Custom Diffuser CFD (pic heavy) - Toyota GR86, 86, FR-S and Subaru BRZ Forum & Owners Community

Joakim3 · 11-26-2014, 01:07 PM

Did some basic CFD fun with an FRS to test two different diffuser designs

*Results are not 100% accurate as the model(s) are semi-high poly, have been modeled with a complete covered belly pan and has a custom front bumper with ~30% more airflow (still pulled a .28 drag coefficient @100mph)

-The diffuser height/width difference, the more aggressive one is significantly more efficient at pulling air despite having a substantially lower attack angle

-Diffuser tunnel lengths and extraction area, the one on the left has almost twice the "airflow volume"

-This is the airflow of the more modest diffuser with pretty efficient vortex's at the rear of the car

-This is the airflow of the more aggressive diffuser, as you can see there is a substantial more blue (lower pressure air) being pulled from the rear thus its more efficient

Wonderbar · 11-26-2014, 05:58 PM

Nice! I love the ferrari diffusers, very cool work.

raven1231 · 11-26-2014, 06:52 PM

Same Id take the first one for sure

Joakim3 · 11-26-2014, 07:55 PM

The first one would definitely reduce drag, but doesn't produce to much downforce due to its rake.... But boy is it pretty lol

OmarGC · 11-27-2014, 12:27 AM

Shut up dude. Make it, sell me it.

Bach415 · 11-27-2014, 04:17 AM

I'll take the one on the right if you do end up making one. Preferably single exit if you can and big enough to fit type 80

Khorne · 11-27-2014, 12:15 PM

Well.....that's one damn sexy diffuser.

Joakim3 · 11-27-2014, 12:25 PM

Quote:

Originally Posted by Khorne

Well.....that's one damn sexy diffuser.

Yeah I stylized the left one of off the 599/F-type diffuser (it did come out biblically sexy lol), while the right is model of off the 15' WRX Sti concept and is definitely more function >>> form.

Yeah i'm thinking of ideal mounting locations atm

Ideally I'd try to mount the diffuser on the 2 rear tow hooks & the attachment points on the lower control arms (where the drive way labs diffusers v1/v2 mounts at)... since one would have to cut the entire "fake diffuser" off the OEM bumper and the weight of the diffuser itself lol

Enders FRS · 12-07-2014, 04:36 AM

Out of curiosity, which program are you using for modeling? My fiancée is about to finish her course work for a PhD in CFD. I'd be lying if I didn't think it was sexy that she could help design my custom car part ideas!

Sent from my iPhone using Tapatalk

Joakim3 · 12-08-2014, 12:25 PM

Quote:

Originally Posted by Enders FRS

Out of curiosity, which program are you using for modeling? My fiancée is about to finish her course work for a PhD in CFD. I'd be lying if I didn't think it was sexy that she could help design my custom car part ideas!

Sent from my iPhone using Tapatalk

For modeling, I use Trimble/Google Sketchup for the rough model, then go to a program like Maya or 3D Max for the HQ model (you can actually use those for 3d printing/custom fabbing). Shit I would kill for a woman who had a doctorate in CFD....... custom aero parts FTFW!!!

Take the new diffuser I concocted (replaces that kiddy diffuser on the right).. lol

By having the exhaust exit directly above actual diffuser exit, one can integrate the exhaust flow with the diffuser airflow allowing the airflow over the top of the diffuser to aid airflow extraction underneath the diffuser (essentially the exhaust gas "pulls" more air from the diffuser)

Granted one would have to remove the rear crash beam to get the exhaust in that set up... so this would really be track "only" diffuser or the for the "idgaf because racecar person" lol

OmarGC · 12-08-2014, 02:14 PM

Make it... I'll buy

Diode Dynamics · 12-08-2014, 02:33 PM

Looks like a Challenge Stradale or Scuderia rear end with those tips and that diffuser

I like it!

Nick C.

Joakim3 · 12-08-2014, 11:22 PM

Quote:

Originally Posted by Diode Dynamics

Looks like a Challenge Stradale or Scuderia rear end with those tips and that diffuser

I like it!

Nick C.

Got the Ferrari part correct, it's based off the Ferrari 458 Speciale diffuser (minus the active aero)

If I'm not mistaken sw20kosh had a similar setup with a custom fabbed Lotus Elise Diffuser

Joakim3 · 12-09-2014, 01:57 AM

Just some spin arounds I did of the race version, shows the airflow from multiple angles, pressure gradients etc..

*note the model is scaled WAY down so the while the airflow behavior & Drag Coefficient are accurate, the pressure reading aren't*

https://www.facebook.com/video.php?v...21&pnref=story

11-26-2014, 01:07 PM	#1
Joakim3 Senior Member Join Date: May 2013 Drives: 04' Saab 9-5 Aero Location: Elkridge, MD Posts: 602 Thanks: 7 Thanked 199 Times in 136 Posts Mentioned: 3 Post(s) Tagged: 0 Thread(s)	Custom Diffuser CFD (pic heavy) Did some basic CFD fun with an FRS to test two different diffuser designs Results are not 100% accurate as the model(s) are semi-high poly, have been modeled with a complete covered belly pan and has a custom front bumper with ~30% more airflow (still pulled a .28 drag coefficient @100mph) -The diffuser height/width difference, the more aggressive one is significantly more efficient at pulling air despite having a substantially lower attack angle -Diffuser tunnel lengths and extraction area, the one on the left has almost twice the "airflow volume" -This is the airflow of the more modest diffuser with pretty efficient vortex's at the rear of the car -This is the airflow of the more aggressive diffuser, as you can see there is a substantial more blue (lower pressure air) being pulled from the rear thus its more efficient __________________ _____________________ You know what they say... pick two: cheap, fast, reliable. Last edited by Joakim3; 12-09-2014 at 01:54 AM.*

