5th Gen Dirty Butt Disorder..... Who can explain this? - Page 2 - Toyota 4Runner Forum

97BlackAckCL · 01-03-2023, 05:49 PM

Am I the only one who thought having a Dirty Butt Disorder sounds like a personal hygiene problem?

skag1T · 01-03-2023, 07:55 PM

I installed airtabs in the hoopes it MIGHT help with this dirty butt.

Still have to go on a dusty road, but the theory behind them is interesting.

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jp.vegas · 01-03-2023, 09:09 PM

Quote:

Originally Posted by Bobby12many

Super interesting....

Is there such thing as a spoiler-less 5th gen?

I wonder how introducing more vortices into the flow of the air over the spoiler would change anything positively? Lie an Evo-style "vortex generator" strip on top of the spoiler....

Vortex generators may reduce drag and clean up the air passing over the spoiler, but you are literally creating a huge sucking vortex behind the truck. The only way to address that is to direct moving air downwards across the back of the truck effectively disrupting that low pressure area.

Removing the spoiler will have zero effect, you literally need some sort of air scoop sticking up into the flow coming off the back of the roof and directing air straight down breaking up that vortex.

The 4th gen was the same way. Rear window was rolled down and back up for effect:

GT0neX · 01-03-2023, 11:51 PM

All vehicles that I currently own have a rear hatch design and they all tend to do this.

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johnnygraphic · 01-04-2023, 08:05 AM

Quote:

Originally Posted by skag1T

I installed airtabs in the hoopes it MIGHT help with this dirty butt.

Still have to go on a dusty road, but the theory behind them is interesting.

Airtab | Aerodynamic Fuel Savers | How Airtabs Work

Airtab - Airtab(R) Improve Stability, Reduce Spray, Save Fuel

I’d deal with the dirty butt disorder vs that.

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ASUMTNEER · 01-04-2023, 08:27 AM

Quote:

Originally Posted by chrisridebike8

is the truck ceramic coated? maybe they forgot the coat the hatch. I've literally seen lines like that between coated and uncoated surfaces, even if they were on the same panel

This was my first thought as well. And, if I paid for this ceramic coating, I would be taking it back to the dealer for them to finish the job. Whoever did the coating obviously did the side of the spoiler while they did that rear quarter panel and never finished the rear of the vehicle.

Toffees · 01-04-2023, 12:15 PM

Quote:

Originally Posted by skag1T

I installed airtabs in the hoopes it MIGHT help with this dirty butt.

Still have to go on a dusty road, but the theory behind them is interesting.

Airtab | Aerodynamic Fuel Savers | How Airtabs Work

Airtab - Airtab(R) Improve Stability, Reduce Spray, Save Fuel

Ah, the vortex generator. Sure to save fractions on your fuel economy, so report back and let us know which fractions are saved. Also, tell us if it whistles at any speeds like the side mirrors. But if it helps with the dirty butt I suspect it will only make the dirty area smaller, not disappear.

Toffees · 01-04-2023, 12:16 PM

Quote:

Originally Posted by jp.vegas

Vortex generators may reduce drag and clean up the air passing over the spoiler, but you are literally creating a huge sucking vortex behind the truck. The only way to address that is to direct moving air downwards across the back of the truck effectively disrupting that low pressure area.

Removing the spoiler will have zero effect, you literally need some sort of air scoop sticking up into the flow coming off the back of the roof and directing air straight down breaking up that vortex.

The 4th gen was the same way. Rear window was rolled down and back up for effect:

Driving with the window down is a good way to share that dust inside your 4R as well

chuckzwood · 01-04-2023, 01:17 PM

I drove an Explorer for 18 years before buying my 4runner, and the Explorer was just as dirty butted as the 4runner is. After this much time driving SUV's, I am completely used to it.

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jp.vegas · 01-04-2023, 02:53 PM

Quote:

Originally Posted by Toffees

Driving with the window down is a good way to share that dust inside your 4R as well

I rolled it down and back up to take the pic, not while driving...because, yeah, I don't need silicosis from offroad adventures.

bigdaddy2021 · 01-05-2023, 01:46 AM

So wierd!!!

Quote:

Originally Posted by Bobby12many

super silly post... hoping someone far smarter than myself can shed some light on this dirty-butt phenomena.

Just recently returned from a trip to NE Iowa, which consisted of 5-15 miles a day of wintery dirt roads. I soon noticed how quickly the back of the 4R gets completely covered un dirt/road-grime, esp compared to most other vehicles.

Considering how flat, boxy and vertical the rear hatch is, I can understand how filthy it gets. One only needs to open the rear window at speed to see how there is a "pressure pocket" formed back there which allows stuff to just "swirl" back towards the vehicle....

Now, what I cant figure out is the perfect line of delineation from the lift-gate to the rear quarter panel. How can the D-pillar be nearly spotless? The rear liftgate curves a bit towards the sides, which makes me think it cant just be attributed to surface-angle changes alone. Likewise, the rear bumper seems to "hold onto" road grime on the side of the vehicle far more than the 1/4 panel.

Is this due to the 1/4 panel, liftgate and bumper all being from discrete materials (al, steel, plastic?)

honda250xtitan · 01-05-2023, 10:24 AM

imagine having this guy show up and complaining that they (Dealer) messed up the cereamic coating cause the hatch is dirty. also if the dealer applied your coating i would put money on 1. itll wash off in 2 washes, 2. they covered up the factory/dealership applied swirl marks.

Bobby12many · 01-05-2023, 11:35 AM

Quote:

Originally Posted by honda250xtitan

imagine having this guy show up and complaining that they (Dealer) messed up the cereamic coating cause the hatch is dirty. also if the dealer applied your coating i would put money on 1. itll wash off in 2 washes, 2. they covered up the factory/dealership applied swirl marks.

Not a chance in hell I would even bring this up to the dealer.... they have proven incompetent and inconvenient, always. Just idiots, man. When I purchased it, they said they "didnt have the proper tools available " to remove the aftermarket roof basket that was on the truck when I picked it up..... those tools you might ask? a fahkin 6mm hex

I literally took it off in front of the sales office in less than 10 minutes with my mountain bike multi-tool.

Wouldnt be surprised if NONE of the vehicle was actually ceramic coated, only because I didnt witness it lol

Also, FWIW the coating was done like 8 months and many washes ago.

It is a good theory as to why ONLY the hatch is coated without a spec on the body 1/4 panel!

patkelly4370 · 01-05-2023, 12:05 PM

I live in a 75 sq/mi dirt road community.
The dirt can pile on the hatch pretty thick, until I get to the highway. Then that "vortex" removes 90% of it.

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Inv4drZm · 01-05-2023, 12:17 PM

In my experience I've always thought the ceramic coated parts of the paint attracted MORE dust than the non-coated parts.

If this is the case, then maybe the ceramic coating has worn off on the sides of the vehicle faster than the rear of the vehicle due to splashing and normal driving wear.

And perhaps the ceramic adhered better to the plastic bumper cover than the paint.

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