speedyxjs
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| posted on 12/1/09 at 07:10 PM |
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Converting EFI to Carbs
What would the advantages be?
How long can i resist the temptation to drop a V8 in?
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flak monkey
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| posted on 12/1/09 at 07:12 PM |
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No electricals to blow up or go wrong. Carbs are pretty simple really....
Less wiring
Less weight
A fat set of DCOEs/DHLAs look better than a set of throttle bodies.
All IMHO of course...
Sera
http://www.motosera.com
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blakep82
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| posted on 12/1/09 at 07:15 PM |
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when i was asking this on some ford forums years ago, everyone kept saying i'd lose a lot of power, i don't think i believe a bit of it
though. just depends how its set up i think.
fuel economy would be the only downside i can think of
________________________
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don't write OT on a new thread title, you're creating the topic, everything you write is very much ON topic!
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mcerd1
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| posted on 12/1/09 at 07:17 PM |
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what they said ^^^
easier to diy tune than a stock ecu, so if its stock EFI vs webbers / bike carbs - then you could even gain power (depending on the engine and so
on.....)
[Edited on 12/1/09 by mcerd1]
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britishtrident
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| posted on 12/1/09 at 07:21 PM |
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Efi using megasquirt is a lot easier to set up than carbs easier ---- jetting up carbs was a pita.
[I] “ What use our work, Bennet, if we cannot care for those we love? .”
― From BBC TV/Amazon's Ripper Street.
[/I]
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mcerd1
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| posted on 12/1/09 at 07:24 PM |
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quote:
Originally posted by speedyxjs
What would the advantages be?
what options are you looking at ?
stock efi / carbs ?
webbers ?
bike carbs ?
Megasquirt ?
[Edited on 12/1/09 by mcerd1]
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MikeRJ
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| posted on 12/1/09 at 07:33 PM |
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quote:
Originally posted by blakep82
when i was asking this on some ford forums years ago, everyone kept saying i'd lose a lot of power, i don't think i believe a bit of it
though. just depends how its set up i think.
Depends entirely on the EFI system, though. If you are talking about a poxy single point injection system, then a decent set of DCOE's is
likely to give a significant improvement on power (but not emissions or economy!).
Individual throttle bodies are a different story though. They don't need a venturi to work, so offer the minimum of restriction to air flow,
but you still get reasonable atomisation because the fuel is pushed through the injector at high pressure.
With a carb, you only have atmospheric pressure to push the through the jet, so you need a decent amount of airflow to achieve good atomisation. This
implies a small venturi and hence more restriction. Going to a larger venturi lessens the restriction, but lowers airflow and you get poor fuel
atomisation.
A decent ITB EFI system will give the best power coupled with good driveability at all throttle openings and engine RPM. A carb is *always* a
compromise somewhere. Make it big enough to show similar power levels to the EFI system and the engine will drive like crap at low speeds; make is
smaller to improve driveability and you hurt power.
If you read Dave Walkers section in PPC, you might know that he tried some 48mm throttle bodies with some 54mm monsters on a tuned Duratec recently,
and was very dubious that they would provide any useful gains. In fact they improved top end power by around 30bhp IIRC, which amazed him.
[Edited on 12/1/09 by MikeRJ]
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scootz
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| posted on 12/1/09 at 07:34 PM |
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Carbs are horrible nasty smelly things that have no place in a civilized society!
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martyn_16v
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| posted on 12/1/09 at 07:35 PM |
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quote:
Originally posted by blakep82
everyone kept saying i'd lose a lot of power, i don't think i believe a bit of it though
You can ultimately get about the same peak power with carbs as you will with throttle bodies, but what you will lose out on is part throttle
torque/drivability and economy. There just aren't enough control methods in a carb to get the fuelling accurate over the whole operating range.
Besides which, there also aren't that many people left that can properly set up what little adjustment you do have.
Comparing individual throttle carbs to a stock EFi system just isn't a fair comparison, the effect of changing the airflow is far more
pronounced than anything you can do with fuelling.
I'd hesitate to say that carbs are easier to set up either, certainly not if you're going to do it properly. Unless you're really
set on being a 50's throwback and use a clockwork dizzy you'll have to find a solution for the ignition. Most carb people around here seem
quite happy using Megajolt, but don't seem to realise the step up from that to Megasquirt is minimal in terms of wiring and complexity.
Carbs are obsolete technology, the sooner you backwards people realise this the better
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clairetoo
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| posted on 12/1/09 at 07:38 PM |
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quote:
Originally posted by scootz
Carbs are horrible nasty smelly things that have no place in a civilized society!
Yep ^ What he said 
Its cuz I is blond , innit
Claire xx
Will weld for food......
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speedyxjs
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| posted on 12/1/09 at 07:57 PM |
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After watching 'a car is reborn' i was considering fitting a classic XK engine if it were to fit straight in. After some enquireies on
jaglovers, i have been offered a 3.6 engine for £50 to replace the hugely unpopular (in most jag enthusiasts minds) 2.9 i currently have. I thought i
could run it on carbs to make it a bit prettier. A cross between the standard engine and the XK engine.
Also i understand carbs a bit better than EFI. Less to go wrong 
How long can i resist the temptation to drop a V8 in?
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stevebubs
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| posted on 12/1/09 at 09:36 PM |
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quote:
less to go wrong
Not necessarily true
Question for you...
Are you happy messing around with digital things or is your brain "more analogue"
Digital happy = EFI
Analogue = Carbs
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zilspeed
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| posted on 12/1/09 at 10:05 PM |
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Carbs - best setup will always be a compromise somewhere. Never absolutely 100% perfect. Close, but not perfect.
Injection - best setup can be spot on.
And if you go for individual throttle bodies, it can sound every bit as good as carbs. I actually wish my engine was injected and because it
isn't I will probably have to mess about with dynojets etc. just to get it running sort of properly as I can't use the original airbox and
exhaust.
If I had injection, I would add or remove fuel wherever required and it could be perfect.
Carbs are easier, but sooooooo last century.
Megasquirt and throttle bodies - YKIMS.
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