The V8 Owners Forum -

Heres one for the experts


I'm possibly going to add a bit of gas to my blower setup. No point in trying to add extra fuel from my exisitng nitrous feed at 8psi if the manifold presure is 15psi eh??

So I will fit an EFI type pump with rail and return reg etc..

My question is more realted to actual fuel flow I suppose. But using my simple brain I can see that fuel at 8psi wont flow out of an open end into a manifold that has a static air pressure on boost of say 15psi.

If I change that fuel delivery pressure to 45psi the fuel flow through the jets is based on the fuel leaving the injector and spraying into a manifold that has no pressure in it!!

So should I assume that the 15psi pressure in the manifold will reduce the fuel flow rate? In simple terms I'm wondering if I should be assuming that the 15psi in the manifold will cancel out 15psi of delivery pressure and therefore reduce the actual fuel flow rate??

Again in simple terms would the 15 psi in the manifold acting upon the 45psi outlet of the injectors reduce the fuel flow down to something that I would expect to see from a 30 psi delivery pressure into a manifold with no pressure in it??

I want to make sure that I jet the fuel side right for the first dyno run later this year

Perry

Yes, higher intake pressure versus fixed fuel pressure would result in less flow.

But obviously you would be using a boost referenced FPR so that fuel pressure pretty much tracks fuel pressure so pressure across the injector remains fairly constant.

If you need 45psi for the injectors, set that FPR to 45psi.

You might ( and this is a guess ) be able to slap on another FPR after this on the return line to achieve the 15psi for the Nitrous side of things. But not sure if that would mess up the first FPR when on boost

Be easier just to use a single FPR and run all fuel injectors off that.

That was sort of my thinking Stevie.

I have an 044 pump to fit and also have a regulator. But I'm not sure how the reg works yet or even how to pipe it up.

I want to get it right first time so I'm not going to rush anything.

The reg has a tapping for what looks like a pressure reference signal. But I dont know if this would be boost or vacuum?

Perry

boost/vacuum are the same thing. Both just a pressure reference.

It's as simple as a feed from tank to pump. Pump to rails/reg then a low pressure return to tank.

What reg is it ?

Its one of these!
No name on the thing ??

No idea what make, but looks relatively normal

From rails to the port on the side. Return out the bottom to fuel tank

And boost/vac reference to the small top port. ( ie reference from intake manifold )