Is the rear bumper ledge a soot collector? - Toyota GR86, 86, FR-S and Subaru BRZ Forum & Owners Community

tzhu07 · 02-19-2018, 07:26 PM

I've noticed this for a while now, but never bothered to comment on it to anyone.

But it seems that the rear bumper ledge collects soot spots whenever it rains. It's like the rain droplets mix with the exhaust fumes and land on the ledge. It's easily the dirtiest part of my car every time I wash it.

humfrz · 02-19-2018, 07:30 PM

Yep .......

Cover it with a dark CF ........

A new mod ...........

humfrz

tzhu07 · 02-19-2018, 07:37 PM

Quote:

Originally Posted by humfrz

Yep .......

Cover it with a dark CF ........

A new mod ...........

humfrz

I don't know what CF stands for.

22R · 02-19-2018, 07:44 PM

Cawbon Fibre !!

22R

Leonardo · 02-19-2018, 07:44 PM

Yes, ledges will collect dust/road dirt/grime/gunk/soot/and the occasional beer can. My car came with the protector. It says scion. Not really a fan, but it is functional.

CF = Carbon Fiber. Or Cash Flow, Cuben Fiber, Cold Fusion...

Decep · 02-19-2018, 07:48 PM

It gets dirty even if it doesn't rain, because the dew from sitting overnight gets blown over the car, collecting all the dirt and it ends up there as you drive. it is what it is...

humfrz · 02-19-2018, 08:07 PM

Quote:

Originally Posted by tzhu07

I don't know what CF stands for.

....... you're NEVER gonna be a big time ricer, if you don't know about CF (Carbon Fiber)!

humfrz

Tcoat · 02-19-2018, 08:12 PM

Actually the build up on the ledge shows a good areo design. The fact that fine dust can and does collect there (in great abundance) means there is little or no turbulence crossing the rear of the car when driving at speed. You do not want air dropping down or blowing across the rear of the car. You could say the dust collecting shelf is a feature!

humfrz · 02-19-2018, 08:20 PM

Quote:

Originally Posted by Tcoat

Actually the build up on the ledge shows a good areo design. The fact that fine dust can and does collect there (in great abundance) means there is little or no turbulence crossing the rear of the car when driving at speed. You do not want air dropping down or blowing across the rear of the car. You could say the dust collecting shelf is a feature!

]

How could you tell on your car (in the winter), if the shelf is collecting anything .......??

OK, back to mopping, that section of the floor should be dry by now ......

humfrz

Impureclient · 02-19-2018, 08:46 PM

Yup, it's a soot collector alright. With a rich OFT canned tune my bumper and really the whole back of the car under the spoiler was a mess with the stuff.
I recently had a member start the process of doing a better tune adjusted for the header and it really has cleared so far up it seems.
While I was stock, it was still collecting a little more dust/soot than the rest of the car but the OFT/header really made it a mess.

Tcoat · 02-19-2018, 09:00 PM

Quote:

Originally Posted by humfrz

How could you tell on your car (in the winter), if the shelf is collecting anything .......??

OK, back to mopping, that section of the floor should be dry by now ......

humfrz

The snow sits there and doesn't blow away. It just gets browner and browner and browner and browner.

Tcoat · 02-19-2018, 09:03 PM

Quote:

Originally Posted by Impureclient

Yup, it's a soot collector alright. With a rich OFT canned tune my bumper and really the whole back of the car under the spoiler was a mess with the stuff.
I recently had a member start the process of doing a better tune adjusted for the header and it really has cleared so far up it seems.
While I was stock, it was still collecting a little more dust/soot than the rest of the car but the OFT/header really made it a mess.

guybo · 02-19-2018, 09:11 PM

I just watched a youtube video about FRS aero and the rear end of the car.

There are 2 vortices that develop behind the car. One from the top swirling from the top down behind the spoiler (if you have one) and a larger one from the bottom up in the opposite direction. The bottom one lifts up dust and delivers it on the bumper.

Tcoat · 02-19-2018, 09:13 PM

Quote:

Originally Posted by guybo

I just watched a youtube video about FRS aero and the rear end of the car.

There are 2 vortices that develop behind the car. One from the top swirling from the top down behind the spoiler (if you have one) and a larger one from the bottom up in the opposite direction. The bottom one lifts up dust and delivers it on the bumper.

