supercharged turbo

[frostburner]

i actually looked into that a few times before i decided on what i was going to do and it sounds good in theory but the only thing is blowers dont put out anywhere near the amount of boost a turbo can put it, this is speaking of an m45, m62, and m90 blowers. so once your turbo is running alot of boost the blower actually becomes a restriction on the turbo since it cannot provide enough airflow that the turbo is taking in and producing. The other thing you could do is once the turbo starts spooling is releasing the blower clutch style as you would the a/c ( lots of blowers with this clutch system ) then having a diverter valve which lets the turbo take in its own air from then on out. So yea basically using the blower to start spooling then switching it off. There are a few different ways of doing it, im experimenting with some. just trying to find some more time from my busy work schedule to do so.

[john1320]

I think you have a sweet idea here!

[The Pope]

Quote:

Originally Posted by frostburner i actually looked into that a few times before i decided on what i was going to do and it sounds good in theory but the only thing is blowers dont put out anywhere near the amount of boost a turbo can put it, this is speaking of an m45, m62, and m90 blowers. so once your turbo is running alot of boost the blower actually becomes a restriction on the turbo since it cannot provide enough airflow that the turbo is taking in and producing. The other thing you could do is once the turbo starts spooling is releasing the blower clutch style as you would the a/c ( lots of blowers with this clutch system ) then having a diverter valve which lets the turbo take in its own air from then on out. So yea basically using the blower to start spooling then switching it off. There are a few different ways of doing it, im experimenting with some. just trying to find some more time from my busy work schedule to do so.

Doesn't work that way. Flow is dictated by mass, the true figure of flow when talking engines. The blower keeps compressing air and moving it forward. The difference is that the blower would be compressing pre compressed air. A blower flows allot more air when the air is allot more dense, a turbo can really make air dense right? The reason why a blower can't be a restriction is that it makes boost without the turbo, and that means the blower flows more air than the engine. It is physically impossible to add a high flow object in path to a low flow object and have a restriction. Looking at compounded turbos from a pressure differental stand point with turbos they are perfect on the turbo side, so a big cam can be used. But a supercharger will take more power to turn as boost goes up. Of course it takes more power to compress something more dense. On a TD you want a S60 cam, engines that would love a compounded system are like a VTEC engine. Where overlap hurts you with just a turbo.

[frostburner]

The blower will help spool the turbo not the other way around. I dont know what your talking about on the blower compressing precompressed air when it will be routed before the turbo. The blower can be a restriction at high rpms* when the turbo is in full force and you are leaving the blowers efficiency range and or taking in more air that it can provide. Check out the flow maps on magnuson blowers, mainly the m45 and m62 and compare them to flow charts of a large garret turbo and you will understand what I mean. As to why I spoke of having it setup clutch style like some factory supercharged engines. All you have to do is figure out at what boost and rpm the blower is becoming a restriction and have it shut off then so the turbo takes over and there is no power loss since the blower is spinning freely. It is very easy to figure out where this threshold is . You take a vacuum gauge and put it inline with which ever airflow piping you are testing and if it gets into vacuum at any time then you know the turbo or whichever device is taking in so much air that the previous item cannot keep up. There are alot of factors that go into it which is why im not rushing and every tech that has done a twin charged vehicle have said the same thing, the blower will become a restriction eventually as to why they all said the best way to do it is a clutch system and diverter valve to get its air independantly afterwards. Seeing as theyve done it multiple times and have alot of experience doing it I believe them on the way it can function and work and what issues might arise.

[The Pope]

Quote:

Originally Posted by frostburner The blower will help spool the turbo not the other way around. I dont know what your talking about on the blower compressing precompressed air when it will be routed before the turbo. The blower can be a restriction at high rpms* when the turbo is in full force and you are leaving the blowers efficiency range and or taking in more air that it can provide. Check out the flow maps on magnuson blowers, mainly the m45 and m62 and compare them to flow charts of a large garret turbo and you will understand what I mean. As to why I spoke of having it setup clutch style like some factory supercharged engines. All you have to do is figure out at what boost and rpm the blower is becoming a restriction and have it shut off then so the turbo takes over and there is no power loss since the blower is spinning freely. It is very easy to figure out where this threshold is . You take a vacuum gauge and put it inline with which ever airflow piping you are testing and if it gets into vacuum at any time then you know the turbo or whichever device is taking in so much air that the previous item cannot keep up. There are alot of factors that go into it which is why im not rushing and every tech that has done a twin charged vehicle have said the same thing, the blower will become a restriction eventually as to why they all said the best way to do it is a clutch system and diverter valve to get its air independantly afterwards. Seeing as theyve done it multiple times and have alot of experience doing it I believe them on the way it can function and work and what issues might arise.

