2020 MTO3 Slip-On Exhaust $147 used from Ebay, also (blacked out Akropovic) unit 1.9 kg lighter & 5.3 db. louder than OEM slip-on

YouTube video covering this upgrade life now https://youtu.be/_3u-hgu-u00?si=C8PqbSaZLY-bHYon

Latest update: got a Used 2020 Yamaha MT03 slip-on exhaust on Ebay that also works on the YZF R3 and R25, and it cost me $147 all said shipped with tax. 

It's 4.2 lb. or 1.9 kg lower weight than OEM unit and 5.3 db. louder according to manufacturer testing table date in the listed table after the image of the blacked out Akrapovič I purchased used on Ebay! 

Order date:Jul 25, 2024 Order Total:US $146.75
Fri, Jul 26, 8:59pm DHL Tracking Number Provided
Sun, Jul 28, 8:16am Departed from DHL HONG KONG-HKG
Mon, Jul 29, 2:14am Departed from DHL CINCINNATI HUB,OH-USA
Mon, Jul 29 4:22am Arrived DHL Sort Facility SEATTLE,WA-USA SEATTLE,WA
Estimated Time of Arrival July 30, 2024 - By End of Day

Monday, July 29, 2024 at 10:19 AM Local time, SEATTLE - Washington - USA

Official slip-on exhaust units for the 20202 MT03 units were $249 to $900, so I did an aggressive price point search for a much lower cost solution, similar to what I did to remedy the catalytic convert thefts from our 2010 Prius III and previous 2005 Prius II. Namely hours of searching Google, Ebay & Amazon.

The OEM exhaust cannister weighs over 5lbs or 2.2kg and will be replaced with the aftermarket akropovic I purchased used on Ebay. 

I was not sure if the aftermarket Chinese parts from Amazon would fit, and after waiting for them to arrive, and removing the stock slip on, I found that the adapter was not right and the fitment would not work correctly even with the included bracket. 

I promptly went on Amazon and returned both parts, drove them in the box they shipped in with QR codes from Amazon for the return to the local UPS shop where they bagged the adapter with a label, then put the pipe in the box and put an label on it, after scanning both QR codes that I had printed out on our antique Brother 2040 B&W laser printer since I don't like fiddling with my phone for such purposed. 

I have modified the exhaust system of almost all the motor vehicles I have ever owned. We deliberately leave the Audi, Prius III, Corolla Hybrid and PCX150 exhaust systems OEM because we like lower sound pressure levels from those engines and exhaust systems. The MTO3 more of a fun commuter and a slightly louder exhaust is something only I will really enjoy and might in some instances improve safety by helping another motorist to detect my bike and I riding nearby. 

The following parts were returned to Amazon, after filling out the item return forms for each online, then bringing printed QR codes for each, with the original shipping packaging and box, to the local UPS shop that bagged, taped, boxed and labeled the items for free, helping to make a painless return. It would have been nice to be able to use these cheaper parts, $60 all said for both with tax and shipping, but Ebay had a great deal on a used version of the expensive one I wanted anyway! 

Heran119 Motorcycle Short Exhaust Muffler 
51mm input (adapter to enable connection to 38mm)
Length 260mm (10.23") 110mm max diameter (4.33")
Stainless Steel 1.17kg (2.58 lbs.) 

Stainless steel middle connecting pipe sleeve adapter connector 

For a related upcoming YouTube video I already recorded the stock exhaust from cold start to full warm, then two full throttle revs with the clutch pulled in neutral to document the sound before the update. 

I will also record the same run from cold to warm with two full throttle twist bursts to redline without the factory or OEM slip-in or straight out of the cat, which should be about 120 db., while the factory system peaks at 88 db., the akropovic unit used from Ebay claimed to be 5.3 db. louder and more throaty or deeper sounding than the somewhat nasal sounding factory exhaust according to comments on the listing of the new akropovic units selling for $348 on sale, so $382 with tax and shipping, so I saved over $236 buying it used vs new, and the blacked out color matched the midnight black color scheme of our 2020 MTO3 anyway :) 

Reflecting on Engine Exhaust Sounds

Noise or sound pressure or harmonics or acoustics, be that from brown noise that people use to help them sleep, or white or pink or red noise for the same purpose, sound pressure consists of air molecules vibrating together transmitting waves of energy like generated on the surface of water if your throw and skip a flat rock across the surface of the water and see and or hear the impacts producing circular radiating ripples that move away from the point of impact.

Engines produces very loud exhaust if you hear a strait pipe racing vehicle or small aircraft with piston engines where small, short metal pipes dump the exhaust without a catalytic converter or muffler or any sort of sound suppression or noise reduction.  

