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-   -   need help. economy smoke generator (

justme1969 01-02-2013 11:33 AM

need help. economy smoke generator
If you see my brag post for 2nd car kia sephia I need a cheapo smoke generator to test aerodynamic flow. Any Ideas???
Currently using a 12v windshield washer bottle with single sprayer and push button but water does not atomize enough for true results.
Ive moved it as far forward as possible to no better effect.
Under 55mph fluid collides with windshield.
I know aerodynamics change with speed and all but I just dont feel like this test is correct with the specific gravity of fluid stream in air.
This may be a better way to test for the air pockett at transition to the windshield though?? not sure but I have no baseline for test so I must conscider all results false.

justme1969 01-02-2013 11:55 AM

Seen tuft test, videos so while more complex may work.? this car looks aero but is not!

justme1969 01-02-2013 02:11 PM

I am thinking that if I can get the water mist up to about center of windshield I have improved the aero. Current test shows it hitting just over the wiper blades.
A temporarily duct taped spoiler before that point may make it slip through air easier?
Just not sure the more I figure out the more questions I get now ...
OK so tape on spoiler 10" before windshield pockett add some tuft strips and spray water same time. see what I get.
This looks more like a blog with no outside team input.
I also think Isopropol alcohol with coolaide if it will mix "for color" would atomize faster thus be much lighter and should grant me better results.
I do believe the pre air register pocket spoiler will make car slip better. I just need a front air dam on it first. Ok will post results later I hope yall agree with my thinking here.

JRMichler 01-02-2013 02:33 PM

Water mist is no good - the water droplets (partly) keep going straight when the air changes direction.

How about a bee smoker?

Sven7 01-02-2013 03:03 PM

Perhaps you're not asking the right questions. How about, "What is the best way to test a new aeromod?" or, "Is dealing with the high pressure pocket in front of my windshield worth my time/money?"

If you're looking to test an improvement, mist or smoke is probably not the best idea. A deflector at the base of the windshield (I assume that's what you're planning) is not going to do much, so even the almighty coast-down test might not even show results. You could try tuft testing or coast-down, but don't expect much- even from the best executed windshield deflector. You might not even see an improvement at the pump.

Try a grille block, air dam and smooth wheel covers instead- they will actually help your FE!

justme1969 01-02-2013 03:39 PM

Air dam is in design phase already because the larger tires raised front of vehicle 3/4" and it looks swoopy but is closer to a brick than aero.
Not complaining about larger tires though as it took the car to the next level for economy. I do mostly hiway driving and it dropped engine rpms down without making it an obstacle at traffic lights. The car is temporary transportation so any mods will imho do no harm.
Also I am about to remove the mirrors and seal the front seams.
There seems to be alot of turbulence infront of windshield and across back window.
As you said it may not be worth the effort to raise the slipstream to 1/2 or 3/4 windhield height but I drive 45 miles each way everyday and we all need a hobby.
In addition I plan to install the rear spoiler in several locations to see its effects so still need the smoke generator.

justme1969 01-02-2013 04:44 PM

I am getting excited!
The conveyor material Ive selected is not very heavy but will be ridgid after wrapping from wheel to wheel under the profile of the fake bumper.
It will be 3 1/2" from the ground, and covers all them cosmetic scoops and vents in the plastic fascia. I hope this will do as my other choice for material was 18" wide and would have to be cut end to end to fit at all.
The 15" moon disks should look cool screwed over stock wheels.
The rear deck spoiler is profiled ok and the trunk is going to work without modifications other than holes when I move the spoiler up to the back window.
I think I am going to have issues 1 gallon bottle feeding the fuel without alot of work but for test to be proven before and after it must be done since there is no other verifiable method. I am going to make a smoke gun,that I can mount before the car for aero testing, Im sure I can make inexpensive mods to the cars profile to make that better beyond the obvious stuff.

justme1969 01-03-2013 02:49 PM

Update#1 front dam now on it, and it looks good. did a few speed bump trials last night.
I found that the conveyor material folds back smoothly when high centering the big ones.
not the harsh grinding sensation I expected.
I diddnt see where anyone listed an optimum height for this mod and when I started installing it wouldnt have mattered.
3 1/4" is just where it had too be to screw it in place solidly.

Next is rear spoiler backed up to rear glass base.

RobertISaar 01-03-2013 04:00 PM

if you want a way to generate smoke, grab some dry ice and throw it in a container of water... the warmer the water, the more "smoke" it will produce in the same period of time.

Sven7 01-04-2013 07:00 PM

"since there is no other verifiable method."

Why can't you do coast-down testing? It would seem a lot more reliable and repeatable than pouring a gallon in. Plus, you'll probably get larger differences before/after so the data will be easier to sort.

If you want something to do in your spare time, design a kammback or boat tail. It'll be the most productive thing (aero wise) you'll do to your car.

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