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Location:
Sydney
Registered:
May 2002
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Supercharging a carby 3T-C
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Thu, 02 October 2003 01:53
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ive had a bright idea, and i need someone to shoot it down in flames... 
im thinking if i remove the 'air pump' (the anti-pollution system) off the side of my 3T, i can bolt on a supercharger from a 4AGZE.
now... im not going to muck around with injection & im not interested in running big boost (or even opening up the engine, for that matter)... i want to change as little as possible (read: nothing).
- can i simply connect the s/c to blow through the stock carby? will boost pressure blow the carb up? (ive heard you need pressurised carbs for turbo applications etc) and will i die as a result?
i'd really like to do it , just for something different, but if the engines only going to last 10 minutes, then i figure its not worth it.
is there anything i need to know? (carbies arent exactly my strong point, as you can see)
cheers
- Haydn 
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Registered:
June 2002
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Re: Supercharging a carby 3T-C
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Thu, 02 October 2003 02:03
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Yes you will have problems blowing through the stock carby. There are a few ways to modify a stock carby to do this but but I am no expert. You should also not that the dizzy will require some modification as you don't what to much advance under boost.
You can inject a 3tc by the way. I used to have a manifold for one but I sold it to toyman. If you can find one of these cheap and through an ljet system on it may be a better option. I was given this manifold and I sold it very cheap. Try the jap wreckers you may be supprised how cheap they are if you can find one. and a Ljet setup won't cost you much over $100 if you go to the right place.
Also consider a carby of something like a mazda 626 turbo. This would just require mounting and jetting and you can get a nice intake pipe that comes with the carby.
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Location:
Brisbane
Registered:
May 2002
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Re: Supercharging a carby 3T-C
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Thu, 02 October 2003 02:26
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The SC12 (4A-GZE supercharger) is a positive displacement type blower, which means it displaces a fixed volume of air (1.2 litres in this case) per revolution. This means if you attempt to use it in a blow-through setup you'll blow your inlet pipes to smithereens or bend the throttle plate like a pretzel the first time you start it up. The correct way to do it is as a suck-through system, ie carby before the blower.
Yes it can be done and would probably work OK if you don't have high expectations, but I wouldn't bother unless you have good metal fabrication skills and can slap it together yourself on the cheap. If you're going to pay someone else to do it for you, it will cost you way more than it's worth.
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Location:
Sydney
Registered:
May 2002
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Re: Supercharging a carby 3T-C
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Thu, 02 October 2003 04:12
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Thanks roger & Norbie.
that second hand turbo-carby sounds like a good idea.
and no, theres no way im paying anyone else to do it... this is 'Team Povo' youre talking to! and no, i dont expect much from it either... i just like the thought of having a blower strapped to my shitbox. 
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Location:
Brisbane
Registered:
May 2002
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Re: Supercharging a carby 3T-C
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Thu, 02 October 2003 04:23
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The turbo-carby idea still won't work - you can't have a blow-through supercharger setup if you're using an SC12. It has to be suck-through which means you can use any old carby. Something like a downdraught Weber from an XE Falcon would probably do the job nicely, and it fits your "povo" ethos.
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Location:
Sydney
Registered:
May 2002
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Re: Supercharging a carby 3T-C
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Thu, 02 October 2003 05:27
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oh, okay.. i was thinking a suck through carby when i mentioned the turbo-carby idea. (wish i bothered paying attention to carburettor-related posts up till now  )
so youre saying i could potentially use the existing 3T carby on the inlet side of the s/c? oooohhh!
i figure the hardest part is going to be the fabrication of the piping & the flange to the inlet manifold etc... im hoping i can rig something up with sikaflex & duct tape.
or i could rip the guts out of the stock carby & use IT as the flange (ie: weld the piping directly to it?!?!) - im like doctor frankenstein! all these ideas just bursting forth out of my brain!
go Team Povo!!!
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Location:
Sydney
Registered:
May 2002
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Re: Supercharging a carby 3T-C
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Thu, 02 October 2003 05:31
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oh, another question!
what about the clutch on the supercharger pulley? isnt it electrically controlled? how do i get around that? (or will the suck-job carby somehow stop it pushing in air while idling)?
