fuel pump options

kupcar · kupcar's Garage

My rear fuel pump on my 76 930 is toast. The car is stock with the 3.0 motor. Replacement oem pump from bosch is anywhere from $550-800! There has to be a better option. Any ideas? Thanks, Jeff

WydRyd · 01-08-2007, 06:55 PM

Ummm... how about a good second hand pump? You should really have a matched pair of pumps. Well, that's what I've been told.

kupcar · kupcar's Garage

Are rebuilds available? It seems like crazy money for a fuel pump specific to a 76 930.

WydRyd · 01-08-2007, 08:38 PM

You can look up Vertex Auto... they typically have new and reman'd components for sale via their WEB site.

slammed1000 · 01-08-2007, 10:01 PM

i would purchase a walbro pump before i spent the money on a bosch. they are specific to model and are a direct replacement. i purchased one a few months ago for around $125 brand new. i think the website was fuelpumps.com

kupcar · kupcar's Garage

I might have to look into a walbro or something aftermarket. The last quote I got was for $819! Any idea what the flow rate is on the stock pumps? I'd like to make this as simple as possible with respect to mounting, plumbing etc. What about a bosch 044?

slammed1000 · 01-09-2007, 11:19 AM

i found a chart somewhere before i ordered a walbro to make sure it was ok.the walbro pump outperformed the stock pump by alot. it flowed more gph and the pressures were about the same

kupcar · kupcar's Garage

slammed- I tried a search for fuel pump flow and it turned up nothing. Do you know which model walbro you used? I found the bosch model 0528 254 990 and the porsche part number 930 608 111 00 that is currently on the car. I wonder why this specific pump is so costly. The rear pump off the 77-89 models is around $325. Why? Thanks-Jeff

WydRyd · 01-09-2007, 05:23 PM

I run two BOSCH 044 fuel pumps in my car... I bought them 3 years ago and can't remember the price, but from memory, it was close to $400ea. That's in Australia dollars tho, which is about USD$300.

kupcar · kupcar's Garage

Merv- I know the 044 is he choice of high hp tuners. I am just wondering if I could just hook up an 044 with the stock pump up front. I'm sure they have different flow rates and operating psi. I'm guessing the 044 flows more with higher psi, because it can support 650 hp. Would this combo work???????Anyone?????? Thanks, Jeff

Porschefile · 01-09-2007, 09:47 PM

Quote:

Originally posted by kupcar
Merv- I know the 044 is he choice of high hp tuners. I am just wondering if I could just hook up an 044 with the stock pump up front. I'm sure they have different flow rates and operating psi. I'm guessing the 044 flows more with higher psi, because it can support 650 hp. Would this combo work???????Anyone?????? Thanks, Jeff

I don't think that's a good idea. That is how my pump setup is at the moment (stock in front, 044 in rear) and my 044 is sucking too fast for the stock one to keep up so my engine is cutting out from loss of fuel pressure under heavy load. One 044 is good for around the 600-700hp level, so technically a single 044 will be good for almost everyone here. If anything, put the stock one in the rear and 044 up front. Personally, I'd just find some fittings or a pipe to eliminate the rear pump and put the 044 up front.

The Bosch 044 can handle up to something like 100+psi, and I believe it is rated at 200lph @ 5bar (72.5psi), 330lph @ ~3.8bar (55psi). Here's a comparison pic of the Walbro 255 and 044:

Here's a flow chart:

The 044 inlet is M18 x 1.5mm and outlet is M12 x 1.5mm. Anyways, just figured I post all the info I've found as there doesn't seem to be too much about the 044 out there. This is the cheapest place I've found 044's for: Jay Racing

Does anyone know if there is any real difference in the pumps on 930's of different years? Kupcar, I recently bought a '80-83 930 front pump for my Carrera. I ended up only using it for a few days and went back to my old setup so it's relatively new. If the pump will work for you, it's yours for $150 shipped.

If you're not interested, you might as well upgrade to a 044 as you'd save money over stock and have more than enough room for the future.

Just FYI, Walbro pumps are designed to operate at lower pressures. I believe they are rated at around ~3bar, though I think they might be able to handle around 4-5bar reliably. There is a specific "high pressure" Walbro 255 model in case anyone happens to be running high fuel pressure for some reason. From what I've seen, at higher pressures (like 5bar+) Walbro pumps seem to have reliability issues. I spent a lot of time researching and the 044 was one of the few pumps I could find that can handle a ton of pressure (100+psi). My ghetto Protomotive setup is running ~6.8bar (~99psi) fuel pressure as a result of the boost level and stupid rising rate fpr. Geez, I can't wait to go with a Protomotive or aftermarket MAP sensing setup so I can get an adjustable fpr and drop the pressure down to a not-so-stratospheric level!

Anyways, if anyone happens to have a similar setup and is running over 5 bar fuel pressure, keep these things in mind when considering fuel pumps. It seems that most around here are running 5 bar or less, so this won't apply for most people.

WydRyd · 01-10-2007, 02:05 PM

Porschefile, I run a Protomotive FPR & CHIP, 944Turbo injectors and twin 044 pumps (in series) in my Turbo'd Carrera. This setup requires the high fuel rail pressures to work, as it "over drives" the 944turbo injectors to flow enough for Stage 3 power levels (i.e: 550-600HP). Many tuners don't like to run such high fuel rail pressures as it puts a lot of strain on the EFI components, but it's been working fine for me for many years without any issues.

kupcar, you should really have two MATCHING fuel pumps, front & rear. I personally wouldn't run only one up in the rear, or in the front, unless you're running an aftermarket EFI with big injectors and need only the one big fuel pump.

