Some fun facts from fellow Tacoma owner and YouTuber Jason Explains things. The Magnaflow overland exhaust provides about 1/2″ of additional ground clearance at the exhaust tip and muffler (which we verified) and about 10 db more of noise. My first honest impression of startup was very stock-like. Sonically there’s something deeper at the low end of the RPM range that just wasn’t there before. The more we drive the truck with this exhaust the more we like it. It’s aggressive but never intrusive or punishing.
Dyno and Sound Clips
At this point you no doubt want to hear what the Magnaflow Overland Exhaust sounds like. Here’s a short video with with various perspectives along with the stock exhaust for comparison.
As pictured previously we’ve run the exhaust with the full Helmholtz pipe and additional muffler in place. It’s pleasant to drive both on the freeway and around town. Strangely sometimes the exhaust seems louder with the windows up! Which may have more to do with the rear exhaust tip being tucked under the body for ground clearance. Regardless, it’s not too loud in the cabin and the noise is good for a V6 truck. We’ll report back after we try the other sound configurations.
5 comments
Is the Helmholtz resonator piping tunable? e.g. you can move it in and out for adjusting to things like perhaps an open element intake or headers sans cats that change the sound for the worse? Or it’s fixed per MF’s own tuning?
Also, great job on all the video cuts showing before and after in all the scenarios. One addition I would request, video of Duffy growling for food for comparison. I mean you did reference him…
Good question. If you go to the top of page 2 you can see all the tube pieces for the resonator. So you can run:
1. The tube off the muffler with the helmholtz resonator (quietest)
2. The tube off the muffler with a cap on the end (louder)
3. The cap on the muffler (loudest)
I have only run option 1 and it’s both loud enough when I want it to be and quiet enough when I want it. My wife said it does get a little loud in the back when the RPM’s are up and the truck is loaded with people and gear. Wives are good for pointing out those details 😀 I would think part of the extra noise is due to the overland setup has the exit pipe underneath the bed where the conventional exhaust has the exit outside of the bed of the truck.
Duffy is a little camera shy but I’ll do my best.
Bummer MF didn’t allow for “tuning,” of the helmholtz filter. Then again, packaging constraints could have prevented that.
The math to figure it out last I looked had you get the EGT, frequency, RPM, cyl count, and a few other things, into a formula.. Of which, I would have to pay someone to figure out for me… And bam you’re given a pipe length to use. Often just a section of j-pipe welded inline.
But perhaps later you change a variable in your intake and exhaust system, and your peak resonance changes by 300 RPM, and your set length doesn’t work as effectively. Re-do the math, and figure out the new length required to tone down that resonance. Here is where being able to slide the helmholtz setup in or out, changing it’s length was where I was getting at. I think I’ve seen a catback like that in the past for a Focus or something like that?
In the end, I do like that the manufacturers are doing more and doing better to control sound in cabin. Not to mention MF nailed it with a great price.
These sorts of nerd level comments are why I love MotoIQ (shameless plug). I had professor Khiem Dinh author of fameous projects like S2000 and Cayman T work up a custom resonator like your mentioning for my now long gone Civic SI exhaust featured here. I never got around to it even though I had all the parts. Welding stainless can get expensive and I decided I needed a car with more torque and then started on project G37. Sorry for all the rabbit hole comments 😀
Oh yeah… I remember doing some estimated calcs back in the day!