Author Topic: 2nd gen TA aerodynamics and modifications  (Read 51301 times)

NOT A TA

  • Oracle Forum Member
  • *
  • Posts: 3079
Re: 2nd gen TA aerodynamics and modifications
« Reply #160 on: September 01, 2016, 09:16:23 PM »
Well the video from the 2nd go round didn't work out as well as I'd hoped it would. The video camera was too far away to see the tufts well being in a different car and the driver of the other car was trying to keep too much distance between the cars. However the regular still shots from the side give me a good idea of whats going on and I can use those pics to compare with pics of my modified car once it's back on the road.

Interesting wind tunnel video here. Shows how fairly small changes can have a big impact on lift/downforce and front/rear bias. https://www.youtube.com/watch?v=Pgpawejpi6o
John Paige
Lab-14.com

NOT A TA

  • Oracle Forum Member
  • *
  • Posts: 3079
Re: 2nd gen TA aerodynamics and modifications
« Reply #161 on: July 24, 2017, 04:41:20 PM »
Now that the dust has settled a bit with the Photobucket mess it looks like the pics I posted in this thread are somewhat safe until 12/31/18 as long as I continue paying on the Plus 20 plan I was on before the cloud of doom wiped out a lot of the 3rd party hosted pics stored in Pbucket. I'm not going to pay 400.00 a year when my old deal with them expires at the end of '18. For now, I'm going to continue using Pbucket and if any of you want to save the info with pics in this thread I'd download it before the end of 2018. If I switch the pic hosting in this thread I'll mention it in a post.

So anyway, I've been working on the under tray for my car recently and figured I'd share a few pics. The car's been completely apart until recently but I've been installing the new PTFB suspension so it's now on wheels with engine/trans installed including the side pipe headers I needed installed to work around for heat extraction. I should be able to fabricate the under tray/rear diffuser sections with the car in it's current state of assembly. Will update my regular project thread on all the cool new suspension and non aero related stuff.

It's been quite a while since I updated so here's a quick review for those who were following along or are just popping into the thread. Keep in mind I don't have any sanctioning body rules and regulations I have to adhere to.

1. Front splitter is 2 piece so I can test different lengths just by making a new (cheap) plywood section. Will be replaced later with nicer lighter permanent one piece unit once testing gets me in the ballpark.

2. Front splitter is hinged at the rear attachment point and suspended by wires in front to the bumper so it can tilt up if I hit corner curbing on road race track. I realize it may "flutter" and require me to make the front supports solid to the bumper, need to test.

3. The entire splitter, under tray, and rear diffuser will be height adjustable and quickly/easily (well fairly)  removable.

4.  There will be five sections to the whole contraption allowing me to change the heights and angles (relative to the ground) of the sections. This will allow me to adjust the entire splitter/tray/diffuser distance from the asphalt independent of the rake of the car itself. This should give me a lot of "tuning" capability. It also allows me to change different sections with different styles and sizes of diffuser tunnels and other features I might want to test.

5. The entire splitter/tray/diffuser assembly will be suspended on poles hanging from the chassis and floor of the car. This is much different than any other set up I've ever seen. Most under tray installations are bolted/screwed directly to the car and mostly sealed pretty well to the bottom of the car. My set up will allow air to freely flow between the floor and the tray from engine compartment to rear and the sides will be open. Hopefully that will allow enough heat dissipation so I don't have to add more coolers for the transmission, rear end etc.  I'm calling it the "Lab-14 Under Tray Design".  If it works well others will copy and if it doesn't work, well, it'll get tossed aside.........

6. With the splitter/tray/diffuser hanging from poles it allows me to have it set as to how far it hangs down but at the same time it can easily be pushed up if it was to hit the ground hopefully reducing the possibility of damage should I have to run over something taller than the ground clearance the tray is set at.

The problem with muscle car era Pro-Touring type cars is that there's a whole bunch of very hot exhaust stuff under the cars. That makes it really difficult to make a smooth floor attached to the body transitioning into a diffuser that actually works to help increase down force (reduce lift). It also makes it difficult to have a dual purpose car used for Auto-X or road course activities without turning the passenger compartment onto an oven if you box in the exhaust between the floor and a proper under tray. The Lab-14 Under Tray Design will allow air to flow around the exhaust removing the heat (while the car is moving) and be completely removable so folks can take it off when they're just using the car on the streets where they'd be sitting in traffic etc.  Now, while the contraption I'm building will be a bespoke combination for my particular car if the concept proves itself to work it could be used on a lot of different types of cars that are used for certain things where there aren't regulations covering what can and can not be done with splitter/under tray/diffuser. Most sanctioning bodies have very specific rules for racing classes that what limit what can be done.