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Location:
Brisbane
Registered:
May 2002
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Re: Supercharging a carby 3T-C
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Thu, 02 October 2003 06:11
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Yes you could use the original 3T carby, but it would be a significant bottleneck since you will be dramatically increasing the engine's airflow capability. That's why I suggested the larger XE Falcon carby.
Don't be dodgy about your inlet piping - remember it will be pressurised so duct tape is unlikely to hold.  Get an exhaust shop to fabricate a pipe for you; it shouldn't cost much if you shop around.
Forget about the clutch if you want to keep this cheap and simple. Just leave it permanently engaged.
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Location:
Sydney
Registered:
May 2002
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Re: Supercharging a carby 3T-C
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Thu, 02 October 2003 06:41
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i was kidding about the sikaflex & duct tape... 
and yeah, that XE carby sounds good i cant imagine theyd be too expensive either... i should go & raid pick n payless on the weekend & see what cool stuff i can come up with!
so it wont damage the s/c too quickly (or blow my inlet manifold off the side of the head) if i leave the s/c constantly engaged? also, how do i determine how much boost the supercharger is putting out? (the lower the better, i figure) is there some equation for working out boost pressure in relation to crank pulley size etc ???
thanks again Norbie!
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Location:
Colac, Victoria
Registered:
May 2002
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Re: Supercharging a carby 3T-C
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Thu, 02 October 2003 08:32
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heres food for the fire
3tc block , 3tgeu exhaust manifold/turbo/oil return lines , 3teu inlet manifold They are about - ask around ), a camira efi computer or similar budgeto efi controllter, stock/mild cam , minor porting job , and some sort of electronic dizzy setup, still running a t50 with a slightly heavier clutch plate, 6-8psi boost max and elcheapo intercooling aka 4agze intercooler
Could this go together and have a low boost budget blaster ?Just throwing ideas about here - i got my factory boost in the 3sgte - but a econo-turbo t-18 or ta22 ( 2t/2tb block ) would be pretty fun
[Updated on: Thu, 02 October 2003 08:34]
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Location:
Brisbane
Registered:
May 2002
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Re: Supercharging a carby 3T-C
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Thu, 02 October 2003 11:58
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| Mr 20Valve wrote on Thu, 02 October 2003 16:41 |
so it wont damage the s/c too quickly (or blow my inlet manifold off the side of the head) if i leave the s/c constantly engaged?
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These superchargers aren't designed to run constantly so you'd have to expect a shortened lifespan. I don't know how much shorter though - this is only what I've heard. Having said that, I can't think of any simple way to disengage the supercharger since you're running fuel through it, not just air. I guess this is a compromise you'll have to make if you want to do it cheap and dodgy!
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also, how do i determine how much boost the supercharger is putting out? (the lower the better, i figure) is there some equation for working out boost pressure in relation to crank pulley size etc ???
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Both the supercharger and the engine are positive displacement pumps, so if you assume 100% volumetric efficiency for both it's pretty easy to determine the pulley ratio for a given boost pressure. Of course neither of them are 100% efficient so this is only a rough guide, but it's a good starting point.
Anyway, the SC12 pumps 1.2 litres of air per revolution. The 3T consumes 1.8 litres of air per 4-stroke cycle (2 revolutions), or 0.9 litres per revolution. So if you wanted to cram twice as much air down the 3T's throat (1 bar boost), you have to gear the blower so it pumps 1.8 litres of air per revolution of the crank. That's 1.5 times the displacement of the SC12, so you have to overdrive the blower 150%. Simple!
Of course these are very rough measurements, and actual boost is determined by many variables - adiabatic efficiency, thermal efficiency, inlet restrictions, cam timing, etc. I might add that 1 bar boost is way more than you should be aiming for if you want the engine to last more than 10 minutes!
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Registered:
June 2002
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Location:
Brisbane
Registered:
May 2002
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Re: Supercharging a carby 3T-C
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Fri, 03 October 2003 00:05
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No, a blowoff valve isn't designed to constantly flow such a huge volume of air, and anyway that would be horrendously inefficient - think of the pumping losses!
