Do I have something missing?

[drive2tractors]

Ok. I was just looking enviously at the pictures in the powder coated thread and I noticed that on my Cerbera I dont have a vacuum return hose. Is this right or should I be looking for a solution?



I also managed to fit my new bonnet stay which I really like! Should I love my stay so much?


(Sorry about the picture quality.)

Andrew

[G20RG B]

There aint one on my SP6 Cerb either and pretty sure you don't need one,,Don't ask me why though I'm a numptie when it comes to engines!!

[Quentin1]

+1

No pipe here as well.

[drive2tractors]

Does it actually do anything? Why do othe S6 engines have one and where does it go?

[NCE 61]

drive2tractors said:

Does it actually do anything? Why do othe S6 engines have one and where does it go?

Goes to the airbox on my Tuscan:-



On my previous Tuscan it was not connected.

[nelly1]

The Fuel Pressure Regulator (gold thing) controls rail pressure to the injectors.

On most EFI engines, the vacuum pipe is connected to the engine side of the throttle butterfly, so that at idle (throttle closed - when the engine needs less fuel), there is a vacuum. This vacuum pulls on the diaphragm in the FPR and lowers the rail pressure.

As the throttle opens (engine needs more fuel), the vacuum decreases and the fuel pressure gradually increases, until WOT (Wide Open Throttle, where the engine needs most fuel) where fuel pressure is at a maximum.

This is done mainly for fuel economy at part throttle.

I guess TVR weren't too worried about MPG around town on what is essentially a race engine, so the vacuum pipe wasn't needed and the ECU mapped for a constant fuel pressure at all throttle openings.

The connection to the airbox in some cars is just a cosmetic exercise as the pressure therein is not too different from atmospheric, and the rail pressure will still be constant.

HTH.

[Basil Brush]

From previous cars I also thought it was partly a safety backup, so if the pressure reg fails it vents into the inlet, rather than blowing fuel all over your motor but that may be rubbish.

[drive2tractors]

nelly1 said:

Really interesting technical engine stuff.

Thanks for that, I understand now and am certainly less worried!

[nelly1]

Basil Brush said:

From previous cars I also thought it was partly a safety backup, so if the pressure reg fails it vents into the inlet, rather than blowing fuel all over your motor but that may be rubbish.

[Basil Brush]

nelly1 said:

Basil Brush said:

From previous cars I also thought it was partly a safety backup, so if the pressure reg fails it vents into the inlet, rather than blowing fuel all over your motor but that may be rubbish.

It's me talking rubbish thinking about it anyway as it was the fuel pressure damper on my old 944 that this referred to not the regulator.

[5MUG]

Sorry, your Cerbera?.................

[S6PNJ]

5MUG said:

Sorry, your Cerbera?.................

Whooaaaa! Family Fued - run away, run away, run for your lives!!!

5MUG drive2tractors