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^^ yep, those all have to be fuel resistant.

when i did the pump in the R31 I put some ordinary closed-cell foam in as a spacer, and the petrol destroyed it in very short order. if I was doing some custom work in the tank I would cut off small pieces of what i wanted to use and soak them in petrol for a week to make sure they didn't dissolve.

sweet setup though, well done B-man :ermm:

Did you have 1 or 2 Duncan ?

Fuel pressure is base - no aftermarket reg

Had to put a check valve on the line just out of the tank as the ones that are allegedly on the Walbros don't work very well - apparently this is common.

  • 2 months later...

So far so good with the Walbros - 45 PSI idle fuel pressure - goes up to 60 when boosting. Not a problem at all.

People seem to love them or hate them the Walbros - the Yankees love them - They flow well, draw less current, have a small form factor - thus in tank fittment of two is not a problem. And they are in-expensive compared to some others.

So - just an update on where I am at with the Cosmo now.

After sorting thru some small issues - Fitting a 4.5" exhaust, new mufflers, re-tune etc - am now at 340rwkw (that's with the auto so engine HP would be close to 400 or so. And that is running 10PSI

Boost starts at 2300RPM, 5PSI by 3000 and Full boost 4000RPM all the way to 8200RPM (nice power band from 4K to 8.2K) Power climbs and climps and is still climbing at redline.

Boost will be going up soon - to 15 PSI. (Need new 3 bar MAP sensor and complete retune - bugga) So hopefully over 400rwkw

I have a MV Stage II built box coming with a 3800 RPM stally.

10s here I come :P:D:)

I took the return fuel line off while on the dyno (Ok Ben at UAS did it but I watched :P) and at 255rwkw the flow completely stopped. Scary stuff. Also had major issues with fuel pressure which went away once I put an R34GTR pump in there.

As you say though, some love em and have no problems and some love em.

It's a MUST to run a dedicated relayed circuit from the Battery for these pumps. They don't voltage step well.

340rwkw - my 1600cc/min secondaries are running at 20% or something - no fuel problems for me

You also gotta ensure you get Genuine Walbros - there's China copies out there that are shite.

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