The heat sheld can be removed completely but beware when you park where the mid pipe touches dried grass!

 

Thank you so much for the reply! Do you by chance know the diameter of the mid-pipe? And is it fine to run the car on an open mid-pipe setup?

 

Don't think you can do that without triggering the CEL light as there is an 02 sensor just before the flange.

 

Oh dang, I was thinking on putting it on either of this side. It's a valve so maybe I can keep it close most the time and open it on meets and on tunnels 😂

 

I thought that valves was a better option than putting the stock muffler every 2 years.

This is EXACTLY what I used to do. I personally saw it as a periodic inspection and refresh. New gaskets, new injector orings, oil change etc.... I think I got it down to about 2 hours to convert to inspection mode. At the time that was fuel rail, turbo, intercooler, ECU and quite a few other things. Then a week or so after passing inspection for the new upgrades that would inevitably go on.

From what I recall of Japan, there seem to be plenty of people who get passed inspection with things that are quite the opposite of stock. Maybe you need to own your own "garage". That would explain why there are so many little workshops that have almost no customers. If you're not from there maybe you could find a friendly person who is shopping at Superautobacs and just ask about their car. When they show you something that clearly is non compliant just ask the question how they keep inspection with that part.

 

This is EXACTLY what I used to do. I personally saw it as a periodic inspection and refresh. New gaskets, new injector orings, oil change etc.... I think I got it down to about 2 hours to convert to inspection mode. At the time that was fuel rail, turbo, intercooler, ECU and quite a few other things. Then a week or so after passing inspection for the new upgrades that would inevitably go on.

From what I recall of Japan, there seem to be plenty of people who get passed inspection with things that are quite the opposite of stock. Maybe you need to own your own "garage". That would explain why there are so many little workshops that have almost no customers. If you're not from there maybe you could find a friendly person who is shopping at Superautobacs and just ask about their car. When they show you something that clearly is non compliant just ask the question how they keep inspection with that part.

Yeah... I have an access to a garage right now (I currently work at Eneos, living that Initial D life) but I'm quitting next year since I'll be graduating and joining another company. So I was looking for a more "permanent" fix. From what I've seen most exhaust valves are allowed in the inspection. It is still a gray area, we do PRE-inspections for customers at my job. I learned that the main inspections is all at the whim of the inspector, so it's basically a hit or miss (It's better when you know someone, unless the modifications are just plain illegal).

 

There are plenty mufflers on Buyee.jp thoses days (~20.000 yens mostly) :

• HKS Legal muffler (x3)
• Trial titanium (ultra rare)
• Rosso Modelo
• Amuse R1 Titan (not the Extra R1 Titan)
• Kakimoto Racing
• Hyper Full Mega N1

If your plan is to remove the main cat for a decat, don't do it. The sound will not be as sporty as an aftermarket muffler. Instead, I recommand to buy a aftermarket exhaust, then re-installing the factory one during inspection. It's only a question of time/tools every 2 years, that's not a lot. From my list, the HKS legal muffler is the best choice. The others brands are more for track used.

I've installed an Apexi Exhaust Control Valve (between the muffler/cat section) to mute my Malian Race exhaust. It does work on full throttle after passing 4k rmp, but the exhauts itself is too much free on low rpm range. Meaning that even at low rpm with a light pressure on throttle with the ECV closed, the sound is still thick. There is some noise reduction of course. But to be very quiet (like a TTE muffler by example), I need to let 3mm of space with valve closed, but the back pressure will be too high. More the exhaust flow is restricted > more back pressure there is > less power the engine make > quicker the exhauts gaskets will fails because of the high exhaust temperature > more damage the engine will take.

From the picture of the Apexi ECV, I did used dremel to reduce the valve diameter. That was too much. Open or closed, the sound level was the same😅 So I cut an other 2mm sheet metal with a bigger diameter and it's better now. I really can hear the difference especially on cold start.But still a little bit loud on night. I need to make a slight bigger diameter.

 

I was thinking of putting it after the cat & before the muffler, basically around the area where you put your control valve. I have an aftermarket exhaust similar to the 5zigen but with a bigger tip. It's really bassy and crackles, I'm basically at the limit of what is "legal" in here. I want it a bit louder, but I'll definitely get pulled over if I run a louder exhaust the whole time.

I've looked into control valves, I was worried that if I keep it close most of the time that it may cause too much back pressure in the system. I have seen people use it, but they only use it on startup and when they leave their house, so they don't bother the neighbors. Most of them recommend that if I do run a control valve that I open it as soon as I get on the main road to release the back pressure. Is it just a misconception? I was thinking on keeping a low profile most the time, but have the option to be loud.

