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-   -   Chin Spoiler and Lower Grille block combo questions (https://ecomodder.com/forum/showthread.php/chin-spoiler-lower-grille-block-combo-questions-36622.html)

svt98t 07-11-2018 12:27 AM

Chin Spoiler and Lower Grille block combo questions
 
Hey folks,
I want to pick your brains a little.
First, I recently hit my best mileage ever, at 567.1 miles on one tank of gas in 97 Crown Vic (On a trip to Indy from NY).
I was so excited about it, that I thought about it a ton, and that I couldn't wait to get home and get the next mods done.
I had a lower grille block made from sheet aluminum from my last car (93 Grand Marquis) that fits decently on the front.
I also had a Mach1 chin spoiler I really wanted to add.
So I installed both of these and now returned back to Indy again for work.

On my record setting trip, my low fuel light came on at 485.3 miles.
On this trip, it came on at 488.7 miles.
I know there's always a ton of variables, like the fact it was over 20 degrees warmer out on the second trip.

I expected these two mods to make a bit more of a difference.
However, I'm starting to think that the forward angle of the chin spoiler is actually killing my mileage and not helping as much as it should.

What say you EcoModders?
It's self-tapped in, and if needed, I will remove it for the trip back home to see if it makes a difference.

Thank you for the input.

-ryan s.

https://i.imgur.com/eS9zEs7.jpg

https://i.imgur.com/bnQrF5M.jpg

https://i.imgur.com/yomXYxu.jpg

https://i.imgur.com/cpGapnC.jpg

California98Civic 07-11-2018 03:11 AM

2 Attachment(s)
Quote:

Originally Posted by svt98t (Post 573565)
.... I'm starting to think that the forward angle of the chin spoiler is actually killing my mileage and not helping as much as it should. ....

From my EM eye, I see two things that maybe make this less than ideal, but I do not think you can know for sure on the basis of the experience you describe.

First, it leaves the spinning forward face of the front tires in the airstream and second it may be too far back from the front of the bumper. Compare how your car and a new Fusion are shaped at the chin.

https://ecomodder.com/forum/attachme...1&d=1531288846

https://ecomodder.com/forum/attachme...1&d=1531288848

The Fusion has a bluff face that extends far below the front wheel hub center. On your Vic the OEM design has a much higher stagnation point--above the hub center. I think you want to lower your stagnation point and move airflow around the tires more than currently.

kach22i 07-11-2018 02:31 PM

If the seal between the chin spoiler and the lower valance has any air gaps, the high pressure there will create some interesting nozzles for air squeezing though on the other side. These jets of air can be real energy wasters despite their small size.

Looks pretty, keep up he good work.

svt98t 07-11-2018 05:43 PM

Quote:

Originally Posted by kach22i (Post 573593)
If the seal between the chin spoiler and the lower valance has any air gaps, the high pressure there will create some interesting nozzles for air squeezing though on the other side. These jets of air can be real energy wasters despite their small size.

Looks pretty, keep up he good work.

Now that you mention it, I thought I heard some type of whistling from the front on the drive out here.

Maybe I should take it off for the return trip and revisit the design once I get home. I'll definitely have to push the air around the front of the tires. Making that work is going to be a challenge. But I like challenges.

Thanks,

-ryan s.

freebeard 07-11-2018 06:45 PM

Agreed with the responses. Replace it with a flat plate diverter. Respect the approach angle, but if you can get to the furthest point forward that will drop the stagnation point.

kach22i 07-12-2018 10:01 AM

The 11th image down is an interesting solution should you ever add a front splitter to the chin spoiler. I have not see this done or discussed in the forum before (a warning).

I found the page searching for a good CDF pressure image to post, and the link certainly has several of those.

S2000 Aerodynamics
https://robrobinette.com/S2000Aerodynamics.htm
https://robrobinette.com/images/S200...litter_Dam.jpg
https://robrobinette.com/images/S200...r_Pressure.jpg
https://robrobinette.com/images/S200...e_Pressure.jpg
Quote:

In the CFD pressure plot above note these standard pressure areas common to most cars: very high pressure (red) bubble on the nose of the car, the slight low pressure (aqua) over the hood, the moderate pressure (yellow) bump at the hood/windshield junction and the very low pressure (dark blue) area above the roof of the car where most of the lift is generated. Graphic by Michael Waltrip Racing.

svt98t 07-13-2018 02:29 PM

Quote:

Originally Posted by kach22i (Post 573652)
The 11th image down is an interesting solution should you ever add a front splitter to the chin spoiler. I have not see this done or discussed in the forum before (a warning).

I found the page searching for a good CDF pressure image to post, and the link certainly has several of those.

Thank you for taking the time to find all of this information and post it.
I truly appreciate it.

I like the idea of the splitter, and adding those side plates, vertical plates...whatever they're called, in front of the tires is an amazing idea.

I didnt' get a chance to remove the chin spoiler on the trip home (and I still yielded my best tank ever @578.9 miles), however all that time in the car gave me free time to think about designs and stuff.

I would like to fab a chin splitter and side plates for now, just to see how they do. They will be removed for winter.
However, I plan on grabbing another bumper cover from the junk yard and try to build myself a complete front clip that will have a flat face on it, and incorporate a splitter. If it's designed properly, I won't need to add the side plates.
Since my buddy owns a junk yard, I might go one step further and grab a Fusion bumper cover and try to graft it onto my bumper. Or at least use some ideas and apply them.

Thanks for everything so far. I'll keep you updated to the progress.


-ryan s.

aerohead 07-14-2018 01:22 PM

S2000 aero
 
Those flat plates ahead of the front wheels would have a Cd over 1.00,with complete flow separation.Maybe good on a race track.Awful for a road car.:(

freebeard 07-14-2018 04:03 PM

Quote:

I like the idea of the splitter, and adding those side plates, vertical plates...whatever they're called, in front of the tires is an amazing idea.
Let's be clear about what we're talking about. Dive planes or wheel spats?

Dive planes for downforce
http://www.timeattack.co.uk/wp-conte...de-870x552.jpg
http://www.timeattack.co.uk/wp-conte...de-870x552.jpg

Wheel spats the block air
http://carphotos.cardomain.com/ride_...4121_large.jpg
http://carphotos.cardomain.com/ride_...4121_large.jpg

My preferred solution would be a shark-fin air curtain:
http://www.corvetteblogger.com/image...4/011614_8.jpg
http://www.corvetteblogger.com/image...4/011614_8.jpg

There should necessarily be a vertical slot But I don't think this 'Vette has one. My poor rendition (lost the original file).

https://ecomodder.com/forum/member-f...23-9-48-49.png

svt98t 07-16-2018 10:01 AM

Either wheel spat or the shark-fin.
I think incorporating the shark-fin idea would be interesting, and more over, functional.
I don't need the downforce; it's not a race car, lol.
I'm on the cusp of breaking into the 30mpg range. I'm really looking into improving the aero on the front of the car.
Thanks a ton for all the help so far!!!!


-ryan s.


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