Exhaust fumes with tail pipe on vehicles with TRD Pro Exhaust?

[RobS10]

We drove a 1999 4R for 20 years and always enjoyed driving with the rear window and Driver's windows down. I never noticed the smell of exhaust at any speed. We now have a 2022 4R, and notice a definite exhaust smell over 35mph with the rear window open. The tailpipe on our 3rd Gen exited on the right side, our 5th Gen exits directly out the back.

Do any of you with a 5th Gen that has the TRD Pro exhaust and tailpipe out the right side notice exhaust smell over 35mpg with the rear window open? I miss being able to drive with the rear window open with impunity, and am considering having a muffler shop move the tail pip[e to the right side IF it would make a difference.

 

[gordonp]

I get some exhaust-smell through the open rear window on my 2021 (TRD Off Road). I think it's the nature of the brick-like shape - low-pressure aerodynamic vortices caused by flow-separation and creating a HUGE low-pressure zone. This low-pressure zone happily sucks in all the exhaust.

For me, it helps if I open some door-windows, and allow flow-through air which (I think) helps break the low-pressure at the rear window, and prevent exhaust suck-in. I often only half-open the rear-window, which combined with my flow-through air from open door-windows may be enough to hold the exhaust-swirl down and prevent it coming in. At least for me, it's enough that I can fully enjoy that partially-open rear window in nice weather.

HTH!

 

[RobS10]

I get some exhaust-smell through the open rear window on my 2021 (TRD Off Road). I think it's the nature of the brick-like shape - low-pressure aerodynamic vortices caused by flow-separation and creating a HUGE low-pressure zone. This low-pressure zone happily sucks in all the exhaust.

For me, it helps if I open some door-windows, and allow flow-through air which (I think) helps break the low-pressure at the rear window, and prevent exhaust suck-in. I often only half-open the rear-window, which combined with my flow-through air from open door-windows may be enough to hold the exhaust-swirl down and prevent it coming in. At least for me, it's enough that I can fully enjoy that partially-open rear window in nice weather.

HTH!

I still get the fumes with the driver's window and the rear window half open, though not as bad as when the rear is all the way down. But it only seems to be a problem at +35mph or higher.
Interesting thoughts on the aerodynamics of the 5th Gen. The 3rd Gen we had seemed a little more aerodynamic, but I'm no expert. I'd like to hear from 5th Gen TRD Pro exhaust users out there with the tail pipe exiting the side instead of the back.

 

[Humble Leader]

ya 4runner 5th gen is bad for rear aero. basically sucks the air right into the tailgate. if I'm driving on unpaved roads in wet / mud conditions, my liftgate gets full of mud spray all the way up to the window. in dry roads that tailgate is full of dust

just the way it is. I don't even use the rear window

 

[RobS10]

ya 4runner 5th gen is bad for rear aero. basically sucks the air right into the tailgate. if I'm driving on unpaved roads in wet / mud conditions, my liftgate gets full of mud spray all the way up to the window. in dry roads that tailgate is full of dust

just the way it is. I don't even use the rear window

Dust and dirt will get inside the rear of ANY generation if you leave the window open off road, which I never do. But trying to find out of people with 5th Gens and the side exhaust like the earlier gens still have a problem with fumes getting sucked in. Our 3rd Gen never did.

 

[ArthurKotb]

My 2004 does the same thing. Years ago, with station wagons that had roll down rear windows, the exhaust pipe was either bent at a right angle to vent to the side or it was about a 30° angle behind the rear tire(s). As long as the exhaust is a straight pipe out the back you're going to get fumes inside the rear window. If the rubber seal is old the fumes will go past it into the cabin. I replaced mine and the fumes stopped as long as the window is closed.

 

[RobS10]

My 2004 does the same thing. Years ago, with station wagons that had roll down rear windows, the exhaust pipe was either bent at a right angle to vent to the side or it was about a 30° angle behind the rear tire(s). As long as the exhaust is a straight pipe out the back you're going to get fumes inside the rear window. If the rubber seal is old the fumes will go past it into the cabin. I replaced mine and the fumes stopped as long as the window is closed.

Exactly. Just wanted to make sure that's the only thing. If people with a 5th gen and the TRD side tailpipe have no problems, I'm considering having our modified.

 

[ArthurKotb]

Exactly. Just wanted to make sure that's the only thing. If people with a 5th gen and the TRD side tailpipe have no problems, I'm considering having our modified.

What's that look like? Can you post a picture? I wonder if there's something I can use for mine

 

[RobS10]

What's that look like? Can you post a picture? I wonder if there's something I can use for mine

Just look for a later TRD Pro and look at the tailpipe. It exits the vehicle just behind the right rear wheel, blowing the exhaust to the side instead of the back.

 

[ArthurKotb]

Here's a 2025 TRD Pro but that exhaust doesn't appear to be coming out over the rear tire

 

[ArthurKotb]

Here are some examples of how it needs to be done to get the fumes away from the rear of the car so the wind can carry it away and not into the rear window. It was standard on all station wagons. I don't know why they got away from it.

 

[RobS10]

Here's a 2025 TRD Pro but that exhaust doesn't appear to be coming out over the rear tire

You have to go back to the later 5th Gen Pros...

 

[RobS10]

You have to go back to the later 5th Gen Pros...

Here's a couple more...

 

[RobS10]

Here are some examples of how it needs to be done to get the fumes away from the rear of the car so the wind can carry it away and not into the rear window. It was standard on all station wagons. I don't know why they got away from it.

It was standard on all generations of 4Runners before the 4th Gen had a side tailpipe. Maybe they thought the rear pipe looked better? Who knows, but BAD more, Toyota!

 

[ArthurKotb]

Yes, that is the proper exhaust for riding with the window down. Thanks for posting

 

[zimmm1]

tailpipe exiting to the side as on the TRD Pro does not keep exhaust fumes from entering the cabin with the rear window down