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peterd

Fuel Economy

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OK, got it-

 

Davies Craig figures are about 1000cfm for a 12" fan. If that area is about a 3/4square foot, then the air comes out at 1300ft/min, which is about 23kph.

 

So an electric fan running in a car is overtaken at 25kph driving speed, and every speed above that is being made less efficient at cooling.

 

I've got a bright idea on how to solve this... might take some time...

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Just remember that the rated figures for the fans are usually free air delivery, and not the actual figure when drawing air through the radiator and anything else in front.

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Can i interrupt and give some insight into the 3k carb.

I run a 4k_U engine with 5k electronic dizzy and coil, and am lucky to get 12.5L / 100ks highway in my 1 tonne chunk of steel jungle made jeep here in Cebu phi;lippines, rated the worlds worst place to own and drive a vehicle.

 

The most significant improvements i have made is opening up the slow jet with an angle grinder to the side of it about 1 mm from the end orifice, adn then compensating for that with turning the idle mixture screw about 30 degrees in from stock position (1..5 turns). Before i did this it was about 15l / 100ks.

The second most significant improvement was by inventing a vacuum operated momentary switch between the carby fuel cut solenoid and its power supply, so that when engine is operating with manifold pressure of 23 inches of mercury suction or more, it opens the circuit and cuts fuel to the engine for engine braking scenarios or down hill coasting in 2-3rd gear. This stops fuel being sucked through the slow jet and being wasted and causign popping and gurgling during these high vacuum scecnarios where power is not being demanded.

This took it down from abou 13.8 to 12.5L / 100ks

 

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Ke35 with twin 3k carbs (not 3kb carbs) on a 5k would run around the 9-10 l/100km high cruising depending on fuel quality. Would empty a quarter of a tank real quick at 160 km/h though (under controlled conditions of course...... ;) )

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inventing a vacuum operated momentary switch between the carby fuel cut solenoid and its power supply,

 

Now THAT is clever!

 

But still, those figures are terrible compared to a KE70 running a highway in Aussie.

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yes they are terrible, but be aware driving here involves slamming on the break every 50 m to avoid children trying to die, and tricylces driving at 30 km/h. you never get beyond 60 kph on even the most major roads,

When I'm back in aus, i get afraid driving at 100 kph because I'm not used to it. But still, if any of you with your well maintained vechicles brought them here they would be a lot better than this. The air that this poor motor has had to ingest in its life is probabyl the biggest issue. The islands that make up this country are magnetic, so the dust that is in the air is magnetic. So vehicles here are ʞ©$ɟed adn thats the primary reason for the polution in this country in my opinion.

That and the understanding of mechanics here as to the purpose of honing a cylinder. They believe it is best to be as shiny and smoooth as possible!! MONKEYS.. absolute MONKEYS, but what more could one expect from a country that elects a boxer who has had his head beaten in all his life; as a senator!!

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Lol !! We think the same of our politicians too!

 

I didn't realise the geology of the Phillipines was magnetic, but I suppose there must be a few places on the Earth that are like that. Impossible to run machinery well.

 

Does the solenoid open & the idle come in as the revs come right down?? Does it pick up the throttle easily if you want to cruise after you have slowed down, so you gently add accelerator?? What is the vacuum-electric switch like??

 

I like that invention!

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yes as the revs come down to about 1500 ish, the manifold is is closer to a standard 20 inches of vacuum so the switch flicks back to close the electrical circuit (let electricity through, let fuel through).

This is if i set the switch to activate at about 23 inches. As soon as u touch the throttle the vacuum is decreased dramatically so the solenoid its immediately re energized. however it take about half a second for the fuel to get sucked through at about 1000 rpm so you don't wanna engine brake down past 1200 ish.

 

Saving 1.5 l of fuel per 100 ks is great!

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