Under hood aerodynamics, et al...
12-23-2008, 10:32 PM
#1
Le Mans Master
Thread Starter
Under hood aerodynamics, et al...
As a reply to the following post on another thread, I've decided it appropriate to open a new one here...
Hey Gene,
Like lift or downforce, radiator air flow relies on pressure differentials too, and anything you can do to increase that differential will encourage better flow thru it. (Having a good seal at the rad bulkhead keeps this differential from bleeding off around it.) Your opening up the grill area has evidently increased pressure ahead of the rad by a significant amount vs. when it was stock w/license plate. However, in lieu of a larger air dam, I'd at least re-install the factory lower rad extension (meaningless as it may appear), as doing so would not only split some additional air into the area ahead of the rad, but secondly (and perhaps more importantly) it will also decrease the amount going beneath the car. That, in turn, means lower pressures in and under the engine compartment and, thus, on the backside of the radiator.
Also, since side vents reduce under hood pressures as well as under body pressures by allowing hot (read, "expanded") air to more readily escape into the low pressure area behind the front wheel wells, it seems logical that larger, less restricted ones would increase the benefit of having them (something else to look into). I'd get a gasket on the back end of the hood, and seal up any opening there if you're not using a cowl induction setup, as it apparently takes only ~30mph for pressures at the base of the windshield to exceed those in the rear of the engine compartment. At speed, by however slight a margin it may be, by not sealing the hood in this area you are likely increasing engine compartment air pressure and perhaps even that beneath the nose of the car. The same may be true of any hood openings into the engine compartment at large which have not been properly located or designed, and IMHO induction hood scoops of any style which aren't isolated are inadvisable aerodynamically. On the other hand, a functional pair of fender well vents are a sound idea.
It's debatable how much effect having a spare or not has, but when you look up under the back of a C3 without one that bumper sure looks a lot like a parachute. Question is, does the tire carrier redirect air flow enough to actually improve its ability to escape out the back? One viable option to address reducing pressure in this area would be to cut some vents behind the rear wheel wells, as per a number of Ferrari models. Additionally, tho not an attractive prospect, holes could be cut directly in the rear panel/bumper (not un-common on racers). Just an opinion, but I don't think I'd go to the trouble of re-purposing the Astro Vents due to the risk of fumes and the likelihood that any benefit would be minimal. Given the ground clearance issues with which we are stuck on the street, a well designed diffuser panel under the entire rear end of the body may or may not have enough practical value to be worthwhile, but IMHO it's an idea that does carry some appeal, nonetheless.
As for your ride height, keeping in mind that a small amount of rake is a good thing, IMHO lowering to Chevy Power specs (or as close to them as is practical) would be a good move from both a mechanical as well as an aerodynamic standpoint. In any event, I'd make certain that your front "Z" height is no higher than your rear "D" height.
If and when I can get my SA back in service, putting some numbers to a fair amount of this stuff and exploring such gray areas as above is on my ever growing list of "research" I'd like to perform. For those who've yet to have guessed, I'm a bit intrigued by the tech side of our hobby. (Donations to the cause gratefully accepted, BTW.
) And, yes, I'll be working from the front to the back, as everything downstream is effected by everything upstream.
Charlie
Hey skunk, curious what you have to say about my observations.....I moved here near 12 years ago from Maryland, up there the ambients were damn rarely ever above 110 on the road, and surely they are lots hotter than that here in Florida, on a summer day in traffic just off the freeway settin at a light, I would say the ambients have to be 140, as my wife's little silver/green Escort hits 165f on paint temp in the sun.....so anyway....I had a problem with the front tags being required in Maryland, so had one on....when noting none needed here in Florida, without any thought, I took my '87 vette tag panel, said Corvette on it, and stuck it on the '72 here, totally stock grill in them days....and had a overheating problem in traffic.....so, one day somehow I took that whole tag mess off there, and the overheating at speed and in traffic was almost cured.....some years later I got a custom aluminum grill made up, and so it's do open in front maybe as well say there is no grill.....no tag crap no lower bumberettes, nothing...not even a lower spoiler section at that time....
the car never had a gasket on the back of the hood, and never had any side metal grill inserts....wide open scoops....
only recently has the center section under the add on aftermarket BB hood bulge, been opened up totally.....
there is no spare tire, which I think would act to allow a air damn in rear under the tail light panel....of course the 'vents' are up top in stock position form the old astro vent setup that never functioned, as it's a a/c car....
so the question is.....overall, that is your opinion of these changes??? do those body mods help or hurt?? the car is stock height, not supposed to be according to VBP with the 460 spring in front, but it is according to frame measurements off the GM literature....
the car never had a gasket on the back of the hood, and never had any side metal grill inserts....wide open scoops....
only recently has the center section under the add on aftermarket BB hood bulge, been opened up totally.....
there is no spare tire, which I think would act to allow a air damn in rear under the tail light panel....of course the 'vents' are up top in stock position form the old astro vent setup that never functioned, as it's a a/c car....
so the question is.....overall, that is your opinion of these changes??? do those body mods help or hurt?? the car is stock height, not supposed to be according to VBP with the 460 spring in front, but it is according to frame measurements off the GM literature....
