Thread: Home Made Blower?

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Instead of building your own, why not adapt something from the junkyard?

Last Saturdays local Harley/Hot Rod show had a slant six Dart with an Eaton blower from a T-Bird - I think, not sure, but Ford did run a small Eaton blower on one of their cars.
The owner reported 8# boost which sounds reasonable to me considering the Slant sixes are 170 or 225 CID.

The blower adaptation was a very simple deal on the Slant six and wouldn't be too much more difficult for a V-8.

Setting up two Eatons side by side at an angle similar to the old Romeo Palamides dragster would be a great setup on a V8 and you could underdrive the blowers slightly so as to keep the temperature down on the intake air.

and i still dont believe you can take a 12 volt fan(that you could get under the hood) and make 20 hp out of it, i don't know what to say about that, except if you could I believe every redneck, shade tree mechanic in the country would have one, but they don't. the no's don't match either. techinspector1 says it takes 1.6 CFM to make 1 HP, kcress says it takes 100 cuft/min to make 2.55 HP. its like denny said to ,its not a matter of pumping a little more air into the motor, it has to override the carb. normal intake. moving CFM of air and pressurizing a cylinder is 2 dif. ball games also. JMP

lt1s10: I think you miss understand... (or I do) My numbers are; How many horsepower it takes to provide that many cubic feet of air per minute with a fan at the stated pressure.

I think Techs number refers to the amount of air required per horsepower put OUT by an engine.

So to repeat I didn't say it takes 100cuft/min to make 2.55HP!!
I said it takes 2.55HP to PROVIDE 100cuft/min of air at the stated pressure. It could be into a leaky shoe box.

Tech:If you want to give me a pressure you think necessary for some horsepower boost AND the total CFM required I would gladly crank out the number for you. DO keep in mind that you cannot add just a little bit of CFMs at some moderate speed because your "system" must provide for wide open throttle too. Also the system cannot just add *some* cfm it must provide ALL cfm!

Anotherwords: You can't have the engine using 100cfm and then show up with a hose putting out 20cfm and add it somewhere. If you want to add 20cfm, you must show up with a hose putting out 120cfm.

I think C9x has a great idea. Adapt a T-bird blower or do like my buddy, buy an off-the-shelf belt driven blower that provides a little boost. His wife drives it everywhere as the family car.

Originally posted by kcress
lt1s10: I think you miss understand... (or I do) My numbers are; How many horsepower it takes to provide that many cubic feet of air per minute with a fan at the stated pressure.

I think Techs number refers to the amount of air required per horsepower put OUT by an engine.

So to repeat I didn't say it takes 100cuft/min to make 2.55HP!!
I said it takes 2.55HP to PROVIDE 100cuft/min of air at the stated pressure. It could be into a leaky shoe box.

Tech:If you want to give me a pressure you think necessary for some horsepower boost AND the total CFM required I would gladly crank out the number for you. DO keep in mind that you cannot add just a little bit of CFMs at some moderate speed because your "system" must provide for wide open throttle too. Also the system cannot just add *some* cfm it must provide ALL cfm!

Anotherwords: You can't have the engine using 100cfm and then show up with a hose putting out 20cfm and add it somewhere. If you want to add 20cfm, you must show up with a hose putting out 120cfm.

I think C9x has a great idea. Adapt a T-bird blower or do like my buddy, buy an off-the-shelf belt driven blower that provides a little boost. His wife drives it everywhere as the family car.

sorry, but I still dont understand, tech stated what he meant and i thought you'll was talking about the same thing, so it wasn't to hard to assume that you said was related to what tech said. if everbody get on the same page maybe dumb old me will be able to keep up. the no's still don't match, which no's then do we need to make a blower? sorry to be so short, but i doubt i was the only one to not understand what you meant. but what really pisses me off is I've spent about 40,000.00 on blowers in the last 20 years and now I find out all I needed was a 12 volt motor hooked to the crab. man.........!!! "i can't belive I did that. enough to give a man a heart attack"

Well this has turned into an interesting post. I had some spare time at work and my buddy and I worked on this(blower)idea of mine and we actually built one but as Denny and others say, the 12V battery will not spin the motor fast enough to get anywheres to the needed 250CFM(my center 2 barrel carb) and beyond to work. We are now trying to see if we can hook the fan directly to the motor somehow. The 12v battery will open the plate we built into the scoop we used and will spin the fan but nowheres near what we need.

Originally posted by chevy 37
Well this has turned into an interesting post. I had some spare time at work and my buddy and I worked on this(blower)idea of mine and we actually built one but as Denny and others say, the 12V battery will not spin the motor fast enough to get anywheres to the needed 250CFM(my center 2 barrel carb) and beyond to work. We are now trying to see if we can hook the fan directly to the motor somehow. The 12v battery will open the plate we built into the scoop we used and will spin the fan but nowheres near what we need.

hope you come up with something chevy 37, i never could and belive me i tried some yrs. ago.

