krazy_racer

by looking at all the stuff u have on your siggy....umm ill take dibs on the rockford head unit and the orion speakers once you fucc your car up....oh and will the strut bar fit my s13? if so i call dibs on that too.

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240sx

old_s13

Hey Red, I hope your car explodes and that you catch on fire..

that way, I wont have to read anymore crap on this topic.

Red

Keep your shirt on. I'm almost done... once I get back from Gencon I'll have it all done and get a dyno.

www.gencon.com <-- For anyone that ever likes Roleplay'n games like AD&D

Ya know I been thinking about that whole blow up thing... If my car does blow up. I have a few options.

A: Get an SR (not a bad idea)

B: Buy the V-Rod I been eye'n (I like dat bike)

C: Get a honda and pimp it out. (I would shoot myself.... in the foot so i couldent drive it)

D: Get a 350z (they are kinda neat)

E: Look for Supra. (nice)

F: Import a 95-96 Silvia and convert it to LHD with my current car (lol that might work)

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s13silady

your a and b choice are the best choices... but id pick the Buelle over the V-rod...350Zs are ok... but the turbo ones are coming out if theyre not already out... supras are cool... for F, you might as well do choice A...

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240racer

It's pretty simple physics that explain why a "fan" will not make more power on your engine. Mostly they have to do with not raising the manifold absolute pressure and things like that. You need a product that makes pressure, which fans do not. You also need something that can flow enough air at whatever pressure you want to make (1psi or 25psi) That's why you can't use an air compressor either, they flow like 3cfm or something. That's why we use turbos and superchargers, they make a pressure differential and they flow enough air at that pressure. If you wanted to have an electirc turbo, you would need a electric motor turning a compressor wheel, then it woudl be called an electric supercharger. It would work fine, but it would be a pain to make and it will put a lot of stress on your alternator. Don't ever tell us that we are guessing ever again.

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Adam
'89 coupe KA24DE+T
14.1 @ 104 MPH

'88 Celica All-Trac turbo
stock, but no more ecu codes!!

einherjar

i am really curious to see how this turns out, but just to help red out with the flames he is getting:

- these are only 4" fans, i bet if he blew on them they spin. so yes this will create some drag, but not THAT much, and besides it will create turbulence which i have heard increase power.

- and i'm sure this will increse power with low RPM's.

after he should try to get some functional cowl induction as well.

krazy_racer

yup he should get all of the above plus NaWWWWZ

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240sx

AKADriver

If he blew on them they'd spin, yes... the fans would spin by the energy of the air moving across them, reducing the velocity of the airflow, in other words creating a restriction (drag). This drag will increase as a square of the velocity of the air flow, and the engine will suck in air much faster than you can blow it.

Turbulence in the combustion chamber increases power, turbulence in the intake tract creates further drag and losses in intake air velocity. Aerodynamics is all about reducing turbulence.

It's impossible for these small fans to push enough air to sustain the engine at any speed, even idle. They just can't do it.

einherjar

way to suck the optimisum out of that one.

i agree with you there will be drag but i feel that it will not be that significant until high reving.

i think to figure this out we need to find out the RPM's of the fans without power at idle, at around 3500 RPMS and 7000 RPMs. this way we can compare to the speed the fans spin at.

it would also be interesting to try and to work with this:
http://www.grc.nasa.gov/WWW/K-12/airplane/drageq.html

Fibercus

Get one of them leaf blow motors, there shaped like turbines already hehe, easy to fab a intake / piping and would be loud as hell hahah

As for power source....

Nice to seem someone with a can-do attitude though

Nix

I wanna see it if it worx!
youll be a legend bro
but if its your only car thenmaybe you
shouldnt risk it

old_s13

Why is this thread still open? Can we delete this thread..

..and then delete Red for being SO RETARDED. :)

Yours truly,
- Mike

AKADriver

It's still open because we should all have a CAN DO attitude.

I'm going to climb to the top of my office building and fly off the roof. Don't try to tell me that's physically impossible! I won't believe anything until someone tries it. Referencing another thread, I can't wait until my AROSPEED COILOVERS come in, so I can try those too, even though they're designed by MONKEYS.

After all that I'm going to pick up my FREE LUNCH.

radrex88

and then I am going to go home to my beautiful wife who cooks and cleans, and Im serious.

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Red

Ok I have some stuff for you people to do. Why dont we play with some numbers and see what people come out with.

