Sedole's Gen 3 - the Iron Hog

sedole

Member
Back to that grill: drawing on inspiration from gen 1 montero grills and the ever so trendy grills of the modern truck world, I ended up with this. The spotties cover it up for the most part, but I still think it adds a nice little flair to the front end.





Now, to add a little more bark to match the tough looks of this truck. On my gen 1 I added a tiny magnaflow can which was loud and burbly but yet didn't give me much drone at all. I figured I'd do the same here.




And loud it definitely was.. Much louder than my gen 1. The tone was deep and smooth and I could set off car alarms at will, but the drone at highway cruising speeds was unbearable. So a couple days later I chopped it off and welded on a larger, yet still straight through free-flowing magnaflow. I also added some new exhaust hangers to fix the saggy old factory ones. Red for the +5 hp gain of course.






This setup is significantly better than the small can. It's pretty much stock noise level at idle, louder than stock yet still quiet on normal throttle, and a loud non-obnoxious loudness when you step on the go pedal. Volume wise, it's perfect for me. However, I'm still getting some drone. It's much less than with the smaller can, and some would probably call it acceptable, but I know that it would drive me crazy on long trips. I'm looking into fabricating a helmholtz resonator. More on that later.
 

Inyo_man

Explorer
Did you delete the OEM resonator?
When I replaced the suitcase size factory muffler and deleted the resonator, I went with a muffler with an internal resonator.
It is certainly louder, but not too bad.
 

AZPAJERO

Observer
You are getting this thing DIALED. Nice work.

Curious to hear what she sounds like now. Possible to post vid ? Also, I'm looking to do something similar to the wifes Gen 3 grill. Any pointers ? ;)
 

Recommended books for Overlanding

sedole

Member
Did you delete the OEM resonator?
When I replaced the suitcase size factory muffler and deleted the resonator, I went with a muffler with an internal resonator.
It is certainly louder, but not too bad.
I kept the OEM resonator. I really like the volume, but it does have a constant highway drone from 2200 rpm and up. Especially bad at 2800 where I tend to cruise. I will say though that my girlfriend hasn't complained at all about it and another friend mentioned he could hear it, but it's tolerable. I played in a wind symphony for several years so maybe I'm just cursed with being able to pick up on all the background noises and not let it just disappear...into the background. ha ha..

I thought about even adding another small resonator in between the factory cat and the muffler, but then my research led me to helmholtz resonators and I feel that will work best since they are (1) cheap to make and (2) can directly target certain frequencies to cancel out...as long as I get my math right lol..been a minute since university physics class!


You are getting this thing DIALED. Nice work.

Curious to hear what she sounds like now. Possible to post vid ? Also, I'm looking to do something similar to the wifes Gen 3 grill. Any pointers ? ;)
Thanks thanks 🙏 Admittedly, I like to tinker just as much (or maybe more) than actually go out and use the truck haha

I'll try to post a vid at some point either here if I can figure out or on the face book. It sounds good buuuut not as good as my Gen 1 good (which was HF cat and the small magnaflow can---basically straight piped hah). If you've ever heard or ridden in a gen 2 Raptor with the stock exhaust, it reminds me a lot of that, except just a touch louder. And same with that truck, it sounds good to some, meh to others.


For the grill just take it off, remove the mesh, and start cutting! I cut off pieces as close to the edge as I could with the angle grinder cutoff disk and then finished it with a sanding drum on a dremel. Honestly pretty quick work with power tools since it's plastic. I didn't even bother re-painting it lol. I ordered new mesh since it was cheap and I wanted to delete the little triangle support on the bottom. Letters were fairly cheap on ebay as well--epoxied on cause I had some laying around.




Tiny update:

Doing more math and research on the helmholtz resonator aka J tube resonator aka 1/4 pipe resonator. All the parts I needed (just a 90* bend and a band clamp) are in now so I'll start welding it up hopefully this weekend. Fingers crossed it works. The physics behind it seem promising!

