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CO2 powered turbo

CO2 or other compressed gas powered turbocharger
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(+2, -4)
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This is my first post after finding this awesome site, and my ideas been touched on before but not exactly as i plan it. My idea at first was to use a powerfull portable blower to spin the exhaust turbine of a turbocharger ( rather than having it hooked to the exhaust stream as it would be normally) but seeing as how the blower might not be strong enough to spin the turbo to the necessary speed or overcome backpressure ive decided that i'd just use a metal plate to seal off the flange leading into the exhaust turbine, while placing 1 or 2 nozzles for compressed CO2 or possibly another non volatile gas.

Ive talked to some turbo/engine freaks on similar ideas such as Thomas Knights electric supercharger (the only such product proven to work) and pressures at the exhaust turbine in a working engine are typically between 20 and 30psi depending on the application, although the exhaust has the high heat/volume factor powering it also. Ive found several portable 15lb CO2 sytems with nozzles capable of 200psi , and with a plate welded to the exhaust entry flange the co2 would have nowhere to go but through the turbine and out what would be the exhaust pipe. Ive heard that the expansion properties of CO2 are ideal and id like to see if you all think that this would work and possibly produce boost on a engine (mines a single cam 3.0l with a 5500 rpm redline) even if just a few psi of boost over a few seconds would be enough to warrant more research and developement.

The turbo will in no way be hooked to the exhaust stream and will have a closed self lubrication system, and i will use a electric cutout so when boost does (if) kicks in or when not in use it can be bypassed to a normal cone/panel airfilter. My engine normally aspirated would flow 288cfm at 100% V.E. at 5500rpm being that cfm= rpm x cid/ 3456. Thanks for your time hope to see some constructive criticism soon!

robwoodcock87, Jul 27 2010


       how 'bout using Oxygen ? make the catalytic converter happy.
FlyingToaster, Jul 27 2010

       also the CO2 will be vented well-away from the engine bay and the interior, dont want anyone passing out! also to -flyingtoaster- this isnt going in the exhaust stream so nothings getting injected into the cat. basically my idea is to mount it like a centrifugal supercharger, bypass it when not in use and use co2 or a non volatile compressed gas to power it rather than a belt or by the exhaust stream.
robwoodcock87, Jul 27 2010

       first of all adding a few psi of intake manifold pressure is NOT the big hurdle that we are struggling to overcome in the field of forced combustion. The ability of the turbocharger to (after spinning up) produce excess, even destructive, levels of pressure is a far more pressing problem. A few psi for a few seconds BAAH! More typically a "few psi" beyond where you want it means skyrocketing EGT, detonation and the end of the engine. Increasing the output of a forced induction engine requires that you either improve induction, combustion efficiency, reduce intake temperature or allow for a decrease in combustion and an increase in induced pressure. Since your idea is a supercharger powered by compressed gas it really brings nothing to the field in terms of power. A simple belt driven turbine can do everything your system does parasitically. Without a tank of wasted gas, and it can do it all day long for nothing more than the price of the fuel to turn it. Your idea requires heavy speed consuming tanks, and can only be expected to produce significant output for seconds. Additionally it does not appear to have any significant benefits over it's closest relative the belt driven centrifugal blower or its meaner cousin the undependable jet turbine induction system. Even with a hot side designed for use with high pressure gas (your idea of using a conventional hot side is ludicrous) you have no tangible benefits over a belt drive supercharger.
WcW, Jul 27 2010

       // Ive heard that the expansion properties of CO2 are ideal //
I think that's a loose interpretation of the Ideal Gas Law.
coprocephalous, Jul 27 2010

