Kingman Posted January 22, 2012 Share Posted January 22, 2012 Except there will be a parasitic drag. An electric charger that'll pump enough air to actually be considered forced induction is more than likely going to suck some serious amperage, thus making the alternator work pretty damn hard. Ever done an alternator load test? At 80A the load on the alternator is enough to drop the idle by almost 300RPM on a 350. Link to comment Share on other sites More sharing options...
SchizophrenicMC Posted January 22, 2012 Share Posted January 22, 2012 Except there will be a parasitic drag. An electric charger that'll pump enough air to actually be considered forced induction is more than likely going to suck some serious amperage, thus making the alternator work pretty damn hard. Ever done an alternator load test? At 80A the load on the alternator is enough to drop the idle by almost 300RPM on a 350. Right, but there will only be parasitic drag under acceleration. Even clutched superchargers have pulley drag at idle. Turbochargers also have a mild parasitic effect, because they place resistance on exhaust gases, but the effect is only notable under acceleration. Link to comment Share on other sites More sharing options...
Tungsten Posted January 22, 2012 Share Posted January 22, 2012 Like I said before, you are going to destroy your battery before anything. Link to comment Share on other sites More sharing options...
Slartibartfast Posted January 22, 2012 Share Posted January 22, 2012 Seems like the advantage of a standard turbo is that it's using what would otherwise be wasted energy, and probably not dragging too badly against the engine. The advantage to an electric blower would be that you wouldn't have to re-do the exhaust, though it does sound like it would seriously load the electricals. Now, if we could just find a way to run a turbo from excess engine heat... maybe stick a couple Peltiers on the exhaust manifolds... actually you'd probably have to cover the entire engine with them to get anywhere close. Guess you could just stick a turbine in the exhaust, with a generator, then wire to an electric turbo... minimal plumbing work and a little wiring. Less effective than a standard turbo of course, but it wouldn't be dragging the alty. Probably better to use something not meant as a boat cooler, though! At that point, though, you're already chopping into the exhaust, so you might as well just straight-up turbo it. (Don't mind me, just overthinking stuff as usual.) Link to comment Share on other sites More sharing options...
Precise1 Posted January 22, 2012 Share Posted January 22, 2012 Have the exhaust feed to a stirling engine (plenty of heat exchange differential!!) and on out, causing little back pressure or disturbance. The stirling motor runs a generator that charges a deep cycle battery. That battery runs the electric fan only, so when it is drained, you need to drive normally until it recharges. You could also over the car in solar panels. B Link to comment Share on other sites More sharing options...
johnm Posted January 22, 2012 Share Posted January 22, 2012 (edited) They make fans that have low power needs but don't make enough pressure to affect performance. They make fans that make pressure but need lots of power (relative to what a car electrical system can produce). The other obstacle is size, all the electric fans that can generate positive pressure that I have seen are too big to fit in a modern engine compartment. For the concept to work, it would have to be a small, low-mid power requirement, and capable of generating 2-4 PSI of pressure. I spent months looking for such a thing and couldn't find one. The closest I came was some of the ducted fans used on the bigger remote control model aircraft. Relative to the power problem, a large capacitor would work, but could only power the fan for short periods. Then you have to think about the airflow restriction from the fan when it's not being driven. Would be a good project for some engineer to work on, though. Edited January 22, 2012 by johnm Link to comment Share on other sites More sharing options...
Tungsten Posted January 22, 2012 Share Posted January 22, 2012 (edited) I was working on a Pathfinder Ram-Air intake project earlier but that made a lot of off-road enthusiasts really unhappy. Although having a snorkel would produce about the same effect there. If anyone is interested in ram air, check out those Volant intakes. http://volant.com/edetail.asp?ID=754 Edited January 22, 2012 by Tungsten Link to comment Share on other sites More sharing options...