I got 275cfm's at 6500rpm on my engine. *shrug* I suck at math tho. here are the numbers

To convert cubic inches to liters use the following formula.

cc = 0.06 for cubic inches

cc x 061037

ci x 16.381

350 ci = 5735.48 cc (cubic centimeters)
.......= 5.735 Liters (cubic liters)

5.7L = 348 ci

and 1728ci = 1 cfm

so

2400 cubic centimeter (cc) = 0.0847552 cubic foot

Now what I dont know is 0.0847552 one rpm or 2 rpm... After talking to a few Coworkers we thought it was 2 rpm so we devided it my 2 and came up with 0.0423776 per rpm.. so that x 6500rpm is 275.4544cfm

Hack it up.. give my YOUR numbers!

EDIT: Anyways if the number is 0.0847552 x 6500 thats 550.9088 cfm's so at 2800 rpm it will suck 237.31456 cfm. At idle 59.32864 cfm.

I think your way wrong. But I could be. do the stupid math.

Go to any CFM calc and I'm fukin right.

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Red

AKADriver - I know I'm right. 275cfm's at 6500rpm if you account for intake loss its less cfm's

People need to start with... I THINK. or IT MIGHT NOT...

(Not) IT WONT WORK!!!! <-- that would indicate you know what your talking about!

get it? good!

(Just remember I never said it will work. I said I think it will)

But just by cfm's it should add some hp.

Just think 5hp at 100$ would be cheaper then allot of mods.

We need to get rid of this (THE WORLD IS FLAT!) attitude.

C'mon... Live outside the air box!

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krazy_racer

you have the wrong attitude...

the world is round, and youre trying to flatten it.

you are not a pioneer in automotive performance..
i do not care about doing the math... if it worked a lot of people would be using it..

and theres more to modding a car than just the intake...even if you could get a million gazillion cfm's of air, it would only net you a certain point of horsepower...



id rather stay in the warmth of the box than mess up my car by trying to get out of it

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240sx

240racer

ok, since we seem to have a lack of math explaining why this fan won't make more power, I'll introduce some. Lets just use turbo sizing formulas, since that's esentially what we are trying to do. First we have to agree that the pressure inside the manifold is all that matters, and the goal is to have higher pressure. That way, when the valves open there is a larger difference in pressure between the cylinder and the intake, so more air flows in. This is the principle behind forced induction engines. Normally aspirated motors have a manifold pressure that is equal to the atmospheric pressure which is 14.7 psi absolute, as long as the throttle is open far enough. Now the pressure (some times called vacuum) inside the cylinder when the intake valves open is lower then that, but not 0, because that is impossible. Lets just say it's 2psi absolute. That means there is a 12.7 psi difference in pressure between the cylinder and the intake, so when the valve opens, the air flows in. That's how engines work. Now, you want to make more power, so that means you need more air, so you raise the pressure difference. Lets make the intake manifold pressure 20psi absolute (that's 5.3psi of boost) and the cylinder pressure (or vacuum) stays the same, 2psi absolute, so now the pressure difference is 18psi and when the same size valves open for the same amount of time, more air flows in and you make more torque (or power). Now we see why a turbo makes more power, this is the only reason, there is no other reasons. So, with the electric turbo your goal is to make a difference in manifold pressure, that's the only way it will make more power. First lets talk about restricion. All restriction does is lower the pressure in the "pipe" the fluid (in this case air) is flowing in. So, when your throttle body is closed, the pressure of the air is lower behind the butterfly valve. That's normally refered to as vacuum on a car and is what powers your cruise control and brake booster. you can measure the amount of pressure drop you get when the throttle is closed with a vacuum gauge, it's usually 20in of Hg or about 10psi less then atmospheric or 5psi absolute. You will notice that I use absolute pressure a lot, that's because it's all that really matters and it's a lot easier to just use psi all the time instead of having to convert from in of Hg of vacuum to psi of atmospheric pressure all the time. Now, some people were saying that the fan would restric the amount of air that goes into the engine and therefore lower your torque (or power). The only reason your engine would make less power is because the pressure in the intake manifold would be lower then if the fan were not there. So the goal is to be able to maintain if not increase the intake manifold pressure. Now lets talk about fans. First, fans are not able to make pressure. By this I mean, if you put a fan in a shroud in a piece of tubing with the end of the tubing blocked (so the fan can pressurize the tube) and measured the pressure on one side of the fan compared to the other, you would fine there is maybe a .5psi pressure difference. In this situation there is 0 flow, because one of the sides is blocked. Now if you raised the flow to lets say 50cfm, the pressure difference would drop to really close to 0psi, like .1psi or less. If the flow was at the rated 250cfm, there would definatly be 0psi pressure difference or pressure gain. This means that if the fan is flowing 250cfm of air, it does not raise the pressure on the front side. If the pressure doesn't raise, then the intake manifold pressure is the same as it was without the fan and therefore you make 0hp more. If you want to give me the model number of the fan or a picture of it, I can give you more specific flow/pressure ratio numbers, but I bet those are pretty close. The difference in pressure between the front and back of a compressor (or fan or pump or whatever) is called the pressure ratio. It always changes relative to flow, even with centrifugal compressors, like those on turbos, roots compressors like those on most superchargers and piston pump compressors like those found on air compressors. If you notice air compressors are rated for flow and pressure at 2 points, like 90psi and 45psi, that's because they flow different amounts of air depending on pressure.
Ok I heard comments about even if we could raise the pressure 1psi, that would help some. This is correct, so lets see what we need to do to raise the intake manifold pressure 1psi at 5000rpm. BTW, if you need to make power below that, you don't know how to shift. Ok, I get about 178cfm at 5000rpm. I am using this site for the formulas if any of you want to play around with them. http://www.grapeaperacing.com/GrapeA...boformulas.cfm
You can use the inlet and outlet pressure for the fan too. Also read the other pages they have, very informative. Our desired pressure ratio is (1psi+14.7psi)/14.7psi=1.068. In physics land, the engine power can be found from this equation too, since you are using that much more air, you will make that much more power, sort of. So you make 140rwhp before, with the 1psi of boost now you make 149.5 Which is not enough to feel, but's that's a completly differnt story for a different thread. However, I still don't feel that a 250cfm 4"
fan is capable of obtaining a 1.068 pressure ratio at 178cfm. And if somebody found one that was, I would be very interested in it. Like I said if you give me the model number of specs of the fan, like it's flow rate at 1psi for instance, then we can talk about whether or not it's possible.

