Supercharged/Turbocharged STI..OMG
08-15-2004, 05:39 PM
#21
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After poking around the inside of my own engine bay, I am 99% convinced that that photo is either a fake, or the engine bay we are seeing was built up for show and wouldn't be able to drive five feet. There is just too much essential stuff that has been tossed to make room for that supercharger...
Furthermore, there couldn't be much advantage to this setup at all. Superchargers are just as parasitic as turbochargers in their own way; if the idea is to have the supercharger drive the engine below 3400 RPM and the turbocharger take over at 3500 and above, the power you gain down low has to be offset by 1) the longer/more convoluted piping, 2) the additional weight and drag of the supercharger and 3) the total lack of an intercooler (I don't see an intake diving down for a FMIC).
Furthermore, there couldn't be much advantage to this setup at all. Superchargers are just as parasitic as turbochargers in their own way; if the idea is to have the supercharger drive the engine below 3400 RPM and the turbocharger take over at 3500 and above, the power you gain down low has to be offset by 1) the longer/more convoluted piping, 2) the additional weight and drag of the supercharger and 3) the total lack of an intercooler (I don't see an intake diving down for a FMIC).
08-15-2004, 08:23 PM
#22
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No, meilers, You are way wrong. Supercharger/Turbo charger combos are very effective. By offering two stages of air compression you can lower the overall rise in intake temperature by keeping the compressors in their most efficient range. Also, the supercharger- being positive displacement- provides boost the entire RPM range. The turbo (which has LOW parasitic losses) on boost reduces the amount of work the supercharger has to perform and that lowers the parasitic losses of the supercharger (the supercharger doesn't have to suck anymore).
This setup does not have a FMIC, you are correct.
Superchargers have GREATER parasitic losses than turbochargers.
The only thing over where the supercharger is located is the ABS proportioner and a few sensors. That location has been used for MANY supercharger kits that are in operation TODAY on subarus just like yours and mine.
AS far as essential equipment is concerned... air/fuel/spark. That's all you need to run the damn engine. Link that to a tranny and VIOLA you're moving five, six, seven, even eighty feet.
I'm not trying to flame, but those are some of the most uneducated sounded assumptions I've read in a long time.
This setup does not have a FMIC, you are correct.
Superchargers have GREATER parasitic losses than turbochargers.
The only thing over where the supercharger is located is the ABS proportioner and a few sensors. That location has been used for MANY supercharger kits that are in operation TODAY on subarus just like yours and mine.
AS far as essential equipment is concerned... air/fuel/spark. That's all you need to run the damn engine. Link that to a tranny and VIOLA you're moving five, six, seven, even eighty feet.
I'm not trying to flame, but those are some of the most uneducated sounded assumptions I've read in a long time.
08-15-2004, 11:56 PM
#23
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I've been following this thread for a while:
https://www.i-club.com/forums/aftermarket-forced-induction-turboed-factory-na-engines-62/supercharging-option-65229/
In that thread, entitled "Supercharging? Is it an option?", many of the most veteran and trusted posters on this board comment that supercharging is a poor option for our engines. There is an EPIC thread linked there about one man's attempt to fit a Mercedes "Kompressor" supercharger into his EJ22, it is amazing (and ultimately gains him a whopping 10 hp.) Perhaps you are referring to the ABS plastic superchargers that sell on ebay for $55, and seem to be built out of leaf blower motors?
You also agreed with 90% of what I said (superchargers are parasitic, no FMIC, etc.) If that's your attempt at a flame, you'd better bring matches and some gasoline next time. I've spent enough time this summer with a heat-soaked intercooler to know that no turbo, no matter how big, should be without one. I'm willing to bet that whomever built the engine pictured below could have saved themselves $5000 by simply stroking and boring the engine and going with a VF34, rails and injectors and put down comparable times at the track. My hat is off to whoever built it for the technical feat alone, but you can't convince me this is a practical approach to sustainable engine power.
https://www.i-club.com/forums/aftermarket-forced-induction-turboed-factory-na-engines-62/supercharging-option-65229/
In that thread, entitled "Supercharging? Is it an option?", many of the most veteran and trusted posters on this board comment that supercharging is a poor option for our engines. There is an EPIC thread linked there about one man's attempt to fit a Mercedes "Kompressor" supercharger into his EJ22, it is amazing (and ultimately gains him a whopping 10 hp.) Perhaps you are referring to the ABS plastic superchargers that sell on ebay for $55, and seem to be built out of leaf blower motors?