       The reason im doing this is to avoid the parasitic losses entirely, the tanks would weigh about the same as a normal nitrous system, and most modern ecu's or fmic can flow enough fuel to keep the fuel/air mixture rich enough to avoid detonation or high EGTs. the lack of parasitic losses would put power otherwise used to belt or exhaust drive the equipment to the wheels instead. the benefits of a system capable of producing similar boost numbers to a parasitic supercharger or turbo without the parasitic losses would in fact be very significant, and such a setup could be adaptable to many vehicles, instead of a application specific super/turbo setup that could only be used on one vehicle. also a few psi can make a big difference, the z32 300zxs used 7psi to make 300hp at a time when most v6s barely broke the 200hp mark. how is using the hot side ludicrous? is this not a site for unconventional thinking? and yes its a loose interpretation of the ideal gas law, and i was hoping someone with more knowledge on the subject would give some CONSTRUCTIVE criticism as im not familiar with the law or its complex math. also, a "few seconds" is about how long an average car touches boost during normal driving, and a "few seconds" is alot longer than you think, if youve ever driven the quarter youd know just how long a second really is. and its "forced induction" not "forced combustion" and the "destructive overboost" you speak of can be dealt with a wastegate or BOV, both have been in use since turbochargers first appeared in production car use on the olds cutlass jetfire and corvair spider turbo.
robwoodcock87, Jul 27 2010

       Welcome aboard, [robwoodcock87].
pertinax, Jul 27 2010

       If you're not running it off the exhaust then an electric supercharger would be more efficient and if you want to play with pressurized tanks then nitrous or O2 would be more fun.
FlyingToaster, Jul 27 2010

       the only working electric supercharger is Thomas Knights ESC-350, it takes a heavy 8hp motor and roots supercharger, long heavy cables and six (six!) odyssey car batteries for a max burst of a few seconds and then needs recharging. total added weight of his system is several hundred pounds. they did however test it on a maxima with the same engine as mine and a dodge avenger in a quarter mile strip and shaved quite a few seconds off the E/T even with the added weight. another reason to eliminate parasitic losses from coventional super/turbocharging!
robwoodcock87, Jul 27 2010

       // eliminate parasitic losses //   

       The whole point about turbochargers is they are intended to harvest "waste" energy to boos output and as such aren't parasitic. Superchargers, however, are.   

       A clearer line needs to be drawn between efficency and performance. We guess you're aiming for maximum output from a given capacity of engine.   

       Using oxygen injection will mess up the combustion stoichomentry and possible burn out the whole engine.   

       You're looking for a volatile gas in equilibrium with its vapour as the power source. Propane sounds good to us.   

       Now, if the propane vapour drives a turbine, this will give pressure reduction and the propane can be subsequently burnt in the engine. Propane vapour and octane can be effectively substituted in engines - it's easy to convert a gasoline engien to LPG. Heat from the exhaust can be routed to the propane tank to comensate for the adiabatic cooling of the propane as its vapour boils off - that's REAL heat recovery. But you might have to vent "excess" propane (into the afterburners ...)   

       It would certainly be a live-fast-die-young solution ...
8th of 7, Jul 27 2010

       I appreciate the rapid comments, but it seems everyones taking a very simple idea ive got and making it far more complex. im not injecting oxygen, or nitrogen, or propane into the intake tract. there are engines that run off propane but im not going for that. my idea is to simply use co2 to drive the exhaust turbine because it has the similar properties of exhaust gas (chemically) only without the large amount of heat, it is more dense than oxygen and at 200psi compared to the average of 20 psi at a turbos turbine the compressed co2 should have plenty of force to spin it up to speed. the exhaust turbine does not in anyway find itself venting into the intake tract, it merely serves to power the compressor side which feeds fresh outside air at a large rate into the engine itself and is a completely seperate system from the compressor side. and turbochargers are parasitic, not as much as superchargers but still increase backpressure and heat, which in turn also cause excess wear.   

       simply put i just need to know if 200psi of compressed co2 could feasably power a turbocharger and produce some if any boost on a engine.
robwoodcock87, Jul 27 2010

       some of us have driven a quarter mile, in a turbocharged car, and do know what goes into cutting down on ETs and 60fts.   

       1) A tank of CO2 will self regulate to a pretty low flow rate under continuous discharge due to the chilling effect of evaporation. see: Nitrous Bottle Heating   

       2) The hot side of a turbocharger is designed to harvest power with minimal restriction from the exhaust of a pulsing exhaust stream, not a high pressure line.   

       3) Your setup could not be adapted to a wide range of vehicles as it does not make the vehicle any more able to deal with the increased combustion pressure, thermal load, EGT, fuel demand, exhaust volume, torque output, etc.   

