'20 TRD Pro Exhaust

[Charles Bronson]

does this really work? I have a borla s-type and just like the Pro exhaust, when you hit a certain rpm the drone gets annoying and/or driving up mountains/hills/etc...

as you can see i'm being very lazy to reinstall the oem.....

I have no idea, but I am willing to try anything. Thank God though, my wife gets how bad this thing drones and is hard on the ears on the highway so she hasn't asked to put that POS back on the truck. I REALLY like driving the truck now. It's so pleasant.

 

[Charles Bronson]

I just put the TRD exhaust on my 2014 over the weekend. I was expecting a bad drone after reading all of the complaints. We are realize that this is a V6, so it’s not going to sound great. I’m guessing from most of the complaints that people have not run an exhaust on a V6 before. I would honestly say that the TRD exhaust is relatively quiet and I don’t experience a drone at all on the highway. Now if you were running a 14” Magnaflow of something like that then that would be another story.


Sent from my iPhone using Tapatalk

It will likely get louder and will drone more as it breaks in. It's also louder when it's hot out; thermal dynamics of the metal at play. Ours did both of these things.

There are only two V6s I'm aware of that sound amazing. One is the first gen NSX and two is the Alfa Romeo Giulia Quadrifoglio. In the past I had modded Nissan/Infiniti cars with the VQ series V6 motors. I learned that you can't modify the catback on those cars unless you're willing to put up with drone and rasp. The 4.0 V6 in the 4Runner is no different and I should have known better. I assumed that since it was an OEM system, Toyota would make it pretty tame and dial out any severe drone. I was wrong. I should have paid attention to what most legit offroaders DON'T do with their 4Runners (i.e., modify the exhaust).

 

[Firesq14]

Tail pipe

Does anyone have the part number for the trd pro tail pipe with the side exit?

 

[USStrongman]

What in your opinion causes the drone in TRD exhaust? My assumption is it has more to do with vacuum created at the rear of the vehicle in a very square, non-aero design than actual exhaust causing it? To me, its creating a positive resonance in a vacuum and it bounces between positive and negative vacuums at speed. Kinda like leaving a rear window down and getting up to speed and the audible drone that happens inside the cabin. Unequal pressures from inside vs outside.

 

[Charles Bronson]

What in your opinion causes the drone in TRD exhaust? My assumption is it has more to do with vacuum created at the rear of the vehicle in a very square, non-aero design than actual exhaust causing it? To me, its creating a positive resonance in a vacuum and it bounces between positive and negative vacuums at speed. Kinda like leaving a rear window down and getting up to speed and the audible drone that happens inside the cabin. Unequal pressures from inside vs outside.

The problem is the resonance the TRD muffler creates and it's impact on the big boxy cabin above it.

The TRD exhaust has an incorporated helmholtz resonator design which is specifically designed to kill drone. Just forward of the muffler, the exhaust pipe splits into two pipes that enter the muffler can. The stock muffler only has one pipe entering the muffler (which is also larger in size). Using my endoscope, I saw that one pipe has perforations as goes through the muffler can and out to the exhaust pipe. The perforations allow exhaust to get muffled within the packing of the muffler can. The other pipe goes straight through the muffler can and has no perforations what so ever and dead ends with a capped pipe that exits about 1.5" at the back of the muffler can.

I have debated about cutting that cap and lengthening the pipe another 5" to 6" to see if I can reduce the drone as helmholtz resonators are very dependent on the correct pipe length to cancel out the resonance wave. I don't think Toyota went far enough with their pipe length design to reduce the drone.

 

[ROKREDY]

Hello geniuses! I am new to 4Runners...came from the Land Cruiser lifestyle. We love our new 2022 TRD PRO...LESS the exhaust.

We don't plan on running wild stuff like we did for years in the Cruisers...so no lift on this 2022, just sliders.

Along these lines about the exhaust...I find it very BAD that the tailpipe exits right behind the rear wheel. I can see dropping down off a ledge off-road and mangling the pipe.

QUESTION: IF I decide to NOT change the loud TRD exhaust (which drives me nuts) is it easy to cut that tailpipe before the bend so it exits out back (like it did on my Cruisers)?

 

[rageandlove]

Hello geniuses! I am new to 4Runners...came from the Land Cruiser lifestyle. We love our new 2022 TRD PRO...LESS the exhaust.

