A single Bosch 044 is a much cheaper alternative than buying any of the dual Walbro setups(i.e. Buschur or FullBlown). Another big advantage that the 044 has is less flow drop off at high fuel pressure compared to a Walbro 255. The dual Walbro 255 setups in parallel will flow more volume of fuel than the 044/255 combo in series however.

 

Two pumps in parallel provide a significant advantage in volumetric capacity. Simply put, they easily flow a much greater volume of fuel.

Two pumps in series provide a significant advantage in pressure capacity, but not so much volumetric capacity. They can provide greater rail pressures, but not a much greater volume.

Adding a Bosch 044 in series is insufficient for applications that demand a high volume of fuel, like high hp E85 power setups. Big power E85 cars need pumps in parallel. Adding a Bosch 044 in series is fine for those who want to experiment with the new high pressure ID1000 injectors and such, or, those who need just a little more volume than a single Walbro can comfortably deliver (e.g. 600whp on gasoline or 500whp on E85).

 

I'm amazed that you get any significant flow from the Walbro when the Bosch is off. I always thought the advantage of running the pumps in series is that if one pump failed, you'd have hardly any flow and the car would die the moment the car made any boost. But I guess this is not correct and if my Bosch dies I might go dangerously lean.

 

The only reason is money. The duel in tank setup will flow better, but is more expensive. ($550 carrier + $90 walbro) = $640 vs. the $200 I spent on the Bosch. With either system you have to buy lines so I don't count that.

Having said that, it will be interesting to test the limits of this in line setup I have. I am hoping it will support around 600whp on E85 with FIC2150s, but we will see. If I have to switch to the duel in tank, I wonder if there is a way I can put the Bosch in there with the walbro since the Bosch is a better pump. Unfortunately I'm thinking it's too big, however, I could keep it inline on one of the walbros as a booster.

I would think if either pump died, you would go lean, but that is the same in any multi pump setup. As far as significant flow when the Bosch is off, I don't get good flow which is why I turn it on at only 5psi.

 

Here is some pump flow data.... i didnt conduct the test's, so i cant vouch for the accuracy.



I believe the bosch was run @ 14v.

 

might be the pump installation, u might need retune after pump installed. I have intank walbro and inline walbro with hobbs switch, my car run perfect at 12.0 afr wot on e85. Good Luck.

 

I believe that test to be accurate. It confirms what I explained about parallel vs. series. Basically, the twin parallel pumps are voumetrically superior until/unless rail pressure exceeds ~82psi.

 

First off, this is one insightful thread as I've always wondered why some chose the dual Walbro over the Bosch 044. For starters, my goal is 500whp on E85 and I'd like to stay with a stock-framed turbo. I'm looking at the 73HTA Green for my choice. If it's any consolation, this will be matched up to a built 2.3L and I currently have the FIC 1050cc injectors. My concern is rather or not I should go with the Walbro double pumper or the Bosch 044.

Assuming that it's better for me to run the Bosch, which FPR do you recommend?

This is very nice to know as well since it seems that many people are partial to the Walbro dual set ups.

This is precisely why I'm interested in this thread.

 

So what do I need to run the Bosch 044 as the bottom line?

 

As far as the fuel pressure regulator goes, I just run the standard Aeromotive. Now as for the Bosch, you will need some wire, -6 fuel line, two fuel rail adapters and a bunch of fittings. You will also need at least one relay to control when the pump turns on (you can tap off the ecu harness where the stock fuel pump control wire is). If you install your pump in a location that makes it noisey, you might also need a second relay with a hobbs switch or if you have an AEM, wired to an output and configured to turn on at 5psi or so.

I ran a positive wire directly from my battery, into an inline 20A fuse, through the two relays then to the fuel pump. You can ground the pump anywhere on the chassis of course.

 

making 500whp with stock frame turbo and e85 is very easy and simple. All u need is an intank walbro plus an inline walbro and an 1200cc or 1600cc inj. plus an red or black turbo, ofcourse with full boltons. There is no need for adjustable fpr or bigger rail. Look at my sig on the 8 car, if we retune it with 35 psi , 500whp will be achieved. In fact, my tuner said i still have plenty of fuel for future boost increase.

 

I must mention that I went through 2 inline walbro (392s) before I bought my Bosch. They were both run full time and both of them burnt up. I am running my Bosch on the same circuit and have no issues. Unless the walbros weren't designed for the 14v you get from the direct battery connection, I am not sure why they failed.

 

Just a couple notes for people considering the 044 inline...

I believe the in/outs for it are M10 in size... maybe one is end M12 I can't remember.

In my experience of owning an Evo for 7 years, I've had a Walbro fail once. And I've run the 044 for 3 years and it's not failed.

You should run a relay to power the 044 which is triggered off the stock fuel pump. There is a fuel pump resistor which you can get the trigger signal from in the engine bay if you choose to mount it there.

I'd recommend you use a barb fitting on the in to the 044 and run a rubber line from the fuel filter in the engine bay to the 044. 5/16" I think is a good size line.

From the out of the 044 to the rail will depend on what type of rail you have.

I run my setup at 3.5 bar base full pressure with sard regulator but I would assume a stock regulator works just fine.

I think the power you can make with this combo is the same as what TedB said. It gives me enough fuel for 40 psi on a 35R on gasoline with RC1000cc.

 

Oh and you'll notice on the 044 there is a little check valve on one end to prevent fuel from flowing back into the tank. I don't use this because presumbly the Walbro has the same type of valve.

 

This is a little misleading. I have seen GREAT pressure variations from pump outlet to rail. The inline pumps will be able to handle the pressure increases seen at the pump well before 82psi at the rail. In order to see 82psi rail pressure I wouldnt be surprised to see 100+psi at the pump outlet. Especially when factoring in people using stock lines. The 044 will kill a dual walboro setup on high boost stock line cars. Now a modded walboro feeding an inline 044 will flow A LOT of fuel and be sufficient for 600whp easily on e85. A single intank modded wally on Fathouses evo went 10.45@130+mph. Fathouse is not a small man either so race weight isnt what I would call "light" even though he has an RS.