Yep. And notice the zero reading across the rear. Right where you want it to be

02-19-2018, 07:26 PM	#1
tzhu07 Senior Member Join Date: Sep 2013 Drives: FR-S Location: WA Posts: 189 Thanks: 1 Thanked 103 Times in 56 Posts Mentioned: 3 Post(s) Tagged: 0 Thread(s)	Is the rear bumper ledge a soot collector? I've noticed this for a while now, but never bothered to comment on it to anyone. But it seems that the rear bumper ledge collects soot spots whenever it rains. It's like the rain droplets mix with the exhaust fumes and land on the ledge. It's easily the dirtiest part of my car every time I wash it. Last edited by tzhu07; 04-27-2020 at 01:51 PM.

02-19-2018, 07:44 PM	#5
Leonardo Country Boy 4 Life Join Date: Jul 2012 Drives: 19' & 06' Ridgelines, 13' FR-S Location: EUGENE Posts: 5,228 Thanks: 6,719 Thanked 5,293 Times in 2,720 Posts Mentioned: 47 Post(s) Tagged: 1 Thread(s)	Yes, ledges will collect dust/road dirt/grime/gunk/soot/and the occasional beer can. My car came with the protector. It says scion. Not really a fan, but it is functional. CF = Carbon Fiber. Or Cash Flow, Cuben Fiber, Cold Fusion... __________________ I LIKE TIRES!

02-19-2018, 08:12 PM	#8
Tcoat Senior Member Join Date: Jul 2014 Drives: 2020 Hakone Location: London, Ont Posts: 69,841 Thanks: 61,656 Thanked 108,294 Times in 46,456 Posts Mentioned: 2499 Post(s) Tagged: 50 Thread(s)	Actually the build up on the ledge shows a good areo design. The fact that fine dust can and does collect there (in great abundance) means there is little or no turbulence crossing the rear of the car when driving at speed. You do not want air dropping down or blowing across the rear of the car. You could say the dust collecting shelf is a feature! __________________ Racecar spelled backwards is Racecar, because Racecar.

02-19-2018, 09:11 PM	#13
guybo Huge E85 fan! Join Date: May 2016 Drives: 2016 Scion FRS Location: Tampa, FL, USA Posts: 1,850 Thanks: 539 Thanked 1,010 Times in 605 Posts Mentioned: 32 Post(s) Tagged: 0 Thread(s)	I just watched a youtube video about FRS aero and the rear end of the car. There are 2 vortices that develop behind the car. One from the top swirling from the top down behind the spoiler (if you have one) and a larger one from the bottom up in the opposite direction. The bottom one lifts up dust and delivers it on the bumper. Attached Images

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02-19-2018, 07:30 PM	#2
humfrz Senior Member Join Date: May 2013 Drives: 2013 FR-S, white, MT Location: Puyallup, WA Posts: 30,409 Thanks: 29,793 Thanked 32,809 Times in 16,829 Posts Mentioned: 715 Post(s) Tagged: 2 Thread(s)	Yep ....... Cover it with a dark CF ........ A new mod ........... humfrz

02-19-2018, 07:44 PM	#4
22R 22R Join Date: Apr 2017 Drives: 2012 Camry SE 2017 Toyota 86 Location: South Louisiana Posts: 236 Thanks: 233 Thanked 141 Times in 79 Posts Mentioned: 1 Post(s) Tagged: 0 Thread(s)	Cawbon Fibre !! 22R

02-19-2018, 07:48 PM	#6
Decep Senior Member Join Date: May 2017 Drives: 2013 FR-S Series 10 Location: CA Posts: 1,073 Thanks: 172 Thanked 497 Times in 326 Posts Mentioned: 6 Post(s) Tagged: 0 Thread(s)	It gets dirty even if it doesn't rain, because the dew from sitting overnight gets blown over the car, collecting all the dirt and it ends up there as you drive. it is what it is...

02-19-2018, 08:46 PM	#10
Impureclient Banned Join Date: May 2015 Drives: 2015 FR-S Location: NPR, Florida Posts: 2,404 Thanks: 1,802 Thanked 2,903 Times in 1,282 Posts Mentioned: 25 Post(s) Tagged: 2 Thread(s)	Yup, it's a soot collector alright. With a rich OFT canned tune my bumper and really the whole back of the car under the spoiler was a mess with the stuff. I recently had a member start the process of doing a better tune adjusted for the header and it really has cleared so far up it seems. While I was stock, it was still collecting a little more dust/soot than the rest of the car but the OFT/header really made it a mess.

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