I was going to weld it on tonight, but I ended up driving 100 ish miles to pick up some new tires! Got these for a serious steal! 5 Yokohama Geolander X-AT LT287/70/17 E tires on 5 JK alloy wheels. Less than 1,000 miles and only $450. !!! The ad was posted for a couple weeks with vague wording and the price seemed way to good to be true. I almost thought it was a scam, but decided to message the guy anyways. Turned out to be true and the guy was just a well to do guy who bought 33s, drove on em for a week and decided to buy the exact same tire in a 35! Yay me! I figure I could also sell the 5 JK alloys for maybe $100 and then get another $100 for the 4 Falken Wildpeaks I currently have on my truck. I also bought another 4runner sr5 wheel since I really should have a matching spare...now that I have 5 matching tires!




The only downsides to this tire that I'm concerned about are that it's E rated (I would have preferred C), they are heavy at 62lbs a pop, and this tread pattern is bound to produce some road noise (though Yokohama claims they engineered the groove angles to cancel out road noise 🤷‍♂️). Other than that, it's a new tire to the market (June 2019) so no real credibility yet, but for the price I figured what the hell, why not! I'm really excited to try these puppies out. I'm hoping I'll love them enough to be able to refer to them as my "yokohammers"

A plus to the E rating is that during the ski season I more often than not am driving and carrying 5 adults (including myself) and ski gear (skis/boots/poles/helmets/clothing) for a weekend for 5 people as well. That extra 1,000 lbs or so should help the tires ride a bit nicer on trips.

I was going to settle for Yokohama G015 AT tires for their significantly lighter weight and 100% for sure less road noise and promise of better mpg, but I did have doubts as to their muddy/several inches of snowy condition abilities--something I encounter a lot during the ski season. Plus I'm sure I would find myself wanting for a little more when I do go offroad (albiet only once every month or so--except in winter!) On road and even wet and lightly snowed road I'm sure these would've blown the others out of the water, but I just couldn't beat that $450 price.


And to add the cherry on top, I picked up some 4.9s from a fellow member on the Facebook socal montero page. Now if I could just track down an LSD...

 
Last edited:

Inyo_man

Explorer
Great find on those wheels!

Don't worry about the E-load...
As you said, it'll be find once you have a constant load.
...bumper, winch, bash plates, roof rack, tools, recovery gear, high lift...then add on cooler, water, food, camping gear, passengers, etc...

Nice build!
Thanks for posting!

Cheers
 

sedole

Member
33's are on!





Carrier flip to fit the spare. Fits very snug! Only about 2mm clearance from the wiper arm!






The rear wheels clear just fine and don't scrub at all, but the fronts needed a little help. No scrubbing during slow speed turns, but faster turns or during articulation I got quite a bit. Quick work with some pliers and a hammer. I just noticed that sharp ish edge on the closest part to the tire. I just went back out and gave it a few more love taps with the hammer.




About 30 on-road miles with the tires now and impressions are great! I don't know if my Falkens (2 years old and 25k miles) were just starting to get hard or if that's how they normally are, but these new Yokos ride fantastic. For an E rated, it honestly feels about the same comfort level as the B rated Falkens. And I don't know how Yokohama does it, but their claim that these have minimal road noise due to tread design is indeed true! These tires are damn quiet! Now, they're no highway tire of course, but even at 75mph the road noise is negligible. I hear the wind and honestly don't hear tire noise at all. Windows cracked I can still hear a muted whir, but man, these suckers quiet! So much quieter than the Falkens! I'm able to keep the volume on the stereo 3 levels lower and can hold a conversation easily. I just realized that I used to have to shout a little before, but now I don't. Handling wise they feel great and honestly acceleration didn't take as drastic as a hit as I had expected. What really suffers is braking performance, however. Something I'll be looking into. Super stoked to try these out off road. 4.90s going in soon! I'm running at 36 psi front and 34 psi rear.

Now, back to that funky resonator I was talking about before. I'll try my best to explain and keep it short. So this thing I've built is commonly referred to as a helmholtz resonator or a 1/4 wave resonator or a J tube resonator. What it does is send a sound wave that is at the exact opposite to the sound wave causing the drone to cancel it out. Pretty much the same way noise cancelling headphones work. So, what you have to do is have a tube coming off your main exhaust pipe (can be anywhere it fits) at 90*. This tube is capped off and then the length has to be 1/4 the wavelength of the soundwave for the frequency you are targeting. So, this means that sound will travel into the tube, bounce back off the end of it, and by the time it reaches the main exhaust pipe, it will be exactly opposite the wavelength and cancel your dronez. It's also slightly variable, so in my reading and personal experience it cancels drone at a certain RPM +/- 200RPM. So a 400RPM range.