Ok, like Mike said, let's all try to get on the same page. Let's say that we have a 350 Chevy that's producing 300 hp naturally aspirated. I don't know if the 1.6 cfm/hp figure is all wet or if it's real, but let's assume it's real. If the motor is producing 300 hp, then 300 X 1.6 shows us that the motor is ingesting 480 cfm to produce 300 hp. Now, in order to produce an additional 20 horsepower, we must add 32 cfm to the motor, so now we are looking for 512 cfm to make 320 hp. Problem is, it's now going to take some unknown pressure over and above atmospheric pressure to force feed this additional 32 cfm into the motor and that's where my math falls on its face. I don't know how to figure it, but I have an idea that it wouldn't take much pressure in this case, maybe 1 psig or less. Can an electrically-driven blower force-feed a 350 with 512 cfm @ 1 psig? I don't know.

Richard I don't either but I'm going to do some research into this. You think 20 HP wouldn't be much to overcome, but given the facts from others on this post it seems like its a long shot. Interesting????

tech: Your numbers look pretty good.
512 cfm @ 1psig.


But..

Sit back and think about what you asking for... Some air under pressure. Well actually a lot of air under pressure..

How does the auto/truck world approach this? Do they use motors running blowers? No. "Why?" we are asking.

The reason is because a single PSI is a whole lot of pressure when you are talking about air. Go look at www.grainger.com the largest supplier of blowers for industry. You won't find a single blower that runs clear up to 1PSI ! It is so hard to get there that the industry doesn't even use the same units of measure. They uses *inches of water column*! Often fractions of an inch even.

1PSI is 27.68inches of water column.

*High* pressure blowers, all of which run over 2HP have output pressures of
maybe 5inches of water column!

Back to the issue at hand. If you want to herd air around at PSI levels you need to do one of two things:

Use a mechanical pump that essentially grabs some air and mashes it into the space of interest.

Or turn a centrifical impeller at truly mind boggling speeds to literally bat the air molecules somewhere like line drives.

A roots type blower (really a mechanical pump) is the first type mentioned. The air gets trapped by the vanes and must go where it is shoved to.

The second type is the turbocharger. It is the impeller type and they often turn at 120,000rpm.

So. If we completely ignore the horsepower issue you will still need to come up with an actual blower that can provide your 1 PSI . There are NO "fans" that can vagely approach this goal.

I know of no blowers that can! The blowers that get to 7inches of water often weight 300 pounds and are 30" in diameter.

There is a belt driven supercharger that gears up the impeller to about 40,000RPM so the system can be small enough to squeeze under the hood.

Back to the roots type blower. They are belt driven because you are going to need several HP to drive it.

Once someone goes to the bother of this and the expense why in the heck would they want only 1PSI so they can add on 20-30HP? There are far easier more reliable ways of coming up with those few ponies.

Tech what I'm saying is never mind the HP show me a blower/fan/pump that you can drive 500 cfm thru @ 1PSI THEN worry about how to drive it.

Richard,

Given some research time, I could probably do the calculations. However, it isn't worth the effort. Consider the fact that you have to spin a turbo up to 150,000 RPM to get decent boost.

There is just no way an electric fan is going to do anything except impede flow to the engine.

Sure, you can buy an 1800 CFM fan. We put them on radiators all the time. But they blow through a radiator with no pressure build. If you have them blow into a sealed box, they won't build any pressure to speak of.

well Chevy, the outlook is bleak to say the least. Maybe you'll want to put that box of blower motors on e-bay

Thanks to Jack and kcress for pitching in and giving all of us an education.

Mike, you knew you were right all along, didn't you, you crafty devil !!!

Thanks to everyone else who responded and/or viewed this thread.

Please don't overlook the source of energy used to drive to electric motor. Let's "guestimate" that a 20HP motor will be adequate to turn a Roots or belt driven centrifugal compressor supplying 4lbs of boost at 600CFM.

1HP is equal to 750 watts (ignoring conversion losses), so a 20HP motor will require around 15kW of power. With a 12V battery that would be around 1200 Amps. With most alternators capable of sourcing only 65-150 Amps the batteries (2 each minimum to support the 1200 Amp demand) would be drained within a couple of minutes.

The approach is technically feasible, I just can't see it being at all practical.

Cheers, Mark

I want to second what Richard said. Thanks to everyone who gave there opions toward this far fetch idea. As I mentioned I'm not an engineer and the idea was a simple one thinking how to make a cheap blower that would give the average guy a 20-25HP gain with a blower look. I can see now that it can't be done and I thank you all for your input. It was fun thinking about it.

I think I'm gonna get 1 of those dayton blowers, and make it a belt driven peice for my go kart or dirt bike, with the low CFM numbers that those carbs pull, it should be feasable.

Mark,

I'm thinking about a really, really long extension cord . . .