We don't plan on running wild stuff like we did for years in the Cruisers...so no lift on this 2022, just sliders.

Along these lines about the exhaust...I find it very BAD that the tailpipe exits right behind the rear wheel. I can see dropping down off a ledge off-road and mangling the pipe.

QUESTION: IF I decide to NOT change the loud TRD exhaust (which drives me nuts) is it easy to cut that tailpipe before the bend so it exits out back (like it did on my Cruisers)?

Many have done the exact opposite (cut the straight tailpipe and weld on a curved one to have it exit out the side) so no reason that it would be any harder to go the other direction.

One reason a lot of people have re-routed the pipe to the side - and this was in the days long before the Pro exhaust that showed up a year or two ago - was that the straight-back pipe deposits the exhaust fumes in a spot where it's easy to make it's way into the vehicle if the rear window is open. So something to think about there.

It also creates room for a second tow point to be added in the back.

 

[ROKREDY]

Ohhhh interesting! EXCELLENT POINT! Cruisers do not have active rear windows so a rear-facing pipe is a non-issue. Hmmm...so ya, if we want to use that window then I might need to rethink this. GOOD INFO! Gawd I can see me mangling that pipe though when dropping down a ledge or rock. Well, I'm learning my 4Runner. Thanks!

 

[02SE]

I'd say the standard exhaust on every 4Runner that is not a TRD Pro, is more at risk of being mangled. I know I keep it in mind when on a 4wd trail. I generally don't go on really difficult trails anymore, so it hasn't been smashed yet.

See my pic for an example of exhaust tip vulnerability.

 

[ROKREDY]

Thanks for the pic. I don't have to go find one now on the road to see the rear type of pipe. LOL
Ya, that does stick out back some...they did on my Cruisers but we cut them back a few inches to shorten them.
I'm just going to have to take the thing out on a trail I know well and experiment.

 

[02SE]

I should add that what you see is the factory optional accessory chrome exhaust tip. I don't mind a little chrome, and it doesn't stick out much further than the unfinished pipe would. If I ever hit it, I'll be looking to modify it to a side exit like your TRD Pro.

 

[Bmnorm2]

It will likely get louder and will drone more as it breaks in. It's also louder when it's hot out; thermal dynamics of the metal at play. Ours did both of these things.

There are only two V6s I'm aware of that sound amazing. One is the first gen NSX and two is the Alfa Romeo Giulia Quadrifoglio. In the past I had modded Nissan/Infiniti cars with the VQ series V6 motors. I learned that you can't modify the catback on those cars unless you're willing to put up with drone and rasp. The 4.0 V6 in the 4Runner is no different and I should have known better. I assumed that since it was an OEM system, Toyota would make it pretty tame and dial out any severe drone. I was wrong. I should have paid attention to what most legit offroaders DON'T do with their 4Runners (i.e., modify the exhaust).

Don't forget the VR6 - Narrow angle V6 with single head. I agree though, typical V6 does not sound great. If i have a choice with 6 cylinders its I6 or H6.

Also agree that the TRD exhaust could be improved by correcting the length/diameter of the resonator.

 

[rageandlove]

Ohhhh interesting! EXCELLENT POINT! Cruisers do not have active rear windows so a rear-facing pipe is a non-issue. Hmmm...so ya, if we want to use that window then I might need to rethink this. GOOD INFO! Gawd I can see me mangling that pipe though when dropping down a ledge or rock. Well, I'm learning my 4Runner. Thanks!

The straight-back is easy to mangle too. Ask me how I know. It's one of the first things that's going to give away the fact you are close to max departure angle ...

 

[matoolie]

[MENTION=704590]ROKREDY[/MENTION]

As rageandlove has pointed out, the rear exit does impact departure angle and fumes can get into back with rear window down.

I also hated the TRD muffler but like the side exit. So I swapped out the TRD muffler for the quieter standard muffler. But it is not a direct Bolt on swap due to Toyotas bright idea of using a 3 bolt flange for the side exit pipe and a 2 bolt flange for standard rear exit pipe. So you have to cut the 3 bolt flange off TRD muffler and weld it onto the standard muffler. Not a big deal for a diy welder or any muffler shop.

 

[Voodoo762]

If anyone with a TRD Pro exaust would like to exchange catbacks, I am willing and located in CT. I have a 2019 TRD Pro with just under 50K miles.