Fuel pressure regulator?

[brummiewedge]

Hi All,

My 400se has an adjustable fuel pressure regulator on the bulkhead, is it standard, and what should the pressure be?
I now have the big valve 4.6 in and it pulls even stronger when its in colder range of temp, the first couple of miles or so, so i am tempted to wind the pressure up a bit to richen it up. Any comments?

[350zwelgje]

Standard setting would be 2.5 bar but 2.75 seems to be the ideal setting (wedge bible). Higher it could provoke injector weeping. For me it is easy to check the pressure as I leave the gauge on. Once every 3 months I adjust the pressure back to what it should be, so it could be necessay to adjust yours. If no gauge you could temporarily plumb one in at the cold start injector end.

All this for standard 350i, don't know about large capacity RV8.

Rob

[number 7]

My 400 has a Webber adjustable regulator, fitted I think when the 4.3 was installed. I had it checked a couple of months back, and it's set at 47 psi (standard would be c. 36 psi), although that's not an issue for me with my mapable set-up. The problem with tweaking them is that it affects the pressure across the whole rev range, so to get it right at the top, you probably find it screws the lower end completely. You also really need a RR session to get it as close as possible.

7.

[v8 racing]

If you are still running the standard ecu i would set it to about 45 psi, no problem with injectors as they will stand upto 50 psi before going mad!!

[v8 racing]

ps this is with the vacum pipe disconected!

[wedg1e]

Just to wibble your thrusset-pouch, my car now runs 1.7 Bar. Big fat injectors, incorrectly calibrated ECU
Foot down.... nothing happening... nothing hapening... noth-JEEEEEEEEEEEEEEEEEEEEEEEZZZZussss...

[brummiewedge]

V8, why do you not connect the vac pipe?
I also have 3 ECU to try Adams/Standard/JE!

[wedg1e]

brummiewedge said:

V8, why do you not connect the vac pipe? I also have 3 ECU to try Adams/Standard/JE!

The fuel pressure is lower at idle because the manifold vacuum sucks the regulator down. If you set it at 45psi with the vac on it'd probably be 60+ at open throttle!

Swappping ECUs isn't necessarily a good thing as they were often matched to a particular airflow meter and the response could change with a different ECU.

I have 5 ECUs and every one makes the car run differently!

[shpub]

v8 racing said:

If you are still running the standard ecu i would set it to about 45 psi, no problem with injectors as they will stand upto 50 psi before going mad!!

The injectors might but the pipework might not... Has been known for them to split at these pressures. I have seen them bulge! Worth replacing the pipes if you go down this route as it is beyond normal spec and the pipes are probably quite old.

[anonymous-user]

Im toying with getting one of these, you can get them preset for your car from places like deman tweeks or RPI... I did a search on this topic and opions vary (allot), general concensus though is they perk up the throttle reponce. Do you have to keep re-setting them though, i.e. do they go out of calibration?

Doug

[brummiewedge]

Checked mine out today, it was at 45psi anyway, so left alone.
Will have to wait till the new rolling road is up and running in solihull, about a month he reckons.

[badredwedge]

Fitted one of these to the 400 last night set it at 45 psi vac pipe off, it drops to about 38 with the vac pipe back on, have not had chance to drive it yet but it sounds smoother.

[anonymous-user]

Darren, where did you get it from? did it come with the pipe and bits to to fit it...

Cheers

Doug

[badredwedge]

Sidewinder said:

Darren, where did you get it from? did it come with the pipe and bits to to fit it... Cheers Doug

Got it from Demon Tweeks 01978 664466 and for the 400 it came as a kit pipes clips etc I also got a pressure gauge that fits into the side (removeable)so you can check it from time to time the valve kit was £86 and the gauge £16 all + VAT the whole job took about 2 hours

good Luck
BRW