Anyone have Aero questions?

Hello! My name is Marcus and I do customer servicer/web-admin/spell-checker/beer-drinker at Nine Lives Racing (9livesracing.com).  Nine Lives Racing is an aerodynamic company that sells race car wings and aero consultations (aka we scan your car and try to find the nicest way to explain your mess). As a courtesy, we at 9LR are offering to answer basic questions that obtain to aerodynamics. 

So just a background of who we are. You're welcome to use this information to validate our answers. 

Johnny C - He started in motorsports in 2006  and graduated to professional motorsports in 2012 working with PFC brakes. Since 2012 Johnny has stayed in professional motorsports working for OG racing. Then in 2018 he started Nine Lives Racing where we still continue consultations for all teams, but professional ones included. 

Race Resue

Directly consulted or was apart of a team that has won

- 2 24hour of Daytona overall wins, (01 Chip Ganassi cars) 

- 2012 NASCAR championship (Joe Gibbs racing) 

- Almost won Le Mans (DeltaWing)

- Overall lap record at Daytona road course (Mazda DPI #77)  

- He's 0.2 seconds away from obtaining the Miata lap record at Road Atlanta in my own car. 

Partners in crime that work at or with Nine lives racing include. 

Rob Lindsey - Famed car builder that directly or indirectly had a hand in some form of the design with....

Riley Mark XXII

Elan Dpo2 

Elan Np01 

Delta wing

Panoz PWC cars. 

Marcus Luttrell - No not the Navy Seal.  Marcus is in the IT field by trade, but a solid passion for motorsports and miatas. Majority of his youth was spent to the dragon(Deal's Gap). SCCA auto-x when the schedule allows. Campaigned a NB1 in TTE over the past few years with NASA and recently converting ST5/TT5.

TTE trim



TT5 trim



Marcus has been around Miatas over have his life. Involved in multiple ways he can, including helping with Miatas at the Gap for many years - http://gapmiatas.com/ 
And most recently helping with Miatas Before the Gap w/ Jzilla Trackdays - https://www.facebook.com/miatasbeforethegap

That's us in a nutshell with basic pictures. Hit us with your aero questions. 

Not so much a question, but say one was to have a 79 Thunderbird and say it has a windshield but no other glass (or plastic, just big gaping holes), how pointless would a wing be for autocross? I'd imagine all that turbulence would render the car pretty useless from an aero perspective..

If you were building a Miata Track Day and Time Trial car with a speed range at your local track of 40 to 100mph. What wing profile would you choose to use? Also we are thinking of a 4" stick out splitter to go with the wing. 

Thanks

i'm just going to lurk here, but i wanted to say a preemptive Thank You for what i suspect will be a highly informative sub-forum.

barefootskater said:

Not so much a question, but say one was to have a 79 Thunderbird and say it has a windshield but no other glass (or plastic, just big gaping holes), how pointless would a wing be for autocross? I'd imagine all that turbulence would render the car pretty useless from an aero perspective..

I wouldn't say it would be pointless, just maybe not optimal? Getting it taller and into clean air would be the problem..... and legally. What class are you running?

optiguy said:

If you were building a Miata Track Day and Time Trial car with a speed range at your local track of 40 to 100mph. What wing profile would you choose to use? Also we are thinking of a 4" stick out splitter to go with the wing. 

Thanks

That's exactly what my car does! I run the 64" swan-neck, currently at 0* AOA. We're front down-force limited, like most cars I suppose.

My rough estimates on my aero currently. Keeping in mind it's never an exact number since I don't have my exact setup tested. But we do at least have some data to reference.

https://9livesracing.com/cfd-testing
Rear wing @ 0* AOA 
@ 60mph

• 42lbs of DF
• 3lbs of drag

@ 100mph

• 126lbs of DF
• 9lbs of drag

https://hanchagroup.wordpress.com/2013/01/29/splitter-or-air-dam-which-design-is-best/
OEM aero (NA not NB, NB is better hope to have CFD on it in the near future)
@ 100mph

• -106lbs of DF, yes negative.
• 141lbs of drag

Front airdam and ~4" splitter
@ 100mph

• 193lbs of DF
• 117lbs of drag

Rear DF ~117lbs
Front DF ~76lbs


I think when I get my air-dam mouth ducting optimized that should help reduce drag quite a bit. Then I might be able to run a few more * of AOA at some tracks, like Barber. The neat thing about the Elan foil, you can set a level on the front of it and on the very end of the wicker. No specialized tool needed to actually measure the AOA.