The concept here is that the amount of down force or reduction in lift is determined by the pressure difference between the upper and lower surfaces of the vehicle. The air pressure between the floor and under tray of my design should have a (relatively) similar pressure difference applying up and down so it doesn't change the amount of grip the car has just like having the windows of the car open or closed doesn't really change the amount of grip by any measurable amount. Meanwhile the very high speed air under the tray will have less air pressure pushing up on the tray (Think of it as a slight suction increasing the weight each tire receives).  The combined area of the splitter/tray diffuser I'm making is roughly 11,000 Sq. In. so a change in air pressure of .1 lb (sea level is about 14.7 Lb) would result in an increase in down force (reduction in lift) of over 1000 lbs.  That would result in a tremendous difference in cornering capability so even if I don't get anywhere near that the whole project might be worthwhile. If nothing else I'll learn something even if it's that my idea doesn't work.

On to some pics! This one shows the splitter and how it hinges on the tubing inside of the box tubing as well as the tubes inserted in the sub frame. The vertical  aluminum tubing will have holes drilled through it that a spring clip gets inserted through so I can set the splitter at different heights. I was trying to use up old scraps of stuff to make my test pieces so thats why there's panel sections in the tray part under the engine. If everything works I'll make nicer lighter pieces later on after testing.



Toward the rear of the engine compartment there is another set of vertical tubes welded to the sub frame for aluminum height tubes to slide into like the ones at the splitter along with another hinge set up where the panels join. This separates the engine section from the section under the cowl area.





There will be a set of height tubes in the cabin by the base of the A pillar and another set in the rear seat footwell. They will function similarly to the ones in the engine compartment except that instead of being welded in place they will be inserted through the floor of the car through a rubber grommet. The steel tubes have a washer welded to them preventing them from sliding down. I will make some caps that insert into the grommets for when I don't have the under tray installed. The aluminum tubes will function the same with a spring clip holding them up and still allow the tray to rise if necessary. I made a set for the rear supports in the trunk also.  These will allow quick changes to the height and pitch of the under tray from splitter to diffuser without having to go under the car.









« Last Edit: July 24, 2017, 04:56:03 PM by NOT A TA »
John Paige
Lab-14.com

1981RoadRace

  • Active Forum Member
  • *
  • Posts: 54
Re: 2nd gen TA aerodynamics and modifications
« Reply #162 on: July 26, 2017, 10:34:05 AM »
I guess it's time for an update, as a lot has changed on the car since I first posted my build. This is a truncated version of the post in my build thread, whittled down to just focus on aero and related mods.

Update 1: Brake Hubs and Wheels. I sold off my spindles and Kore3 conversion hubs and brackets to buy new spindles that allowed me to put C6 hubs on the TA. A friend has a sideline business parting out wrecked C6s, so I go the hubs cheap ($25 each, with 20k miles). This gained me a better, leak-free hub design, in addition to the lower operating costs. Since taking these pics, I fabricated dust shields with provisions for brake cooling ducts. I also made a tenmplate that can be printed out on 8.5x11 paper and traced onto the steel plate of your choice. Pics of both coming later. In the meantime, spindles:



Update 2: Aero: If you look back in this thread, I had a short splitter and was making the argument with a buddy for a longer one. I got lots of great input, and I won the argument, but one thing I didn't consider at the time was needing to stay within SCCA rules. CAM wasn't that big of a deal, as the rules are still pretty loose. However, if I wanted to run slicks, the car would probably end up in one of the hairy Street Prepared classes.

In a nutshell, I could have a splitter, but I needed to stay within the rough outline of the car, as viewed from the top. No long beaks sticking out the front :-) . I also could not extend the splitter beyond the halfway point of the front axle. Side and rear aero is still being planned. I'll certainly mooch off Not A TA's ideas above :-) and also copy the idea of extending the rear spoiler that was illustrated earlier in this thread.

For the front, in practical terms, this meant the splitter's rear edge was about 1" forward of the centerlink. Here is the result. One thing I am contemplating is relocation of the brake cooling inlets to the area above the splitter and then placing smoked lexan in front of the upper grill/headlight area. Opinions?


I've only blocked off maybe a foot of the open space above the splitter, at the very ends (the area directly in front of the tires). The rest of the area remains completely open -- I've never had the insert that goes below the bumper, so I get to make one out of scrap aluminum sheet from a local circle track fabricator.

Update 3: underhood air direction: I blocked off the open area between the top of the core support and the car's nose with a 1/4" smooth ceiling tile at Menards. Air coming in from the grill and bottom feed is now forced through the radiator, air intake or oil cooler. Water temps remain the same as before, but I've noticed that the car will not need the radiator fan to assist with cooling above 20 mph. Before I blocked this space off, that number was more like 35 mph.

When moving, the water temp never exceeds 185 degrees, even in hot weather or racing. The worst spikes come from driving in heavy stop-and-go traffic.