Like lift or downforce, radiator air flow relies on pressure differentials too, and anything you can do to increase that differential will encourage better flow thru it. (Having a good seal at the rad bulkhead keeps this differential from bleeding off around it.) Your opening up the grill area has evidently increased pressure ahead of the rad by a significant amount vs. when it was stock w/license plate. However, in lieu of a larger air dam, I'd at least re-install the factory lower rad extension (meaningless as it may appear), as doing so would not only split some additional air into the area ahead of the rad, but secondly (and perhaps more importantly) it will also decrease the amount going beneath the car. That, in turn, means lower pressures in and under the engine compartment and, thus, on the backside of the radiator.
Also, since side vents reduce under hood pressures as well as under body pressures by allowing hot (read, "expanded") air to more readily escape into the low pressure area behind the front wheel wells, it seems logical that larger, less restricted ones would increase the benefit of having them (something else to look into). I'd get a gasket on the back end of the hood, and seal up any opening there if you're not using a cowl induction setup, as it apparently takes only ~30mph for pressures at the base of the windshield to exceed those in the rear of the engine compartment. At speed, by however slight a margin it may be, by not sealing the hood in this area you are likely increasing engine compartment air pressure and perhaps even that beneath the nose of the car. The same may be true of any hood openings into the engine compartment at large which have not been properly located or designed, and IMHO induction hood scoops of any style which aren't isolated are inadvisable aerodynamically. On the other hand, a functional pair of fender well vents are a sound idea.
It's debatable how much effect having a spare or not has, but when you look up under the back of a C3 without one that bumper sure looks a lot like a parachute. Question is, does the tire carrier redirect air flow enough to actually improve its ability to escape out the back? One viable option to address reducing pressure in this area would be to cut some vents behind the rear wheel wells, as per a number of Ferrari models. Additionally, tho not an attractive prospect, holes could be cut directly in the rear panel/bumper (not un-common on racers). Just an opinion, but I don't think I'd go to the trouble of re-purposing the Astro Vents due to the risk of fumes and the likelihood that any benefit would be minimal. Given the ground clearance issues with which we are stuck on the street, a well designed diffuser panel under the entire rear end of the body may or may not have enough practical value to be worthwhile, but IMHO it's an idea that does carry some appeal, nonetheless.
As for your ride height, keeping in mind that a small amount of rake is a good thing, IMHO lowering to Chevy Power specs (or as close to them as is practical) would be a good move from both a mechanical as well as an aerodynamic standpoint. In any event, I'd make certain that your front "Z" height is no higher than your rear "D" height.
If and when I can get my SA back in service, putting some numbers to a fair amount of this stuff and exploring such gray areas as above is on my ever growing list of "research" I'd like to perform. For those who've yet to have guessed, I'm a bit intrigued by the tech side of our hobby. (Donations to the cause gratefully accepted, BTW.
) And, yes, I'll be working from the front to the back, as everything downstream is effected by everything upstream.Charlie
Last edited by TheSkunkWorks; 12-24-2008 at 12:41 AM. Reason: correction
12-23-2008, 10:48 PM
#2
Safety Car
Charlie....very interesting!You're the man,and it's this stuff why I follow all your threads/posts.
When you are talking about the rear underbody pan...are you refering to something similar to the 295k 69 that was just on ebay,and the fellas were talking about?Arn't Nascar cars also,like this?
I was going top lower the car per the power book,but didn't go all out,and whack into the frame for the application that this car is being built for,but I am getting ready to tear my car down for some updates,and just saw the member that installed the batwing...removing the rear crossmember,and the mounting brace.He achieved getting the rearend up 3/4 of a inch I believe.The batwings are cheap,and it is nonthing more than alittle cutting,welding,and making some install brackets.I could do this w/the body on the car.Is it worth the trouble?
I am in the beginning stages of drawing ideas for a front lower dam w/air ducts to feed the front calipers.How low should this be for a street driven car w/496,VB&P front/rear mono setup,and 17s.What about the angle?
Merry Christmas,and thanks for your thoughts here.Someone like you that has ACTUALLY raced,and ran these cars......I am ALL ears...well...eyes.
