$50 Super Charger (the strange red button explained)

[brushcutter]

Hey Keith, glad you joined in, hadn't really intended to bring this thread back but here we are. In my case it would be very difficult to hook up to any dyno since I no longer own any of these machines, nor the components. The housing I used had 0.002" clearance between the OD of the blades and it's ID. There was always a stumble at initial acceleration, this was not the case if I powered up the fan then hit the throttle, so I have no doubt that something had changed. Also the measured distance from standstill to max rpm was shortened by some feet. We did 20 repetitions each with and without the fan being powered both sets of results were fairly consistent, I was surprised at that! Honestly I was quite skeptical of this whole thing when the guy who told me about it was actually doing it on an S-10 of all things and swore he could feel a difference, he had also tried on of the whirlygig things and said it was bs and that is what gave him the idea. I changed my mind when I immediately noticed the stumble was gone. We did timed tests and took all sorts of notes, and as I said they are probably still here, if they didn't get tossed like a lot of other stuff when I moved into the new shop. As I said I'm not going to bother looking for it, as I don't see where it will be of any benefit on my current project.

[brushcutter]

Hold it guys, I realized this morning that this thread has gotten headed in the opposite direction from where I hoped it would go. I knew there would be some debate about whether it would work or not, and that is where it got hung up like a hustler tub hump on a stump. That is not what I wanted. Fred, Keith, WFO and everybody who have replied, my apologies for getting caught up in arguing, it's time for a re-direct. I'm going to be out of pocket for a few hours this morning, but PLEASE let's think about this: Do you see an advantage to this idea if it could be made to work? If your answer is yes then let's do the 6X6 world thing and work together to see what WE CAN do to get it to work. Keith, if you were working on this what would be the next step? You have to admit that an electric blower that takes no hp from the engine has to be an advantage... sooo... help us out on this. Ok class listen up...

[JohnF]

... You have to admit that an electric blower that takes no hp from the engine has to be an advantage...

Hey brushcutter, an observation from the sideline: It looks like you are wanting to do some science. Cool, I love science.

Something for nothing always sounds great but ideas claiming such will only get engineering folks to roll their eyes at you.

Conservation of energy - it's the law.

So let's say you have a 10 horsepower engine and you want to bolt on an electrical device that will add 1 horsepower. Horsepower is a unit of power (imperial) and watt is also a unit of power (SI) so we can convert how we think of engine power to how we think of electrical power very easily. 1 watt = .00134 HP so 10HP = 7463 watts and 11HP = 8209 watts. Your bolt on device need to net 746 watts. If we assume a perfect conversion (no losses), that the gain in the system is all from electricity, and that your device is 12V DC then we have to get 62 Amps of electrical current from somewhere.

I know that superchargers and turbochargers expect gains from the fact that cramming more fuel/air into combustion produces more watts. In superchargers, a device that takes watts directly from the engine, a balance is made; something like, take 1000 watts to produce 1200 watts for a gain of 200 watts. A turbo gets most of its energy of operation from the wasted energy that leaves the engine as exhaust heat. It sounds to me that your device is more the supercharger model and will get its energy of operation from the alternator (and therefore directly from the engine) rather than from somewhere else like a battery which would be more turbo like.

So, if we argue that this device is taking advantage of the same gains that superchargers are (and I think we are) then let's do some math. Now computing gains for superchargers is black magic to me because there are many variables involved that I don't want to mess up my simple black box example we are working on so I am going to be super generous with a number that I just pull out of the air. Let's say that your device will produce 3 units of power for every unit of power it consumes for a net gain of 2 units of power. Remember, I have no idea how realistic that is but it gives us something with which we can do math.

We want to net 746 watts. 746 / 2 = your device needs 373 watts = 31 amps of electrical current that have to come from somewhere.

I'm betting that the power to drive your device is coming directly from the engine.

But, what do you want to achieve?

This is the big question. Teeny gains are sought in high power games like drag racing and your device may be just the ticket. Be specific because in a vacuum an engineer is likely to choose the average case for the cases that the engineer designs to. The responses to your design may be biased by the average use case of AATVs. If you stated: I want to add 1HP to my engine for $50 and I don't care if the engine lasts only .25 seconds then I think you will get all kinds of different ideas. If your goal cannot be met then an engineer will tell you that too so you should be prepared to hear it.

Remove confirmation bias. You telling me that what you did felt like it worked doesn't tell me anything. Heck, I don't even trust me making such statements. Small variances in your engines performance are expected due variance in the environmental conditions so if you didn't record all of that then your timing data is worthless too. Actually, without the experimental protocol followed for your timings experiment no real scientist would take your trial data seriously.

So, my advice, since it looks like you seriously want to pursue this:

Get everyone to agree on a specific set of goals.
Calculate what it would take reach these goals.
Then research and experiment to find the cost/gain sweet spot.

For example:

I want to improve throttle response time. Throttle response time is affected by fluid losses in the intake system as well as inertia of the mass flow. I think I can overcome some of this by maintaining a higher energy state in the intake (boost) via a low cost electrical fan "supercharger". ...

