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Re: A Series Turbo Build
No life (a.k.a. DattoMaster)
Joined:
2008/10/10 22:02
From Melbourne Australia (and likely under the car)
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if you go to yahoogroups.com look for carburetedblowers (one t, it's the US spelling of carburettor) or click

http://autos.groups.yahoo.com/group/Carburetedblowers/

and sign up. that list used to be called the 'blowthruturbo' list and was dedicated to blowthrough carb prep. There's lots of info on holleys, rochesters, carters (and their modern edelbrock clones) as well as the more traditional weber and dellorto carbs - even SUs. If you look at the first couple of years of the list (before the list owner decided to embark on a belt driven turbo conversion and take hte list in that direction) there's more info there than you can point a stick at. I learned a lot there (contributed a little as well) and pretty much any question you could ask would be covered there. There's also some info on blowthrough lpg - which is in practice such a simple option I'm surprised more people don't go for it.

There's also the 'turbomustangs.com'

http://turbomustangs.com/

forums - one of the sections is devoted to blowthrough carbs, and there's guys there running absolutely insane ets with carburetted combos.

I know you didn't ask specifically for carb related info, but I feel there's an abundance of efi related tech on the net, almost too much, but the carb related info (if you chose to go that way, and nobody can decide that but you) is harder to get. The info that is out there is good, and the above mentioned places are about the pick of the bunch as far as blowthrough carbed info goes.

Failing that ask a more specific question here.

For example if you were looking for a recommendation about carb choice and size, I'd probably suggest a holley 350 2 barrel (or a 500 if the rpm was to be somewhat higher than std). They are teh 'fisher price' of carbs in terms of design and tunability, but in practice they work exceptionally well in a blowthrough setup, are easy for a befinner to tune, reliable, and tend not to have problems with gaskets seeping fuel even up above 20psi boost (I've run one up to near 30psi in a 3K corolla engine, unintercooled, which was enough to blow the headgasket and take a chunk of the head with it, but the carb didn't have the slightest leak or anything!) . They are a lot easier to get bits for than webers, though the 32/36dgv would likely (if you spent a long enough time on it to get the fuelling perfect) have a slight edge with part throttle economy...

If lpg was more your liking, then an impco 125 with model L convertor will supply enough airflow for a blowthrough a series and the convertor can supply up to around 200bhp worth of lpg constantly without icing up. If you were to go drawthrough lpg, then the impco 200 mixer (which has the same air valve as the 225 impco, so flows pretty close, but is a bit more sturdy in air hat construction, and less likely to break in the rare case of a backfire (mixer is lpg equivalent of carburettor.) and again the model L convertor. YOu'll notice I didn't mention GRA. There stuff is good, but it's a lot more costly. and the impco lpg gear has a sliding air valve, a bit like the piston in an SU carb, so it automatically varies the venturi size with air flow requirements, which looked at the opposite way - at lower flows, it closes down the size, so there's still a stong signal and excellent fuel metering and dispersion. IMHO the GRA wouldn't be as good off boost (not even close) on such a small engine, because they are a fixed venturi.. Impco convertors/mixers are able to be run blowthrough 'as is' you just need to run a big enough diameter air line from the carb hat to the convetor front side, so it increases pressure on the convertor diaphragm and increases main lpg output in sync with the onset/increase of boost. They can run blowthrough as is, but you'd still technically want to run the balance line. It's 'normal' function is that if the air cleaner becomes massively clogged up, it notices the slight vac increase in the air filter case, and lowers lpg output - so it won't go rich and waste lpg if the air filter is restrictive.

Posted on: 2010/5/26 8:36
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John McKenzie
Transfer the post to other applications Transfer

Subject Poster Date
     A Series Turbo Build real_lifer 2010/5/25 13:32
       Re: A Series Turbo Build Gylezy 2010/5/25 14:12
       Re: A Series Turbo Build bige 2010/5/25 14:33
         Re: A Series Turbo Build Dundee1000 2010/5/25 16:54
       Re: A Series Turbo Build jmac 2010/5/26 8:36




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