super turbo?
#12
03-10-2005, 07:24 PM
RE: super turbo?
when using a supercharger on a turbocharger kit a roots blower is usually used. i know u guys arent down with rice but these are the people that have built these kits to perfection. i know the mini cooper offers one but its puttin a turbo on its already supercharged engine which is a roots blower. there are a few kits and its really only for show as you cant gain as much power as you can get from a single but its the power curve thats attractive on this kit.
#13
03-10-2005, 09:02 PM
RE: super turbo?
Dude, explain how a roots would help the turbocharger? For example, lets say that this roots/screw blower is making 12 psi. Now how would that help if your turbo is puchin more than 12psi? Eventually the turbo would out flow the supercharger causing it to spin faster than the pulley would allow. Now if you used a centrifugal supercharger (preferably electric so you can turn it on and off and regulate boost from the cockpit) you could, instead of routing the superchared air into the intake, could route the supercharged air into the turbo charger. This would require 2 BOV's. And yes, they HAVE to be BOV's. If you had 2 DV's where would they recirculate the air too? So in theory this could be done. I hope one day I am able to experiment with this idea.
#14
03-10-2005, 10:19 PM
RE: super turbo?
lol an electric supercharger...classic. what did u buy it from ebay or one that your gonna need 5 car batteries in your trunk to supply the power to run it. go do some research. let us know how ur theorys work out some day. if u really want me to show u i will. yes i know what ur think a centrifigual is parisitic and creates less heat so its more efficient but what it is is that u use a small turbo to feed into a supercharger not a supercharger into a turbo. thats what in-line turbos are for. the only real application i could see this working on is a semi or a tractor bc u in the first place would need a hudge turbo in order to have a paxton blowing into it and 5 psi isnt just 5 psi.
#15
03-11-2005, 12:40 AM
RE: super turbo?
I dont see how a turbo would help a supercharger by feeding into it. I mean a supercharger is driven by a pulley, putting more air into it will not make it spool any faster. Where as low boost from an electric supercharger would help eliminate spool almost fully.
BTW electric superchargers are used commercially. For example, my companies electric "bobcat" has an electronic supercharger.
BTW electric superchargers are used commercially. For example, my companies electric "bobcat" has an electronic supercharger.
#20
03-12-2005, 02:04 AM
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RE: super turbo?
Hey Tex...
Duplox's explaination is also fairly basic, ableit more in-depth than my earlier comments. Now... I wonder if I can do something like this to my riding mower... Hmmm...
So, anyway, it sounds like you'd basically be over-pressurizing the blower. Kinda like jamming more people into a consistantly spinning revolving door than can comfortably fit. As long as the door frame holds, and the glass doesn't bust, and as long as you keep turbo-ing people into one side they'll keep spewing out the other side. This all assumes that the blower, or revolving door, in this case, will push (pressurize) a certain amount of people through for a given spin rate (PSI=PEOPLE per SQUARE INCH). The blowers' PSI will remain a constant percentage for any given spin rate, right? Using a turbo to crush more people into the volumn within the vee of the doors (imaging how cool THAT would look, BTW) will similarly give you more people (PSI, remember) out the other side.
[sm=happybounce.gif]
ORIGINAL: near the top of the thread, from the link I posted, above
duplox
This has been done and it fairly common among drag cars. Generally you put the turbos before the supercharger. You can't Y them together, the pressure the supercharger creates will just leave out the turbo, and since its flowing backwards through the compressor would pretty effectively stall the turbo out so it will never make boost. I've only seen it done on V8s, and I don't know what types of superchargers are available for 4cyl engines. What is done on the v8 drag motors is they'll put a roots blower on top:
http://www.uncommonengineering.com/r...thead%2001.gif
The roots blower is the big ribbed box with the thick belt driving it on top of the motor. The turbo(s) feed into the top of this, where the carbs are on that motor. The reason this works so well is the roots blower is a positive displacement supercharger, meaning for 1 turn it always pushes the same ammount of air. So before the turbos are spooled, it sucks air through the turbos, compresses it, and feeds it to the motor. The increase in exhaust will quickly spool the turbos, which then increase the pressure between them and the supercharger. The supercharger then takes in a big gulp of the pressurized air, compresses it further, and feeds it to the motor. So if you're running a blower that gives you a 2:1 pressure ratio without the turbos(1 bar boost), and turbos that give you a 3:1 ratio(2 bars boost), you'll have a combination that'll potentially produce 5 bars of boost, or around 70psi. Not too shabby... you can probably do something similar on the street, but in order to gain any low end, you need to use a positive displacement supercharger, which basically means either a roots type or a screw type(aka whipple, lysholm type). The problem now becomes you may be producing too much pressure since its a sequential system. If set the supercharger up to run 6psi(1.4:1 pressure ratio) and wastegate your turbo at 6psi, you'll end up with a total pressure of around 14psi.
duplox
This has been done and it fairly common among drag cars. Generally you put the turbos before the supercharger. You can't Y them together, the pressure the supercharger creates will just leave out the turbo, and since its flowing backwards through the compressor would pretty effectively stall the turbo out so it will never make boost. I've only seen it done on V8s, and I don't know what types of superchargers are available for 4cyl engines. What is done on the v8 drag motors is they'll put a roots blower on top:
http://www.uncommonengineering.com/r...thead%2001.gif
The roots blower is the big ribbed box with the thick belt driving it on top of the motor. The turbo(s) feed into the top of this, where the carbs are on that motor. The reason this works so well is the roots blower is a positive displacement supercharger, meaning for 1 turn it always pushes the same ammount of air. So before the turbos are spooled, it sucks air through the turbos, compresses it, and feeds it to the motor. The increase in exhaust will quickly spool the turbos, which then increase the pressure between them and the supercharger. The supercharger then takes in a big gulp of the pressurized air, compresses it further, and feeds it to the motor. So if you're running a blower that gives you a 2:1 pressure ratio without the turbos(1 bar boost), and turbos that give you a 3:1 ratio(2 bars boost), you'll have a combination that'll potentially produce 5 bars of boost, or around 70psi. Not too shabby... you can probably do something similar on the street, but in order to gain any low end, you need to use a positive displacement supercharger, which basically means either a roots type or a screw type(aka whipple, lysholm type). The problem now becomes you may be producing too much pressure since its a sequential system. If set the supercharger up to run 6psi(1.4:1 pressure ratio) and wastegate your turbo at 6psi, you'll end up with a total pressure of around 14psi.
So, anyway, it sounds like you'd basically be over-pressurizing the blower. Kinda like jamming more people into a consistantly spinning revolving door than can comfortably fit. As long as the door frame holds, and the glass doesn't bust, and as long as you keep turbo-ing people into one side they'll keep spewing out the other side. This all assumes that the blower, or revolving door, in this case, will push (pressurize) a certain amount of people through for a given spin rate (PSI=PEOPLE per SQUARE INCH). The blowers' PSI will remain a constant percentage for any given spin rate, right? Using a turbo to crush more people into the volumn within the vee of the doors (imaging how cool THAT would look, BTW) will similarly give you more people (PSI, remember) out the other side.
[sm=happybounce.gif]