i was cruising thru the latest issue of Dsport (generally filled w good tech) and came upon an article re MSD's Fuel Pump Voltage Booster (FPVB). since i run a Kenne Bell Boost A Pump (BAP) i was especially interested.

as we modify our air and fuel hungry (rotary requires around 30% more air to make the same hp as a piston engine) Fds we have to make important fuel system component decisions.

around 400 rwhp is the point where the commonly used cosmo/supra pumps become marginal. dual pumps, bosch pumps, along with uprated wiring often provide the answer in higher hp applications.

looking for a higher hp application, i chose a different solution.

i already was running a cosmo pump... (bought from SR in 99). what to do? rip out the pump and replace it w a Bosch? do 2 pumps?

i chose not to mess with my fuel system and bought a Kenne Bell BAP. i knew Kenne Bell had been making the unit for many years, that they had at least a 30-40 year business history and i really appreciated the tech info re fuel/fuel pumps on their site.

i like that the system triggers in boost so the fuel pump only gets boosted for brief time periods. i have been running it for 4 years. i run 850/1600s and i digitally log fuel pressure so i know it is doing the job. the BAP is user adjustable from zero to 50% voltage boost. i run it at plus 20%.

back to Dsport....

"With the MSD Fuel Pump Booster, the same single in-tank pump that was previously only able to supply enough flow for 600 rwhp may now be able to support an additional 200 to 400 more wheel hp. On a racing application, an 800 hp external racing pump wired into the FPVB could easily supply enough flow for 1000 hp."

"When we performed our fuel pump testing on page 36, we tested the same pumps under the same conditions, at two separate supply voltages, 13.5 volts and 16.5 volts. As the results show, each pump responded differently to the increase in supply voltage. On average, the additional 3.0 volts increased the pumps output by 30%."

WOW.

the FPVB and the BAP both are boost triggered so they don't add voltage at cruise. the FPVB has a vacuum line feed with a MAP sensor while the BAP comes w a solenoid that converts the signal to an electronic impulse.

i prefer the solenoid as it allows me to mount the module near my battery in the compartment behind the passenger seat. it also allows for a short wire from the module to the fuel pump. further, the BAP has a nice adjustment dial that is separate from the module. i have it mounted in the compartment also and it is easy to adjust from the driver's seat.

i am not knocking MSD as i run their coils (MSD HVC #8253) and Superconductor plugwires but i much prefer the features on the BAP.

some other interesting comments from the accompanying Dsport article entitled "Fuel Systems 101".. a 2 part series BTW.

"Two pumps better than one?

.... So are two pumps better than one? No. Two pumps are a compromise. Whenever possible you want to design a fuel system around a single pump. For one, when a single pump failure occurs, no fuel is delivered to the engine on a single pump application. The tuner can diagnose the problem and remedy the situation with a replacement of the pump. On a multi-pump application, you may have only a half or a third of your total fuel supply available. You may not know anything is wrong until it is too late and engine damage has already occurred. Not only will you be replacing a pump, you'll also be replacing a set of pistons (HC note.... what are pistons).

the other consideration with multiple pumps is the fact that in fuel systems one plus one doesn't add up to two. By this we mean to say that if you have a pair of 255 LPH pumps, you won't get the flow delivery of a single 510 LPH (255X2) pump. In fact, at best you will get 1.65 times the output of a single pump, or about 421 LPH for example. According to Bob Miller of Weldon Pump, whenever you join the flow of two identical pumps in a parallel configuration, the best flow you will get is 1.65 times the flow of one of the pumps by itself. To achieve this 1.65 factor, the pumps need to join in a low-restriciton Y adapter...

If the plumbing configuration has the two pumps fighting against each other (faced 180 degrees apart) in a tee the combined flow may be as low as just the capacity of a single pump."

all very interesting stuff. the 2 part series, written by Dsport Michael Ferrara, Publisher Dsport and Sami Sharaf, Managing Editor uses no less than RC Engineering for it's fuel pump flow tests and has lots of good stuff in it.

proper fuel tech is especially important re the rotary V piston engine.... why?

the rotary needs 1.3 times their intake V a piston engine to make similar power. so it also needs at least 1.3 times the fuel, especially when you consider we need a bit more fuel (richer AFR) to cool v the piston engine.

it is sort of ironic for me to be talking fuel as i am now running an Auxiliary Injection (AI) system and have replaced 32% of my pump w methanol. my injector duty cycles have dropped from 87% to 59%. maybe i might just turn down my BAP settings.

do pick up the Oct and Nov Dsports. take a close look at the BAP. if you are running twin pumps check they are not Tee'd...

howard coleman

 

2 rails...2 pumps...coincedence?? j/k. I think if I were to run to dual pumps, I'd plumb one pump per rail. Would that flow more that 1.65 factor?

But I like simple, and have eye balled the BAP gadgets for awhile.

87% to 59% DC...wow! Turn down the BAP, you might be able to eliminate it.

 

If you hooked them to both sides of the FPR it would be equivalent to T'ing them which = not good. A buddy of mine has the same dual pump fuel setup as I do but plumbed differently. Mine is Y'd together from tank then split to rails and his is completely seperate until FPR. He cant get the setup to work (and he has changed everything twice except plumbing). FPR drops at .2 bar.

He is now replumbing and the info above seems to support that decision.

Im happy with my setup and dont think I will change at this point. Couldnt a BAP fail in a way to loose an engine also? Trust me on this - if you loose a pump and you are not WOT you will know it. If you go WOT after that you deserve to loose an engine.