When you are talking about the rear underbody pan...are you refering to something similar to the 295k 69 that was just on ebay,and the fellas were talking about?Arn't Nascar cars also,like this?
I was going top lower the car per the power book,but didn't go all out,and whack into the frame for the application that this car is being built for,but I am getting ready to tear my car down for some updates,and just saw the member that installed the batwing...removing the rear crossmember,and the mounting brace.He achieved getting the rearend up 3/4 of a inch I believe.The batwings are cheap,and it is nonthing more than alittle cutting,welding,and making some install brackets.I could do this w/the body on the car.Is it worth the trouble?
I am in the beginning stages of drawing ideas for a front lower dam w/air ducts to feed the front calipers.How low should this be for a street driven car w/496,VB&P front/rear mono setup,and 17s.What about the angle?
Merry Christmas,and thanks for your thoughts here.Someone like you that has ACTUALLY raced,and ran these cars......I am ALL ears...well...eyes.
12-24-2008, 12:15 AM
#3
Le Mans Master
Thread Starter
Afraid I haven't seen the '69 you're referring to. Link?
Not sure if Bee Jay has completed the batwing conversion yet. After getting it hung the question of pinion angle came up, and he may have to make some minor adjustments to finish setting it up. Believe he's going to end up with having achieved ~1/2" in raising the diff. While I believe raising the diff height on low C3's is a good idea, I'm on the fence about changing over to the batwing. I don't know by how much rear chassis stiffness is effected, and it imposes limitations on your choices of diff pumpkins. Given these questions and that I'm committed to keeping my 12-bolt IRS it's not something I'll be doing, however, I don't see anything wrong with the conversion for anyone not overly concerned with these matters. My own preferences aside, FWIW, TT went with a batwing, but has done a significant amount of chassis bracing.
It would be very nice if there were an attractive, modern air dam for our cars with functional brake ducts. The nearer the nose of the car, the higher it's going to have to be for ground clearance on the street. If it's going to be in about the same area where the stock PC dam is, I'm guessing you might be able to go a 1/2" - 1" lower that that one, but on the street a lot depends on any one individual's application and on what type(s) of surfaces they'll be driving. Of course, ideally for a smooth track you'd want the "splitter" just about brushing the ground when the suspension is fully grunched at speed, virtually eliminating air from going under the nose...
...and, Merry Christmas.
Not sure if Bee Jay has completed the batwing conversion yet. After getting it hung the question of pinion angle came up, and he may have to make some minor adjustments to finish setting it up. Believe he's going to end up with having achieved ~1/2" in raising the diff. While I believe raising the diff height on low C3's is a good idea, I'm on the fence about changing over to the batwing. I don't know by how much rear chassis stiffness is effected, and it imposes limitations on your choices of diff pumpkins. Given these questions and that I'm committed to keeping my 12-bolt IRS it's not something I'll be doing, however, I don't see anything wrong with the conversion for anyone not overly concerned with these matters. My own preferences aside, FWIW, TT went with a batwing, but has done a significant amount of chassis bracing.
It would be very nice if there were an attractive, modern air dam for our cars with functional brake ducts. The nearer the nose of the car, the higher it's going to have to be for ground clearance on the street. If it's going to be in about the same area where the stock PC dam is, I'm guessing you might be able to go a 1/2" - 1" lower that that one, but on the street a lot depends on any one individual's application and on what type(s) of surfaces they'll be driving. Of course, ideally for a smooth track you'd want the "splitter" just about brushing the ground when the suspension is fully grunched at speed, virtually eliminating air from going under the nose...
...and, Merry Christmas.
12-24-2008, 05:41 AM
#4
Team Owner
As a reply to the following post on another thread, I've decided it appropriate to open a new one here...
Hey Gene,
Like lift or downforce, radiator air flow relies on pressure differentials too, and anything you can do to increase that differential will encourage better flow thru it. (Having a good seal at the rad bulkhead keeps this differential from bleeding off around it.) Your opening up the grill area has evidently increased pressure ahead of the rad by a significant amount vs. when it was stock w/license plate. However, in lieu of a larger air dam, I'd at least re-install the factory lower rad extension (meaningless as it may appear), as doing so would not only split some additional air into the area ahead of the rad, but secondly (and perhaps more importantly) it will also decrease the amount going beneath the car. That, in turn, means lower pressures in and under the engine compartment and, thus, on the backside of the radiator.