If you don't go with a splitter, but air-dam only I believe optimizing the under-tray would be your best bet. I've recently learned the trailing edge is very very important.

Marcus_NineLivesRacing said:

barefootskater said:

Not so much a question, but say one was to have a 79 Thunderbird and say it has a windshield but no other glass (or plastic, just big gaping holes), how pointless would a wing be for autocross? I'd imagine all that turbulence would render the car pretty useless from an aero perspective..

I wouldn't say it would be pointless, just maybe not optimal? Getting it taller and into clean air would be the problem..... and legally. What class are you running?

Umm... Challenge class? I thought a wing could be fun. In all honesty though we removed the bumpers for weight and I am very seriously thinking about splitters and diffusers so I’ll be keeping an eye on this forum for everything I can learn about those. 

In reply to Marcus_NineLivesRacing :

Thanks for the reply. I have seen the Hanchagroup data before. I am running an air dam on one of our Miatas. The front opening is about 35% of the radiator area. My local track is Thompson Speedway in CT. Which is an interesting track with a variety of corner radii. And one long straight. I know this is a  question you most likely will not want to answer but do you have a favorite wing profile( I am a retired composite fabricator and make everything myself)? And lastly, do you have a preferred fore and aft mounting position of the rear wing in relation to the rear axle?

Thanks, Bill

Marcus_NineLivesRacing said:

If you don't go with a splitter, but air-dam only I believe optimizing the under-tray would be your best bet. I've recently learned the trailing edge is very very important.

Would you mind clarifying this a bit for me? Are you referring to a tray just under the air dam? Trailing edge of the bottom of the dam? Almost a front diffuser, or... As you can see, I'm lost enough by the description to be just guessing...

I think Competition Car Aerodynamics discusses that. There's more going on at the back of the engine undertray than you might think.

optiguy said:

In reply to Marcus_NineLivesRacing :

Thanks for the reply. I have seen the Hanchagroup data before. I am running an air dam on one of our Miatas. The front opening is about 35% of the radiator area. My local track is Thompson Speedway in CT. Which is an interesting track with a variety of corner radii. And one long straight. I know this is a  question you most likely will not want to answer but do you have a favorite wing profile( I am a retired composite fabricator and make everything myself)? And lastly, do you have a preferred fore and aft mounting position of the rear wing in relation to the rear axle?

Thanks, Bill

We'd say radiator inlet % of radiator face area is good way to measure that as well. One could adjust that up or down based on the average speed of particular tracks or even for key sections of certain tracks.

We do have a favorite wing profile, the Elan, and that's why we tooled it! 

Rear axle is not as relevant as fresh air and of course..... rules. Many of our mounting positions are dependent on rule structures. For example, NASA ST/TT4-5 the wing cannot protrude 12" past the rear of the air and the wing cannot be higher than the roof-line. For fresher air higher is better and typically further rearward is cleaner as well. Further rearward also means more rear balance, but one could go too far with that depending on the front-end balance.

Ransom said:

Marcus_NineLivesRacing said:

If you don't go with a splitter, but air-dam only I believe optimizing the under-tray would be your best bet. I've recently learned the trailing edge is very very important.

Would you mind clarifying this a bit for me? Are you referring to a tray just under the air dam? Trailing edge of the bottom of the dam? Almost a front diffuser, or... As you can see, I'm lost enough by the description to be just guessing...

Referring to tray just under the air-dam. You'd want to make this surface as smooth as possible and as far back as possible. There will certainly still be air coming under the dam and under this surface, so any type of ramp you have behind it should generate a diffuser effect, may be small though depending on how it all works together.

In reply to Marcus_NineLivesRacing :

Thanks for all the answers guys. We are lucky as we are building a car with no regard for any rule set. When we get into TimeTrials we will let the chips fall and run whatever class we are thrown into. Like the SCCA says" Fun with Cars".

I have a general question- in your opinion, what would be some worthwhile aero modifications for a stage rally (or other offroad racing) car?  Splitters and diffusers need to be close to the ground to work well, so what are the options for something which needs to maintain a bunch of ground clearance and not rip stuff off constantly?  Bonus points if it works at high slip angles!