 

Brand new, the HKS is as loud as factory (3.8k rpms > ~90db). It's when pushing the pedal gas that make the HKS louder.
Currently I received a used HKS legal muffler bought on Buyee.jp for very cheap. I removed the broken part inside the muffler and have to wait the welder that will weld the hole I've made. Then I will make a comparison between the Malian and HKS (open and closed valve) with a DB meter with the EUROPEAN sound regulation for a reliable measures.

It's not a misconception. From factory the Apexi ECV valve inner diameter is big. Not much gas can flow. I did looked YouTube video of Japanese N/A car with decat using the Apexi ECV. It does work well even if still "loud", but too well to be safe for the engine.

That's why I make an other valve with almost the right diameter. I can drive valve closed when I want without thinking about back pressure. It's easy to tell when the back pressure is too high. I pushed full throttle in 1st gear until feeling the losing power. When the back pressure is too high, the power lost is like 100hp quickly and very soon (~3k rpms for my experience). With my current valve diameter, I can go full throttle until 4.7k rpms without issue. Above that, I feel a tiny power and sound reguation, but nothing of really dramatic. The gas exhaust flow is still enough during some pulls, but not during a trackday.

Tip if the APEXI ECV got interest by a MR-S owner : you need to order the ECV made for Mitsubishi Lancer EVO (bolt 92~110mm). The factory 2m cable being too short, you need to buy the extended 3.5 meter cable. Even if is still short. The only way to gain ~20cm is to cut a hole next to the engine harness, then passing the cable along the center console.

 

Brand new, the HKS is as loud as factory (3.8k rpms > ~90db). It's when pushing the pedal gas that make the HKS louder.
Currently I received a used HKS legal muffler bought on Buyee.jp for very cheap. I removed the broken part inside the muffler and have to wait the welder that will weld the hole I've made. Then I will make a comparison between the Malian and HKS (open and closed valve) with a DB meter with the EUROPEAN sound regulation for a reliable measures.

It's not a misconception. From factory the Apexi ECV valve inner diameter is big. Not much gas can flow. I did looked YouTube video of Japanese N/A car with decat using the Apexi ECV. It does work well even if still "loud", but too well to be safe for the engine.

That's why I make an other valve with almost the right diameter. I can drive valve closed when I want without thinking about back pressure. It's easy to tell when the back pressure is too high. I pushed full throttle in 1st gear until feeling the losing power. When the back pressure is too high, the power lost is like 100hp quickly and very soon (~3k rpms for my experience). With my current valve diameter, I can go full throttle until 4.7k rpms without issue. Above that, I feel a tiny power and sound reguation, but nothing of really dramatic. The gas exhaust flow is still enough during some pulls, but not during a trackday.

Tip if the APEXI ECV got interest by a MR-S owner : the factory 2m cable is way too short. You need to buy the extended 3.5 meter cable. Even if is still short. The only way to gain ~20cm is to cut a hole next to the engine harness, then passing the cable along the center console.

Gotcha thanks for the tip! Looking forward to the comparison.

 

The official MR-S has been homologated at 90 db at 4800 rpms. For European Resident, it's writen in the "grey card" in section "U1" and "U2". U1 mention the db level and U2 the specific rpm.

I used the European noise control homologation. Exactly like in the video
Mentions : nothing should be 3 meters around the car, at the exception of the control guy and driver only. The ambiant db level (engine off) should be record. Ambiant db level is used when the car db level is very close to. In this case, European regulation tolerate the car to make 2~3 db more.

 

So this is just measured free revving? At most tracks it is measured a distance from the track at a high load point. Free revving does not create the same noise level as a loaded engine especially with forced induction.

 

No it's not just free revving. There is a specific rpm target of 80% of the max power. In France, way before all those noise regulation, tracks (not all) are db measuring tool equipped at some points of the track. Now, your car shoud meet db noise level before being allowed to drive on track. You can't anymore be alowed to drive without passign the first checkpoint. Even meet the static level, you can get black flaged during driving for being too noisy, clamed by the db measure tool around the track. This is the blind spot like in every things.

Probably Toyota did claimed that 80% was equivalent to 4800 rpms. In Japan, the db measuring I've read are at 3800 or 4800 rpms. Quick reading some USA regulation, it seem that there are no specific rpm range noise measure. Mainly the car is driving at 38 mph 3 feet away of the db measuring tool. Maybe it changed over years.

Cars manufacturers that sell their car in Europe plays with "words" while selling theirs with factory valve equipped to meet the db limits. In European laws it's not stippulate that the car should meet the db level with valve open. Now, car manufacturers have ~3k rpms limits in static that wasn't here before, just because somes peoples did judges that drivers was making too much noise while revving their car too much. Mention : some cars can outpass the 3k rpm limit while using the launch control mod. Like if highs grades peoples adds/modified laws function of cars meets videos they seen in YouTube.

We can speak about how the Porsche 911 GT3 RS was able to meet European regulations with the huge, sharpy wing equipped. Easy reply... It just do not outpass the total wide and height of the car. It's about playing with the words again.