uh, why would anyone stick the lesser flowing induction first? Hell yes "if" you actually flowed the blower into the turbo it would be a restriction but I've never heard of anyone doing that. Do you know how hard that would be with a screw type? No, you run a turbo in stock location like any T2 car, and then the boost goes into a IC. Then out of the IC into a big TB into the blower, then into the engine. Before the turbo spools the blower will vac air through the turbo and the BOV. Then boost pressurizes the IC and blower. Thats compounding a turbo/blower and it works great. Some one with a B&M could do this fairly easy. Efficiency range for a blower is based off of abosolute manifold pressure. The range is based off of a figure of mass or CFM. Take a blower moving 5 CFM of air mass. Then turn each CF of air into 5 CF of air with compression. Then the 5 CFM of precompressed air is equal to 25 CFM of total true air flow. Old roots blowers bleed boost pressure, so it isn't as much as it should be. The concept is sound and it is how twin turbos make a total boost leave equal to what one turbo can do. But the compounded twins can compound boost pressure to over 130 PSI of boost. Old news with Desiel people. Tractor pulls use 3 compounded turbos for over 250 PSI of boost. The smallest flow goes closest to the engine to spool the larger flowing boost devices, never smallested boost device into a larger then into the engine. So yes, if that is what your seeing than your right.

[turboking]

the lancia s4 came with both supercharger and turbo
http://www.carsfromitaly.com/lancia/index.html

[frostburner]

Quote:

Originally Posted by The Pope meow.

It is not a screw type it is a roots type, 2 different things. And no it is not difficult just takes some time. And yes ive heard and seem some of the projects the techs I know have worked on. And yes it works exactly in the setup I described with great results. You've never heard of anyone doing it so I guess you learn something everyday huh . Everything can be done differently as to why im experimenting with a few while getting tech help from guys who have actually done the setup, ran and tested it with great results. Personally id rather take advice from people who have done this setup on various vehicles than someone who hasnt. Experience counts. So to end this debate im done on this thread

[mx5rush]

I'm no guru, but I've heard that in insane boost modes, this hybrid setup can actually see the supercharger 'add' power to the crank. I think the theory (maybe just bench racing noise) is that in a real high boost situation the turbo can actually blow hard enough into the roots blower, that it is basically 'spinning' the blower harder than the belt is. At that point the supercharger would be trying to add power to the crank via the belt!

Maybe thats all baloney, but from what I've read, it seems the added complexity of such a dual system would be limiting the effeciency of both systems. The Lancia Delta S4 setup apparently worked pretty well, but they had the tuning skills of Magnetti Marelli types behind them, so trying to make it work at home might be a challenge. Also its worth remembering that as seriously bad-a$$ as the Lancia was... sheer HP wasn't their goal. People interested in dragracing probably wouldn't need the bottom 1/2 of the torque curve that rally car needed.

I do think there is a underground group of turbo/supercharger combo owners out there in the Toyota MR2 world. There are definitely guys who have turbo'd the old 1.6 liter Toyota MR2's that came with factory superchargers, without chucking the roots blower.

[The Pope]

Quote:

Originally Posted by mx5rush I'm no guru, but I've heard that in insane boost modes, this hybrid setup can actually see the supercharger 'add' power to the crank. I think the theory (maybe just bench racing noise) is that in a real high boost situation the turbo can actually blow hard enough into the roots blower, that it is basically 'spinning' the blower harder than the belt is. At that point the supercharger would be trying to add power to the crank via the belt! Maybe thats all baloney, but from what I've read, it seems the added complexity of such a dual system would be limiting the effeciency of both systems. The Lancia Delta S4 setup apparently worked pretty well, but they had the tuning skills of Magnetti Marelli types behind them, so trying to make it work at home might be a challenge. Also its worth remembering that as seriously bad-a$$ as the Lancia was... sheer HP wasn't their goal. People interested in dragracing probably wouldn't need the bottom 1/2 of the torque curve that rally car needed. I do think there is a underground group of turbo/supercharger combo owners out there in the Toyota MR2 world. There are definitely guys who have turbo'd the old 1.6 liter Toyota MR2's that came with factory superchargers, without chucking the roots blower.

