21 replies to this topic

[HUBBA.HUBBA]

Got a tech question about how they run

[nicklouse]

Ask the question then!

[David128]

go for it

[Spider]

Off topic, sorry in advance.

 

The end of a joke always pops in to my head when ever I hear / read the words 'Does anyone know anything about,,,,,,'

 

A guy parachuting out of a plane, pulls for the Main Chute and it fails to Open, he's only just done his training and this is his first solo Jump. A little bit of panic set in and then he goes for the Reserve. Same happens again - nothing.

 

On his way down, he passes another guy going up;-

 

"Hey mate, know anything about parachutes?"

Nope - you know anything about Gas BBQs?"

 

OK, so back on topic

 

Steve on this forum I'm sure know about parachutes.

 

What do you need to know about Gas BBQs?

Edited by Moke Spider, 07 February 2016 - 07:16 PM.

[HUBBA.HUBBA]

On a turbo hif, just wondered when the trottle is opened and compressed/charged air comes through is the air after the throttle still a vacuum. Cause how I understood forced induction is that the air/fuel mixture is forced into the cylinders, so that would be a positive pressure, but if that is the case how does the fuel get drawn through? Doesn't that rely on vacuum to draw fuel through the jet ? Or is it still the case that compressed air/ fuel mixture is still being sucked/drawn into the engine? 
Cheers

Edited by HUBBA.HUBBA, 07 February 2016 - 08:22 PM.

[David128]

venturi still applies

[Spider]

It can go from Vacuum to Pressure on a boosted application.

 

There is a special HIF used in Boosted applications, though it's quite feasible and easy to modify a stock one, mainly for the problem that you've highlighted.

[David128]

speed of air over fuel inlet

[mingy]

venturi still applies

Correct, negative or positive pressure passing over the bridge in the carb creates the venturi effect which draws fuel through the jet then in turn is metered by the needle. 

[Spider]

This was how they plumbed up the MG Metro Turbo

 

 

though there maybe better set ups.

[Spider]

 

venturi still applies

Correct, negative or positive pressure passing over the bridge in the carb creates the venturi effect which draws fuel through the jet then in turn is metered by the needle. 

 

 

Yes, but on the over-run, you'd be venting quite a bit of fuel out through the Float Bowl vent.

[HUBBA.HUBBA]

venturi still applies

Correct, negative or positive pressure passing over the bridge in the carb creates the venturi effect which draws fuel through the jet then in turn is metered by the needle.

Ahh that explains it. I thought the venturi effect only worked in the carb with a negative pressure venturi with neg pressure drawing the fuel out.
It now makes sense to me saying its the speed of the air flow.
Thanks chaps
One other thing, anybody know how far up or down the piston/needle is likely to be at cruise speed.

[mingy]

 

 

venturi still applies

Correct, negative or positive pressure passing over the bridge in the carb creates the venturi effect which draws fuel through the jet then in turn is metered by the needle.

Ahh that explains it. I thought the venturi effect only worked in the carb with a negative pressure venturi with neg pressure drawing the fuel out.
It now makes sense to me saying its the speed of the air flow.
Thanks chaps
One other thing, anybody know how far up or down the piston/needle is likely to be at cruise speed.

 

What speed do you call "cruise" ? 

[David128]

its only going to be approximate but would expect to be about 3/4 it really depends on needle profile, compression ect

[ANON]

It can go from Vacuum to Pressure on a boosted application.

 

There is a special HIF used in Boosted applications, though it's quite feasible and easy to modify a stock one, mainly for the problem that you've highlighted.

 

 

spindle seals go on the wrong way and it's got the dashpot seal.