Well i am using a pair of bosch fuel pumps for my motor this year and i know that they aren't the highest flowing bosch pumps out there......

lately they have come out with a big bosch pumps that flows 420lt/hr and the usual old performance pump everyone would use was the bosch 216 pump that would flow 255lt/hr

well i'm curious as to what mine are rated at and was wondering if there was a way i could test it.....

i was thinking of something like run the inlet of a pump to a gas tank and then the outlet to a regulator and have the return flow into a different gas can and time how fast it takes to do that?

Any help?

 

The flow rating... e.g. 255lph..... is meaningless, without a corresponding pressure on the discharge of the pump. In effect, the performance of the pump is defined by the "pump curve", a plot of the flow that the pump can achieve against any system pressure. Typically, the flow will be low at high pressure (100psi for an EFI pump) and very high at low pressure (approaching 0psi).

So, unless you have the ability to set up a system with a variable (and controllable) back pressure, (or the exact pressure you plan to run your system at... say 3bar/43.5psi or 4bar/58psi) it would be hard to develop the pump curve at home. As a minimum, you would have to have the pump discharge into a line that has a pressure pressure gauge and a device to regulate the pressure in the line. Plumbing in an AFPR would be one way, or simply using a valve that can be opened and closed to adjust the system pressure. Then, for each discharge pressure you could measure how much fuel is removed from the reservoir in a given period of time, at a specified discharge pressure.

I have a Kinsler FI catalog that shows the flow ratings for a number of pumps that have numbers corresponding to the Bosch series of pumps, and although labled as "Kinsler", appear to be the Bosch pumps. Models appear to be 208 (325#/HR @ 50psi), 210 (*same as 208, but threaded in and out), 211 (420#/HR @ 50psi), 270 (210 #/HR @ 50psi, not recommended over 70psi) and 271 (390#/Hr @ 50psi, not recommended over 100psi).

To convert #/HR to lph, you can divide by 1.60. e.g. 325#/HR = 202lph at a fuel specific gravity of 0.73 (6.1#/GAL).

And to give you a feel for the variation in flow rating vs. pressure for a typical pump, here are the figures for the 208:

400#/HR @ 0 psi, 5.5amps
370#/HR @ 20psi, 6.9amps
325#/HR @ 50psi, 8.7amps
300#/HR @ 70psi, 10.0amps
260#/HR @ 100psi, 11.7amps
200#/HR @ 120psi, 13.0amps

I run dual 208's, with a rating of approx 200lph at the pressure in my system, and they each support 500crankHP.

 

next time i'm at the garage i'll look at the numbers on the pumps

thanks

 

Well, here are the part numbers on my pumps:

0580254980

and underneath that to the right a bit is:

810906091 C

---Can you make anything of that with your catalog?

On the pump it seems to have the Volkswagen and Audi logos and according to my friend who is letting me use these pumps they came out of a volkswagen

thanks for any help

 

That's a hard call. My pump is marked .....984 on the invoice. It seems to have an identical appearance to the pump Kinsler calls their 10208. But it is also supposed to be identical to the NOS part #15764. That came with my 5176 kit back in early 1995 when I bought it from NOS (I think they include a different pump with the kit now). When I was having some problems with teh kit, I drove down to NOS's shop and they tested the pump. When they were testing it, they said they never failed, because they were the factory pump from a Porsche Turbo (who knows how accurate that statement was???). But the pump curve in the NOS catalog for their version of the pump does not match the flow numbers in the Kinsler catalog. The NOS numbers would not support 500HP. The Kinsler numbers will, allowing for a 20% return to the tank for a safety cushion.

I can't find any cross-reference to Bosch part #'s on the web. I have looked for them for a long time.

 

I looked at your website and you do have the more faborable pump with the long neck outlet....

My bosch pump is more of a second choice...kinda if you cant get the kind you are using.

Maybe i'll try and give them a test and throw the regulator on the end of the feed line and see what i come up with

all i need them to support is about 800hp.....they should do the job. They have a barbed 7/16" inlet and a -6 outlet

Lastly.......most of the turbo porsche's DID use pumps that looked exactly like yours. In fact from some small research i've done they used two of them. One was a primary and the other was a secondary. Porsche probably had the other come on at a pre-determined boost level and the computer would notice and click the other relay. Thats my idea anyway....i wouldn't think porsche would use hobbs switches.

Thanks for checking though.....

 

I've tested some pumps at home. All tests at 13.8volts and 43psi, at the input of the fuel rail, in order to correctly assess the losses through the lines from the tank and the filter.

Stock Impala pump: 134lph at the fuel rail
Walbro 225lph: 177lph at the fuel rail
Aeromotive 1000: 364lph at the rail.


Needless to say, I now have the Aeromotive.

I would recommend EVERYONE with a modified motor to run this test. Since at WOT you're only looking at one specific pressure, you don't really need to develop a curve. You would be suprised to learn that generally, the flows are lower than expected.

Of all the motor problems I've seen, my guess is that the majority are related to insufficient fuel for safe combustion. Another thing often overlooked is BSFC of the motor, and pressure. A 1500HP carburated motor at 9 psi and 0.5 BFSC will be supported by a pump that could only handle 600hp on a 6psi blown motor running 90psi pump pressure and 0.6 BSFC.

That's a HUGE difference. So when you see a pump advertised for 500hp, you'd better do some research.

 

So basically what you are telling me is that you tested your pumps through the entire system?

meaning you turned on the pumps and had them pump gas through the feed line, through the rails, out the regulator @ 45psi setting, and then let the return line dump gas in a container and just watched how much fuel it could return in 1 minute?

is that what you are saying? i cant quite picture it

 

Almost.

I took the line off where it enters the fuel rail, added a pressure gage, then added a petcock at the end. I then adjusted the petcock until the gage read 43psi and pumped into a bucket for 30 seconds.

I then poured the bucket contents into a quart measuring cup.

 

ah, ok. Cuz i couldn't understand why you would put it through the rails...you were just measuring AT the rails.

Ok...what i will probably do is at the end of my 1/2 feed line and -8 tube nut, i'll just put the regulator there and adjust it for 45psi and turn the pumps on for 30 seconds and see how much they flow into a bucket and then into a measuring cup like you

thanks for the ideas

 

If you want to flow your pumps at home, all you need is the pump, a power supply, a return-type regulator set for the desired pressure, and a measuring system. I'd recommend using something less-flammable than gasoline - kerosene may work.

Simply set up the pump to feed the regulator, and block off the output of the regulator. Feed the return line into your measuring system, and you've got a way to measure the fuel flow. The regulator provides the restriction necessary to determine the pump flow at a given pressure. Make sure that the regulator is up to the task of flowing 100% of the pump flow through the return line, or else the line pressure will creep up and the measured flow numbers will be less than expected (a pressure guage mounted on the feed line would be a good idea).

Just be careful when playing with gas and electricity