Off the top of my head thoughts about your design:

Turbo lag is a reduction in throttle response due to having a turbo stuck in the middle of the intake system. The turbo itself adds a bunch of resistance that dissipates once the turbo "fan" spools to a higher RPM and once again gets ahead of the flow. Your supercharger will operate at only one RPM. I suspect gains at one engine RPM will show up as losses at another since your fan will not spool higher. I would look at experimenting with adding your fan to the side of the normal intake flow so it would not add resistance.

And hey, as a scientist I am accustomed to sticking my neck out and looking the fool. It's just part of the territory. Don't be afraid to say that I am all wet... I actually expect it here since supercharging engines is not my expertise.

[kghills]

It may be important to differentiate between driveability and measured performance. Typically you will use the engine dyno for measuring power. Like peak hp and torque. Single sweep, starting at a few thousand RPM and going to just over where peak HP is made. I consider this the performance of the engine. Driveability is a different animal to me and where we use the chassis dyno most. With an eddy current chassis dyno we can see what happens off idle, at speed, light load, heavy load, acceleration, deceleration any thing you like. This is where engines that have the exact same performance can differ immensely. Now lets say just for fun that most 4 stroke engines used for AATVs are really designed for things like lawn mowers and generators. Applications where they run at wide open throttle. Carbs, air box, intake all designed to run at WOT. My guess is what a person would "feel" has nothing to do with the actual HP or torque the engine is making especially given the loss through the drive. Now lets say just for fun that you place a small fan in the cold air intake of an engine designed to run at WOT. All of the sudden at the moment you open the throttle blade there is air flow past the venturi which gives a stronger signal for more fuel in a carb that has no accelerator pump. Walla, no hesitation. Now does this 18HP engine make more power? Probably not but it would sure "feel" more powerful.

I talk often with the engineers for various manufacturers and research engineers involved in engine development. Power and power adders almost always follow certain laws of physics it is true and there is usually good math to show why. As a regular guy working on engines I usually ask myself more simple questions like "if a small electric fan in a cold air intake made any kind of difference, why isn't it on every car I work on"? Soooo...I'll leave the rest in your hands.

Remember, gains will need to be pretty substantial when you loose about 50%






Keith.

[JohnF]

... Power and power adders almost always follow certain laws of physics it is true and there is usually good math to show why. ...

LOL, I'm pretty certain that they always follow all laws of physics. But you are right, power adders exploit different means towards gain and there is math to show why.

Your explanation of the design vs use of these engines makes sense to me. The Kaw FD620D carb has a metered immersion tube that looks to be designed to get from low idle to high idle (WOT). Always thought it was a poor excuse for an accelerator pump. Now it makes sense.

Brushcutter, perhaps it would be better to search out a carburetors to test with too.

A small boost that creates a stronger signal is doing something. But at what cost?

[Stonewall]

This is so cool, it looks like we've got some real experts now!! I smell some math coming up... I love math, this should be fun!

So are y'all saying that the advantage that Brushcutter was feeling was just because the carb was designed for idle to WOT? I also experience some throttle lag on my Vanguard, would a rig like this solve that problem? I think it would be cheaper than converting to a different carb.

Since y'all clearly know quite a bit on the subject, maybe it would be a good time to take another look at putting a turbo on a Vanguard? I'd really like to give this a try.

[wfo]

remember a natually asperated engine will only take so much air into the combustion chamber, if adding a fan to drive as much flow as possable to the intake will only make it run efficient and not any better than if the engine was running at sea level, thats the whole point of forcing the air and pressure at the same time to increase pressure and voluum in the chamber
thus supper charged, another efficient way to run one of these engines is to make it fuel injected, that alone would be worth the money, another noval idea is to cool the fuel before entering float bowl, that also helps but still every bit counts if you decide not to supercharge, if your looking to gain everybit of ponies from a small engine, basics like engine ballencing, carburation , oil weight, intake flow and valve timing and clearences are a must...............just my .02

[Stonewall]

Here's something to think about, remember the title of this thread? It's "The $50 Supercharger", I think your going the wrong way with this idea. We're not trying to get the maximum performance out of the engine, we're just trying to have some fun with a cheap project that anybody can put together, and seeing if we can get a little bit of gain from it.

[kghills]

For me there is a difference between moving air and compressing air. I tend to think of any sort of supercharger as something that will compress air and create a positive charge in the intake manifold. In any build if the customer is running a supercharger I need to know how much boost he plans to run. Anything else is just moving air along and naturally aspirated. So when I read $50.00 supercharger I think to myself "not likely", more like a $50.00 fan. Hens the discussion.

Keith.

[brushcutter]

Holy Cow now we're having some fun! You guys just made my day, I'm gonna have to read this all over again, and watch the videos. I have a question though, er is it just me or is that max missing something. One point that really caught my attention and is directly in line with something I've been wondering about, the compressed air thing... Sucks that I don't have a machine to experiment on right now.

I gotta agree with Stonewall when I started tinkering with all this, my main intent was to play around with something that any member on this forum could throw together and play around with. But that the "hardcore" power fanatics could possibly play with also. I do agree what I "feel" is definitely not grounds for irrefutable proof,(nor arguing either, apologies for the rant WFO and Southpaw) it never even crossed my mind to record barometric pressure or relative humidity.

You guys are just more proof of why this is the greatest Forum on the web!!! By all means PLEASE continue!