Hey Gene,
Like lift or downforce, radiator air flow relies on pressure differentials too, and anything you can do to increase that differential will encourage better flow thru it. (Having a good seal at the rad bulkhead keeps this differential from bleeding off around it.) Your opening up the grill area has evidently increased pressure ahead of the rad by a significant amount vs. when it was stock w/license plate. However, in lieu of a larger air dam, I'd at least re-install the factory lower rad extension (meaningless as it may appear), as doing so would not only split some additional air into the area ahead of the rad, but secondly (and perhaps more importantly) it will also decrease the amount going beneath the car. That, in turn, means lower pressures in and under the engine compartment and, thus, on the backside of the radiator.
That lower air dam was damn well destroyed when I got the car so it was removed for years, just recently I decided to put something back on there.....I mounted some Hela lights in back of that custom drill, and '63 vette turn signal bulbs, the recent addition of the up/over air cleaner assy meant the hood was extensively modified, and opened up in the center under there...no choice, reverse hinged too, opens like a real car now hinged from the cowling...not the front....
since the license plate removal the car has never heated at speed, but I went to Tom Dewitt's dual spal setup about 4? years ago, did my own install so the shrouding is 100% now, and it really cools down fast, that cured the off freeway traffic problem, the '87 vette fan in the OEM '72 shroud was not able to adequately keep up.....maybe the late F body radiator, a single row plastic tank thing with same size core as OEM is not but barely adequate either, but it IS cheep.....NOW I see other better aluminum rads for same money just not long ago....figgers...Also, since side vents reduce under hood pressures as well as under body pressures by allowing hot (read, "expanded") air to more readily escape into the low pressure area behind the front wheel wells, it seems logical that larger, less restricted ones would increase the benefit of having them (something else to look into). I'd get a gasket on the back end of the hood, and seal up any opening there if you're not using a cowl induction setup, as it apparently takes only ~30mph for pressures at the base of the windshield to exceed those in the rear of the engine compartment. At speed, by however slight a margin it may be, by not sealing the hood in this area you are likely increasing engine compartment air pressure and perhaps even that beneath the nose of the car. The same may be true of any hood openings into the engine compartment at large which have not been properly located or designed, and IMHO induction hood scoops of any style which aren't isolated are inadvisable aerodynamically. On the other hand, a functional pair of fender well vents are a sound idea.
NOW, that is a surprising comment, I would think that brick of a cowling would want to blast air off the surface in any direction, not just under it.....the w/s does have more of a rake to it....and smooth wrapped sides....
I could do that with relative ease, but since the temps are fine even with a/c on, I dunno it's worth it....the hood don't lift at speeds....maybe those side scoops by previous owner work better than I would give credit for....It's debatable how much effect having a spare or not has, but when you look up under the back of a C3 without one that bumper sure looks a lot like a parachute. Question is, does the tire carrier redirect air flow enough to actually improve its ability to escape out the back? One viable option to address reducing pressure in this area would be to cut some vents behind the rear wheel wells, as per a number of Ferrari models. Additionally, tho not an attractive prospect, holes could be cut directly in the rear panel/bumper (not un-common on racers). Just an opinion, but I don't think I'd go to the trouble of re-purposing the Astro Vents due to the risk of fumes and the likelihood that any benefit would be minimal.
eh, the car is a rag top, so those vents are just decorations, maybe they can drop some pressures, but being so far forward, I suspect useless......
Given the ground clearance issues with which we are stuck on the street, a well designed diffuser panel under the entire rear end of the body may or may not have enough practical value to be worthwhile, but IMHO it's an idea that does carry some appeal, nonetheless.
As for your ride height, keeping in mind that a small amount of rake is a good thing, IMHO lowering to Chevy Power specs (or as close to them as is practical) would be a good move from both a mechanical as well as an aerodynamic standpoint. In any event, I'd make certain that your front "Z" height is no higher than your rear "D" height.
I maybe well explore some of that when I get around to finally replacing the slightly loose upper inner control arm bushings, they were redone with urethane some 15 years ago, and are almost as tired as me now.....
If and when I can get my SA back in service, putting some numbers to a fair amount of this stuff and exploring such gray areas as above is on my ever growing list of "research" I'd like to perform. For those who've yet to have guessed, I'm a bit intrigued by the tech side of our hobby. (Donations to the cause gratefully accepted, BTW.
) And, yes, I'll be working from the front to the back, as everything downstream is effected by everything upstream.Charlie
I agree Charlie, hotrodding is name of the game for over 1/2 century for me now....since I was age 8 or so and some California hotrodders showed up in the hood 35 Ford hotrod, '49 Ford lowered, chopped, channeled, sanitary de-chromed, frenched tail lights, headlights...louvered hood....like I say, been a while.....
every car I have ever had has been modified in some fairly major way, new, used, didn't matter, never lasted as stock for longer than a week.....
my '87 vette got my into DPFI and engine controls, as it got some 26-8? mpg at speed and so the car was fairly quick for it's point in time.....and so I wanted SPFI on a old Pontiac 455 my tow car, which is what I did with an old Caddy system from the junkyard....still have that modded induction system....