You also agreed with 90% of what I said (superchargers are parasitic, no FMIC, etc.) If that's your attempt at a flame, you'd better bring matches and some gasoline next time. I've spent enough time this summer with a heat-soaked intercooler to know that no turbo, no matter how big, should be without one. I'm willing to bet that whomever built the engine pictured below could have saved themselves $5000 by simply stroking and boring the engine and going with a VF34, rails and injectors and put down comparable times at the track. My hat is off to whoever built it for the technical feat alone, but you can't convince me this is a practical approach to sustainable engine power.
Last edited by meilers; 08-16-2004 at 12:11 AM.
08-16-2004, 03:06 AM
#24
Big Baller
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Trust me, I know all about heat soak- my 1320 times show it. I don't have an intercooler on my turbo setup-it's in the works. But I still net some pretty quick times.
Turbos have always been capable of more power on the street we all know that.
This is meerly a way of getting boost at low RPM's and minimizing turbo lag while still maintaining the ability to scream on the top end. Adding a supercharger to a turbo setup like this one does in no way hurt performance (when properly tuned). When the turbo spools it feeds the inlet of the supercharger and every bit of boost still makes it to the engine. This type of setup will give you a much larger "area under the curve" and better everyday driveability because you have more torque on tap at normal driving rpms. But when the foot goes down, the turbo gives you all the punch you want in the top end.
The main reason subaru drivers don't recommend supercharger setups isn't because they aren't good options, they just aren't well supported. They are also very hard to get good mounts for. Many people with the Rimmer Kits have had the mounts work loose or crack because they are so far out to the side. Most people who have the supercharger kits love them when they are working properly. Throttle response and torque are awesome. Makes you feel like you are driving a V8. Something turbo kits just don't provide at low rpms.
This system is almost the perfect way to do forced induction and get all around performance. But the key is the Positive Displacement supercharger, a centrifugal doesn't act the same.
AS far as the flame thing is concerned. People always take my posts and flame jobs. I was just specifying that I didn't want you to think I was flaming, that's all. Thanks for not acting like a twit by swearing at me and stuff.
Turbos have always been capable of more power on the street we all know that.
This is meerly a way of getting boost at low RPM's and minimizing turbo lag while still maintaining the ability to scream on the top end. Adding a supercharger to a turbo setup like this one does in no way hurt performance (when properly tuned). When the turbo spools it feeds the inlet of the supercharger and every bit of boost still makes it to the engine. This type of setup will give you a much larger "area under the curve" and better everyday driveability because you have more torque on tap at normal driving rpms. But when the foot goes down, the turbo gives you all the punch you want in the top end.
The main reason subaru drivers don't recommend supercharger setups isn't because they aren't good options, they just aren't well supported. They are also very hard to get good mounts for. Many people with the Rimmer Kits have had the mounts work loose or crack because they are so far out to the side. Most people who have the supercharger kits love them when they are working properly. Throttle response and torque are awesome. Makes you feel like you are driving a V8. Something turbo kits just don't provide at low rpms.
This system is almost the perfect way to do forced induction and get all around performance. But the key is the Positive Displacement supercharger, a centrifugal doesn't act the same.
AS far as the flame thing is concerned. People always take my posts and flame jobs. I was just specifying that I didn't want you to think I was flaming, that's all. Thanks for not acting like a twit by swearing at me and stuff.
Last edited by ImprezaRSX; 08-16-2004 at 03:10 AM. Reason: add more info
08-16-2004, 04:14 AM
#25
You don't have to intercool a turbo. Lots of old turbos, diesel turbos, and v8 twin turbos use no intercooler. The super charger would cool the air, a water to air cooler could be set up through the super charger. This would lower intake air temp. It sounds neat. Really expensive though IMO.