I'll try to get pics of all this posted tonight.
« Last Edit: July 26, 2017, 11:45:20 AM by 1981RoadRace »
Karl R. - Editor, Silver Blade Magazine
2008 Grand Prix GXP | 1981 Trans Am WS6 - LS3, T56 + other bits of gearhead joy.


NOT A TA

  • Oracle Forum Member
  • *
  • Posts: 3079
Re: 2nd gen TA aerodynamics and modifications
« Reply #163 on: August 13, 2017, 09:21:08 PM »
Karl, You can get the air for the brake ducts anywhere from the core support forward. They don't need to be facing directly forward into oncoming air. If you take it from down near the splitter you're taking away some of the pressure you want on top of the splitter. If you take it from up high near the hood (but behind the grills) you'll be taking air reducing lift on the underside of the hood/upper bumper cover. Seems like the first choice to make would be whether to make it a bottom breather or front. Drag guys have found higher top speeds with the upper grill/headlight blocked with plexiglass.

Your top of radiator block off is working well as you noted. Do you have any pics of the closeout?

The splitter should work much better than the other one. You may notice the back end feels loose compared to the front until you put a taller rear spoiler into effect because the splitter and tray in front will move the center of pressure forward until it gets balanced by something in the rear. Initial turn in will be better but then as the pendulum effect starts mid corner the rear might feel loose. I'd put a rear spoiler extension right to the limit of the rules for auto-X. And make it tall all the way out on the sides, more like Camaro spoiler ends, kinda squared off. Might be too much drag for road track use though.

John Paige
Lab-14.com

NOT A TA

  • Oracle Forum Member
  • *
  • Posts: 3079
Re: 2nd gen TA aerodynamics and modifications
« Reply #164 on: August 13, 2017, 09:31:49 PM »
Here's a couple more pics of my contraption laid out in the driveway so you can get a better idea of what I'm doing. Still need 4 more support rods and a couple sticks of box tubing as well as some aluminum sheet, but it's coming along! The big white sheets are a couple different thicknesses of corrugated plastic. With side pipes I don't have heat/melting issues from about the front seats back in the middle of the car. The curved up section at the rear is measured to be pretty close to what the actual diffuser will be when finished.



John Paige
Lab-14.com

Re: 2nd gen TA aerodynamics and modifications
« Reply #164 on: August 13, 2017, 09:31:49 PM »

70RAIV455

  • Oracle Forum Member
  • *
  • Posts: 4375
Re: 2nd gen TA aerodynamics and modifications
« Reply #165 on: August 14, 2017, 05:13:41 AM »
Kinda Neat John but I find it also Insane.

Top Speeds Gains are easily solved with a Cubic inch Bump.
And Turbo Charging or Supercharging.
No need to go beyond 462 cubic inches today.
480 ci Drag Racing Twin Turbo Charged.

That setup comes free Your areo mods it may destroy you car.
Just my 2 cents.

70RAIV455

  • Oracle Forum Member
  • *
  • Posts: 4375
Re: 2nd gen TA aerodynamics and modifications
« Reply #166 on: August 14, 2017, 05:15:13 AM »
Bonneville Salt Flat cars use on Giant Belly Pan.
Worked for Mickey Thompson going 406 mph.

NOT A TA

  • Oracle Forum Member
  • *
  • Posts: 3079
Re: 2nd gen TA aerodynamics and modifications
« Reply #167 on: August 14, 2017, 08:18:38 PM »
Kinda Neat John but I find it also Insane.

I'm sure you're not the only one. I've done a lot of things where I was ahead of the times. This may be another case, OR, you may be right.

Top Speeds Gains are easily solved with a Cubic inch Bump.
And Turbo Charging or Supercharging.
No need to go beyond 462 cubic inches today.
480 ci Drag Racing Twin Turbo Charged.

All of those things ^^^ require considerable amounts of cash and make the car less reliable. I try to get the most performance with the minimum of things that can go wrong.

That setup comes free Your areo mods it may destroy you car.
Just my 2 cents.

Like we tell everyone else "It's your car do whatever you want with it." The aero mods may also take it to cornering levels where no 2nd gen has been.

John Paige
Lab-14.com

NOT A TA

  • Oracle Forum Member
  • *
  • Posts: 3079
Re: 2nd gen TA aerodynamics and modifications
« Reply #168 on: August 14, 2017, 08:37:02 PM »
Bonneville Salt Flat cars use on Giant Belly Pan.
Worked for Mickey Thompson going 406 mph.

Although I took my car to Land Speed Races in the past and will likely do so in the future the splitter/under tray/diffuser in the pics above is for road course type use for cornering. I'll have a different aero set up for Land Speed Race use with less down force and less drag.