I also built a sender unit for a GM computer that ran a Volvo DPFI setup on my boat, picked up 10 mph easy and 3 prop sizes for that little changeover on the boat too.....
the kids knew that '70 Lemans convertible could haul *** pretty good, I"d open up that unsilenced 1000 cfm t-body and that dual exhaust and that poor car just cut loose, boat or no boat, all 8000 lbs of rig went uphill FAST......
since then the '87 has gond by the way side, but still have the shop manual and so the '72 has grown some interesting mods too.....rack, HBoost, O ring calipers, body mods, just now went to '89 vette wheels/tires which IMO look better than the '92's that were on it.....of course DPFI and overdrive auto 200 4r...., all electronic'd up with custom anti theft system, built in GDoor opener, HVAC controls, hurst shifter, 8 ball handle....TT wheel, lowered brake and gas pedals, firewall moveed forward about 3" down lo for more footroom, seat slammed for more headroom....like I said, nothing stock from wheels to roof, not nuttin'.....
12-25-2008, 02:46 AM
#5
Intermediate
Member Since: Jul 2008
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Charlie....very interesting!You're the man,and it's this stuff why I follow all your threads/posts.
When you are talking about the rear underbody pan...are you refering to something similar to the 295k 69 that was just on ebay,and the fellas were talking about?Arn't Nascar cars also,like this?
I was going top lower the car per the power book,but didn't go all out,and whack into the frame for the application that this car is being built for,but I am getting ready to tear my car down for some updates,and just saw the member that installed the batwing...removing the rear crossmember,and the mounting brace.He achieved getting the rearend up 3/4 of a inch I believe.The batwings are cheap,and it is nonthing more than alittle cutting,welding,and making some install brackets.I could do this w/the body on the car.Is it worth the trouble?
I am in the beginning stages of drawing ideas for a front lower dam w/air ducts to feed the front calipers.How low should this be for a street driven car w/496,VB&P front/rear mono setup,and 17s.What about the angle?
Merry Christmas,and thanks for your thoughts here.Someone like you that has ACTUALLY raced,and ran these cars......I am ALL ears...well...eyes.
When you are talking about the rear underbody pan...are you refering to something similar to the 295k 69 that was just on ebay,and the fellas were talking about?Arn't Nascar cars also,like this?
I was going top lower the car per the power book,but didn't go all out,and whack into the frame for the application that this car is being built for,but I am getting ready to tear my car down for some updates,and just saw the member that installed the batwing...removing the rear crossmember,and the mounting brace.He achieved getting the rearend up 3/4 of a inch I believe.The batwings are cheap,and it is nonthing more than alittle cutting,welding,and making some install brackets.I could do this w/the body on the car.Is it worth the trouble?
I am in the beginning stages of drawing ideas for a front lower dam w/air ducts to feed the front calipers.How low should this be for a street driven car w/496,VB&P front/rear mono setup,and 17s.What about the angle?
Merry Christmas,and thanks for your thoughts here.Someone like you that has ACTUALLY raced,and ran these cars......I am ALL ears...well...eyes.
Air dams are more effective the farther forward and lower they are mounted. However, height wise there is an optimum near the rule of thumb mentioned above. Lowering it below this point will actually increase drag.
The air dam should turn the gently turn the corner in the plan view and shield as much of the front tires as possible. See the C5 and C6 for inspiration. C5 is about 100 mm to the ground and C6 is about 90.
A little known fact is that all C3s had air dams and radiator seals. Installing the proper air dam and seals on your car will reduce drag and improve engine cooling.
In general the face angle should be vertical. A forward facing splitter at the bottom edge will allow you to run a higher air dam with the same benefit as a lower one.
Brake cooling ducts on C5 and C6 are 100 mm or 4 inches in diameter. The C6 base car duct is closed off to about 50 mm to reduce CD. Most of the bad things that happen to hot brakes happen to the calipers. Fluid boils, bridges aneal, pads wear quickly, etc. The rotor is the heat sink of the system. Its job is to remove the heat from the pads and reject it to the environment. One of the pads jobs it to insulate the heat and keep it out of the fluid. So make sure some air goes to the center of the rotor so it can pump cool air through the vanes. However, some air needs to go to the calipers too. The balance of how much air goes where is brake system design specific. Again, there is an optimum.
I would always run a spare tire carrier on C2, C3 and C4 models. In addition to Skunk Works comments, the angles are set up for a drag reducing diffuser and the spare actually provides a load path to the rear differential in the case of rear collisions.
I hope this helps, good luck and Merry Christmas!