There are calculations you can do to figure out what frequency to target and from there you can also calculate the length of the tube you need. I calculated the frequency as well as used a free iphone app to measure the drone. My targeted droning RPM for the speed I cruise at is 2800. The calculated frequency using formula f = 2800 rpm * 3 pulses/rev * (1/60) came out to 140 Hz. The measured frequency seemed to peak at 125 Hz with 110 Hz and 140 Hz also quite high. Now you have to calculate the wavelength and length of pipe you need. So, using 343m/s as the speed of sound, speed of sound divided by frequency will give you the wavelength in meters. Divide this by 4 and you have the length of pipe you need, in meters.

Now, these calculations will not be perfect for a couple reasons. Pipe diameter makes a difference in how broad/narrowly your drone cancelling range will be. Narrower will cancel out better, but have a smaller effective range. Opposite for larger. I chose 2.5" pipe cause that's what I had available to me. Also speed of sound might not be exactly 343 m/s in this instance. Pressure and temperature will affect it, I think. Therefore, I made my pipe with a slip fitting in the middle so I can experiment with different lengths and tune my system. Also once I add 4.90s it's gonna throw my cruising RPM off, soooo I needed adjustability.

That in mind, I decided to go with the lowest frequency giving me the longest pipe cause it's a lot easier to shorten than lengthen. So 110 Hz gives me a pipe length of about 30.5 inches. For consistency sake, I'm measuring from the midpoint of the 90* elbow to the end of the pipe. Time to break out the sparky gun and hope this works! Not pictured is the band clamp for the slip fitting. Also I did all these calculations of cruising RPM when I still had the 32's on the truck.




Holy hell it works! I love science! Exhaust volume is not changed. But, drone starts to build around 1900 RPMs then at 2300 RPMs it's DEAD SILENT until 2700 RPMs where drone quietly starts to taper back into ear hole detection. My cruising speed with the 33's is about 73-74 mph at 2550 RPM. It is literally SILENT. NO DRONE AT ALL! Or shall I say: no drone at all! Get it, because it's quiet? These new tires are quiet and the exhaust at cruising is silent like stock. I love it! Then, when you punch it, the beast roars to life and I still get a sporty, loud exhaust note! Best of both worlds! It's honestly such an interesting sensation because then drone starts to build and since I've gotten used to it being there I start to groan ughhh here it comes, and then it's just silent! Amazing!

One other thing I've noticed with these exhaust modifications is that the magnaflow unit seems to put out a lot of heat. The floorboard in the passenger area directly above it gets pretty warm and the undercoating starts to take on a little bit of a "wet" look. I very well may have small exhaust leaks at my welded joints, but also some of these marks are directly over the 18" span of the muffler which is one continuous piece of metal sheet. I've ordered some head shields to try and combat this.
 
Last edited:

sedole

Member
Update!

Following the recommendation from SONICMASD's thread, I too decided to replace my 4wd solenoid. And bingo! Cured the grindy-vibration type noise I was having at 80mph +. Now we're rollin smooth as silk!



Also added a generic heat shield to the exhaust because as you can see..things were looking a little melty above the new muffler. This has actually helped tremendously.





And the big ticket item I spent all weekend on: 4.90 gears! Definitely one of the more labor intensive jobs so far. My scrawny ass wrestling this behemoth by myself underneath the Montero while on the ground on my back was definitely not a winning scenario. Eventually I got smart and figured out I could use ratchet straps to help balance and guide the pumpkin into place while jacking it up. My recommendation: phone a friend, use a lift, or pay someone else to do it. ha ha. I started Friday and didn't finish until Monday morning. Maybe a total of 8 hours across those 4 days. It didn't help that most of my bolts were corroded and hard to break loose (and I don't own an impact gun).. Because of this, I didn't get to do the front, but I'll be out of the country for the second half of september so not a huge deal to me. I'll find time later.

Also, because I'm a lazy ass, I decided partway through dropping the gas tank that I should just chop the bolt and buy a new one instead. A hillman 9/16-12x3 grade 8 bolt was a perfect fit! It fit the bushing sleeve with a tighter tolerance than the oem one! If I had to do it again though, I'd buy 3.5" length to fit a lock washer on as well. I used loctite instead. Should be ok.






