MSSLGECKO Posted October 6, 2005 Share Posted October 6, 2005 A thread about on-board compressed air systems got me thinking about this. I would like to have an on-board system on my off-roader; if I had a setup in my car, I would like to try this: Route a line from the holding tank into the exhaust manifold near the collector. Using a remote-activated valve, pressurized air would be introduced into the manifold and thus spool the turbo. What are the thoughts/comments on this? I can't see why it wouldn't be really cool. It would be nice for off-roading at low rpms w/ a turbo. Link to comment Share on other sites More sharing options...
Ross Posted October 6, 2005 Share Posted October 6, 2005 You would need a fair bit fo compresed air for quite a short burst...might work though. My idea was to have a small pulse jet (a very simple and easy to make jet, that makes more noise than anything else) running the turbine instead of the exhaust. Boost regardless of engine on or not! Of course, its a rather silly idea, but it would be good for a laugh! Link to comment Share on other sites More sharing options...
Snowman Posted October 6, 2005 Share Posted October 6, 2005 What about introducing propane in the up-pipe and somehow igniting it? Could that work? Link to comment Share on other sites More sharing options...
Kostamojen Posted October 6, 2005 Share Posted October 6, 2005 That motor has single port heads right? I guess a twin scroll turbo wouldnt work then... You could do the leaf blower trick Link to comment Share on other sites More sharing options...
soobme Posted October 6, 2005 Share Posted October 6, 2005 I can turn U on to a 12V compressor that makes about 8cfm@100psi right off the compressor:brow: It cost about $150 to build, but oh man, the air!! Link to comment Share on other sites More sharing options...
TomRhere Posted October 6, 2005 Share Posted October 6, 2005 I remember reading an article in some mag years ago about a guy that added nitrous to a turboed engine. He plumbed the nitrous jet into the turbo on the air side so that it would help spool it up faster when the jet hit the vanes. Maybe you could do that with the compressed air on the exhaust side. I have no-clue really, don't have anything turboed here, and have never held a turbo in my hand for a look-see of it Link to comment Share on other sites More sharing options...
4WDFrenzy Posted October 6, 2005 Share Posted October 6, 2005 The only thing with a compressed air setup, is the fact that you would absolutly have to pipe it into the compressor side. If you introduce compressed air into the exhaust, it would mess with the ecu's air/fuel readings. The other option, which incidently is more expensive, would be to either try a compound supercharger setup, nitrous, or have a custom built hybrid turbocharger made to work under certain operating conditions. The downside is that you would sacrifice some sort of operating efficiency. Not to mention that it will still take time to spool. Link to comment Share on other sites More sharing options...
nipper Posted October 6, 2005 Share Posted October 6, 2005 You do realize that you are talking about an eingine that at idle uses 41 CFM (600 rpm), then when the power starts coming on uses 164 CFM (assuming 2500 rpm) ,then a t 6000 rpm uses 410 cfm (on paper, valve timing does have a little to do with it). What would be wiser, but i dont know how it would p[lumb in, is get a turbo setup from a saab, Thise are low mass turbos and spin up really fast. Also adjuting the turbo dump valve or getting an adjustable one will help. What ever you may think you gain, you will loose in weight and complexity. The engine wont even notice an 8cfm increase in the powerband. Now if you want to cool the air and make it more dense, THEN you will have a power gain. nipper Link to comment Share on other sites More sharing options...
archemitis Posted October 6, 2005 Share Posted October 6, 2005 compressed air wont work, for previously stated reasons by nipper. Link to comment Share on other sites More sharing options...
oddcomp Posted October 6, 2005 Share Posted October 6, 2005 do a search on google or something for VNT i am currently trying to figure out how 2 use 2 smaller vnt units on my rx eventually woot almost 0 spool time Link to comment Share on other sites More sharing options...
subyrally Posted October 6, 2005 Share Posted October 6, 2005 just looki into an antilag system from a rally car, shoots unburnt fuel into the turbo, which ignites and keeps the turbo spooled. happens any time your foot isnt on the gas between shifting. Link to comment Share on other sites More sharing options...
WJM Posted October 6, 2005 Share Posted October 6, 2005 VNT+AntiLag=t3h win! aka 51 PSI at 2500 RPM on or off throttle. Link to comment Share on other sites More sharing options...
soobme Posted October 6, 2005 Share Posted October 6, 2005 He is not looking to pump the air from the air sys. into the engine as a boost, so 8cfm@100psi WILL work just fine. He wants to use an air jet to help SPIN the turbo;) I think it's an interesting idea. Link to comment Share on other sites More sharing options...
