DDP

...yeah...how much power until the pump should be upgraded?

RogueM3

This is a very stupid comparison to make and it might be way off...but on 3.0 m3 engines which are turbocharged the pump needs to be upgraded at 360rwhp.

I know this is a 6cyl, and a 3.0L...but I thought i would throw that out there.

DDP

LOL, thanks for the effort. I bet they are different pumps. But I could be wrong too. I am just nervous, I dont want to hit the limit and not know it.

Bengt Sweden

It needs to be replaced now since it is almost 20 years old and can fail any minute.
And I always follow the rule of upgrading when changing .
Bengt

Dal Heger

I only replaced mine on the S2 when it was so loud that I couldn't stand it. I heard that these pumps can support upwards of 500bhp. These pumps are overkill for these engines.

Dal.

sweanders

What kind of pump did you use Bengt? Didn't think of asking when you showed me. I was feeling wierd just standing that close to you hot rod (and I'm not talking about the yellow thing in your garage)..

Bengt Sweden

My fuel pump is a
Bosch 0 580 254 942
2276:- SEK at Mekonomen
Same as Lindsey Racing are selling

Bengt Sweden

or $195 here
http://www.importeccatalog.com/

Bengt Sweden

or $169.95 at lindseyracing

sweanders

How much bigger capactiy has that pump compared to the stock ones?

zerMATT951

I believe that the Bosch high-flow pump that LR sells is the Bosch 10208. I've found several charts that show it flowing in the neighborhood of 54gallons/hr (320lbs/hr) at 50psi. Unfortunately, I haven't been able to locate any numbers on the stock pump (Porsche 944-608-102-04). Does anyone have that data?

Laust Pedersen

And I quote for chapter 20 of the Service Manual:

Checking fuel pump delivery rate:
1. Unscrew fuel return hose on pressure regulator and hold end of hose in measuring glass (volume: approx. 1500 cm3).
2. Pull off DME relay in central electric board and bridge terminals 30 and 87b with a piece of wire.
Let fuel run into measuring glass 30 seconds. Delivery rate should be at least 850 cm3/30 seconds. Replace fuel pump if necessary.


Being careful with the units this should correspond to ~190 lb/hr (at 2.5 bar), as the minimum allowable flow for the standard fuel pump. As I recall the standard injectors flow ~37 lb/hr each or 148 lb/hr total. In other words the fuel pump should flow at least 30% more (and therefore handle 30% more HP) than the standard injectors.

Laust

Bengt Sweden

So already when you run the next size injectors 55lbs/hr = 220lbs/hr, the pump is the bottle neck. Especially since the injectors are rated at 3 bar where the pump will flow a little less.
I believe it is important to keep the 30% overcapacity to not get pressure fluctuations.
Bengt

Laust Pedersen

I agree.
As to alternatives, here is what I got (Walbro GLS392, 255 ltr/hr, with flow chart) for my (now deceased) white 951 and ready to be installed in the black car.
Laust

Tomas L

Also remember that the boost pressure gets added to the fuel pressure. If you run a 3 bar regulator and 1 bar boost, then the pump has to produce 4 bar which lowers it's capacity further.