The AUSubaru.com.au Forums

I wanna s/c my rebuilt ea81 and blow thru a 32/36 dgev weber, any one done any thing simular using a s/c

I take it by S/C you mean supercharge or supercharger, and you want to do that to an EA81.
I would love to see that running. are you going suck / draw through or blow through?


USMB

http://www.ultimatesubaru.org/forum/sho ... hp?t=72291

TOONGA

TOONGA wrote:I take it by S/C you mean supercharge or supercharger, and you want to do that to an EA81.
I would love to see that running. are you going suck / draw through or blow through?

TOONGA

Scheffer1986 wrote:I wanna s/c my rebuilt ea81 and blow thru a 32/36 dgev weber, any one done any thing simular using a s/c

I'm going out on a limb here and saying blow through

hence the link to USMB, it is way easier to have a draw through setup as you don't need to make sure the carby is properly sealed.

I should have said "are you sure you want to make it blow through?"

TOONGA

and you don't get pressure on the flutterbys

Hahahahahaha.. I was just having a joke just as I thought the question was (no disrespect to Scheffer1986). I could never see a s/c work as a blow through.. you got to think of what happens to the forced air when (like Jonno says) the flutterbys are shut.. there is only 2 places.. out week joins or through the jets and breathers in the carby. Either way you're not going to have a very healthy running engine. The case is different when the engine is direct injection and the s/c is electronic controlled (as in the case of the Toyota's).

Scheffer1986.. why you looking to use a s/c for forced induction? IMO it's a lot easier/cheaper to use a turbo. You can use carby (albeit designed for the purpose) or without too much expense you can setup a fuel only ECU unit. I understand the idea of having low down torque but this can be done with ball bearing turbos and the correct a/r on the exhaust housing.

ive heard and seen photos of supercharged EA81 and 82 i expect the usmb link would help

Planes mostly but carby is not the way to go, sorry, too much f***ing around to work it, with blow through carbies you NEED a wastegate that works when off throttle or carby goes pop =)

Why is a supercharged carb'd motor hard? Suck through of course.

You don't need anything like a rising rate fuel supply, and because the SC is more or less locked to the speed of the engine the results are predictable.
Use a wideband O2 setup and get a jetting kit and you're set. Probably take a few hours of screaming around while keeping an eye on the A/F ratio (or just logging it using a notebook), swapping jets and taking note it'd be no more difficult really than dialing in an N/A carb'd motor.

I'm already running a weber and you can buy a plenum that sits over it sealing the carbs vents and a small s/c would be plenty for a 1.8lt then i can intercool i was gonna draw thru with a eaton m45 and run a side draft su or weber but they lack acce pumps , and is needed at high rpm

When going blow though, the carb should be inside a box for best results, stops boost fuel leaks out via the throttle shafts.

Carb should also have boost referenced power valve, nitrophyl float not brass.

SU carbs and all Webers works fine on suck through, and they all have accelerator pumps.

Webers as a fixed choke carb have an accelerator pump circuit.

SU carbs, known as CD or CV (constant depression or constant vacuum) carbs have the dampened effect on the piston rising causing a heavier draw on the jet for acceleration enrichment.

I am tossy up now between turbo or s/c go to http://www.turbogemini.com and have a look at some of his stuff can be easily modded for any thing turbo kit with blow thru carb looks nice or even just the blow thru carby kit and a centrifugal s/c some pipe work intercooler and i'm done

This would be cool

Nice to hear that from an EJ convert

Someone is happy to make a basic relaible engine design work harder eh ?

Nice bonnet clearance there too, efi and coil packed EA81 !

Yeah Gannon, that aircraft engine does look pretty cool.. I don't know about the black oil underneath though that s/c looks like the Vortech system??

RSR 555 wrote:I don't know about the black oil underneath though

i think its paint, the yellow is ontop of an orignial black trolley