Quote:
Originally Posted by GuidoK
The only thing that doesnt make them very suitable for boost applications is that they have an internal fuel pressure regulator (with internal I mean that it sits in the white assembly, not in the pump casing), and that fuel pressure regulator is not vacuum (or boost) regulated but a set value.
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I don't agree 100%! I'm running the OEM setup just fine. The trick is to run a solid state fuel pump controller. I am running 25psi at idle, ramping up to 72psi at boost, with 1200cc injectors. Works very well, no need to use an external fuel pres. regulator (although I bought everything to do a return-fuel system incase I ran out of fuel, which to date is not an issue).
Quote:
Originally Posted by GuidoK
For the 3.0si/z4m thats maybe less of an issue as they run on a fairly high pressure (I estimate 5 bar or so) but the 3.0i pump is regulated at 3,5bar (as far as capacity goes its the same internal pump I believe), so if you have 0,5 bar boost, that leaves 3.0 bar fuelpressure to get proper atomazation in/from your injectors.
With boost and thus the large pressure difference between vacuum and full boost I think boost/vacuum dependant regulated pressure would be better with the proper tuning (different fuel pressure automatically means new tuning of course).
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I have a 3.0i and 2.5 pump here as well, and those pumps are different. Must be the 3.0si/Z4M which utilize a more powerful pump.
Quote:
Originally Posted by GuidoK
This is btw the fuelpump on the m54 (pre-fl) versions:
Can length is 82mm, overall lenght (without the barbs/connector) is 97mm.
Can thickness is 39/46mm
No fancy qr code yet on this version, too old  (these are the only markings)
I'm not sure if its equivalent to the walbro 400 or 450. The 450 is e85 compatible and the 400 is the pump gas version of basically the same pump. I have no idea if a stock z4 is e85 compatible (we dont get that here afaik).
These bmw pumps are probably specifically made for bmw with non generic/bmw only electric connectors molded into the housing. |
The pump above is not the same as any of the TI Automotive/Walbro pumps. The lower fatter section is actually smaller diameter. Most likely a different vendor/pump model.
You are probably right - who knows exactly what the flow rate of the OEM pump really is, but the fact this pump is flowing enough with quite a bit of headroom, I suspect it is very close to the Walbro 400 in output. 1200cc, 6cyl, 72psi, 500whp (or ~600bhp if you incorporate 15% drivetrain), and 45% duty cycle, quite a bit more left in it...