I feel that the only guessing I have done here was on a couple numbers, but they should be pretty close to accurate. If I had the actaul specs then we could redo the math and get closer. However the pressure principles that I talked about stand true and the numbers do not affect them. If you have any more questions feel free to post them or PM me, I'll explain something more if needed.

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Adam
'89 coupe KA24DE+T
14.1 @ 104 MPH

'88 Celica All-Trac turbo
stock, but no more ecu codes!!

old_s13

Damn Adam, why did you have to write all that shiet? You know no one wants to read all that crap anyway!

You could have just happily told him what I told him:

YOU ARE AN IDIOT.

There.. job done. Instead, you guys sit here yapping back and fourth talking about CFM, boost, pressure, etc.. just delete the thread and delete red, done.

Red, we dont need all this nonsense. Love dont live here anymo'

misnomer

Y'know, I have to give Red props for taking all this bull****. Granted, he's pursuing a pretty bad idea. Doesn't mean his car should blow up and he should die. So congrats for putting up with all the bull**** and keeping your composure for the most part, Red!

Furthermore
is a very ignorant statement. There are countless examples of people not moving to something that may be better simply because it is unfamiliar. You are working on a Windows pc right now, are you not? :P

All that said, this fan based electric turbocharger whatchadealie is a pretty bad idea :P I put it one notch above a Tornado pinwheel-in-the-intake, and two below a super chip.

. . .you don't want to know how long I wandered eBay to come up with that analogy :P

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dk

"better" in my eyes is a function of utility divided by investment (time and money).

yes, i drive a nissan (not a kit car).
yes, i use windows 2k.

:P

</OT>

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1991 240sx coupe

lotusdrift

Thanks for that good, and about only worthwhile post, in this whole thread 240racer (despite what some might say). Arguing through namecalling will get everyone nowhere, while using math and physics to explain a simple phenomena is going to teach everyone willing to read it(ie, those not incredibly lazy -- we are all supposed to interested in how cars work on this MB are we not??) the correct way to think about a topic, and where NOT to waste our money...

Anyways, thanks for the post, hope other people besides me bothered learning from it.

WIshb0ne

I can't beleave that you guys are Being such to him.. he's coming up with an alternative and you guys are flaming, him calling him an idiot.... and sykikchimp you have promlems you Private messaged me the other day to lighten up and stop flaming... Yea the door swings both ways Practice what you preach... Leave him alone if you don't like his idea....

Chew Slice