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QIK59 (07-24-2021)
12-25-2008, 08:57 AM
#6
Race Director
With no disrespect to anyone else Greg you and Charlie have made this a very informative thread. This thread has lots of real world information that even a hobbist can benefit from. Greg your profile is very impressive (as well as many other members here
). Welcome to the site. I'm sure your expertise will be well received.
Merry Christmas to all.
). Welcome to the site. I'm sure your expertise will be well received.Merry Christmas to all.
12-25-2008, 01:40 PM
#7
Melting Slicks
Member Since: Sep 2007
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It really is nice to read this stuff, even if you know it or not. Good job guys. I think this is why we are all members of this forum, to learn and to teach when we can. Keep it up, this is the best forum on the entire net.
BBTank
BBTank
12-25-2008, 03:10 PM
#8
Safety Car
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Not sure if Bee Jay has completed the batwing conversion yet. After getting it hung the question of pinion angle came up, and he may have to make some minor adjustments to finish setting it up. Believe he's going to end up with having achieved ~1/2" in raising the diff. While I believe raising the diff height on low C3's is a good idea, I'm on the fence about changing over to the batwing. I don't know by how much rear chassis stiffness is effected, and it imposes limitations on your choices of diff pumpkins. Given these questions and that I'm committed to keeping my 12-bolt IRS it's not something I'll be doing, however, I don't see anything wrong with the conversion for anyone not overly concerned with these matters. My own preferences aside, FWIW, TT went with a batwing, but has done a significant amount of chassis bracing.
:
:
Bee Jay
12-25-2008, 04:44 PM
#9
Le Mans Master
Thread Starter
I recall reading an article several years back which discussed the importance of the spare's function as an "impact attenuator", to borrow a term from the IRL mandated piece. That the carrier's presence could have some aero benefits makes good sense when you consider it's positioning, but as to how significant it may or may not be I was not sure.
BTW, last time I checked (don't feel like wading back thru their site just now), Tracy Performance had a nifty looking panel kit which filled in the areas on each side of the spare carrier (believe it works w/stock exhaust), as well as functional front fender vents and other bits which may be of interest...
http://www.tracyvette.com/index.html
BTW, Bee Jay, I'm curious enough that I plan on fabbing up some plates such as you've installed behind your grill in order to test just how they effect pressures ahead of the rad and behind the air dam. I wouldn't try them w/o a dam, but they may not have a detrimental effect with one. I assume you've yet to have any cooling issues, right?
BTW, last time I checked (don't feel like wading back thru their site just now), Tracy Performance had a nifty looking panel kit which filled in the areas on each side of the spare carrier (believe it works w/stock exhaust), as well as functional front fender vents and other bits which may be of interest...
http://www.tracyvette.com/index.html
BTW, Bee Jay, I'm curious enough that I plan on fabbing up some plates such as you've installed behind your grill in order to test just how they effect pressures ahead of the rad and behind the air dam. I wouldn't try them w/o a dam, but they may not have a detrimental effect with one. I assume you've yet to have any cooling issues, right?
12-25-2008, 06:37 PM
#10
Melting Slicks
I took a different approach to Bee Jay's block off plates behind the grills and installed my brake cooling ducts there. I installed them earlier this summer and haven't seen any cooling issues with the front grills blocked off.
12-26-2008, 02:27 AM
#11
Racer
Hi Skunk,
Nice thread on air pressure and . There has been lots of comments about the C3 "nose rise" at high speed (~100 MPH). Most of these have been subjective reports about reduced directional control. I was wondering if the nose rise or weight shift has been quantified. If there was a way to quantify it, various features like chin spoilers, fender vents, lower ride height, etc. could be evaluated. I was looking at a recent issue of NASA Tech Briefs and noticed an item called a "string pot." Essentially this is a potentiometer (variable resistor) that changes resistance based upon pulling a spring-loaded string out of the body of the pot. I would think that it may be possible to attach a string pot to each end of the front shock and measure the average position at rest, 25MPH, 65MPH, etc.
Nice thread on air pressure and . There has been lots of comments about the C3 "nose rise" at high speed (~100 MPH). Most of these have been subjective reports about reduced directional control. I was wondering if the nose rise or weight shift has been quantified. If there was a way to quantify it, various features like chin spoilers, fender vents, lower ride height, etc. could be evaluated. I was looking at a recent issue of NASA Tech Briefs and noticed an item called a "string pot." Essentially this is a potentiometer (variable resistor) that changes resistance based upon pulling a spring-loaded string out of the body of the pot. I would think that it may be possible to attach a string pot to each end of the front shock and measure the average position at rest, 25MPH, 65MPH, etc.