 
John Paige
Lab-14.com

70RAIV455

  • Oracle Forum Member
  • *
  • Posts: 4375
Re: 2nd gen TA aerodynamics and modifications
« Reply #169 on: August 14, 2017, 10:09:40 PM »
Bonneville Salt Flat cars use on Giant Belly Pan.
Worked for Mickey Thompson going 406 mph.

Although I took my car to Land Speed Races in the past and will likely do so in the future the splitter/under tray/diffuser in the pics above is for road course type use for cornering. I'll have a different aero set up for Land Speed Race use with less down force and less drag.
If You Can TIG Weld it together the Main Aero Under body frame it would be the strongest.
Or find someone close by that can do it.
If you were in Illinois my Bud Ed could do it for You.
He is self employed and doing Drag racing chassis work now.
Custom builds Fuel cells from Stainless and aluminum.
Roll Bars.
Back Halving cars.

6 - 8 drop down supports needed looking and thinking.
Doing the Chaperal Thing I know.

70RAIV455

  • Oracle Forum Member
  • *
  • Posts: 4375
Re: 2nd gen TA aerodynamics and modifications
« Reply #170 on: August 14, 2017, 10:12:47 PM »
Kinda Neat John but I find it also Insane.

I'm sure you're not the only one. I've done a lot of things where I was ahead of the times. This may be another case, OR, you may be right.

Top Speeds Gains are easily solved with a Cubic inch Bump.
And Turbo Charging or Supercharging.
No need to go beyond 462 cubic inches today.
480 ci Drag Racing Twin Turbo Charged.

All of those things ^^^ require considerable amounts of cash and make the car less reliable. I try to get the most performance with the minimum of things that can go wrong.

That setup comes free Your areo mods it may destroy you car.
Just my 2 cents.

Like we tell everyone else "It's your car do whatever you want with it." The aero mods may also take it to cornering levels where no 2nd gen has been.
455 Shortblock. Reuse Your 16 Heads, ISKY Race Cammed flat tappet solid.
Spank LSX & New C7 Vettes.

70RAIV455

  • Oracle Forum Member
  • *
  • Posts: 4375
Re: 2nd gen TA aerodynamics and modifications
« Reply #171 on: August 14, 2017, 10:15:39 PM »
4130 Roll bar tubing lighten things up too some.

Dreamn2

  • Oracle Forum Member
  • *
  • Posts: 2723
Re: 2nd gen TA aerodynamics and modifications
« Reply #172 on: August 15, 2017, 02:42:02 PM »
Since taking these pics, I fabricated dust shields with provisions for brake cooling ducts. I also made a tenmplate that can be printed out on 8.5x11 paper and traced onto the steel plate of your choice. Pics of both coming later. In the meantime, spindles:




Can you still post the dust shield templates?
79 Fire Am
76 Fire Am
78 Fire Am

skisix38off

  • Active Forum Member
  • *
  • Posts: 656
Re: 2nd gen TA aerodynamics and modifications
« Reply #173 on: August 16, 2017, 06:51:28 AM »
In the meantime, spindles:



What spindles are those?  Do they help any with caster?

Box

  • Oracle Forum Member
  • *
  • Posts: 5878
  • (>*.*)>#<(*.*<)
Re: 2nd gen TA aerodynamics and modifications
« Reply #174 on: August 16, 2017, 10:33:13 AM »
Any new super cars have smooth bottoms through panels that bolt to the underside.  Here's the underside of a McLaren P1 for instance:


I think it's a good idea to experiment upon, obviously it's proven to work when done right.

1996 Pontiac Firebird Formula hardtop 6-speed

Re: 2nd gen TA aerodynamics and modifications
« Reply #174 on: August 16, 2017, 10:33:13 AM »



70RAIV455

  • Oracle Forum Member
  • *
  • Posts: 4375
Re: 2nd gen TA aerodynamics and modifications
« Reply #175 on: August 16, 2017, 06:34:45 PM »
The C7 Z06 does 198-202 MPH Top end with 650 HP.
The C8 is supposed to have 750 HP. Wont see it till maybe next year.
The Fat Pig Hellcats also run 198-202 Mph Top End with 707/ actually 780 Flywheel HP.

Going to take HP no matter what.

Box

  • Oracle Forum Member
  • *
  • Posts: 5878
  • (>*.*)>#<(*.*<)
Re: 2nd gen TA aerodynamics and modifications
« Reply #176 on: August 16, 2017, 07:26:44 PM »
Well yes eventually you hit a top speed wall either via power, aerodynamics, or gearing, but the more aerodynamic the less power needed.  The fourth gens with the 6-speed were capable of 160-170 mph new with only 300 horsepower since they're so aerodynamic.  The McLaren F1 back in the early 90's had a top speed of over 240 mph but only had 627 horsepower, so aerodynamics are a huge factor.  I think he's on to something, there's a lot of room for improvement on most any mass produced car and especially on one that's older.  People successfully do aero mods on all kinds of cars all of the time either seeking increased fuel efficiency or better performance on the track, so it's worth investigating.

