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slide throttle carburetor

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Grey 57 Old Grey Cruiser

2,937 posts · joined Aug 2002 ·

#935247
Porsche used sliding throttles in racing cars in the 70's

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Birdman Wolfsburg Wizard

428 posts · joined May 2010 ·

#935317
Slide throttles are not used in street cars because of their tendancy to jam.

Gracey Wolfsburg Wizard

511 posts · joined Feb 2003 ·

#935322
Flat slide carbies have been used on motorbikes for years, I've owned a few and they've never jammed on me.

I'm not sure why they're not as common on cars, maybe price.

silver Dangerous when poked

2,169 posts · joined Dec 2002 ·

#935362
Birdman wrote:Slide throttles are not used in street cars because of their tendancy to jam.
but these are from an aircraft application their reliability would be paramount
Keeping it real !

Birdman Wolfsburg Wizard

428 posts · joined May 2010 ·

#935411
not much dust and gravel in the sky 😂😂😂

vlad01 Compulsive Aussie Vee Dubber

4,270 posts · joined Jun 2010 ·

#935469
why stray from traditional butterfly when its a simple fail proof design?

I see no advantages of using other designs over the butterfly.


what next? iris throttle? 😂

71 notchback,
Past owner of, 70 NB, 73 SB and 72 FB TLE

68AutoBug Beetle Restorer - Experience over 138\% - YIKES --

11,654 posts · joined Aug 2002 ·

#935506
Many of the carbies I've seen on Motor bikes have had slides

as did the old VICTA Mower... lol

they must be simpler with less moving parts...

I agree Vlad that once a carby like the Solex PICT series was made and worked well, and then they just made them better
with improvements...

but up in the air.... lol

a slide type of carby is going to give less trouble than one with butterflies... I would guess... lol

LEE
- Helping keep Air Cooled VWs on the road - location: SCONE in the Upper Hunter Valley - Northern NSW 320 kms NNW of SYDNEY---

vlad01 Compulsive Aussie Vee Dubber

4,270 posts · joined Jun 2010 ·

#935517
how do you get more trouble from butterfly?

more/less moving parts? they are the same. only 1 part moves !

71 notchback,
Past owner of, 70 NB, 73 SB and 72 FB TLE

silver Dangerous when poked

2,169 posts · joined Dec 2002 ·

#935518
When the slide is in wide-open position, there are no other obstructions in the way of the air flow except for the needle, thus allowing for much greater air flow than with throttle bodies which have typical butterfly valves. The flat side of the needle is oriented towards the engine and produces a low-pressure on the back side which in turn causes fuel to flow in relation to the air flow.
Under certain moist atmospheric conditions with air temps ranging anywhere from 20 to 90 degrees F it is possible for ice to form in the induction system. The rapid cooling in an induction system using a float type carburetor is caused by the absorption of heat from the air during vaporization of fuel and, also due in part to the high air velocity, causing a low pressure area through the carburetor venturi. As a result of the latter two influences, the temperature in the mixing chamber may drop as much as 79 degrees F below the temp of incoming air. If this air contains a large amount of moisture, the cooling process can cause precipitation in the form of ice, generally in the vicinity of the butterfly which may build up to such an extent as to cause engine stoppage. In a float type carb, the fuel jet is ahead of, or just below, the venturi and throttle butterfly which means that the fuel is being impinged directly in the worst possible place for icing…the carb venturi. Since the RevFlow injector carburetor does not contain a venturi, nor a butterfly valve, the fuel and air is mixed further downstream, beyond the float type venturi refrigeration chamber. The absence of these parts accounts for the decreased likelihood for ice in this type of system.
Keeping it real !

matberry Moderator Go hard or go home

8,114 posts · joined Mar 2006 ·

#935520
silver wrote:but these are from an aircraft application their reliability would be paramount
I agree but think of the difference in number of operations per hour. A car would have millions more operations of the throttle than an aircraft.
Matt Berry Motorsports...air cooled advice, repairs and mods Ph 0408 704 662
OFF-ROAD,CIRCUIT,DRAG,STREET,ENDURANCE

vlad01 Compulsive Aussie Vee Dubber

4,270 posts · joined Jun 2010 ·

#935526
yes and modern butterfly TB in a EFI car have sealed needle roller bearings on the shaft and could easily outlast 5 engines and beyond from what i gather, having machined and made my own big boreTBs before.

71 notchback,
Past owner of, 70 NB, 73 SB and 72 FB TLE