       4) Most sensible daily driven turbocharged vehicles utilize their supercharging as a significant fraction of their total output. otherwise it would simply be a novelty. We need more than a few seconds of breakaway torque.   

       5) pressure doesn't make horsepower, flow does. PSI in the intake manifold means nothing if it cannot flow into the cylinders. In this way the high output (not remarkable really) of the 300zx was due to intelligent combination of induction, valve timing and cylinder head design. if you ran 11psi in that same engine without other modification it became an instant piston melter.   

       6) Your device has every downside of a turbocharger and nitrous but none of their upsides. Your induction air will be heated by turbulence and compression, you will have heavy, bulky tanks, and for what? So you can very briefly have some extra engine output?   

       7) The math that you are asking for is relatively complex because there are no standard equations for "use a turbine that does not exist to drive a known turbine against an unknown load". A high output valved CO2 tank can put out 31cfm open flow. Even without standard equations we can see that the solution is "no".
WcW, Jul 28 2010

       //but it seems everyones taking a very simple idea ive got and making it far more complex//
Welcome to the HB!

//im not familiar with the law or its complex math//
You'll fit in nicely.
Now all you have to do is locate the shift keys on your keyboard.
coprocephalous, Jul 28 2010

       I'll make sure to use better punctuation in my next annotations and posts for sure, just ended up rushing this one due to a poor and constantly disconnecting internet connection.
robwoodcock87, Jul 28 2010

       also, to WcW, yes it could be adapted to a wide variety of vehicles in the same manner as a nitrous system could be, granted that the proper precautions for the added power are taken ( many shops offer dyno tuning and ecu remapping near me) not every vehicle has a belt drive supercharger system available although the rear mount turbo system might be the answer for vehicles with little aftermarket support.   

       2. instant piston melter?! i own a Z and even the early z31's can handle quite a bit of boost, 11psi is more than doable on a stock engine, the Z31 84-89 series were not intercooled but with IC could easily tolerate up to a full bar of boost, and yes better flowing induction systems and head design contributed greatly to the increased output, and in the early (very) 90's 300hp was king.   

       3. The EGT, thermal demand, exhaust etc etc etc you speak of would be a problem on a completely stock vehicle but even the 3-deck rear wing having dragon "jdm" sticker using fast and furious guys know you cant put more in to an engine without first being able to exit it, and these restrictions you make out to be impossible to overcome can be solved with relative ease if youre mechanically inclined.   

       4. yes more flow does mean more power, but the PSI is the reason for the increased output, which is why the bilge pump leaf blower fans dont increase the power on a engine, you have to be able to pressurize the intake to exceed the max cfm a engine will flow, and overcome the inefficencies in the engine, even with a expert port and polish job, the lightest and smoothest valvetrain and best intake manifold you still will have inefficencies.   

       5. yes a LOT more goes into reducing ET's and 60ft times, but the fact that a relatively stock vg30e automatic maxima went from mid 17's to mid 15's in the quarter using Thomas Knights ETC system is astounding if youre familiar with the old single cam VG's   

       6. i have no clue where you keep getting the whole "bulky heavy tank" thing from, unless youre assuming im going to stick a auto shop sized scuba tank thing in the back of my hatch and call it a day. Also it would have the flow increasing benefits of a turbocharger and the adaptability of a installation ease (somewhat) of a nitrous system, and since it would only be run a few seconds at a time the temperature increase due to compression would be slight. Many early imports never used a intercooler on their boosted vehicles and the supercharged l67 3.8 v6s in gm's sedans didnt either and still made power. stupid? yes. did it work? yes.   

       6. thank you ( and i mean that) for your input on co2 tank flow, i didnt take into consideration the low flow rate/ chilling effect from constant use, i know heat volume and pressure (and the exhaust pulse!) are what drives a turbo.   

       im not trying to sound like a smart ass and i appreciate you criticisms -WcW- at least someones giving me some sort of input, youre obviously intelligent and i needed someone to say yay or neigh. this was a coffee fueled hair brained idea i had at boosting my car as easily as possible.
robwoodcock87, Jul 28 2010


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