1996 Pontiac Firebird Formula hardtop 6-speed

70RAIV455

  • Oracle Forum Member
  • *
  • Posts: 4375
Re: 2nd gen TA aerodynamics and modifications
« Reply #177 on: August 16, 2017, 07:49:58 PM »
Well yes eventually you hit a top speed wall either via power, aerodynamics, or gearing, but the more aerodynamic the less power needed.  The fourth gens with the 6-speed were capable of 160-170 mph new with only 300 horsepower since they're so aerodynamic.  The McLaren F1 back in the early 90's had a top speed of over 240 mph but only had 627 horsepower, so aerodynamics are a huge factor.  I think he's on to something, there's a lot of room for improvement on most any mass produced car and especially on one that's older.  People successfully do aero mods on all kinds of cars all of the time either seeking increased fuel efficiency or better performance on the track, so it's worth investigating.
John Birdman will follow through. I know him from another forum.
Drag cars rely upom Aerodynamics too.
Likely what happened when that 5.0 Stang cut into Big Chief and His Crow GTO a few years back.
Its risky business testing Areodynamics.
A wind tumnel blowing 150-200 mph wind speeds be nice to use.

roadking77

  • Oracle Forum Member
  • *
  • Posts: 8019
Re: 2nd gen TA aerodynamics and modifications
« Reply #178 on: August 17, 2017, 08:50:19 AM »
John, I too think you crazy!(in a good way) But love what youre doing with that car. My brother races motorcycles, and his mentor/racing buddy is always doing something to get that extra bit of power of his bike. My brother told him to skip a couple of beers instead! They guy is german, over 6 ft, and must weigh well over 250lbs.
Finished!
77 T/A - I will Call this one DONE!
79 TATA 4sp-Next Project?
79 TATA - Lost to Fire!
86 Grand Prix - Sold
85 T/A - Sold
85 Fiero - Sold
82 Firebird - Sold
'38-CZ 250
'39-BSA Gold Star
'49-Triumph 350
'52-Ariel Red Hunter
'66-BSA Lightning
'01-HD RoadKing

NOT A TA

  • Oracle Forum Member
  • *
  • Posts: 3079
Re: 2nd gen TA aerodynamics and modifications
« Reply #179 on: August 18, 2017, 12:44:24 PM »
As I mentioned back on page 1 of this thread, I'd like this thread to remain focused on aerodynamics of 2nd gen TA's for any kind of use.  Whether it's drag racing, road racing, Auto-X, Land Speed, hypermiling aero aids,  or just ways to make the car quieter in the cabin for daily drivers and Sunday cars. Why GM installed Astro Flow Through Ventilation and other topics like mirrors, drip rails, side window blow out clips, external antenna and other items can all be discussed as long as we remain focused on 2nd gen aero.  If anyone wants to discuss how much power it takes to achieve certain speeds or ET's, mechanical grip with modern suspensions, aero stuff about 1st, 3rd, 4th gens etc. please start another thread to cover your topic. I will happily participate having personal experience with all gens.

If anyone's tested various aerodynamic things to change the performance of 2nd gens whether it worked as hoped or not please share it in this thread. We can all learn from what others have tried.

My contraption might seem a bit crazy to many. However although I put an engineering disclaimer in my first post I've been involved with aero/fluid dynamics for a long time. The basic concepts used for the Lab-14 Under Tray Design are proven. Where the Lab-14 design differs is the mounting method of it being suspended on rods, being (relatively) quick release,  and the sides above the tray being open rather than sealed to the bottom of the vehicle. I have a series of articles I've been writing with more details about this splitter/under tray/rear diffuser that include short stories about some of the more memorable aero experiences I've had if anyone is interested.  Part of the reason I started posting the articles on linkedin is because the pics I've posted in this thread will probably disappear when my Photobucket 3rd party hosting agreement ends and the linkedin article will remain intact. https://www.linkedin.com/pulse/height-adjustable-rake-fully-suspended-multi-section-quick-john-paige
John Paige
Lab-14.com

NOT A TA

  • Oracle Forum Member
  • *
  • Posts: 3079
Re: 2nd gen TA aerodynamics and modifications
« Reply #180 on: September 20, 2017, 08:30:25 PM »
I've been working on the under tray and have the part from the A pillars to the rear foot wells ready for test fitting and some final tweaking in the area where the side pipe headers are. Currently working on cardboard mock up of the rear diffuser section.