In higher performance motorcycles, sports cars, supercars, the makers or manufacturers pay extra attention to tuning the sound of the exhaust system. The use words like "fun, engaging, exotic" to describe tastefully tuned louder exhaust systems. The engines intake system can also be tuned to improve the sounds the rider or driver hears. I am thinking of the Lexus LFA or BMW M cars or Chevy Corvette or Dodge Viper or Moto GP race tuned sports motorcycles with 1000 cc or 1 liter engines that make 180, 200, 220 or 240 hp and rev to 18,000 rpm like and F1 cars engine. 

No replacement for displacement was a term describing large V8 engines naturally aspirated that idle at lower RPM levels with a low pitch deep rumble that many motor vehicle enthusiasts find pleasing to listen to or hear. These V8 exhausts sound amazing from idle to redline and everywhere in between, but they also tend to be over 600 lbs. or very heavy as engines and result in very low fuel economy and higher maintenance costs, and worse emissions, though in something as smooth and refined as the 1UZ engine of the Lexus LS400 with its 4 liter V8 engine sports closed loop 3 way catalytic converters and four O2 sensors feeding the ECU voltage signals as a way of measuring exhaust gas temperature electronically. 

Even our 2020 Yamaha MT03 water/glycol cooled, electronic fuel injected, with O2 sensor catalytic converter exhaust system featuring air induction to burn any unburn HC or hydrocarbon by allowing air into the cat to enable it to burn hotter and more efficiently convert poisonous exhaust gas NOX, HC, SOX, PM and similar to be converted into safe carbon dioxide, nitrogen and oxygen gas, water vapor or 95% cleaner exhaust in terms of the reduction in smog forming components. The 320.3 cc offset twin's crank case vapor is filtered in an activated carbon cartridge connected to the engines air intake so that oily fumes of lighter molecules exiting the crank case are burned as fuel in the engine, further reducing emissions. 

Cat back exhaust system like the one in this post, mean the aftermarket pipe attached downstream of the catalytic converter and do not alter the emissions controls. They primarily increase exhaust sound pressure levels and change the tone of the exhaust. 

In this specific case the MTO3 OEM slip on sounds nasal higher pitch or airy with a peak 88 db. sound pressure level at 12,500 RPM, while the aftermarket slip-on makes the exhaust sound deeper with lower pitch tone and about 7 db. louder. Removing the slip on entirely and straight piping off the catalytic converter sounds much louder and harsh with around 110 db. at idle and 120 db. near redline according to others who have tested and posted online articles about it. 

I am effectively adding $50 of stainless steel to gently increase the exhaust sounds without going to the extreme of a a full race exhaust like I did on our previous 2019 Honda Grom SF to eek as much power out of its little 125 cc engine as possible to up the highway speed in 4th gear, but even going from 9 hp to 12.5hp did not result in good highway performance. 

The Grom's shorter wheelbase and lack of 5th or 6th gear meant it was super fun and nimble around town in city use cases, but very lackluster above 50 MPH and I live in America where everything connected by 60 MPH freeways and highways as the only practical way to get around. Even on 35 MPH local neighborhood or street level 25 MPH roads, the hills are so steep that the Grom barely had enough power to work well. 

I spent a lot of time in 2nd and 3rd gear in the Grom and traded it in for the MT03 since the MTO3 produces ~40 hp and has a top speed of 112 MPH, while it can cruise in 6th gear at 65 to 85 MPH all day, which I recently did a lot of on a longer 800+ mile road trip. Honda revised the Honda Grom in 2022 and added a 5th gear and increased the size of the fuel tank from 1.1 to 2.1 gallons. They did the same thing with revision of the Honda PCX-150, increasing the engines displacement from 153 cc to 156 cc, and increasing the fuel tank size from 1.1 to 2.1 gallons. 

Noise Pollution

Motorsports can be very loud, and virtually everyone understands this. When the catalytic converter was stollen off of Meg's 2010 Prius III, she went out to leave for work, then came back inside and said "Aaron, something is terribly wrong with the car, it is making a horrendous loud harsh noise. I went outside and looked under the car to see the header pipe dangling with no cat or O2 sensor downstream, so I said "Meg, that is what your car's engine exhaust sounds like without an exhaust emissions control and muffler noise reduction system, or what we call "Straight pipes" in motorsports lingo. The same thing happened when someone stole the cat off the 2005 Prius II that now belongs to Allan. I drove it around loud without the cat for over a week to and from work without bother from anyone, while waiting for the replacement parts I ordered online to fix the problem DIY on her car and mine. 

I spent less than $500 all said fixing both cars, but both have to have the MIL lamp reset using an OBDIII tool plugged into the related port under the steering wheel since the thermal performance of the aftermarket cats and cheap O2 sensors produce the out of parameter voltage so the ECU logs and emissions problem causing the master warning light on the dash to glow orange with its problem symbol. 4 button presses of the tools OK button resets the emissions codes P0000 and P0420 respectively, and we have to do that every time we drive Meg's car now. 