 

Couldn't a BAP fail in a way to loose an engine also?

funny you should mention that... the first year i had my BAP in i had a "failure." it was the fuse. i had the BAP set at 40% gain. the engine just turned off like a fuel cut, which it was. no damage except to the fuse. i currently run my BAP at plus 20% gain on my cosmo pump and it runs 850/1600s to 90+% duty cycles with NO pressure drop off.

howard coleman

 

Howard,

I'm glad to see you being so active in this forum again. Thanks for posting up good info/articles.

As far as pumps go, the way I have it figure out in my head is this. A 255lph in tank feeding my surge tank. Then an external Bosch 044 from the surge tank to the FPR. That system seems to work great and will flow more fuel then I'll ever need. But the external pump is loud. That seems to be the only drawback to the entire setup.

What about that PTP dual pump setup? I remember them selling a direct drop in dual 255lph setup. I just don't remember how they had it plumbed.

 

What gauge wire are you running from the bap to the fuel pump and is there a inline fuse between the two?..

 

I skimmed the fuel pump article in Dsport and was impressed.

The Weldon A-600 inline pump looked very good to me from a cost/flow/amp draw perspective.

At the highest fuel pressure rating listed (90 psi?) for the pumps the inline Weldon flowed something like 360 lph where the external (higher flow than in-tank) Walbro flowed 190 lph. I recall the Weldon had pretty low Amp draw as well.

I would have liked to see the Bosch pumps (...044, especially) in the tests as it seems that is what ALL the foreign tuners use.

Now for the dual pump set-ups that are gaining popularity for their easy install.

It would seem to me dual pumps INLINE would seem to work better than dual parallel pumps for the high pressures turbo EFI cars operate at. We don't need high flow at low pressures and at the high pressures we require the high flow the pumps really drop off flow.

Therefore it would really seem to work better to have one pump feeding another pump as to compound their pressure ratios yet have the same total flow as if one of the pumps was being used at 1/2 the final pressure (look at the charts to see how much more flow that is).

Still not as good as one great pump, since as Howard mentions there are twice the pumps to fail and one pump will kill the engine faster than no pump. But, at least each pump is working half as hard as in a parallel set-up, so failure would be less common.

Anyone runing a in-tank directly (without a surge tank to drop pressure) to an external?

 

I agree wholeheartedly. This forum needs all the knowledgeable members it can get. Thanks Howard

 

Hmm, my last time on the dyno the fuel pressure would drop 1.5 lbs at 16psi...at that point, Ralph did'nt want to go any further. This could be a nice solution to get some more rwhp without the dual pump/lines setup like i was thinking.

I also would like to know how the bosch pump does with either of these units. CJ

 

I was just looking for bigger fuel pumps and stumbled upon the bosch 044 and remember seeing it as the "billy badass" a while ago. Isn't this the porsche gt1 fuel pump?

I saw on horsepowerinabox they also have a intank version of the 044.

"Approx 270L per hour flow rate at 3 bar fuel pressure"

I'm wondering how loud it is compared to the winebros as thats a minor concern of mine. But I'll deal w/ a little winey fuel pump rather than a blowed up rotary.

I ruled out the supra pump as theyre rumored to be very very voltage dependent and need a solid 13v or something like that. A friend of mine had some alternator issues and blew his motor w/ the supra pump.

I have a FD pump currently.

 

My intake 044 is barely noticable. Outside of the car you can hear it...but inside i don't even notice it. CJ

 

What filter did you used?

I want to install one as an "intank" but have not been able to find a filter for it (under $75 that is).

 

running 16.5v with a walbro instead of 13.5 adds as much as 90lph when you get up into high pump pressure like the 80-90psi of pump pressure range (which includes any line losses). I was a little suprised to know that 2 1600cc injectors will outflow a single Walbro thats at 13.5v. If your running one Walbro per rail where you have one feeding 2 1600's even at a boost level around 25psi it seems like I calculated that youd start to get close to maxing the pump when the 1600's get to about 70% inj duty cycle. Of course if your running higher boost it goes even faster because at 13.5v the pumps flow drops like a rock at high boost levels. Bumping the voltage up to 16.5 makes a real big different in flow, especially in high boost areas. Seems like at 90psi of pump pressure it went from 150lph up to about 240lph.

The boshe 044 at 13v is about like a Walbro at 16.5 volts.

Great info Howard!
Stephen

 

I saw that magazine a few days ago (should have bought it). If it's the same one it has the charts which shows flow level at different voltages and different boost. At 12.9v & 15lbs the Apexi GTR (same thing as my Nismo) can handle 700hp and do 280l/hr. I thought I might have had to do the KB BAP as well but my pump outflows my injectors and I don't see ever going past 20lbs with water/meth injection. I was told the same thing about dual pumps before I purchased the GTR from a mechanic friend and that's why I paid >$400+ for it. This whole thing is an expensive frustrating learning process for me and I shure appreciate help with the technical stuff I don't understand.

 

I've heard from a few people that have used BAP's that they burn out the pumps that don't like running on higher voltage, mainly the Denso's.

 

Stock fuel pump is Denso, right?
I've been running a BAP for over 5 years now with no burn out problems.


-Ted

 

i have 4 years on mine w a cosmo pump. it runs my 850/1600s to 90% duty cycle on a 20% gain setting. 15,000 miles no problems. i digitally log fuel pressure.

howard coleman

 

Doh, I just looked the article over again and they do list the Bosch '044 pump as supplied from Kinsler Injection. At the 90psi setting it flowed almost twice as much as the highest flowing Walbro external! Impressive indeed.