 
John Paige
Lab-14.com

NOT A TA

  • Oracle Forum Member
  • *
  • Posts: 3079
Re: 2nd gen TA aerodynamics and modifications
« Reply #181 on: September 25, 2017, 05:36:07 PM »




John Paige
Lab-14.com

FormTA

  • Oracle Forum Member
  • *
  • Posts: 2442
Re: 2nd gen TA aerodynamics and modifications
« Reply #182 on: September 25, 2017, 09:21:06 PM »
What is that surf board going to weigh? It's neat all of this aerodynamic testing. Some major forward thinking. Just curious as to the weight addition. To me blocking off the sail that is the under car should prove beneficial.
79 Trans am 301 (work in progress) LS swap n progress
79 Formula 301 (Work in progress)
67 RS Camaro (Work in progress)
See the recurring theme???

70RAIV455

  • Oracle Forum Member
  • *
  • Posts: 4375
Re: 2nd gen TA aerodynamics and modifications
« Reply #183 on: September 26, 2017, 05:16:36 AM »






It looks pretty neat John from the back view.
Like Rocket Boosters.

What would be really fun is spraying gasoline out them with a Snow Performance Methanol injection pump or windshield washer pump.
Ignite with a spark plug & Model T ignition coil.

Thinking of the F-Bomb Camaro.
It was very radical too.

Have to paint some custom graphic on the sides.
Use John C, In NY.

1981RoadRace

  • Active Forum Member
  • *
  • Posts: 54
Re: 2nd gen TA aerodynamics and modifications
« Reply #184 on: January 10, 2018, 01:45:09 PM »
Egads, it's been forever since I took some time to research things at TAC, and it looks like I've got some catching up to do. I will post the backing plate template and a pic of the upper core support block off tonight when I get home (sorry it took so look to see this). My Spindles are from CPP, model CP30014.

I *may* also get a set of 3rd gen side aero bits in a trade later this month. I'm thinking about seeing how well I can get them to work on a 2nd gen without looking stupid. Thoughts on this idea?
Karl R. - Editor, Silver Blade Magazine
2008 Grand Prix GXP | 1981 Trans Am WS6 - LS3, T56 + other bits of gearhead joy.


1981RoadRace

  • Active Forum Member
  • *
  • Posts: 54
Re: 2nd gen TA aerodynamics and modifications
« Reply #185 on: January 11, 2018, 12:07:03 AM »
Block off:

Karl R. - Editor, Silver Blade Magazine
2008 Grand Prix GXP | 1981 Trans Am WS6 - LS3, T56 + other bits of gearhead joy.


Jack

  • Oracle Forum Member
  • *
  • Posts: 9818
  • 1971 Esprit TA Clone W72 1972 Formula 68 350 HO
Re: 2nd gen TA aerodynamics and modifications
« Reply #186 on: January 11, 2018, 07:49:41 AM »
My contraption might seem a bit crazy to many. However although I put an engineering disclaimer in my first post I've been involved with aero/fluid dynamics for a long time. The basic concepts used for the Lab-14 Under Tray Design are proven. Where the Lab-14 design differs is the mounting method of it being suspended on rods, being (relatively) quick release,  and the sides above the tray being open rather than sealed to the bottom of the vehicle. I have a series of articles I've been writing with more details about this splitter/under tray/rear diffuser that include short stories about some of the more memorable aero experiences I've had if anyone is interested.  Part of the reason I started posting the articles on linkedin is because the pics I've posted in this thread will probably disappear when my Photobucket 3rd party hosting agreement ends and the linkedin article will remain intact. https://www.linkedin.com/pulse/height-adjustable-rake-fully-suspended-multi-section-quick-john-paige

Great article John, following you on LinkedIn as well.




Regards, Jack

1981RoadRace

  • Active Forum Member
  • *
  • Posts: 54
Re: 2nd gen TA aerodynamics and modifications
« Reply #187 on: January 11, 2018, 05:34:59 PM »
I've been working on the under tray and have the part from the A pillars to the rear foot wells ready for test fitting and some final tweaking in the area where the side pipe headers are. Currently working on cardboard mock up of the rear diffuser section.


That looks like a pretty serious diffuser.  How far does it extend past the rear bumper? Do you expect any impact on fuel tank location? Or watts link?
Karl R. - Editor, Silver Blade Magazine
2008 Grand Prix GXP | 1981 Trans Am WS6 - LS3, T56 + other bits of gearhead joy.


NOT A TA

  • Oracle Forum Member
  • *
  • Posts: 3079
Re: 2nd gen TA aerodynamics and modifications
« Reply #188 on: January 11, 2018, 08:34:32 PM »
The cardboard diffuser in the pics is actually oversize on purpose so I can cut it down to fit rather than try to make one from measurements with the car on the ground. If it was as big as it is in the pics I'd probably (almost certainly) experience a loss due to stall. With 3" ground clearance to pavement at the entrance to the diffuser the area ratio is way to high (at 7.3) for a diffuser that wasn't designed using CFD and/or wind tunnel testing. I'll make sure I'm below a ratio of 5 when I can get the car on the ground at ride height and get some final measurements for diffuser construction. The curvature is within tolerances so the flow will stay attached.