Porschefile · 01-10-2007, 10:10 PM

Quote:

Originally posted by WydRyd
Porschefile, I run a Protomotive FPR & CHIP, 944Turbo injectors and twin 044 pumps (in series) in my Turbo'd Carrera. This setup requires the high fuel rail pressures to work, as it "over drives" the 944turbo injectors to flow enough for Stage 3 power levels (i.e: 550-600HP). Many tuners don't like to run such high fuel rail pressures as it puts a lot of strain on the EFI components, but it's been working fine for me for many years without any issues.

kupcar, you should really have two MATCHING fuel pumps, front & rear. I personally wouldn't run only one up in the rear, or in the front, unless you're running an aftermarket EFI with big injectors and need only the one big fuel pump.

Honestly, I really don't see that as being a very good route for over 400whp. Sorry, I'm not trying to knock on your setup. The stock 951 injectors are 37#, which equates to about 380cc. At ~400whp they are pretty much maxed out and upping the fuel pressure can only help so much. I put down 431whp and my a/f's were HORRIBLE. I only have the dyno chart from my 2nd run that day, which was ~426whp and my a/f's jumped up to ~13.5-14:1 above 5k rpm. Anyways, I had Todd retune the chips for some Siemens 55# injectors and the car still runs great. There is a small amount of surging at very, very light low rpm throttle situations but, it otherwise runs fine. I just don't get why people don't spend the extra few hundred for properly sized injectors and a retune to do it right the first time. According to Todd, he was saying the high pressure rising rate FPR is also necessary for it to function properly on the stock afm. That makes sense as the stock afm is well out of resolution above 400whp. I'm toying with the idea of either going to his MAP setup, going with an AEM, or trying out a piggyback (Greddy E-Manage Ultimate) and eliminating the afm with a MAP so that I can run a constant rate of 5bar instead. Anyways, I'd rather have more injector than is necessary and have some room to work with rather than running at the limit and risking something bad.

rotorhead · 01-16-2007, 01:27 PM

The rear pump is the expensive one I have a 88 930 and I just replaced the rear pump for an alternate pump.

First download this pdf http://apps.bosch.com.au/motorsport/downloads/fuelpumps.pdf it is the full specifications for Bosch motorsport fuel pumps.

My 1988 930 has a front pump with the number
0 580 254 967
and a rear pump 0 580 254 979
Your 1976 930 probably has the same setup. (For info the rear pump was also used on 928's and 944 turbo's I believe)

If you look at the motor sport pdf you downloaded you can see that there are two alternative pumps with the same specifications. The only difference is the inlet connection.

I purchased a 0 580 254 984 for $200 cheaper than the original and fabricated an adapter (Actually just a piece of 3/8" fuel hose clamped over the fitting).

I am sure that there are other alternatives out there such as pierburg, ACDelco or walbro. But I couldn't match the fittings/electical connections or mounting easily.

WydRyd · 01-16-2007, 02:51 PM

Quote:

Originally posted by Porschefile
Honestly, I really don't see that as being a very good route for over 400whp. Sorry, I'm not trying to knock on your setup. The stock 951 injectors are 37#, which equates to about 380cc. At ~400whp they are pretty much maxed out and upping the fuel pressure can only help so much. I put down 431whp and my a/f's were HORRIBLE. I only have the dyno chart from my 2nd run that day, which was ~426whp and my a/f's jumped up to ~13.5-14:1 above 5k rpm. Anyways, I had Todd retune the chips for some Siemens 55# injectors and the car still runs great. There is a small amount of surging at very, very light low rpm throttle situations but, it otherwise runs fine. I just don't get why people don't spend the extra few hundred for properly sized injectors and a retune to do it right the first time. According to Todd, he was saying the high pressure rising rate FPR is also necessary for it to function properly on the stock afm. That makes sense as the stock afm is well out of resolution above 400whp. I'm toying with the idea of either going to his MAP setup, going with an AEM, or trying out a piggyback (Greddy E-Manage Ultimate) and eliminating the afm with a MAP so that I can run a constant rate of 5bar instead. Anyways, I'd rather have more injector than is necessary and have some room to work with rather than running at the limit and risking something bad.

I agree with you here. I'm about to get a new Stage3 chip from Todd for a twin plug setup, so I'll have him callibrate it for 55# injectors. I'd rather have peace of mind

Porschefile · 01-17-2007, 02:35 PM

Quote:

Originally posted by WydRyd
I agree with you here. I'm about to get a new Stage3 chip from Todd for a twin plug setup, so I'll have him callibrate it for 55# injectors. I'd rather have peace of mind

Cool, sounds like you have some fun projects ahead of you.

Just fyi but, these Siemens 55# high impedance injectors will work just fine Racetronix I'm running them in my Carrera and haven't had any issues with the injectors themselves. They are able to withstand higher fuel pressures than most injectors so they are certainly up to the task. Todd uses some Ford 52# injectors with adapters but, last I checked I believe it was ~$1200 for a set whereas these are $350 and do the same job perfectly fine.

No sense in paying more if you don't have to.