dual or quad throttle bodies supercharged

[jordanangel]

so I've been thinking up the idea of building a dual or quad throttle body supercharged engine, and well started wondering if add the extra throttle bodies would really help the supercharger breathe more or not, i know if i did it i would have to make a custom throttle body intake, but any feed back would be helpful

[Flashmn]

I dont really see the point of the whole idea.

[eage8]

yeah... normally the super charger comes before the throttle body, so it's just forcing air into the throttle body, it's just sucking the air through the filter.

it's going to be way more work than it's worth.

that being said, you might as well go with 4, you can use the 20V 4age throttle bodies if you fabricate an adapter.

[PhatRoyale]

I think this is a classic case of an either-or situation.

If you want ITB's, it's better to stay N/A and just get a 4A-GE 20V swap.

If you want to be supercharged, then get a 4A-GZE swap.

Either case requires you to ditch the stock engine and get a swap.

[Flashmn]

Not really, you can do that with the base engine aswell. Just depends on the money, parts are available, but referring to the op's post, its fairly pointless. Going with dual 4a-fe size bodies is going to open a can of worms, good luck getting that kind of setup to function properly. ITB's would work fine, but for the money, I dont see the gains there since you already would have a supercharger on it.

[jordanangel]

it was more of an idea really, and yea i know it would cost a lot of money and time, and i would have to fab up things, and i cant figure out how the intake setup on the 4agze is from pics and haven't really found anything telling me how they are set up, if i knew how that was setup maybe it would help with the idea and how hard it would be, what I'm saying is that i don't know where the throttle body is mounted

[Flashmn]

it would be at the beginning of the intake manifold.

[eage8]

Originally Posted by Flashmn

it would be at the beginning of the intake manifold.

it's in pretty much the same place as your 4AFE.... you just pipe a supercharger between the throttle body and the intake filter.

done

[canadianae92]

well supercharger setups that worked well in the past used carburettors on the supercharger inlet... same concept with a throttle body... while with a supercharger mounted with carburettor needs to be withstand fuel although the fuel helps cool, with efi you dont need to worry about that... the advantage is you don need a bypass valve to remove pressure between the sc and throttle body when the throttle shuts... single tb for our motors though with forced induction

[jordanangel]

so it would be possible to get a ITB then make a manifold to mount the supercharger above the throttle bodies and that would be just about it really besides fitment and tuning ect.

[canadianae92]

Why would you want to do that?
If youre just looking to throw money away there are better ways to do it. Superchargers themselves provide nice instantaneous torque that would blow away a naturally aspirated motors(with itbs) feel of ¨response¨. Also adding itbs to a supercharged motor has absolutely no possibility of improving horsepower, torque, or response infact itĺl likely complicated the addition of a supercharger.

You´ll need a 4agze ecu, wire harness and electronics, OR standalone ems
Whichever you chose you will have a lot of wiring to do.
You will need a manifold to mount the itbs. You´ll need an airbox for the itbs or a way of fixing the sc onto you´re itbs if for whatever reason youd want to do that.
If your throttle(s) are after your supercharger you´ll need to adapt a bypass valve.
SC has to be securely mounted at the designed angle for the particular sc.
You need a belt of proper length and a reliable tensioner setup for it.
You need a crank pulley and supercharger pulley that have matched designs suited for the belt and sized appropriately to spin the supercharger in its efficiency range and/or at a boost level your motor can handle.
Last but not least you need an engine that can handle boost at the very least but it would be better to have dished pistons and a proper compression ratio for forced induction.
You also need a clutch that can handle the new torque levels, and transmission/axles if you plan on ever flogging it.

If it was my own setup I would likely use a large single throttle body mounted on the intake side of the sc. The outlet routing to the intake manifold.

[jordanangel]

like i said it was just an idea, doesn't mean I'm really gonna do it, and as for the engine that i plan to do this with it wont be a 4afe it would be a built 7age

[Hiro Protagonist]

As an aside, if you're going to be using a Roots-style supercharger (like the SC12 that the 4AGZE has), you need to have the throttle/s BEFORE the supercharger, otherwise bad things can happen. This alone is a big-enough reason to not run ITBs/multiple throttles, as there is no point - you are still having to cram it all through one supercharger intake, negating ANY benefit.

A compressor-style charger (ie one like the intake side of a turbocharger) though is perfectly fine to run pre-throttle.