1994SEV6 Posted January 22, 2012 Author Share Posted January 22, 2012 Except there will be a parasitic drag. An electric charger that'll pump enough air to actually be considered forced induction is more than likely going to suck some serious amperage, thus making the alternator work pretty damn hard. Ever done an alternator load test? At 80A the load on the alternator is enough to drop the idle by almost 300RPM on a 350. "to actually be considered forced induction" LOL. On the whole, this was my exact thought. Even if the electric motor could spin a big enough turbine at a high enough RPM, the power consumption would be ridiculous. I was thinking of having a 2nd alternator, but that would probably be the exact same as a mechanic supercharger with the drag and crank and pulley wear. Right, but there will only be parasitic drag under acceleration. ... but the effect is only notable under acceleration. Correct me if I'm wrong, but during acceleration is the only time you use the effects of a supercharger. Forced induction at idle isn't very helpful, and you wouldn't want it while deceleration. Like I said before, you are going to destroy your battery before anything. Pretty much. In theory, if you wanted to keep thinking about this, I think you would have to have a 2nd alternator and 2nd battery. Link to comment Share on other sites More sharing options...
SchizophrenicMC Posted January 23, 2012 Share Posted January 23, 2012 Correct me if I'm wrong, but during acceleration is the only time you use the effects of a supercharger. Forced induction at idle isn't very helpful, and you wouldn't want it while deceleration. During acceleration is the only time you want to use the supercharger. However, being fixed to a pulley, there are 2 things that can happen. 1. The pulley is a fixed pulley. Whenever the engine is running, the supercharger is drawing energy from it, and compressing air. At idle, at acceleration, at deceleration. (Theoretically, it can increase engine resistance, because the engine must not only fight vacuum, but resist compression against the throttle plate from the blower) As long as the engine spins, so does the blower. This results in instant power, with few parts. But it is constantly sucking energy. 2. The pulley is a clutched pulley. When the engine is at idle, or decelerating, the clutch is open. When you accelerate, the clutch closes. This reduces engine draw at idle, but adds a short lag between starting and engagement. (Like an A/C compressor) The mass of the pulley adds an amount of resistance to the engine, but not much. Obviously, a pulley-operated supercharger is going to be more efficient, since there is a direct flow of mechanical energy. However, an electrically-driven supercharger has advantages, in reducing engine load during non-boost conditions, with less lag than clutched setups. The blower can also generate maximum boost pressure at engine RPM below what would be necessary on a conventional blower. That being said, it creates a lot of electrical strain to use an electric blower. As tested, centrifugal blowers require high RPM, but are fairly heavy. It may cost as much as 20A to operate a blower of that specification. On a car's electrical system, this is a massive draw. A second alternator would not be strictly necessary, but a larger one than average would be. Of course, automotive electrical systems are becoming far more robust than they used to be. You can't buy some cars without power windows, 6-speaker stereo, GPS, electronic power steering, electronic braking, and power sunroof. These are all massive drains that were once considered premium features, requiring large, expensive alternators. EPS and ESC are fairly new features once unimaginable. Now they're all fairly common. So, I wouldn't rule out legit e-blowers some time in the future. 1 Link to comment Share on other sites More sharing options...
Kingman Posted January 23, 2012 Share Posted January 23, 2012 It may cost as much as 20A to operate a blower of that specification Do you mean 200A? An electric fan can and usually does draw more than 20A, hell the rear defroster is pushing 35A. 20A is nothing. Link to comment Share on other sites More sharing options...
1994SEV6 Posted January 23, 2012 Author Share Posted January 23, 2012 Do you mean 200A? An electric fan can and usually does draw more than 20A, hell the rear defroster is pushing 35A. 20A is nothing. 35Amps? An our alternators only produce 70amps? Or am I getting the units of measurement wrong on this? Link to comment Share on other sites More sharing options...
edicer2 Posted January 23, 2012 Share Posted January 23, 2012 one of my buddies in high school had a old beater saturn that he was about to junk and he put some bigger injectors and found a cheap broken leaf blower on craigslist. He then installed them both and when you were driving and flipped the on switch for the leaf blower you could actually tell a difference it was funny.Car never blew up i was surprised. Sad part was it was actually faster than my 86na 300zx with that blower on there hahaha Link to comment Share on other sites More sharing options...
1994SEV6 Posted January 23, 2012 Author Share Posted January 23, 2012 for a beater car and an old leaf blower, that's actually a cool idea. Link to comment Share on other sites More sharing options...