12-26-2008, 12:17 PM
#12
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Hi Skunk,
Nice thread on air pressure and . There has been lots of comments about the C3 "nose rise" at high speed (~100 MPH). Most of these have been subjective reports about reduced directional control. I was wondering if the nose rise or weight shift has been quantified. If there was a way to quantify it, various features like chin spoilers, fender vents, lower ride height, etc. could be evaluated. I was looking at a recent issue of NASA Tech Briefs and noticed an item called a "string pot." Essentially this is a potentiometer (variable resistor) that changes resistance based upon pulling a spring-loaded string out of the body of the pot. I would think that it may be possible to attach a string pot to each end of the front shock and measure the average position at rest, 25MPH, 65MPH, etc.
Nice thread on air pressure and . There has been lots of comments about the C3 "nose rise" at high speed (~100 MPH). Most of these have been subjective reports about reduced directional control. I was wondering if the nose rise or weight shift has been quantified. If there was a way to quantify it, various features like chin spoilers, fender vents, lower ride height, etc. could be evaluated. I was looking at a recent issue of NASA Tech Briefs and noticed an item called a "string pot." Essentially this is a potentiometer (variable resistor) that changes resistance based upon pulling a spring-loaded string out of the body of the pot. I would think that it may be possible to attach a string pot to each end of the front shock and measure the average position at rest, 25MPH, 65MPH, etc.
12-26-2008, 02:19 PM
#13
Safety Car
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[QUOTE=
BTW, Bee Jay, I'm curious enough that I plan on fabbing up some plates such as you've installed behind your grill in order to test just how they effect pressures ahead of the rad and behind the air dam. I wouldn't try them w/o a dam, but they may not have a detrimental effect with one. I assume you've yet to have any cooling issues, right?
[/QUOTE]
Nope, no problem until I removed my Pace Car front spoiler for repainting. I like my temps around 180-195, but with the spoiler off, the temps ran 190-210. Normal for most people, but higher than I like. Auto trans cooler is what used to be my AC condenser, its (tranny fluid) temps went up too. I took the block off plates off temporarily until I reinstall the front spoiler.
Bee Jay
BTW, Bee Jay, I'm curious enough that I plan on fabbing up some plates such as you've installed behind your grill in order to test just how they effect pressures ahead of the rad and behind the air dam. I wouldn't try them w/o a dam, but they may not have a detrimental effect with one. I assume you've yet to have any cooling issues, right?
[/QUOTE]Nope, no problem until I removed my Pace Car front spoiler for repainting. I like my temps around 180-195, but with the spoiler off, the temps ran 190-210. Normal for most people, but higher than I like. Auto trans cooler is what used to be my AC condenser, its (tranny fluid) temps went up too. I took the block off plates off temporarily until I reinstall the front spoiler.
Bee Jay
12-26-2008, 02:23 PM
#14
Safety Car
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Hi Skunk,
Nice thread on air pressure and . There has been lots of comments about the C3 "nose rise" at high speed (~100 MPH). Most of these have been subjective reports about reduced directional control. I was wondering if the nose rise or weight shift has been quantified. If there was a way to quantify it, various features like chin spoilers, fender vents, lower ride height, etc. could be evaluated. I was looking at a recent issue of NASA Tech Briefs and noticed an item called a "string pot." Essentially this is a potentiometer (variable resistor) that changes resistance based upon pulling a spring-loaded string out of the body of the pot. I would think that it may be possible to attach a string pot to each end of the front shock and measure the average position at rest, 25MPH, 65MPH, etc.
Nice thread on air pressure and . There has been lots of comments about the C3 "nose rise" at high speed (~100 MPH). Most of these have been subjective reports about reduced directional control. I was wondering if the nose rise or weight shift has been quantified. If there was a way to quantify it, various features like chin spoilers, fender vents, lower ride height, etc. could be evaluated. I was looking at a recent issue of NASA Tech Briefs and noticed an item called a "string pot." Essentially this is a potentiometer (variable resistor) that changes resistance based upon pulling a spring-loaded string out of the body of the pot. I would think that it may be possible to attach a string pot to each end of the front shock and measure the average position at rest, 25MPH, 65MPH, etc.
Bee Jay
12-26-2008, 03:02 PM
#15
Team Owner
I wondering how to keep any wind/airflow from affecting any simple idea/home cobble up for a string pot I have a ten turn precision pot with a 1/4 inch shaft....which surely would have enough rotation to give up string enough and get resolution enough for monitoring the ride height off the upper control arm....but the problem is wind loading giving false readings..
when clocking even 90-120 the breeze will pull that pot string pretty good....stronger return spring???
when clocking even 90-120 the breeze will pull that pot string pretty good....stronger return spring???
