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Suck through carb supercharger set up.


Vintage Grumble

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Hello, just out of interest, if one was to do a suck through carb supercharger set up, what mods would one need to do to a standard dirty old carbed engine? Can you use any old carb, or do you need a special set up for the extra vacuum? Bigger jets maybe? I guess you would need to go to an electric fuel pump over the std mechanical? Would you need to do anything with the timing? With the set up I have in mind the boost levels would be fairly low I would say, like no more than 9psi or so, so there would be no need to lower the CR of the engine.

Any info/thoughts on such set ups would be great/interesting.

Cheers, VG.

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Shit son, this is my feild of expertise. (That and binge drinking)

What engine you romancing fitting a huffer to?

Some motors can take it like a dirty girl, and others squal like a piggy when it gets forced in.

Richer jetting is always a good idea. Even if it's just the secondaries on a two barrel two stage carby.

On holley carbs, it really helps to externally reference the power valve. The existing CR of your engfine will dictate if you need to drop the compression ratio of not. Water injection can be a terriffic way to limit detonation.

As for timng, if you get you car running, you can see how much timing it can stand, and then either lock the dizzy, or limit the amount of mech advance it can develop.

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i dunno how carbs work. but would think it would be a matter of changing jets or running something bigger.

as for timing. depends on engine. guessing if its a shitty old carb engine, its going to be designed to run on pretty crap fuel. so you would likely get away with running 98 and mild boost. and possibly just playing with the base timing. getting timing right is the main thing, if you dont want it to blow up. getting the fuel wrong will just make it gutless, shit and blow up after ages

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I would never run blowthrough carb on a roots blown engine.

With the blower intake open wide, the blower will be pumping flat out all the time. When the carb isn't wide open, all the air will pressurise the carb/intercooler/piping etc. The pressure will spike, and blow all the seals in the carb/pop off the piping. A BOV might alleviate this somewhat, but ALL the air the blower pumps will pass out the BOV. I've seen that done, and the BOV sounds like 10,000 duck callers through a megaphone.

The only other way it could work would be to use a shit toyota blower and wire up the clutch to a wide open throttle switch. So the engine doesn't see boost unless the holes are open.

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Thank you for the info chaps. I was toying with the idea of putting an SC12 on my lada at some point, being a low comp 1.5L I thought the SC12 would be pretty close to correct. I'll do a bit more research into what carbs best suited for it and so on. If I used the SC12 I guess I could have the clutch kick in and out when ever I wanted, but would no doubt need to bypass the SC when its not running? Will most likely just have it running all the time TBH. Thought its probably the chapest and easiest way to get a bit more power out of it.

Also thought it may be good to have some tech info about such things on here, we need more carb'ed SC cars on OS, haha.

Mr Bart, whats the details of your set up?

Cheers, VG.

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i dunno how carbs work.

pretty simply - they work because they have holes in them!

a single DCOE on draw through would work pretty ideally in your case VG. SC12 will be heaps for the lada 1.5

no idea on how the internals on them hold up though. but who cares really? I say thrash it till it pops/another second hand engine cant be expensive - you could even get a big bore 1.7 from a niva!

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