Internal Body Aerodynamics
- Thread starter vette427sbc
- Start date
Help Support VetteMod Forum:
phantomjock
Well-known member
AI -- I gotta just crawl the InterWeb...
Here is a useful graphic from Dr. ING S.F. Hoerner. Compares the aft section drag coefficients that (by analogy) fit the Corvette (a bit):
Found that version in Japan.
Now this from Sophia University FSAE team (in Japan) shows using an Air Curtain (well, really a splitter End Plate) to influence underbody downforce:
Me LIKE! I COPY this!
Cheers - Jim
Here is a useful graphic from Dr. ING S.F. Hoerner. Compares the aft section drag coefficients that (by analogy) fit the Corvette (a bit):
Found that version in Japan.
Now this from Sophia University FSAE team (in Japan) shows using an Air Curtain (well, really a splitter End Plate) to influence underbody downforce:
Me LIKE! I COPY this!
Cheers - Jim
rtj
Well-known member
- Joined
- Nov 5, 2011
- Messages
- 3,598
- Reaction score
- 211
I’m assuming YouTube uses AI. If you create an account and login, it remembers your search/watch history. Then, whenever you open or refresh the main page it recommends videos. I get a lot of newly released videos that way.
phantomjock
Well-known member
NAHH - It's the NSA, just baiting us...
I do get a heap of music loaded that way. Just guessed it was some tracking of "favorites" algorithm. Guess that qualifies as AI. I thought maybe you had a search engine squired away.
I do get a heap of music loaded that way. Just guessed it was some tracking of "favorites" algorithm. Guess that qualifies as AI. I thought maybe you had a search engine squired away.
![Pampers Sensitive Baby Wipes, Clinically Proven, Fragrance Free, Unscented, Water Based, Hypoallergenic, Multi-Use, Hand Wipes 336 Wipes Total (6X Flip-Top Packs) [Packaging May Vary]](https://m.media-amazon.com/images/I/41KLBHu9CAL._SL500_.jpg)
phantomjock
Well-known member
Under-Hood Internal Aerodynamics
"Return with us now..."
One way to lower internal drag would be keep the air out of the engine bay. With a "boxed radiator" to improve its flow, vented outside the engine bay, there would still be air from underneath the engine to eliminate. An oversized "Skid Plate" could help - but heat in the bay still a concern.
With louvers, air could be pulled from the bay - at speed, but some fan setup would be needed when stopped. Digital temp gauges are pretty cheap, as are some stainless steel louvers.
If you're into electronics the fan(s) could be setup to run at a set temp.
Seems like a worthy experiment. I'll put it on my ever growing list of 2-Dos.
Hi Ho Silver!
"Return with us now..."
One way to lower internal drag would be keep the air out of the engine bay. With a "boxed radiator" to improve its flow, vented outside the engine bay, there would still be air from underneath the engine to eliminate. An oversized "Skid Plate" could help - but heat in the bay still a concern.
With louvers, air could be pulled from the bay - at speed, but some fan setup would be needed when stopped. Digital temp gauges are pretty cheap, as are some stainless steel louvers.
If you're into electronics the fan(s) could be setup to run at a set temp.
Seems like a worthy experiment. I'll put it on my ever growing list of 2-Dos.
Hi Ho Silver!
vette427sbc
Well-known member
With my plan to "belly pan" my car, I have thought alot about a sealed engine compartment and the heat generated by headers and such... The louvers are a good idea but like you said only work at speed. Temperature operated fans are a good idea, but something powerful enough to move enough air is going to be heavy (and where to mount it??) Im going to experiment with some simple vents in the hood to see if the natural tendency of hot air to rise will self evacuate and keep underhood temps reasonable.
All thoughts that wont happen for another year considering the current state of my car though :skeptic:
phantomjock
Well-known member
Ditto, my friend. But I think at last I'm settling in on a wheel tire combo. So soon a "roller."
I'm gonna try the pan under engine - and thermostat fan(s). Also want to Jet-Hot the headers too - may push some heat out of the bay and down the tailpipe - so they say...:search:
Cheers - Jim
phantomjock
Well-known member
On second look - what are they trying to accomplish? Load the inside tire - makes sense, roll the chassis to help that effort - makes sense, but there must be simpler means - thinking the Porsche dual rear elements - (I owe a post of that too.)
But in any case -- That is WILD
But I already said: WHUT! when I saw this one:
[ame]https://www.youtube.com/watch?v=1wmp4I0pShY&list=PL5_EsQr7eMvFJQuZm2i3Ba1_JDUrB6-hy&index=8[/ame]
It works - in spite of being sort of "Red Neck" aluminum siding?
Gotta' have that canard steer for real effect.
Cheers - Jim
But in any case -- That is WILD
But I already said: WHUT! when I saw this one:
[ame]https://www.youtube.com/watch?v=1wmp4I0pShY&list=PL5_EsQr7eMvFJQuZm2i3Ba1_JDUrB6-hy&index=8[/ame]
It works - in spite of being sort of "Red Neck" aluminum siding?
Gotta' have that canard steer for real effect.
