Underbody Panel Effectiveness... - Toyota GR86, 86, FR-S and Subaru BRZ Forum & Owners Community

bfeeney · 04-04-2021, 01:30 PM

Hi everyone. Happy Easter! I'm new to the forum here, and new to these cars. I was wondering if anyone has done a full underbody panel kit with diffuser with a stock (height) suspension? Do they have a noticeable effect with that height? I know that an underbody kit works better the lower the car is, but for a DD I don't think I want to go that low. To back up, my last car was a '99 Prelude SH on Tein coilovers and was set to have about 3" clearance to the lowest point. The car looked cool, but it has its draw-backs. #1 I scrapped the ground a lot (of course), #2 I couldn't go through a car wash because I would bottom out on the guide rail. My plans for my FR-S is to do a full underbody kit to increase the downforce at interstate speeds, but I still want to go through the wash and I dont want to destroy the $600 diffuser every time I back out of my driveway. Has anyone done these aero mods with a stock height? Thanks everyone

norcalpb · 04-05-2021, 01:01 PM

Not stock height but was on STi springs (only 10mm drop) with my diffuser/suspension covers/unbody panels, I never scraped the diffuser. You should be totally fine.

Also you won't be adding downforce but rather reducing lift and drag.

NoHaveMSG · 04-05-2021, 01:23 PM

Quote:

Originally Posted by bfeeney

My plans for my FR-S is to do a full underbody kit to increase the downforce at interstate speeds

Sent from my iPhone using Tapatalk

Wally86 · 04-05-2021, 01:56 PM

Quote:

Originally Posted by NoHaveMSG

Sent from my iPhone using Tapatalk

Smoothing the air below and lowering pressure underneath the car, maybe?

JD001 · 04-05-2021, 02:07 PM

Does our "sports" car generate enough momentum to kick-start underbody aero-shenanigans?

NoHaveMSG · 04-05-2021, 02:07 PM

Quote:

Originally Posted by Wally86

Smoothing the air below and lowering pressure underneath the car, maybe?

All the info:

https://www.verus-engineering.com/informative-packets

Wally86 · 04-05-2021, 03:39 PM

Quote:

Originally Posted by NoHaveMSG

All the info:

https://www.verus-engineering.com/informative-packets

Oh dang. According to those CP charts, yeah, lowering pressure underneath definitely does help.

NoHaveMSG · 04-05-2021, 04:19 PM

Quote:

Originally Posted by Wally86

Oh dang. According to those CP charts, yeah, lowering pressure underneath definitely does help.

It is also quite efficient.

bfeeney · 04-05-2021, 06:38 PM

Quote:

Originally Posted by norcalpb

Not stock height but was on STi springs (only 10mm drop) with my diffuser/suspension covers/unbody panels, I never scraped the diffuser. You should be totally fine.

Also you won't be adding downforce but rather reducing lift and drag.

That's good to know. I would hate to damage such a pretty piece like a diffuser. I might get a set of TRD springs at some point, they have a 1" drop. That can't be any worse than the Prelude lol. Thanks

bfeeney · 04-05-2021, 06:39 PM

Quote:

Originally Posted by NoHaveMSG

All the info:

https://www.verus-engineering.com/informative-packets

That's awesome. Thanks

bfeeney · 04-05-2021, 06:45 PM

Quote:

Originally Posted by JD001

Does our "sports" car generate enough momentum to kick-start underbody aero-shenanigans?

I know I'm not going to get F1 effects here. Those panels start working right about where I'm having troubles, so every bit will help. I have an Electro-Mechanical degree, not Aeronautical.

NoHaveMSG · 04-05-2021, 06:58 PM

Quote:

Originally Posted by bfeeney

That's good to know. I would hate to damage such a pretty piece like a diffuser. I might get a set of TRD springs at some point, they have a 1" drop. That can't be any worse than the Prelude lol. Thanks

1" drop is pretty mild, you should be okay everywhere but the steepest driveway entrances/exits. I'm at around -2.5" right now with a splitter and diffuser and as long as I am paying attention, I don't scrap.

ZDan · 04-06-2021, 07:28 AM

Aero engineer here. For sure way way less effective at stock ride height. If you look at the Ventus stuff you see their model is slammed. Also, the application is for cruising at freeway speeds? A smidge more downforce/less lift is going to make no real difference for you. If you want it for looks that's fine. But it's not going to be doing anything useful for you, I don't think...

jflogerzi · 04-06-2021, 05:28 PM

I am starting to get all the pieces for a flat bottom why because racecar. So far I have the following

Splitter up front
OEM Under Panels
Verus Trans Tunnel and rear Suspension covers

Just need the diffuser and diff cover

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04-04-2021, 01:30 PM	#1
bfeeney Member Join Date: Apr 2021 Drives: 2015 Scion FR-S Location: Columbus, OH Posts: 16 Thanks: 0 Thanked 3 Times in 2 Posts Mentioned: 0 Post(s) Tagged: 0 Thread(s)	Underbody Panel Effectiveness... Hi everyone. Happy Easter! I'm new to the forum here, and new to these cars. I was wondering if anyone has done a full underbody panel kit with diffuser with a stock (height) suspension? Do they have a noticeable effect with that height? I know that an underbody kit works better the lower the car is, but for a DD I don't think I want to go that low. To back up, my last car was a '99 Prelude SH on Tein coilovers and was set to have about 3" clearance to the lowest point. The car looked cool, but it has its draw-backs. #1 I scrapped the ground a lot (of course), #2 I couldn't go through a car wash because I would bottom out on the guide rail. My plans for my FR-S is to do a full underbody kit to increase the downforce at interstate speeds, but I still want to go through the wash and I dont want to destroy the $600 diffuser every time I back out of my driveway. Has anyone done these aero mods with a stock height? Thanks everyone Last edited by bfeeney; 04-04-2021 at 04:17 PM.

04-05-2021, 01:01 PM	#2
norcalpb Senior Member Join Date: Oct 2013 Drives: 2013 BRZ, 2023 Model 3 Location: SF Bay Area Posts: 2,296 Thanks: 1,212 Thanked 861 Times in 570 Posts Mentioned: 15 Post(s) Tagged: 0 Thread(s)	Not stock height but was on STi springs (only 10mm drop) with my diffuser/suspension covers/unbody panels, I never scraped the diffuser. You should be totally fine. Also you won't be adding downforce but rather reducing lift and drag.

04-05-2021, 02:07 PM	#5
JD001 Senior Member Join Date: Apr 2015 Drives: Subaru BRZ Location: UK Posts: 6,027 Thanks: 7,651 Thanked 6,183 Times in 3,472 Posts Mentioned: 25 Post(s) Tagged: 2 Thread(s)	Does our "sports" car generate enough momentum to kick-start underbody aero-shenanigans?

04-06-2021, 07:28 AM	#13
ZDan Senior Member Join Date: May 2011 Drives: '23 BRZ Location: Providence, RI Posts: 4,584 Thanks: 1,376 Thanked 3,890 Times in 2,032 Posts Mentioned: 85 Post(s) Tagged: 0 Thread(s)	Aero engineer here. For sure way way less effective at stock ride height. If you look at the Ventus stuff you see their model is slammed. Also, the application is for cruising at freeway speeds? A smidge more downforce/less lift is going to make no real difference for you. If you want it for looks that's fine. But it's not going to be doing anything useful for you, I don't think...

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