, they are extremely reliable.

the new BG King sumo pump will support a 2000 hp engine, as I said before, and that is far and above what any current modified 928 engine is producing. they are very quiet and operate at 12volts without any additional controls.

for those who are worried about added heat in the fuel, BG makes a heatsink that lowers fuel temps by nearly 100 degrees that can be installed in series, with no reduction in fuel flow.

it would appear to me that those who are in the market for fuel delivery system upgrades would look "outside" the Porsche box, for a solution to fuel supply starvation, fewer pieces to worry with, and noise relief.

if you could buy a product that solves all of these issues, what's not to like about it? your car is modified anyway, so why not change out the antiquated Porsche system for a more modern alternative?

[928sg]

from what I saw when looking at aftermarket pumps is that they High flow units didn't have very good duty cycle numbers when compared to the Bosch 044 pump. The area is also very small, and most of the really high flow stuff is large.....

When I went with my 044 pump I wasn't concerned about sticking with a specific brand... just fitting in the factory spot as well as meeting my needs....

[Herr-Kuhn]

My 044 pump makes a bit of noise too. It's not too bad, though I can say I wish it was a little quieter. I wanted to stay with something that fit the factory slot as well and for the flow the 044 is the only real pump that will fit back there. The A1000 is quite a bit larger and it has only minimal flow over the 044 upstairs...but the line size plays a role as well. I think an A1000 with a larger line would be higher flowing, but it's such a tight squeeze. I've also heard that those pumps fail regularly as compared to a Bosch.

I'm almost done with the high-flow pick up...just trying to get the soldering down perfectly on the brass screen.

Lots of people running the 044 pump with decent results. It is supposed to feed about 650 HP. I should have a bit of overhead with the increased voltage...hopefully not sacrificing pump life in the process.

I tend to think a lot of the dynos out there read differently so it's hard to be able to compare system to system. I know for a fact that I use the entire load map on my fuel mapping and that corresponded to about 560 HP on the rollers with the Dynojet. There was only 1 cell I didn't get to on the load map and that was where the engine torque drops back above 5800 RPM. I've seen a lot of other power results but never heard how low on the maps these cars were dropping. For example, I had by brother's car on a Dyno Dynamics dyno and it made 480 ft-lbs and 400 HP in 95F heat!...he put the car on a different dyno in Florida and with 2 psig more boost it made less HP and torque on that dyno. When I called the guy who was running the dyno session at the Ford show on the Dyno Dynamics and told him about it, his response back was that he had turned the correction factor up because peeople wanted to see "bigger numbers". He claimed 20% increase on the numbers had been used that day. I've still got those sheets around here somewhere. There are more variables than you would care to guess at when trying to compare multiple dyno sheets. My stance now is to not do it any longer, because it is not an even playing field until you get all the cars on the same machine on the same day.

Anyway...I'm just looking to have more safety on the fuel system. The weather here is nice today and I should be able to get some photos of the install now. I got lost in pool and yard work over the weekend and now it's time to go to work!!!

[Herr-Kuhn]

Here are the pictures of the finished installation of the pump voltage unit and the high-flow strainer filter.






The strainer is made from strainer grade brass screen and has been implemented with a machined aluminum pickup with an AN-10 line size to feed the pump with less restriction than the factory plastic unit and small line. Seams are soldered to avoid dirt getting past the screen. The piece turned out really well I think.

Notice the boost pressure line to the pump voltage module. There is a 30 amp power relay in the battery box which is fired by the factory fuel pump relay. In turn, high current lines run to the voltage unit and then back directly to the pump. 12 gauge wire was used throughout.

If you are running a big pump off of the factory lines you are not getting the full potential out of your pump. I have a 1-2 volt voltage drop off of the factory lines. You say, 1 to 2 volts isn't much, but in actuality it is, because it is a significant percentage of the voltage the pump runs on. I can now step fuel pump voltage up on boost. The unit allows the pump to run just about normal voltage when in vacuum...that's a large portion of the time when the car runs. Pull out the vacuum and the voltage steps up, then swing into boost and the voltage is stepped further. The rate of increase is adjustable.

[Herr-Kuhn]

Should be instaling this stuff today for final use.

[Danglerb]

Whats the failure mode of this voltage booster, does the pump still get normal 12v?

[Herr-Kuhn]

I don't know what happens if it fails...I assume the pump would not get voltage just like if the factory relay tanked.