[Flashmn]

As an aside, if you're going to be using a Roots-style supercharger (like the SC12 that the 4AGZE has), you need to have the throttle/s BEFORE the supercharger, otherwise bad things can happen.

And what bad things would those be? Galaxies are going to be sucked into a singularity, nuclear explosions are going to happen or maybe the supercharger will turn into a black hole and suck everything on earth into it? AFAIK 4A-GZE has the throttle body after the supercharger, Mercedes compressor 200K has the throttle body after the eaton supercharger. Only real difference between a rotrex or lysholm style compressor vs a roots compressor is that a roots compressor has no internal pressurizing and it pressurizes the air after the supercharger when the intake is "filled", thus having worse efficiency. No real magic there.

The reason dual carbs and like were used on cars were to enhance resonance pulse charging and gaining performance from that and the same with ITB's, you can use it on a supercharged/turbocharged car (some have done it, like a nissan 240Z, IIRC they had 3 twin solexes mounted). they'd work just fine, but its unncessary work. As or dual normal sized single throttle bodies, you're going to really kill your engine operation with that, opening the throttle from idle will bring an surge of air and it will cause real issues off the line.

As for having the carbs before the supercharger on older setups, thats because fuel evaporation will cause charge air cooling and thus eliminating the need of an intercooler. Besides you cant even use an intercooler on a suck through setup, it would be a fire hazard. Situation doesnt change much if the throttle body is up front and you have no intercooler, you need fuel to cool the air charge so you'd want to put the inectors right there.

Then again all this is crap if you're going to put it into your corolla, its not an 1960's american V8 with associated supercharger systems and assemblies, which were pretty much the only systems available at the time that would offer decent performance, as EFI wasnt around at that time.

[Hiro Protagonist]

Originally Posted by Flashmn

And what bad things would those be? Galaxies are going to be sucked into a singularity, nuclear explosions are going to happen or maybe the supercharger will turn into a black hole and suck everything on earth into it? AFAIK 4A-GZE has the throttle body after the supercharger, Mercedes compressor 200K has the throttle body after the eaton supercharger. Only real difference between a rotrex or lysholm style compressor vs a roots compressor is that a roots compressor has no internal pressurizing and it pressurizes the air after the supercharger when the intake is "filled", thus having worse efficiency. No real magic there.

The reason dual carbs and like were used on cars were to enhance resonance pulse charging and gaining performance from that and the same with ITB's, you can use it on a supercharged/turbocharged car (some have done it, like a nissan 240Z, IIRC they had 3 twin solexes mounted). they'd work just fine, but its unncessary work. As or dual normal sized single throttle bodies, you're going to really kill your engine operation with that, opening the throttle from idle will bring an surge of air and it will cause real issues off the line.

As for having the carbs before the supercharger on older setups, thats because fuel evaporation will cause charge air cooling and thus eliminating the need of an intercooler. Besides you cant even use an intercooler on a suck through setup, it would be a fire hazard. Situation doesnt change much if the throttle body is up front and you have no intercooler, you need fuel to cool the air charge so you'd want to put the inectors right there.

Then again all this is crap if you're going to put it into your corolla, its not an 1960's american V8 with associated supercharger systems and assemblies, which were pretty much the only systems available at the time that would offer decent performance, as EFI wasnt around at that time.

4AGZE definitely has the throttle pre-supercharger. Intake order is: filter, AFM (if fitted), throttle, SC12, top-mount intercooler, intake manifold (w/ MAP sensor if not AFM), engine.

And the reason why you should have the throttle before a Roots-style charger is because they are a positive-displacement pump with no internal compression - they work by pumping air against the back of the intake valves, generating pressure in the plenum. If you have a throttle body in the way, then you end up building pressure agaisnt the throttle plate whilst you have vacuum behind it. This can cause problems both with the throttle and with back-pressure through the supercharger if not properly dealt with (since superchargers don't generally run blow-off valves).


And if you want a perfectly obvious example, take a look at a Top Fuel dragster or Funny Car (almost invariably running a Roots-type supercharger). What is the first thing you see in the intake? Throttle/s. What are they sitting on top of? Supercharger. The reason they run multiple throttles pre-charger is purely for air-flow reasons - a single throttle body would have to be massive to provide the same amount of mass air flow as 3 or 4 smaller ones. In a road car application though, where air mass flows are smaller by probably a whole order or magnitude, a single throttle is perfectly fine.