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Club Member
Location:
sydney
Registered:
May 2002
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Re: efi vs carby
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Mon, 07 October 2002 04:25
 
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Seeing as this question was started in my for sale post I suppose I had better respond.
But before I do lets take an actual engine to base this discussion on, and as the parts were for a 4AGE lets use the bigport variant for the example using the standard factory EFI vs a twin sidedraft setup.
OK now weve got that sorted...
lets talk about the way these two systems introduce air in to the manifold.
I am sure some of what I will say here is not 100% correct and is based on conversations Ive had with more technicaly minded people who could also be wrong, but as I have understood it a carby uses atomisation to deliver an air fuel mix where as injection tends to use vapourisation by aiming the injector at a hot surface like a valve or the head itself and the fuel vapourising when it hits that hot surface. Of course some of the air is atomised on the delivery as well.
Obviously the vapourisation effect relys on a lot of variances like temp air speed etc to make it work effectively which is where its drawbacks are...fortunately the use of a computer and sensors overcome the poor mixing problems
(I havent taken in to account squish area here as that is something I understand little of at this point although I do know it does have an effect, but that effect would be advantagous no matter what delivery system you would use)
..without those injection would not nearly be as efficient or controlable. On the other hand a carburettor atomising the fuel from a much smaller jet further away from the valve can have a better mixing effect if everything is tuned correctly. Basically the size of the fuel particles are much smaller (better mixed) than straight out of an injector (where the particles are larger until they hit a hot surface)
The main advantage of injection is as has been stated before its ease of adaptability over varying conditions. Obviously if you had a computer able enough you could have a million maps to use for just about any given situation to overcome the mixing issue. Plus the fact that these days emmissions and fuel economy are big issues so this favours injection as well.
IMHO a carb will deliver a better throttle response (particularly low in the rev range where velocity is slower and the injected fuel struggles to vaporise) over all.
As an example try towing a trailer with a small load in a 4AGE powered car at 100Kmh in 5th gear, put your foot down and see the response..Ive done it many times towing trail bikes and generally the response from a standard engine is very slow ( the computer trying to figure whats going on with such small changes indicated from its sensors)
basically the EFI just decides to dump max fuel but this seems to bog the engine a little (flooding?) and the car is slow to recover and gain speed, where a carb delivers a much quicker response and the car starts to pull away at a much greater rate than the efi variant (no other changes were made to this engine BTW)possibly because you can control with your foot the fuel supply better but also because of improved fuel mixture (obviously more modern engines than a 4AGE have improved some of the mixing issues!)
ok thats enough typing for now...Ill wait for Bill to respond as I expect he will before I go into this any deeper 
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| | Subject | Poster | Date |
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efi vs carby
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Ribbo | Mon, 07 October 2002 02:03 |
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Re: efi vs carby
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EMP-2TG | Mon, 07 October 2002 02:43 |
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Re: efi vs carby
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Bill Sherwood | Mon, 07 October 2002 03:31 |
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Re: efi vs carby
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IRA11Y | Mon, 07 October 2002 04:25 |
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Re: efi vs carby
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Bill Sherwood | Mon, 07 October 2002 04:50 |
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Re: efi vs carby
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floody | Mon, 07 October 2002 05:17 |
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Re: efi vs carby
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Blown86 | Mon, 07 October 2002 05:29 |
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Re: efi vs carby
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GIN51E | Mon, 07 October 2002 05:32 |
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Re: efi vs carby
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floody | Mon, 07 October 2002 06:15 |
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Re: efi vs carby
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Norbie | Mon, 07 October 2002 08:24 |
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Re: efi vs carby
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gianttomato | Mon, 07 October 2002 10:18 |
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Re: efi vs carby
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RWDboy | Mon, 07 October 2002 06:41 |
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Re: efi vs carby
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GIN51E | Mon, 07 October 2002 08:27 |
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Re: efi vs carby
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Ribbo | Mon, 07 October 2002 08:21 |
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Re: efi vs carby
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SUPRAGTE | Mon, 07 October 2002 09:20 |
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Re: efi vs carby
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Grega | Mon, 07 October 2002 10:39 |
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Re: efi vs carby
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GIN51E | Mon, 07 October 2002 13:49 |
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Re: efi vs carby
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5KinKP60 | Mon, 07 October 2002 15:19 |
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Re: efi vs carby
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justcallmefrank | Tue, 08 October 2002 00:20 |
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Re: efi vs carby
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mrshin | Tue, 08 October 2002 00:34 |
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Re: efi vs carby
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thetoyman75 | Tue, 08 October 2002 00:39 |
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Re: efi vs carby
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mrshin | Tue, 08 October 2002 01:34 |
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Re: efi vs carby
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chrisss | Tue, 08 October 2002 09:18 |
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Re: efi vs carby
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Remedy | Tue, 08 October 2002 10:03 |
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Re: efi vs carby
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GIN51E | Tue, 08 October 2002 10:31 |
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Re: efi vs carby
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chrisss | Tue, 08 October 2002 11:24 |
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Re: efi vs carby
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rjenman | Fri, 21 October 2005 22:24 |
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Re: efi vs carby
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rjenman | Fri, 21 October 2005 22:25 |
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Re: efi vs carby
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hemi twofifteen turbo | Sat, 22 October 2005 01:29 |
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Re: efi vs carby
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Bill Sherwood | Sat, 22 October 2005 07:28 |
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Re: efi vs carby
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September_Squall | Sat, 22 October 2005 05:24 |
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Re: efi vs carby
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170bhp | Sat, 22 October 2005 08:03 |
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Re: efi vs carby
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oldcorollas | Sat, 22 October 2005 08:07 |
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Re: efi vs carby
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170bhp | Sat, 22 October 2005 08:15 |
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Re: efi vs carby
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river | Sat, 22 October 2005 10:26 |
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Re: efi vs carby
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170bhp | Sat, 22 October 2005 10:41 |
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Re: efi vs carby
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170bhp | Sat, 22 October 2005 10:44 |