SchizophrenicMC Posted January 23, 2012 Share Posted January 23, 2012 Do you mean 200A? An electric fan can and usually does draw more than 20A, hell the rear defroster is pushing 35A. 20A is nothing. The difference being a supercharger isn't a fan. It's a compressor. I estimate a motor of the same power draw as a Dremel 4000 could drive a centrifugal compressor at 10,000RPM easily, and that motor only has a 1.6A draw at 120v. That's 16A at 12V, drawing 192W (.257hp). Given, this can only generate 1 or 2 PSI of boost, but a more powerful motor at a higher power draw would generate more boost. At 32A, you could expect 2-5PSI, depending on the compressor. And if the mass of the compressor turbine is lightened, the amount of potential boost increases further. Like I said, I would not rule out the use of electric superchargers in the future. Not leafblowers, but legitimate electrically-driven centrifugal compressors. They're within the growing capacity of the automotive electrical system, and have a number of advantages over mechanically-driven superchargers. Link to comment Share on other sites More sharing options...
johnm Posted January 24, 2012 Share Posted January 24, 2012 I think you are under estimating the power requirements somewhat. A benchmark would be what it takes to drive a small centrifugal supercharger. Link to comment Share on other sites More sharing options...
SchizophrenicMC Posted January 24, 2012 Share Posted January 24, 2012 I'm operating under the assumption a centrifugal charger could be driven as easily as a turbocharger, given that it's on a small electric motor shaft. At full 1.6A draw, the Dremel 4000 motor can spin at 35,000 RPM unloaded. Under the load of the inertia of the turbine in a T25, this drops to 25-30,000 RPM max. This isn't a lot; the maximum turbine speed of a T25 is roughly 100,000 RPM. However, adjusted to an automotive electrical system, a motor of proportional power to that one could rotate twice as fast under a not-unreasonable 32A draw. This equates to a good few PSI of boost. And this is to say nothing of a purpose-designed motor on a purpose-designed turbine. Given: Centrifugal Superchargers use large turbines, to create power at lower revolutions available on a crank pulley. Electric motors can be immediately brought to full speed, however, and at higher available revolutions, smaller turbines can be used to produce the same amount of boost. Looking at it from the perspective of a purpose-built system, it is fully within the realm of automotive electronics, especially as they continue to evolve. The 1995 Nissan Pathfinder has a 70A alternator. The 2010 Nissan Pathfinder has a 130A alternator. The output has nearly doubled in 15 years. (Less, actually, since it's the same alt throughout the R51 line) If Mazda wants to do it, I want to see it. It's completely possible, so why not? Link to comment Share on other sites More sharing options...
johnm Posted January 24, 2012 Share Posted January 24, 2012 Though I don't dispute that it's theoretically possible, the fact that no one has done it yet, suggests that it is not easy to accomplish. 1 Link to comment Share on other sites More sharing options...
SchizophrenicMC Posted January 24, 2012 Share Posted January 24, 2012 Though I don't dispute that it's theoretically possible, the fact that no one has done it yet, suggests that it is not easy to accomplish. Nothing worth doing is ever easy. I bet they said that about 4-speed manual transmissions at one point, too. Link to comment Share on other sites More sharing options...
1994SEV6 Posted January 24, 2012 Author Share Posted January 24, 2012 Nothing worth doing is ever easy. What about a lint roller? Tape on a stick. I think that's worth doing. Link to comment Share on other sites More sharing options...
SchizophrenicMC Posted January 24, 2012 Share Posted January 24, 2012 What about a lint roller? Tape on a stick. I think that's worth doing. SE, shut up. Link to comment Share on other sites More sharing options...
Reshma Posted January 30, 2012 Share Posted January 30, 2012 SE, shut up. Link to comment Share on other sites More sharing options...
Fukinitupagain Posted February 29, 2012 Share Posted February 29, 2012 You're going to have to do some slight modification to your hood to fit this... just sayin, lol Link to comment Share on other sites More sharing options...
1994SEV6 Posted March 5, 2012 Author Share Posted March 5, 2012 You're going to have to do some slight modification to your hood to fit this... just sayin, lol naw chill. Rig it under the cargo area like a spare tire and pipe it to the intake. Link to comment Share on other sites More sharing options...
nunya Posted March 5, 2012 Share Posted March 5, 2012 What about a lint roller? Tape on a stick. I think that's worth doing. You know the guy who decided "let's roll the masking tape backwards on a broken handle here and sell it to cat owners" is rich. Lint rollers are awsome for a product that costs a buck Link to comment Share on other sites More sharing options...
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