11-26-2014, 06:52 PM	#3
raven1231 Senior Member Join Date: Aug 2013 Drives: 2013 Firestorm FR-S, 2016 DGM WRX Location: Cincinnati, Ohio Posts: 4,580 Thanks: 8,264 Thanked 3,118 Times in 1,667 Posts Mentioned: 24 Post(s) Tagged: 1 Thread(s)	Same Id take the first one for sure __________________ http://www.ft86club.com/forums/showthread.php?t=59870

11-26-2014, 07:55 PM	#4
Joakim3 Senior Member Join Date: May 2013 Drives: 04' Saab 9-5 Aero Location: Elkridge, MD Posts: 602 Thanks: 7 Thanked 199 Times in 136 Posts Mentioned: 3 Post(s) Tagged: 0 Thread(s)	The first one would definitely reduce drag, but doesn't produce to much downforce due to its rake.... But boy is it pretty lol __________________ _____________________ You know what they say... pick two: cheap, fast, reliable.

11-27-2014, 12:27 AM	#5
OmarGC My FR-S has 5 gears Join Date: Aug 2012 Drives: FRS/280z/Tundra Location: St. Louis Posts: 1,994 Thanks: 626 Thanked 1,065 Times in 572 Posts Mentioned: 49 Post(s) Tagged: 3 Thread(s)	Shut up dude. Make it, sell me it. __________________ Omar GC 2JZ - 6870 - stock block - 1000whp? Instagram: 2jzus

11-27-2014, 12:15 PM	#7
Khorne Super 86 Join Date: May 2013 Drives: Red 86 GTS Location: Aus/Perth Posts: 361 Thanks: 124 Thanked 252 Times in 128 Posts Mentioned: 9 Post(s) Tagged: 0 Thread(s)	Well.....that's one damn sexy diffuser. __________________ 230rwhp/184ftlb on 98RON/93AKI Build thread Red 86 GTS MT \| Sprintex Intercooled Twin Screw SC \| Invidia N1 \| Mocal 10 row \| Invidia Front Pipe \| Motiv Overpipe\| Enkei RPF01 with Bridgestone RE002s \| MCA Blue Coilovers \| Radium Catch Can

11-27-2014, 04:17 AM	#6
Bach415 Senior Member Join Date: Feb 2013 Drives: Whiteout FRS Location: San Francisco Posts: 1,253 Thanks: 909 Thanked 416 Times in 297 Posts Mentioned: 31 Post(s) Tagged: 2 Thread(s)	I'll take the one on the right if you do end up making one. Preferably single exit if you can and big enough to fit type 80

12-07-2014, 04:36 AM	#9
Enders FRS Senior Member Join Date: Apr 2014 Drives: FRS MT SE 10 edition Location: Virginia Posts: 102 Thanks: 26 Thanked 15 Times in 13 Posts Mentioned: 0 Post(s) Tagged: 0 Thread(s)	Out of curiosity, which program are you using for modeling? My fiancée is about to finish her course work for a PhD in CFD. I'd be lying if I didn't think it was sexy that she could help design my custom car part ideas! Sent from my iPhone using Tapatalk

12-08-2014, 02:14 PM	#11
OmarGC My FR-S has 5 gears Join Date: Aug 2012 Drives: FRS/280z/Tundra Location: St. Louis Posts: 1,994 Thanks: 626 Thanked 1,065 Times in 572 Posts Mentioned: 49 Post(s) Tagged: 3 Thread(s)	Make it... I'll buy __________________ Omar GC 2JZ - 6870 - stock block - 1000whp? Instagram: 2jzus

12-08-2014, 02:33 PM	#12
Diode Dynamics Join Date: Aug 2012 Drives: 2013 Scion FR-S Location: St. Louis, Missouri Posts: 2,770 Thanks: 1,503 Thanked 1,761 Times in 877 Posts Mentioned: 197 Post(s) Tagged: 5 Thread(s)	Looks like a Challenge Stradale or Scuderia rear end with those tips and that diffuser I like it! Nick C. __________________ John C. Diode Dynamics Follow Us: FB // IG // YT // TikTok

12-09-2014, 01:57 AM	#14
Joakim3 Senior Member Join Date: May 2013 Drives: 04' Saab 9-5 Aero Location: Elkridge, MD Posts: 602 Thanks: 7 Thanked 199 Times in 136 Posts Mentioned: 3 Post(s) Tagged: 0 Thread(s)	Just some spin arounds I did of the race version, shows the airflow from multiple angles, pressure gradients etc.. note the model is scaled WAY down so the while the airflow behavior & Drag Coefficient are accurate, the pressure reading aren't https://www.facebook.com/video.php?v...21&pnref=story __________________ _____________________ You know what they say... pick two: cheap, fast, reliable. Last edited by Joakim3; 12-09-2014 at 02:17 AM.

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