NorthWet Posted October 6, 2005 Share Posted October 6, 2005 You do realize that you are talking about an eingine that at idle uses 41 CFM (600 rpm)... Not accurate or applicable in this situation. The figure is computed using WOT position, not idle/off-idle. And, he is not looking to supplement the intake air charge with the compressed air, but rather effect how it is compressed; trading the potential energy of the compressed air for the kinetic energy of the turbo (or intake charge). Besides possibly messing with A/F ratio by introducing it before the EGO (mitigateable by moving the EGO to the uppipe, as in certain versions, or forcing open-loop operation), the compressed air (implementation as described) would have a chilling effect on the exhaust stream, causing a reduction in pressure to the turbine (mitigateable by preheating charge using downstream plumbing). It would seem to me to be better to introduce the compressed air stream to the compressor inlet as 4WDfrenzy suggested, though that would definitely mess with the A/F ratio of a MAF-based system (MegaSquirt, anyone?). An advantage to doing it on the inlet side is the chilling effect is beneficial there. Another, more direct, way to use the potential energy of a compressed air stream is to design a thermocompressor, basically the corrollary of a carb venturi. You use the pressurized stream coming out of the jet to entrain the intake charge and compress it through the venturi. Link to comment Share on other sites More sharing options...
nipper Posted October 6, 2005 Share Posted October 6, 2005 i think what you really just need to do is to get a small roots superchager and be done with it. You can spin up the turbo with the compressed air, but its not going to be doing anything. They have to be spinning incredible fats to start making a perfomance impact, and a little air compressor is not going to get a turbo pre spinning anywhere near fast enough to do anything. You would probbalbly get a beter effect from a ram induction hood. FYI http://www.answers.com/topic/turbocharger http://www.automotivearticles.com/Turbochargers_Design_and_Related_Parts.shtml Turnbos spin at 80,000 to as high as 190,000 rpm. your not getting anywhere near that with a little compressed air. nipper Link to comment Share on other sites More sharing options...
archemitis Posted October 6, 2005 Share Posted October 6, 2005 you could always weld your wastegate shut, force all the air through the turbine all the time. then use a blow off valve to regulate boost. but youd blow up your turbo, and have crappy top end. its called forced induction for a reason, not just a fan blowing towards the intake ports. you can take a turbo in your hand, shoot compressed air into the exhaust turbine, and get it to blow alot of air, and make a cool noise, but once you put some load on the blower end of the turbo, it will quickly slow down. air moving by the turbo doesnt make boost. heat is what is realy doing it. Link to comment Share on other sites More sharing options...
All_talk Posted October 6, 2005 Share Posted October 6, 2005 Archemitis is right, a turbocharger extracts energy from the exhaust stream and that energy is mainly provided as heat. Sure velocity has some effect but even at high velocity the exhaust gases have very little mass so they carry little kinetic energy. It’s all about thermodynamics and the key is the pressure vs. temperature relationship for compressible fluid flow. In the same way the compressor boost temperature along with pressure the opposite is happening in the turbine… maximize the temperature (and pressure) drop across the turbine and you maximize the energy extracted. On the subject at hand… Anti-lag, the competition system used by WRC and the like typically use the “bang-bang” type which dumps raw fuel into the exhaust manifold on throttle close, where it ignites keeping the temp and pressure ahead of the turbo high. Any functional anti-lag system will have to accomplish the same. Gary Link to comment Share on other sites More sharing options...
[HTi]Johnson Posted October 7, 2005 Share Posted October 7, 2005 SOmeone might have said this...but why not use that compressed air and route in to the intake. I know you'd have to put it in front of the maf...and make some sort of device that prevents it from cleaning out your airfilter(Going the wrong way). This would help in short bursts, but having your car compress the air in an air compressor then sending it through the intake would probably be redundant in long usage. Good Idea tho. Link to comment Share on other sites More sharing options...
JWX Posted October 7, 2005 Share Posted October 7, 2005 On the subject at hand… Anti-lag, the competition system used by WRC and the like typically use the “bang-bang” type which dumps raw fuel into the exhaust manifold on throttle close, where it ignites keeping the temp and pressure ahead of the turbo high. Any functional anti-lag system will have to accomplish the same. Gary do the new ones still use that? Link to comment Share on other sites More sharing options...
4WDFrenzy Posted October 7, 2005 Share Posted October 7, 2005 Hey Noah, If you decide to go the nitrous route, ZEX makes an air filter that has a provision for a nitrous jet at the very end of the cone filter, that will allow the nitrous a "straight shot" into the intake system. Now I'm not too sure what nitrous would do to the insides of the MAF, but I'm sure it wouldn't be good. I would do as Northwet said and go the MegaSquirt route to eliminate the MAF. Patrick Link to comment Share on other sites More sharing options...
nipper Posted October 7, 2005 Share Posted October 7, 2005 Actually, has anyone seen a sooby with a supercharger on it? nipper Link to comment Share on other sites More sharing options...
Kostamojen Posted October 7, 2005 Share Posted October 7, 2005 Actually, has anyone seen a sooby with a supercharger on it? nipper Yes. There are a few custom jobbies floating around out there. Link to comment Share on other sites More sharing options...
nipper Posted October 7, 2005 Share Posted October 7, 2005 see now that i would like to investigate more thanks nipper Link to comment Share on other sites More sharing options...
rol1 Posted November 9, 2005 Share Posted November 9, 2005 How about some way to extend the shaft on the intake side and hook up a oversize dentist drill to spin the shaft. The airmotor only has to spin-up a second while the turbo catches up. An earlier post brought this to mind: http://groups.yahoo.com/group/DIYGasTurbines/ Link to comment Share on other sites More sharing options...
Free Range Posted November 9, 2005 Share Posted November 9, 2005 noah, you've got the ea82 turbocharger, or just the water jacketed ea81 turbocharger on you ea81T? I ask becuase the ea81 turbo unit is a little smaller to begin with, so it spools faster... To get real fast spooling, just make smaller diameter headers, but your top end will suffer of course... I like the raw fuel between shifts WRC style... Link to comment Share on other sites More sharing options...
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