Cheers - Jim
Last edited:
phantomjock
Well-known member
so here are some of the ones I owe -
Porsche 908 -
[ame]https://www.youtube.com/watch?v=rNor06VRwJQ[/ame]
and about half way through this video they get some track time:
[ame]https://www.youtube.com/watch?v=QT1Aj5bu9t8[/ame]
ARDUINO anyone?
Cheers - Jim
Porsche 908 -
[ame]https://www.youtube.com/watch?v=rNor06VRwJQ[/ame]
and about half way through this video they get some track time:
[ame]https://www.youtube.com/watch?v=QT1Aj5bu9t8[/ame]
ARDUINO anyone?
Cheers - Jim
phantomjock
Well-known member
Revisit the early C3s
Here is something that has been brewing a while in the "eco-mod" world. Finally making mainstream:
Ready for the 68-77 mods?
In fact could be better flow than the GM 78 that has some areas of "less than optimum," given over for "style."
Cheers - Jim
Here is something that has been brewing a while in the "eco-mod" world. Finally making mainstream:
Ready for the 68-77 mods?
In fact could be better flow than the GM 78 that has some areas of "less than optimum," given over for "style."
Cheers - Jim
vette427sbc
Well-known member
Regarding Jim's thought on venting the engine compartment with a "boxed radiator" ...
Oddly enough I had two new trucks in my shop with the front grilles removed, both had active aero grille shudders. I didnt have any time to test them electronically, but watching their movement my guess is that they are controlled with stepper motors. Using a engine compartment temp sensor and a vehicle speed sensor, a simple code could be written to control the shudder position. For a full belly pan'd car Im picturing this unit being mounted directly under the engine.
At high speeds, but low load (ie: highway cruising) the vents could be totally closed for max efficiency. As load and heat increase the vents could open at the rear to vent the underhood air. And low speeds (traffic, or low speed autocross maybe?) where the engine compartment temp is high from lack of airflow, the vents could be opened to create a ram-air effect.
Surely this could be implemented anywhere on the car, but this is where my head is at currently :shocking:
Oddly enough I had two new trucks in my shop with the front grilles removed, both had active aero grille shudders. I didnt have any time to test them electronically, but watching their movement my guess is that they are controlled with stepper motors. Using a engine compartment temp sensor and a vehicle speed sensor, a simple code could be written to control the shudder position. For a full belly pan'd car Im picturing this unit being mounted directly under the engine.
At high speeds, but low load (ie: highway cruising) the vents could be totally closed for max efficiency. As load and heat increase the vents could open at the rear to vent the underhood air. And low speeds (traffic, or low speed autocross maybe?) where the engine compartment temp is high from lack of airflow, the vents could be opened to create a ram-air effect.
Surely this could be implemented anywhere on the car, but this is where my head is at currently :shocking:
69427
The Artist formerly known as Turbo84
- Joined
- Mar 30, 2008
- Messages
- 3,080
- Reaction score
- 42
- City & State/Province
- Clinging to my guns and religion in KCMO.
Regarding Jim's thought on venting the engine compartment with a "boxed radiator" ...
Oddly enough I had two new trucks in my shop with the front grilles removed, both had active aero grille shudders. I didnt have any time to test them electronically, but watching their movement my guess is that they are controlled with stepper motors. Using a engine compartment temp sensor and a vehicle speed sensor, a simple code could be written to control the shudder position. For a full belly pan'd car Im picturing this unit being mounted directly under the engine.
At high speeds, but low load (ie: highway cruising) the vents could be totally closed for max efficiency. As load and heat increase the vents could open at the rear to vent the underhood air. And low speeds (traffic, or low speed autocross maybe?) where the engine compartment temp is high from lack of airflow, the vents could be opened to create a ram-air effect.
Surely this could be implemented anywhere on the car, but this is where my head is at currently :shocking:
I'm a bit confused here. Are you dumping the "excess/hot engine compartment air under the car?
(Off topic question to you: I'm getting close to opening up/venting the hood at the valley area of the hood scoop. How did you cut that area out without chipping/ripping off chunks of paint? Just taping it first, or what? Thanks.)
69427
The Artist formerly known as Turbo84
- Joined
- Mar 30, 2008
- Messages
- 3,080
- Reaction score
- 42
- City & State/Province
- Clinging to my guns and religion in KCMO.
vette427sbc
Well-known member
The ones I had in shop were a 16 ram and a 17 sierra. I was thinking the speed sensor might be needed because of the way they vents need to position based on speed... with high temps and high speeds, I would not want the shudders to open for a ram-air effect. The air moving under the car might be enough to draw out the air in the engine compartment with the shudders in "louver position". But at lower speeds like an autocross, there is likely not enough air moving under the car to draw it out, so positioning the shudder for a ram air might be more effective without generating massive lift/drag.
Yes and no... At speed, it would be drawn out like the louvers Jim posted:
"Return with us now..."
One way to lower internal drag would be keep the air out of the engine bay. With a "boxed radiator" to improve its flow, vented outside the engine bay, there would still be air from underneath the engine to eliminate. An oversized "Skid Plate" could help - but heat in the bay still a concern.
