Hello from Calshot near Southampton

[Fury1630]

Agree with Tony on this over pressure on the needles is normally critical. Not sure about the 3psi figure though. That sounds low to me as on a Jenvey TB setup the pressure regulator is set to 3.5 Bar but someone will have a better view on what the pressure should be.

Throttle bodies need pressure to squirt the fuel, whereas carbs use the engine airflow to draw the fuel through, so want just a little positive pressure to keep the float chamber topped up.

Sorry Dean your "hello" thread's gone a little awry - it happens round here.

[Nash]

Interesting. so what produces the 3 PSI ? a fuel pump of some description?

......Neil

[Fury1630]

Interesting. so what produces the 3 PSI ? a fuel pump of some description?

Yep, that's why there are "low pressure" fuel pumps, for carbs & "injection" pumps for - erm - injection. To Invade Dean's thread a little more, engine's with mechanical pumps don't have a problem as when they're not using much fuel (at idle) they don't make much pressure. When you use an electric pump the flow is constant, so at idle the pressure can build & overcome the needle valve. So you need a pressure regulator to cap the pressure.

[Nash]

Interesting. so what produces the 3 PSI ? a fuel pump of some description?

......Neil

Yep, that's why there are "low pressure" fuel pumps, for carbs & "injection" pumps for - erm - injection.

I knew there was a difference but I wasn't aware there was such a difference in pressure. I've learned something new today.

Ta............. Neil

[bigstuff]

Just to put things into perspective, Neil your 3.5 bar is 50.75 psi, quite a difference !

[Nick]

Hi Dean, glad to see a proper engine car has joined the forum.

I run a 2.1 Vulcan pinto with an Fr33 cam arp bolts the works..

[DeanS]

Hi Dean, glad to see a proper engine car has joined the forum.

I run a 2.1 Vulcan pinto with an Fr33 cam arp bolts the works..

Nick, that sounds sweet! In answer to the over fuelling issues above I was led to believe you must use the bikes electric pump which runs at 3 psi, I couldn't believe how gently it ran!
I bought a fuel pump blocking plate off eBay and bye bye mechanical fuel pump thereby freeing up at least a fifth of a horsepower!

[Red27]

Welcome Dean, I like the way you said that - "improving" your car. I see you've sussed that photos are required from the outset, but not knowing how to post them is not an excuse

All types of cars and engines are welcome, and as you can see there is plenty of advice on offer - whether you've asked for it or not

[DeanS]

Welcome Dean, I like the way you said that - "improving" your car. I see you've sussed that photos are required from the outset, but not knowing how to post them is not an excuse

All types of cars and engines are welcome, and as you can see there is plenty of advice on offer - whether you've asked for it or not

Hi Linda

It's just that I want to post pictures when "Grin" is finished not while he's still a project

[bigstuff]

You'll be accused of it being too shiney