I believe when looking at Rally car stuff before the same aero rules are always true where lower is better its just a compromise you either want something strong or something that can break without breaking other stuff and is easily replaceable, WRC cars run full undertray aero/armor

In reply to ¯\_(ツ)_/¯ :

Absolutely. we can use the Pikes peak cars of the early 2000's (before it was paved) as an example. Huge wings and splitters.  General motorsport process is to mount a splitter as close to the ground as you can to provide maximum downforce, that is not wrong although what is overlooked is the rate of change as suspension moves. (these numbers are an example) Let's say you mount a splitter 4" high, and your suspension will allow it to move 2", the downforce can change 50%. even worse if the splitter hits the ground it could stall, your downforce will cycle between 200lbs-0lbs-200lns-0lbs.  This can lead to very inconsistent handling issues generally making the car harder to drive. My point is if you can't mount the splitter super low it's not the end of the world.   

(  just here to say I was a big Deltawing fan from start to finish of its career (even bought a shirt and a hat)... would daily-drive one to work if I could ! (almost... at least once per week :P ). 
Always impressed by how comparatively fast it was and how well it moved up the field (which I suppose could have been the driver too), 
and forever hoping that it would have finished an IMSA or ALMS race on the podium without suffering one of its gearbox-related problems, or occasionally getting taken out by another car.  
long live the DW !  )

carry on :) 

Less aero question more platform parts availability question. I noticed NLR does not offer a 8th gen Civic Si Coupe wing... have you guys just not had the opportunity to scan one yet? 

I will have a lot of aero questions. I have almost completed my Exocet (Race version). It's not going to be a street car, just track attack, time trails and AutoX. Going to Sebring Friday for first testing. I have the big Wang on the rear. Planning to install a flat bottom, a diffuser and a front wing on it. I have heard a lot of people state that the Exocet is a an aero brick. Any ideas on how to reduce the drag caused by all the exposed steel tubing, the race version has a full roll cage all exposed. I considered sourcing some type of plastic light weight fairing to put over the tubing. Also thought about a Bimini top that would cover the upper fall the top roll cage tubes and wrap around to totally enclose upper pipes by having material on the top and bottom. Any ideas? Thanks

Jerry  

spacecadet said:

Less aero question more platform parts availability question. I noticed NLR does not offer a 8th gen Civic Si Coupe wing... have you guys just not had the opportunity to scan one yet? 

That's correct, but we would love to scan one and get a kit going for it. Are you interested or know of anyone interested in getting that project going? We'd need a trunk lid or the car itself at the shop in Buford, GA.

In reply to Marcus_NineLivesRacing :

sent you a message. 

BlackSweeper said:

I will have a lot of aero questions. I have almost completed my Exocet (Race version). It's not going to be a street car, just track attack, time trails and AutoX. Going to Sebring Friday for first testing. I have the big Wang on the rear. Planning to install a flat bottom, a diffuser and a front wing on it. I have heard a lot of people state that the Exocet is a an aero brick. Any ideas on how to reduce the drag caused by all the exposed steel tubing, the race version has a full roll cage all exposed. I considered sourcing some type of plastic light weight fairing to put over the tubing. Also thought about a Bimini top that would cover the upper fall the top roll cage tubes and wrap around to totally enclose upper pipes by having material on the top and bottom. Any ideas? Thanks

Jerry  

hi jerry. it's not a brick but it's close to. the good news is we can fix a lot.  converting a tube shape to an airfoil would help on individual bars. The biggest challenge we have with EXO builders is getting them to understand they now have an open wheel car, and no longer a GT car. So kicking air off the front tires is a big deal and splitters are less effective. Go for the nose wing, and add a gurney we need to get the air away from the tires and that will free up a lot of horsepower. 

In reply to Johnny_at_NineLives :

Perhaps wheel fairings? I don't think I have seen any on an exocar before...

I have a question: Could you discuss what's going on with the 488 GT3 splitter? I haven't found any pics of the underbody, or discussions about it. I'm open to theories and conjecture too.

send pics of the 488 in question. 

gencollon said:

In reply to Johnny_at_NineLives :

I have a question: Could you discuss what's going on with the 488 GT3 splitter? I haven't found any pics of the underbody, or discussions about it. I'm open to theories and conjecture too.

are you talking about the "raised center" of the splitter here?