Great job! Thanks!

-SGC

 

now ya done it

 

Hmmmm, now I'm thinking turky pan!

 

yaaaaaaaaahooooooooo!

for the first time in my life, i'm GLAD i got one-upped!

here is my first thread in case someone stumbles on this one first:

http://www.ffcars.com/forums/showthread.php?t=217227

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Great Video! Looks like a turkey pan might be in my future as well. Thanks for your effort.

Also, You're very trusting of that camera mount. Especially at 80mph! Is that mounted with just a suction cup?

Bill

 

I appreciate the feedback. The mount is pretty steady. I've had it over a 100 before and thought what would be the difference on the body behind me or the hood. Either way I loose the camera and mount. That's why I bought a cheap camera. The mount was pretty inexpensive. It came from Amazon for under $20.

 

Oh sure air goes into the scoop at 80 mph, but what about at 130 mph. I want to see that, before I am satisfied...:evil:

 

Go buy your own camera, mount, sign up for a track day and make sure to post the video. :stirthepot:

If I get the chance I'm definitely not shooting the hood scoop.

OK, I'm confused. What difference would a turkey pan make?

Got the image from Finish line:

http://www.finishlineaccessories.co...roduct_info.php?cPath=21&products_id=31&osCsid=b8f298a41420df72961a33b42983ca0f
It keeps the hot engine air out of the carb. You can get one from them.

How much air could flow through the hood scoop opening? C'mon math guru's.

 

WOW!! I'm truly impressed!!!

 

OK, I'm confused. What difference would a turkey pan make?

 

the turkey pan isolates the cold air into the filter. The engine compartment air is hot.

 

Ahh, that make sense. I knew what a turkey pan was, not why it was used. Thanks

 

Okay... maybe I'm being slow here, but was there some theory (for some reason) that an opening straight in the airflow over the body at 80mph wouldn't let air in?

Whats the reasoning behind that?

 

Okay... maybe I'm being slow here, but was there some theory (for some reason) that an opening straight in the airflow over the body at 80mph wouldn't let air in?

Whats the reasoning behind that?

George,

There are a couple of beliefs that have lead to this -

1. The huge oval opening at the front of the Cobra, where there is obviously high pressure air, takes in more air than can be let out of the engine compartment and it is forced out of the hood scoop opening.
2. Several people in the past have reported that when they drove their Cobras in the rain, they didn't seem to get any water coming into the scoop.

Steve

 

Great work looked like air going in not out. Um kinda like it was designed to do. No low pressure there. Good job.

 

The dead bugs on the fire wall of my car know the scoop works too.
David W

 

Another vote for the turkey pan and reason why

Guys: On the video, when the car slows down the air inside the engine compartment looks like it is trying to come back out. ( the yarn starts to blow out) That means that hot air is coming up into the carb area and that will make the gas boil in the float bowls on a really hot day. It also looks like from what Randy is saying, that at high speed the air pressure inside the engine compartment and the venturi effect of the high speed air over the hood is causing the hood to lift at which point I suspect the scoop is now flowing the other way and letting hot air out. The turkey pan keeps the air going to carb cool all the time, or at least until the hood bows up so much that it loses contact with the bottom of the hood.

Next test? Who's got the cojones and a camera that won't come off at 145 mph.

Ron

 

Guys: On the video, when the car slows down the air inside the engine compartment looks like it is trying to come back out. ( the yarn starts to blow out) That means that hot air is coming up into the carb area and that will make the gas boil in the float bowls on a really hot day. It also looks like from what Randy is saying, that at high speed the air pressure inside the engine compartment and the venturi effect of the high speed air over the hood is causing the hood to lift at which point I suspect the scoop is now flowing the other way and letting hot air out. The turkey pan keeps the air going to carb cool all the time, or at least until the hood bows up so much that it loses contact with the bottom of the hood.

Next test? Who's got the cojones and a camera that won't come off at 145 mph.

Ron

at a low speed, the air from the fan alone may be enough to blow the strings out. it happened with my t.p. twice, but tucked back inside. i bet a turkey pan would help keep the strings inside at lower speeds.

they look awesome too!

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as curious as i am about it, DO NOT try to re-create Randy's hood-popping anomolie with camera!

be safe, lock hood!

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This is fun! Thanks for taking the time to set this up and video tape it. There are lots of variables with these cars that would also effect these results - radiator aluminum, hood fit, ride height (front end high will change the shape of the body "airfoil" Wonder how much of a difference these things would make?

I also wonder what yarn tufts attached to the hood surface (not the top of the scoop) would look like. I suspect the airflow at the top of the scoop opening is different than the airflow at the bottom of the opening.

 

So the ram air effect from the 60's still works?

And it only took us 43 years to figure out how to prove it?

So, if we took our air cleaners off and setup the turkey pan...... INSTANT SUPERCHARGER!

 

So the ram air effect from the 60's still works?

And it only took us 43 years to figure out how to prove it?

So, if we took our air cleaners off and setup the turkey pan...... INSTANT SUPERCHARGER!

Oh yea... but don't tell anyone or we will lose a reason to take the Roadsters for another ride!

Jim

 

Nice! thanks to both you and
Eddie for some fun and closure to that question.

Now...if you could mount your camera inside the fuel tank during filling to explain the phenomenon of the fuel bubbling out all over the car instead of filling the tank////:devil2:

 

Now you need some one with hood louvers to do the test to see how they effect the airflow.

 

Kinda off topic but...

I remember reading that on subaru sti's that the big scoop becomes ineffective at around 120 mph. They say the air travels over the scoop. They have a big undertray though. This car may do the same thing once the speeds get higher. It would be interesting to see a higher speed test.

 

about Randy's hood lift... we are forgetting that the hood scoops are angled down a wee. i imagine this will help lift the hood.

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So I would guess for us EFI guys then you could maybe come up with some type of CAI from the hood scoop then? If it works for you carb don't see why us EFI guys can't enjoy as well. Something to think about when I get back on my project in the next month or so.

 

There you go. Proof these cars suck
As to Randys experience. Guessing at some point/speed. Louvers just can't handle the large amount of air that comes into the scoop along with what comes in the radiator opening. To allow this air out thru louvers combined with air trapped from escapeing out the bottom of the engine compartment. Hood has to be pushed up?

 

dankster,

I talked to a STI guy at VIR, he said the samething. The scoop wasnt working at very high speeds, just causing drag. He changed it into a mesh screen instead. He also had a full underbody tray. He relocated the intercooler in the nose.
Just a note. I forgot to latch my hood at VIR in March. My hood did not come up at 140+. BUT, I have a 9" hole cut in the top after the scoop.

 

It’s nice to see how one little question like this can generate so much enthusiasm. We really need to take one of these cars to a wind tunnel some day, but that would just end this discussion and this has been fun. Has anyone thought of putting some string in various places under the hood and filming that to see were the air goes?

 

See this car. It's a Fiat 124 sedan Special and I owned a few of them throughout the years. It's hood hinges in the front like our FFR's at 100 mph the hood will lift and float at the rear. The grill opening is a bout 1 sq. ft. I always thought it was aerodynamic lift affecting the hood since not much air flows through the grill. As you can see it has the aerodynamics of a brick sitting on a shoebox. Food for thought.

Michael S.