The diffuser should clear the gas tank and I re-positioned the sway bar mounting to the axle tubes instead of the bottom of the shock plates the way the stock bars mount to provide additional clearance for the diffuser tunnels and reduce drag when I don't have the under tray assembly on the car. Will post pics of the sway bar mount modification when I get the pics uploaded, I'm waaay behind.

I contemplated a block off panel similar to yours instead of the rubber seal I installed and if air pressure blows my seal out (which is quite possible) I'll make a panel like yours. Have you blocked off the other areas where air can get past the core support?

I believe the air coming in under the sides of the car at the rockers is detrimental and probably reduces the speed of air under the car increasing lift/reducing down force.   You can see in the tuft test pic below how the air flow below the body line angles down getting pulled in under the car while above the body line the tufts point straight back. The rocker extensions from the 3rd gen would probably reduce that if you can fit them and they're legal for whatever class you run in. During the ground effects era of the late 80's early 90's F1 cars had sliding skirts that literally slid along on the pavement that were eventually banned. I will be installing skirts on the sides of my under tray to help keep air from entering but will maintain a gap to pavement for safety reasons.

Jack, thanks for following on Linkedin.  Reminds me I need to write articles there about some municipal water and wastewater projects I've been doing designs and fabrication of for regular work. Car stuff and aerodynamics is more "fun" to me but today I was designing a Vortex Butchering Basket for vertical turbine pumps used by municipalities so that's kinda cool (well to me anyway) and helps pay the bills.

John Paige
Lab-14.com

Box

  • Oracle Forum Member
  • *
  • Posts: 5878
  • (>*.*)>#<(*.*<)
Re: 2nd gen TA aerodynamics and modifications
« Reply #189 on: January 11, 2018, 08:47:46 PM »
People make skirts and body aero out of the plastic garden edging stuff you get from Home Depot or Lowe's, since it's dirt cheap and easy to work with.  That and it's impact resistant while still maintaining its shape, and if you do break it or drag it off it's cheap and easy to replace it.  Comes in a variety of widths to suit what's needed in a given application.  At the very least would be good to experiment with before developing parts in metal or fiberglass.

1996 Pontiac Firebird Formula hardtop 6-speed

NOT A TA

  • Oracle Forum Member
  • *
  • Posts: 3079
Re: 2nd gen TA aerodynamics and modifications
« Reply #190 on: January 11, 2018, 09:51:20 PM »
What is that surf board going to weigh? It's neat all of this aerodynamic testing. Some major forward thinking. Just curious as to the weight addition. To me blocking off the sail that is the under car should prove beneficial.

Sorry I missed this question back in Sept.  The whole contraption that will be used for testing is just over 100 lbs. If it works well I'll make a lighter version and think I could get down to 50-60 lbs without using carbon fiber. If my disposable income level rises and I could go with some carbon sheets etc. I think I could get down under 50 lbs. Most higher end race cars now have one big flat carbon fiber sheet now. You can see it in these pics of a Mercedes AMG World Challenge car I got to poke around.

Sticking out the sides below door in pic below to reduce air getting under the car and perhaps also create a virtual seal with a vortice. The aerodynamicists that worked on it would know.



You can see the flat carbon fiber sheet in pic below under the air jack.

John Paige
Lab-14.com

NOT A TA

  • Oracle Forum Member
  • *
  • Posts: 3079
Re: 2nd gen TA aerodynamics and modifications
« Reply #191 on: January 11, 2018, 09:55:11 PM »
People make skirts and body aero out of the plastic garden edging stuff you get from Home Depot or Lowe's, since it's dirt cheap and easy to work with.  That and it's impact resistant while still maintaining its shape, and if you do break it or drag it off it's cheap and easy to replace it.  Comes in a variety of widths to suit what's needed in a given application.  At the very least would be good to experiment with before developing parts in metal or fiberglass.

Yes sir, hypermiler's use it as well as race car guys. Another cheap material for skirts is conveyor belt material.
John Paige
Lab-14.com

70RAIV455

  • Oracle Forum Member
  • *
  • Posts: 4375
Re: 2nd gen TA aerodynamics and modifications
« Reply #192 on: January 11, 2018, 10:26:11 PM »
The exhaust headers create Immense amounts of heat Road racing and drag racing John.
Have to get that heat out or the engine oil temps will really skyrocket.
Without an engine oil cooler the engine will not last then.  Hit 300F or more oil temps is not good.
Only True Straight 50-70 weight Racing oil will take that kind of heat.  Used In Nirto Drag Racing usually.
Dirt track racing 900-1000 HP level also.