As for fuel going through the supercharger, I have no idea. It's quite common to do this with old-school supercharger setups, but of course Toyota didn't have this in mind when they designed their superchargers.
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Location:
Sydney
Registered:
May 2002
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Re: Supercharging a carby 3T-C
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Fri, 03 October 2003 01:44
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i figure i can budget $500 for this entire job & then put the engine back to normal when its tiem to sell...
im sort of really looking forward to being a dodgy prick regardng this job! :D:D
and no, im not considering turbo... couldnt be bothered changing manifolds etc
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Location:
Brisbane
Registered:
May 2002
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Re: Supercharging a carby 3T-C
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Fri, 03 October 2003 01:52
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Couldn't be bothered? A 3T-GTE manifold will bolt straight on, which is a whole lot easier than fabricating a custom bracket and pulley arrangement for a supercharger! If ease of installation is a factor, turbo is a clear winner.
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Location:
Sydney
Registered:
May 2002
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Re: Supercharging a carby 3T-C
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Fri, 03 October 2003 02:57
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you think?
all ive gotta do is bodgy up a bracket for the s/c, fix up some pipes & mount the carby with a ram-flo. dont even have to touch the exhaust or anything.
if i go turbo, i gotta but manifolds, a turbo, piping, carb, & a whole new exhaust.
if i go the s/c route, all i need is the s/c, a bodgy bracket, a carb & some pipes.
the supercharger is gonna be cheapest i reckon, i dont care how much power it makes, to be honest, long as its a bit more than what its spitting out now...
ALTHOUGH, if someone can sell me a turbo exhaust manifold & an injection inlet manifold for an obscenely cheap price, i might change my mind!
(whats the flange pattern on the 3T turbo exhaust manifold, by the way?? ie: what turbos fit onto it?)
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Location:
Brisbane
Registered:
May 2002
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Re: Supercharging a carby 3T-C
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Fri, 03 October 2003 06:36
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Making a nice solid steel bracket which perfectly aligns the SC pulley with the crank pulley isn't as easy as you might think. On top of that you'll need come sort of tensioner arrangement and of course a custom pulley to go on the end of the crank (I doubt these are available off the shelf).
By contrast the turbo route will require a new exhaust manifold which bolts straight on with no mods, a short section of exhaust pipe has to be re-made (you don't have to change the entire exhaust), and that's it.
The rest of the stuff you mentioned (inlet piping and carby) is the same work for both. Sorry but I can't see the SC being the easier option, or the cheaper option!
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Registered:
June 2002
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Re: Supercharging a carby 3T-C
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Fri, 03 October 2003 06:50
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go the 3tgteu manifold and turbo you will get it setup for under $500 if you find the parts cheap enough.
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Registered:
October 2003
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Re: Supercharging a carby 3T-C
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Fri, 03 October 2003 09:20
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hey i'm interested in the turboing my 2t with the 3tgeu manifold, can this be done with the original carb or weber?
i dont really have high expectations, what would the whole job be worth (including parts) i can do most the work myself
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Location:
Sydney
Registered:
May 2002
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Re: Supercharging a carby 3T-C
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Sun, 05 October 2003 22:55
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Okay Norbie, youve shot the idea down in flames successfully. thankyou.
ill start hunting around for a set of manifolds.
whats the flange pattern on the turbo exhaust manifold? what type of turbos fit? the old Garrett style (T2/25/28)?
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Registered:
June 2002
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Re: Supercharging a carby 3T-C
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Sun, 05 October 2003 23:53
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Just use a CT20 that comes with the 3tgteu. Try and get a water cooled one. I cant see you putting out over 200hp which is ~ the limit of the ct20. You should be able to pick up manifold and turbo for ~ $300-$400 put a T piece in the oil sender for oil supply and a hole in the sump for oil drain. run some water pipes. Make an adapter for the front of the turbo for a carby and a pipe from the turbo to the current intake manifold. then attemp to tune the thing. I make it sound easy but I don't think it would cost much over $500-600 dollars I would imagine.
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