12-26-2008, 06:16 PM
#16
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I had to jump in on this thread. The Aeronautical Engineering Department at the Air Force Academy is also called Skunkworks. Our shirts say "sharpening the cutting edge". Although, you are undoubtably referencing Lockheed Martin. Remember to clarify that it isn't pressure that moves air, it's the pressure differential, so sealing gaps as much as possible helps.
My car handles fine at 110 mph (the front end seems fine).
I considered putting holes in the 427 hood wells, but came to the conclusion that Eddy Currents would actually push air out. Anyone know?
I took out my headlight blinders behind my grills in order for my driving lights (part of Cibie CSRs) to show through. I should be getting some higher velocity air to go through my radiator, though I never have any cooling issues.
The 2400 hp / 2200 ft-lb torque vette at Carlisle had a complete blockout plate underneath it which would prevent induced drag from creating lift > 200 mph. It is a very cool concept.
I liked the idea of having black Ferrari holes in the back of the car. I actually have the holes and chrome for the tailpipes, but run sidepipes. Some black fiberglass would look sweet.
I look forward to this thread as it developes. Remember to minimize the amount of elbows in tubing and make the inside as frictionless (reduce the roughness factor) as possible to maximize flow (Q).
My car handles fine at 110 mph (the front end seems fine).
I considered putting holes in the 427 hood wells, but came to the conclusion that Eddy Currents would actually push air out. Anyone know?
I took out my headlight blinders behind my grills in order for my driving lights (part of Cibie CSRs) to show through. I should be getting some higher velocity air to go through my radiator, though I never have any cooling issues.
The 2400 hp / 2200 ft-lb torque vette at Carlisle had a complete blockout plate underneath it which would prevent induced drag from creating lift > 200 mph. It is a very cool concept.
I liked the idea of having black Ferrari holes in the back of the car. I actually have the holes and chrome for the tailpipes, but run sidepipes. Some black fiberglass would look sweet.
I look forward to this thread as it developes. Remember to minimize the amount of elbows in tubing and make the inside as frictionless (reduce the roughness factor) as possible to maximize flow (Q).
12-26-2008, 06:20 PM
#17
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I wondering how to keep any wind/airflow from affecting any simple idea/home cobble up for a string pot I have a ten turn precision pot with a 1/4 inch shaft....which surely would have enough rotation to give up string enough and get resolution enough for monitoring the ride height off the upper control arm....but the problem is wind loading giving false readings..
when clocking even 90-120 the breeze will pull that pot string pretty good....stronger return spring???
when clocking even 90-120 the breeze will pull that pot string pretty good....stronger return spring???
12-26-2008, 07:15 PM
#18
Le Mans Master
Thread Starter
Hi Skunk,
Nice thread on air pressure and . There has been lots of comments about the C3 "nose rise" at high speed (~100 MPH). Most of these have been subjective reports about reduced directional control. I was wondering if the nose rise or weight shift has been quantified. If there was a way to quantify it, various features like chin spoilers, fender vents, lower ride height, etc. could be evaluated. I was looking at a recent issue of NASA Tech Briefs and noticed an item called a "string pot." Essentially this is a potentiometer (variable resistor) that changes resistance based upon pulling a spring-loaded string out of the body of the pot. I would think that it may be possible to attach a string pot to each end of the front shock and measure the average position at rest, 25MPH, 65MPH, etc.
Nice thread on air pressure and . There has been lots of comments about the C3 "nose rise" at high speed (~100 MPH). Most of these have been subjective reports about reduced directional control. I was wondering if the nose rise or weight shift has been quantified. If there was a way to quantify it, various features like chin spoilers, fender vents, lower ride height, etc. could be evaluated. I was looking at a recent issue of NASA Tech Briefs and noticed an item called a "string pot." Essentially this is a potentiometer (variable resistor) that changes resistance based upon pulling a spring-loaded string out of the body of the pot. I would think that it may be possible to attach a string pot to each end of the front shock and measure the average position at rest, 25MPH, 65MPH, etc.
Nope, no problem until I removed my Pace Car front spoiler for repainting. I like my temps around 180-195, but with the spoiler off, the temps ran 190-210. Normal for most people, but higher than I like. Auto trans cooler is what used to be my AC condenser, its (tranny fluid) temps went up too. I took the block off plates off temporarily until I reinstall the front spoiler.
Bee Jay
Bee Jay
Last edited by TheSkunkWorks; 12-26-2008 at 07:19 PM.
12-26-2008, 07:22 PM
#19
Le Mans Master
Thread Starter
Suspect you've heard of these guys, too.
OK, back to our regular programming.
Last edited by TheSkunkWorks; 12-26-2008 at 07:46 PM.