08-16-2004, 01:13 PM
#28
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Pretty amazing stuff -- how is this possibly managed by the ECU? Is there some sort of physical solenoid that switches between the two, or would the turbo just suck air through the supercharger until it became the more efficient of the two devices? Where the hell is the wastegate?? I definitely need to see more pictures, and perhaps a video clip w/ sound if anyone has one. I still think this has to be an enormous strain on your engine block and internals, and would shorten the life of that engine. Any idea on how much this setup would cost? I think I'd just buy a used Porsche 911 GT instead, or a Firebird with a 350...
I'm amazed you are able to get good times without an intercooler. The underhood temps on my WRX are terrifying; I wish I hadn't gotten an oil temp and EGT gauge, the readings freak me out -- I just don't want to know that my downpipe and turbo are about 400 degrees away from molten just with normal daily driving. "Within tolerances" my foot.
I'm amazed you are able to get good times without an intercooler. The underhood temps on my WRX are terrifying; I wish I hadn't gotten an oil temp and EGT gauge, the readings freak me out -- I just don't want to know that my downpipe and turbo are about 400 degrees away from molten just with normal daily driving. "Within tolerances" my foot.
Last edited by meilers; 08-16-2004 at 01:16 PM.
08-16-2004, 02:11 PM
#29
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there isn't any switching between the two. The turbo discharges into the suction of the supercharger. That way as the turbo spools, it feeds the supercharger. This relieves the supercharger need to SUCK air in, which in turn lowers the power used to turn the supercharger.
There are many types of losses in a super charger:
Windage losses- just turning the charger through the air creates friction and therefore requires power to overcome.
Frictional losses- Bearings have friction, belts have friction
Compression losses- energy is used to compress the air
Suction Losses- energy is used to pull the air into the superchargers plenum
Adding the turbo removes suction losses and reduces compression losses. These are the biggest of the losses associated with a supercharger. The turbo takes these away and all you have are bearing friction, belt friction and air friction. Instead of being a 10% drag on the system it's only say a 3% drag (Hypothetical numbers)
Superchargers have internal pressure regulators and don't require ECU or boost controller support. This is also governed by the size of the pulley driving the charger
Turbos still use wastegates, this setup most likely has a divorced wastegate due to the amount of power this system creates. SO it would be out of site merging the up-pipe with the downpipe. Boost control for the turbo could very easily be ECU or boost controller controlled.
AS far as heat soak is concerned. TMIC's suffer from heat soak due to engine bay temps and not just turbo added heat (from compression). I don't have a TMIC so I suffer my majority of heat soak from compression. If you were to go to a FMIC you'd lose your heat soak due to engine bay temps and be much happier.
Oh and superchargers DO NOT cool intake charge. They are a compressor, period. You show me a compressor that lowers air temps and I'll show you a millionare.
There are many types of losses in a super charger:
Windage losses- just turning the charger through the air creates friction and therefore requires power to overcome.
Frictional losses- Bearings have friction, belts have friction
Compression losses- energy is used to compress the air
Suction Losses- energy is used to pull the air into the superchargers plenum
Adding the turbo removes suction losses and reduces compression losses. These are the biggest of the losses associated with a supercharger. The turbo takes these away and all you have are bearing friction, belt friction and air friction. Instead of being a 10% drag on the system it's only say a 3% drag (Hypothetical numbers)
Superchargers have internal pressure regulators and don't require ECU or boost controller support. This is also governed by the size of the pulley driving the charger
Turbos still use wastegates, this setup most likely has a divorced wastegate due to the amount of power this system creates. SO it would be out of site merging the up-pipe with the downpipe. Boost control for the turbo could very easily be ECU or boost controller controlled.
AS far as heat soak is concerned. TMIC's suffer from heat soak due to engine bay temps and not just turbo added heat (from compression). I don't have a TMIC so I suffer my majority of heat soak from compression. If you were to go to a FMIC you'd lose your heat soak due to engine bay temps and be much happier.
Oh and superchargers DO NOT cool intake charge. They are a compressor, period. You show me a compressor that lowers air temps and I'll show you a millionare.
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