In the process of dropping the tank I noticed a big dent :oops:. I was hoping to be able to blame the previous owner, but since she was a literal soccer mom, I doubt she ever got it into a sticky enough situation lol. Then I remembered that I high centered myself on some snow/rocks this winter....Sooo I probably only have myself to blame 🤫

Anyways...first impressions of the 4.90s with 33s: This beast can Hustle! Seriously it's noticeably quicker with this setup than it was when I originally bought it! (stock tire size but heavier-ish aftermarket wheels). I'm definitely a fan!

For those wondering, my city mpg on the one tank of 33s and 4.30 gears I did was 10.2 mpg. I'll report later how the 4.90s affect it.

Another update on the tires: I still think they are quiet, very smooth riding, and provide good on road handling. And they look great too! I've only had them in dirt and gravel so far, but so far I'm impressed! Grip is excellent and they ride a little nicer than my old Falkens. They definitely like to go fast and have a some hoon style fun in the dirt--which is what Yokohama seems to advertise. Now all I'm wondering is how much lighter on her feet the truck would feel with some lighter weight 33s (These yokos are 62 lbs each 😬)!
 

southofantarctica

Brush Dawg
Ah yes, I remember well the process of swapping in the 4.90s... I'd phone a friend for the front too, while it is easier than the rear I still was using two jacks to get it all lined up and pretty much a whole day. I bet I would have saved several hours with help.

Are you going to try to fix the dent? I'm in the same boat, but I can blame the previous owner!
 

Recommended books for Overlanding

sedole

Member
Spent my Friday morning doing a little maintenance to try and fix the grumbling noise I was getting at 3k rpms during highway speed, as well as the excessive driveline slop. After some researching, I concluded the likely culprit was old transmission fluid causing the ever so common torque converter shudder. Even though I previously did a drain and fill I (reluctantly) accepted that I wasted my money in doing so and the fluid was still crap. This time around I did a proper flush, including flushing through 8 quarts of new Aisin sp3 until fresh fluid came out, dropping the pan to clean the magnets/sludge, replace the filter, and while I was in there, replacing crossmember bushes and the trans mount.





Little bit of sludge and metal shavings in the pan...not too bad for nearly 180k miles.


And filled her up with the goods:


Verdict: The mounts and bushes have definitely improved the driveline slop. It's not gone, but is now probably 20% of what it used to be. The shudder was still present for the first 15-20 miles, but as I put more miles in it slowly started to go away. I'm at about 100 miles into this fluid now and it's decreased significantly to the point where I'm only barely able to detect it. It used to be a 8/10 loud annoyance and now it's probably down to 1/10. Hoping that it will continue to go away. I might do another flush after a pretty short interval if it doesn't completely go away. Or I might do it anyways just to make sure all that old junk gets out of my fluids.


Lastly, another quick mod to just make life a little easier: a yellowbox v5 speedometer corrector. It enables you to manually calibrate your speedometer up to a 100th of a percentage and for a small extra charge, can be made plug and play from the company. Install and setup took all of about 5 minutes. Drove around a bit and adjusted again to fine tune the calibration and adjust again. It works perfectly! I know having a speedometer be off by a little is not a huge deal, but it's annoying and these units really aren't too expensive. With the 33s and 4.90s, I calculated (using GPS) my speedometer read 5.5% high. Now it's pretty darn accurate.



The adapter harness plugs into this plug:





Also, just wanted to mention that I have noticed that the 4.90s recovered some of the mpg that I lost from the 33s. My city mileage (with 265/70/17s) was 11.5-12 mpg. Keep in mind my "commute" is 2.1 miles and has 7 stop signs and 2 stop lights. With the 285/70/17s I saw 10-10.5. After the 4.90s I'm seeing 11-11.5 mpg. I've been having fun with all this newfound getup and go so I'm sure that number will go up slightly over time haha.
 

southofantarctica

Brush Dawg
Also have one of those yellow box things....mines just been sitting on my desk for two months. I've kept convincing myself that it's going to take at least an hour, looks like I've been wrong. How much back and forth did it take to get the calculations right?
 
Top