« Last Edit: January 11, 2018, 10:32:36 PM by 70RAIV455 »

70RAIV455

  • Oracle Forum Member
  • *
  • Posts: 4375
Re: 2nd gen TA aerodynamics and modifications
« Reply #193 on: January 11, 2018, 10:29:10 PM »
I do like the Surf Board.
Looks like nothing else.

I would not put it on 1970 TA though. Like it as is .

70RAIV455

  • Oracle Forum Member
  • *
  • Posts: 4375
Re: 2nd gen TA aerodynamics and modifications
« Reply #194 on: January 11, 2018, 10:34:59 PM »
If things get tough John you can use Aviation Piston engine oils in a Pontiac V8.
I have tried it out.
Aero Shell.

Works great in Air Cooled Harley Davidson engines.
Superior to most Auto oils.

A entire another topic.


1981RoadRace

  • Active Forum Member
  • *
  • Posts: 54
Re: 2nd gen TA aerodynamics and modifications
« Reply #195 on: January 12, 2018, 12:07:58 AM »
I contemplated a block off panel similar to yours instead of the rubber seal I installed and if air pressure blows my seal out (which is quite possible) I'll make a panel like yours. Have you blocked off the other areas where air can get past the core support?

Not quite yet. When It gets warmish enough, I'll venture out into the garage to correct the gaps depicted in the below under-hood shots :-)

The bottom shot attempts to show what I have going on in front. Most of the air entering the left marker light hole is forced through the oil cooler and out through the gap between the core support and driver side fender. Both grill sections by the headlights are blocked, so the only air entering the engine bay from the front comes through the bottom feed and marker light holes.





« Last Edit: January 12, 2018, 12:11:08 AM by 1981RoadRace »
Karl R. - Editor, Silver Blade Magazine
2008 Grand Prix GXP | 1981 Trans Am WS6 - LS3, T56 + other bits of gearhead joy.


Dreamn2

  • Oracle Forum Member
  • *
  • Posts: 2723
Re: 2nd gen TA aerodynamics and modifications
« Reply #196 on: January 17, 2018, 09:28:31 AM »
Have you guys done anything for rear brake cooling ducts?
79 Fire Am
76 Fire Am
78 Fire Am

79T/Aman

  • Oracle Forum Member
  • *
  • Posts: 2506
      • http://www.pro-touringf-body.com
Re: 2nd gen TA aerodynamics and modifications
« Reply #197 on: January 17, 2018, 11:38:22 AM »
Have you guys done anything for rear brake cooling ducts?

Not sure the rear brakes need anything much unless it is a roar race car that is going to do more laps than your average track day but I'm sure John will be all over it :-)
www.pro-touringf-body.com  your source for making your Trans am do what it does best!......SHOW OFF!

1981RoadRace

  • Active Forum Member
  • *
  • Posts: 54
Re: 2nd gen TA aerodynamics and modifications
« Reply #198 on: January 17, 2018, 05:33:35 PM »
I share my car with a friend who happens to be a track day instructor. Its one od those arrangements where you get free track time in exchange for instructing. We had an event last fall at Gingerman where the student's car developed mechanical problems the day before. Rather than letting the guy get screwed out of his entry fees, we made the Trans Am do double-duty. So, instead of the usual 20 minutes on and 40 to 60 minutes off, it was 20 on, switch drivers, 20 minutes on again, 20 off.

The rear brakes had no issues during this day, and in fact remained on the car as I drove it home 3 hours afterward. Front brakes needed the pads switched out, and besides a LOT of heat, were ok.

So, I'd say rear cooling ducts probably aren't needed unless you're going to do an endurance race.
Karl R. - Editor, Silver Blade Magazine
2008 Grand Prix GXP | 1981 Trans Am WS6 - LS3, T56 + other bits of gearhead joy.


70RAIV455

  • Oracle Forum Member
  • *
  • Posts: 4375
Re: 2nd gen TA aerodynamics and modifications
« Reply #199 on: January 17, 2018, 06:43:13 PM »
I have not been around road racing much at all but I have been around lots of Dirt track racing here in Illinois.
Tracks here are 1/4 mile High banked Clay Oval, 1/2 mile Flat tracks.
1 mile long, Springfield mile.
Springfield mile allows for 140 + mph speeds on dirt.
Cars have no windshields because rocks thrown up from the track will knock break them out.

More than once I have seen the rear brakes glowing red to white hot incandescent after 50-250 lap races.
Front brakes too.
Drivers are on the brakes hard to slow down into the corners.
You can see it happen sitting in the Grand stands.

Everything from Hornet 4-bangers to Street Stock V8, to Unlimited super late model packing 750-900 HP Normal aspirated SBC V8 engines.

Forced air cooling can not hurt anything.
Front or rear.





Re: 2nd gen TA aerodynamics and modifications
« Reply #199 on: January 17, 2018, 06:43:13 PM »
You can help support TAC!