Where You Live 

I live just south of interstate 90 in Issaquah about 700ft elevation, and every night I hear different high performance loud motorcycles and cars going well over 100 MPH at high loud RPM engines speeds ripping down I90 eastbound and wonder what the Washington State Patrol are doing at 3am, since I never hear these speeders or street racers being pulled over?

Through streets often have more road noise, so sound sensitive people often buy housing or rent homes in dead ends without through traffic or not near noisy transportation systems. Sound pollution means sounds you cannot control, like air pollution from the airport and very high levels of sound pollution from commercial airports. 

Public Transportation

I post, read online, watch videos about, and have a mild obsession with vehicles of all kinds. I love motors and engines and the sound of engines and smell of gasoline and diesel and associate all of those with progress, innovation and applied technology, but also the freedom to go places or easily quickly get to and from places commuting or while running errands driving on public roads in a car that you own since local bus system vastly slower and very inconvenient, rarely on time, requiring standing around a lot and making it take 4X longer to go somewhere and it's not free either. Almost the opposite of the rail in New York City or London England or Tokyo Japan, where its cheaper, faster and easier to use public transportation as busses, trams, light rail, or railroad passenger transportation. 

Engines & Vehicles Have Improved Greatly

Consider the earliest Benz Patent Motorwagen made by Karl Benz, with its externally lubricated 954 cc single engine making barely 1 hp, later versions with improved lubrication and less maintenance made 2 hp. Engines of the same displacement today, 1 L singles, make over 40 HP or are twenty times more powerful, smaller, lighter weight, can rev higher, make more torque over a broad range of RPMs, get better fuel economy, and are cleaner burning with 95% reduction in toxic smog forming tailpipe emissions vs earlier carburetor fueled engines, using a combination of fuel injection, better gasoline, better engines, exhaust catalytic converter and O2 EGT voltage sensors feeding the ECU data to tune the spark timing, variable valve, variable fuel injection timing and duration, using MAF air flow hot wire sensor voltage signals, and signals from the engines knock sensor and crank position sensor. Modern ECU have 3D maps for fueling and ignition timing and take in data from many engine sensors to tune on demand based on user throttle requests, the vehicle speed, engine operating temperature, the air temperature, slope of the roadway, transmission gear selection and many other channels of data. Automobiles sold in in America after 2014 have an electronic black box data recording system in the OBDII as embedded passively cooled computer modules and have a persistent mobile data connection with ECU OBD wireless 4G-LTE mobile broadband that is always on if the vehicles 12vdc battery charged, even when you turn the vehicle off, the computer stays on to listen for the smart-key. 

Dead Vehicle Batteries

Even battery electric vehicles with large lithium-ion traction batteries like a Nissan Leaf or Tesla Model 3 or Model Y, still have a mission critical 12-volt battery that runs all the vehicle systems that were designed and long used with alternators and SLI batteries in gas powered vehicles before electric vehicles became widely available. 

This means your BEV can have a dead 12v battery that makes it impossible to drive until you recharge the 12v battery or jump it with a jump pack or jumper cables hooked up to other vehicles 12v battery and ground to a chassis bolt nut on the strut tower for example or the engine grounding cable connection, where you can attach the negative black cables. 

Almost all modern vehicles have a negative "black" ground attached to the metal body of the vehicle. In the early days of cars, the did "red" positive connections to the chassis, but because electrons in reality flow out of the positive, that causes increased corrosion or rusting. 

From chemistry, OIL RIG oxidation is lost electrons, reduction is gained electrons, so corrosion from salt water and oxygen facilitated more effectively with a positive vehicle ground. Thats why negative ground systems are used on almost all vehicles today, doing so is safer and reduces corrosion. 

If you park a newer than 2017 vehicle for more than 10 days all the always on computers can drain your vehicle battery flat or deplete its charge completely so you come to dead vehicle, and have to use a mechanical key to open the driver's door to pull the hood latch and then use another vehicle with jumper cables to boost the battery or hook up a battery charger and wait 20 hours for the charge to complete.

You can buy and keep a portable lithium-ion battery jumper or jump pack with your car, in the truck tray area where the spare tire or tire repair kit located. These portable battery jumpers are compact, and also typically have LED flashlights and screens displaying relevant information like the state of charge of the jump pack, or voltage of the vehicle battery when you connect the jump pack to your vehicle's battery. 

Always connect the red positive cable first as that usually prevents a high amperage current pulse from damaging your vehicles electronics, fuse box, relays or wiring harnesses that can be easily damaged if your hook up the negative first and then put the positive connection on, when using jumper cables always connect the positives or red cable first!