With louvers, air could be pulled from the bay - at speed, but some fan setup would be needed when stopped. Digital temp gauges are pretty cheap, as are some stainless steel louvers.
....
At lower speeds, fresh air would be pushed into the engine compartment.
I still chipped the paint a bit, I think its inevitable, but an abrasive cutting tool works better than a saw blade with teeth. I used a sharpie to mark my cut, and tape (not on the cut edge) to protect the body from when I slip with the tool. I found that if you cut on the tape it can pull the paint up from the edge when you remove it.
phantomjock
Well-known member
Maybe use tape and a Dremel/high speed rotary tool? (mini-circ saw.)
Been hanging out at the eco-mod world. They are always trying to get 40+mpg and I want 200+MPH, but same techniques apply.
Here are a couple of ideas I've harvested, that fit this discussion.
https://ecomodder.com/forum/showthread.php/automated-grille-shutters-31585.html
These are "cheap as chips"
We have a couple on the boat to control fridge/freezer on off. You can adjust setpoint and temperature range. Because they are 12v makes it eazy-peasy too. One more device to set up in the cockpit - but may avoid a trip through the ARDUINO convention. :goodevil:
EBay linkie https://www.ebay.com/itm/DC-12V-F-F...m=141777090187&_trksid=p2047675.c100011.m1850
Here is an implementation one of the guys is working:
recall about a hundred bucks into it or so. The effort is dated (2015) and no updates - but a good start.Cheers - Jim
phantomjock
Well-known member
Here is another quick link (from 2013) https://www.ecomodder.com/forum/showthread.php/idea-auto-adjusting-grill-block-25096.html
Interesting link using radiator - as well as engine compartment.
They never produced the results - unfortunately...
Cheers - Jim
Interesting link using radiator - as well as engine compartment.
They never produced the results - unfortunately...
Cheers - Jim
mfain
Well-known member
A couple of comments. You don't want to dump air downward out of the engine bay - that causes a high pressure area and kills downforce. Better to vent upward through the hood, or out side vents.
As to cutting a painted surface, I just cut fender air pressure relief holes in a buddy's $20K Viper hood using painters tape and a right angle cut-off wheel. I rounded the corners with a drum wheel (220 grit) and wet sanded all of the edges - no paint chips! The silver car shows the factory cut holes on my ACR. I used it to pull a template from. From a aero perspective, the car normally has louvers in the fender holes, but there is no/very little airflow out of them at speed (verified by yarn tufts). Removing the vents causes a lot of air (and debris off the tires) to be released and the increase in front downforce is quite noticeable. You also get a downforce increase by removing the six plastic grills in the other vent holes in the hood. You can just see some of those vents at the bottom of the silver picture.
Pappy
View attachment 36680View attachment 36681
Attachments
vette427sbc
Well-known member
Pappy- My thoughts were that since the engine compartment is essentially sealed, the venting under the car is just to remove heat, not high pressure air. Do you think this is still detrimental to under car airflow? In my own case, Im trying to solve a *potential* underhood heat problem with a solution that is least intrusive visually (hood vents) and has the least aero impact.
mfain
Well-known member
Here are my thoughts on the potential cooling issue. I am dealing with the same "potential" with a 515 inch big block in my C-1. I went with a wide, double pass Ron Davis radiator. Then I built diffuser duct work from the grill opening to the face of the radiator. This duct work smoothly increases the cross-sectional area as it approaches the face of the radiator, which decreases velocity and increases pressure. Then, after the radiator I used a "chimney" style nozzle that ducts the air upward out vents in the hood. Pretty standard race car stuff. You could open up the fake vents in the C-3's big block hood to keep it from changing the appearance too much. Then I opened up the side vents quite a bit. Actually the 56 didn't have side vents, but I added the vents from a later model C-1 and made them functional to draw air out of the engine bay and out the sides. A long time ago I saw someone selling puller fans for a C-4 than sucked air out of the engine compartment and forced it out the car's side vents.
For the aero question, one of the most effective downforce additions is a good splitter with diffuser tunnels built in the bottom. The splitter pan needs to extend back as far as practical (usually limited by the front suspension). The diffuser tunnels drastically improve the performance of the splitter and they leave low velocity air behind the splitter, which would be negated by dumping radiator air out the bottom of the engine bay.
Pappy
vette427sbc
Well-known member
That is almost exactly my plan, except my side vents are sealed off to provide ducting for my oil and power steering cooler using air fed from the wheel wells... My main concern with the heat is not cooling the engine, its just keeping everything in the engine compartment from seeing 200*+ temps . I was hoping with the active aero shudders underneath the engine I could vent heat when necessary and applicable to what the car is doing.
All of this is just "mental engineering" as I have zero hard data to say I even need to do this, but I like to have some kind of plan in place so I can think about it in the back of my head and tweak it as I get the rest of the vehicle systems in place.
All of this is just "mental engineering" as I have zero hard data to say I even need to do this, but I like to have some kind of plan in place so I can think about it in the back of my head and tweak it as I get the rest of the vehicle systems in place.
Similar threads
