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170bhp Regular Registered: January 2004	Re: efi vs carby Sat, 22 October 2005 08:03 Hemi twofifteen turbo has hit the nail well and truly on the head, by design the carburettor relies on air speed across a venturi to create a low pressure, the faster this airspeed across the venturi the greater the pressure drop, now the fuel bowl has atmospheric pressure acting on it, and this difference in pressure is what causes the fuel to flow from the bowl thru the jets into the carburettor throat, here lies it's downfall.....IT RELIES ON AIRSPEED ACROSS A VENTURI!!! Fuel injection doesn't due to the fuel being pressurised, now with a carb if we want a good strong signal at the venturi, either the venturi has to be small or the airspeed has to be high, if you have every played with Weberes and replaced the venturis(removable, often called chokes) and replaced for larger ones to increase the amount of air that can be flowed at higher rpm, you will find that due to the lower air velocity across the venturi at lower rpm we get a weak pressure signal and not much difference between the pressure at the venturi and pressure acting on the float bowl, this causes bad mixing of the air fuel ratio(basically said!!), of course with fuel injection you can also run into problems where the air speed is also low, but back to back if you had two motors one efi and one carb and airspeed was low, the efi engine would be the more drivable. You could go on and on about this topic in depth but it all comes back to one very important factor..... A CARBY RELIES ON AIRSPEED ACROSS A VENTURI TO CREATE A LOW PRESURE!!! This effect is also how front spitters work on cars, fast moving air has a low pressure, so when this fast moving low pressure air hits the front of the car, it slows down and it's pressure comes up, this higher pressure acts on the splitter like a leverage arm, also if any air goes underneath the splitter we want to accelerate this air as it's pressure will reduce(fast moving air has a lower pressure remember) which will help the pressure onto of the splitter force it down....make sense?? [Report message to a moderator]

	Subject	Poster	Date
	efi vs carby	Ribbo	Mon, 07 October 2002 02:03
	Re: efi vs carby	EMP-2TG	Mon, 07 October 2002 02:43
	Re: efi vs carby	Bill Sherwood	Mon, 07 October 2002 03:31
	Re: efi vs carby	IRA11Y	Mon, 07 October 2002 04:25
	Re: efi vs carby	Bill Sherwood	Mon, 07 October 2002 04:50
	Re: efi vs carby	floody	Mon, 07 October 2002 05:17
	Re: efi vs carby	Blown86	Mon, 07 October 2002 05:29
	Re: efi vs carby	GIN51E	Mon, 07 October 2002 05:32
	Re: efi vs carby	floody	Mon, 07 October 2002 06:15
	Re: efi vs carby	Norbie	Mon, 07 October 2002 08:24
	Re: efi vs carby	gianttomato	Mon, 07 October 2002 10:18
	Re: efi vs carby	RWDboy	Mon, 07 October 2002 06:41
	Re: efi vs carby	GIN51E	Mon, 07 October 2002 08:27
	Re: efi vs carby	Ribbo	Mon, 07 October 2002 08:21
	Re: efi vs carby	SUPRAGTE	Mon, 07 October 2002 09:20
	Re: efi vs carby	Grega	Mon, 07 October 2002 10:39
	Re: efi vs carby	GIN51E	Mon, 07 October 2002 13:49
	Re: efi vs carby	5KinKP60	Mon, 07 October 2002 15:19
	Re: efi vs carby	justcallmefrank	Tue, 08 October 2002 00:20
	Re: efi vs carby	mrshin	Tue, 08 October 2002 00:34
	Re: efi vs carby	thetoyman75	Tue, 08 October 2002 00:39
	Re: efi vs carby	mrshin	Tue, 08 October 2002 01:34
	Re: efi vs carby	chrisss	Tue, 08 October 2002 09:18
	Re: efi vs carby	Remedy	Tue, 08 October 2002 10:03
	Re: efi vs carby	GIN51E	Tue, 08 October 2002 10:31
	Re: efi vs carby	chrisss	Tue, 08 October 2002 11:24
	Re: efi vs carby	rjenman	Fri, 21 October 2005 22:24
	Re: efi vs carby	rjenman	Fri, 21 October 2005 22:25
	Re: efi vs carby	hemi twofifteen turbo	Sat, 22 October 2005 01:29
	Re: efi vs carby	Bill Sherwood	Sat, 22 October 2005 07:28
	Re: efi vs carby	September_Squall	Sat, 22 October 2005 05:24
	Re: efi vs carby	170bhp	Sat, 22 October 2005 08:03
	Re: efi vs carby	oldcorollas	Sat, 22 October 2005 08:07
	Re: efi vs carby	170bhp	Sat, 22 October 2005 08:15
	Re: efi vs carby	river	Sat, 22 October 2005 10:26
	Re: efi vs carby	170bhp	Sat, 22 October 2005 10:41
	Re: efi vs carby	170bhp	Sat, 22 October 2005 10:44

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