it actually makes turning the blower harder, the blower is compressing thicker air. The blower still moves more than the engine does, that doesn't change. So it isn't possible to spin them faster with a turbo, physics doesn't allow it. However the blower is working harder on the head side and not at all on the turbo side. The down side is heat, at high pressures the blower adds back a bunch of heat you can't get rid of. You see allot of compounded systems in the mags. SCC has had them win the ultimate street car challenge they have, the yellow MR2 had a blower on the V6 and a turbo. Then there is there red project car. Mod mag has a compunded twin turbo Focus in it. Compounding is great but twin turbos is way too much boost for gas.

[mx5rush]

If the blowoff valve was after the supercharger, wouldn't it be theoretically possible to have a turbo pushing more psi than the BOV was set at... therefore you could have more psi before the supercharger, than after.

Say 27 psi coming out of the turbo and into the rootes pump, and a BOV after the supercharger set at 20psi... wouldn't that give you 7 psi of positive push on the rotors of the supercharger?

I don't remember too much from physics, this hot bodied blonde in class had my focus from day one.

[The Pope]

Quote:

Originally Posted by mx5rush If the blowoff valve was after the supercharger, wouldn't it be theoretically possible to have a turbo pushing more psi than the BOV was set at... therefore you could have more psi before the supercharger, than after. Say 27 psi coming out of the turbo and into the rootes pump, and a BOV after the supercharger set at 20psi... wouldn't that give you 7 psi of positive push on the rotors of the supercharger? I don't remember too much from physics, this hot bodied blonde in class had my focus from day one.

to start it would be like having a BOV on a Desiel, without a TB to close off the boost there is no blast. The TB would be before the blower. If you have individual TBs and a BOV on the intake it would still be more PSI after the BOV unless it was 4" in diameter. The blower loses it when the air from the turbo is too dense for it to compress it again before it enters the engine. So the added boost from the blower gets smaller as the turbo boost level rises. The new screw type work allot better than the B&M roots style, they would make allot higher total boost. I had an EX cheerleader hot blond in my class, but she asked questions all the time so I had to pay attention enough to help her out

[Pandemoniac]

Quote:

Originally Posted by BrassMonkey this is the second time i heard of turbo'd 2 strokes.. how do you give a 2 stroke forced induction (without nitrus)? me and my rc car would love to know.

2-stroke diesels need forced induction just to function. They're not like 2-stroke gasoline engines, they have a closed oil-filled crankcase, and an air intake at the bottom of the cylinder sleeve and exhaust poppet valves in the head. A supercharger or turbocharger is needed to force the air in through the ports as the engine produces no vacuum.

Another interesting fact, the popular roots blower sizes of 4-71,6-71 and 8-71 come from the names of some old detroit 2-stroke diesel engines. Those blowers were originally used on these engines. For example the 6-71 was a 6 cylinder 2-stroke diesel displacing 71 cubic inches per cylinder.

[mx5rush]

In an another attempt to prove my lack of knowledge I have to ask this...

Weren't some of the gmc style blowers we see, actually used on the exhaust side of the big diesel engines that were mounted on? Actually scavenging the exhaust rather than pressurizing the intake side? I'd swear I've read this somewhere... my personal observation of large earth moving equipment is limited to cursing as I drive thru construction zones. (Don't take offense... I work for a RR and you can feel free to curse me at crossings waiting on trains carrying goods from China to your local Walmart!) (and our diesels are turbo'd!)

[tkelly27]

I don't think it would work that way. I think the HP cost to turn the S/C would be much more than you would gain from active scavenging.

[nemesismachine]

'05 Evo Gotta be links, the pics are big

http://www.thisideup.com/DSCF5374.JPG
http://www.thisideup.com/DSCF5375.JPG