EvolutionM - Mitsubishi Lancer and Lancer Evolution Community - Another quiet exhaust project (BluEVOIX and beyond)

Rather than continuing to go off-topic in the “Project Valve Technology Muffler” thread, I figured I’d start a new thread. *BluEVOIX has blazed the trail for those seeking an ultra-quiet exhaust with good flow. *However, since his car has stock cams and a small turbo, it’s become clear from my attempts at implementing his methods that they don't necessarily yield similar results on a more modified car like mine with large lumpy cams (BF 272s) and a turbo with a larger exhaust housing (FP Black in my case). *I can imagine the difference is even more for someone with a T3/T4 kit. *Ever since my car came back from Buschur Racing with a ported head and the BF cams last fall, it has been noticeably louder with the same exhaust. * I’m not complaining about that BTW. *The car runs great, but there’s a noise penalty to making power, and where I live this additional noise equals exhaust tickets or, at a minimum, unhappy neighbors.

My car has been through many exhausts over the years. *I started with a Buschur TBE with a test pipe and a “race” muffler in 2004. *That was uber-loud. *Then I added a Buschur high-flow cat, which was a Catco ceramic cat as I recall. *It made it much quieter. *When I substituted a Magnaflow muffler it was actually civil and that’s the exhaust I ran for a few years (except that I later substituted a Random Tech metallic core cat). *Later, after reading on the board that putting a Buschur “bullet” style muffler in the test pipe location quieted things down to almost stock levels, I tried that in place of the cat. *There was really very little change in volume from the cat, but it did free up power when I was around 350 whp.

Fast forward to last year, I added rods and pistons, a Buschur head and an FP Black turbo. *With these parts, the car got much louder. *I think the greater exhaust duration of the cams contributed as well as the larger exhaust wheel in the turbo. *Both give a more open path for the exhaust to flow out of the combustion chamber and contribute to a louder exhaust. *I noticed the same thing when I cammed my Camaro. *Note that before the Buschur cams I had Comp 280 cams, which were much quieter and smoother. *I think that my car also sounded louder because it had to idle at around 1150 rpm to have a stable reliable idle and acceptable off-idle stop light manners. *On top of that, exhaust enforcement has become a major issue where I live, particularly since there are fairly few modded cars around here. And then I'm also getting old so I'm generally more grumpy and less tolerant of my car making noises ;)

Earlier this year when I took my car in for inspection, I decided to put the stock catback on it with a high flow cat. *I was very surprised as the car was actually not nearly stock quiet. *I have a bone stock Evo X so I’m very in touch with what stock quiet really sounds like. *(It’s easy to forget). *Wanting to get my car closer to stock quiet but with good flow, I decided to give the new Dynomax VT muffler a try. *This muffler has a “trap door” in the middle of it controlled by a spring. *The idea is at low throttle the door stays mostly closed and at high throttle it swings open and allows full 3” of flow through the straight through muffler. *Well, it was a disaster on my car due to my cams. *I returned it to Dynomax and they sent me a new revised design, which was similarly a disaster. *I posted a video on YouTube of the New and Improved version:

www.youtube.com/watch?v=iL_4Z9baCJU

This was very disappointing, as this new muffler worked well for BluEVOIX and gave him stock-like quiet, but clearly at this point the mods on my car were working against me. *So, I returned that muffler and decided to try the “double Magnaflow” option pioneered by BluEVOIX (Magnaflow at the test pipe location and Magnaflow at the rear of the car). *At not insignificant expense, I bought the Maganflow 14x6” roundx3” muffler off ebay for $81 shipped and a couple of SS flanges off ebay for $50 shipped. *Then I paid two hours labor to have it all put together on the car. *$300 later the car was a little quieter, but FAR FAR from stock quiet. *It was actually just a shade quieter than the Magnaflow Buschur system with a high flow cat in the middle. * I still had a nasty drone at 2000 rpm and it still was loud enough to draw attention at stop lights. It was also much much louder than the stock catback.

At this point, it became clear that the only way I was going to get it quiet enough was with the stock muffler, but that kills performance. *So, what I decided to do was use the stock muffler and a boost-actuated cut-out. *Most people put cut-outs on the DP for the max HP gain, but when you open one of these it is horrendously loud inside the car and is just not something that I would ever use. *Also, completely *unmuffled exhaust sound where I live is not okay, even for short bursts. *(For this same reason, I would never use a wastegate dump.) *However, I could be okay with the car being normal modded muffled loud in short bursts. *So, I figured that if I put a cut out after the Magnflow in the cat position, it wouldn’t be louder than a normal modded Evo when at WOT. *Only problem is that I didn’t want to dump the exhaust, even muffled, right under the car. *Aside from the hideous noise, I know that my car shoots flames on the road course and that’s not something I really want happening under the car where there are fuel lines, gas tank, etc. *This meant that I needed to have the cut out behind the passenger compartment and run 3” piping all the way back. *However, this presents a problem hooking up the stock muffler with its unusual orientation and flange. *Luckily for me, someone in my area was selling a Works 76mm stock fitment intermediate pipe and ABM, both of which are interchangeable with the stock pieces. *The IP was a 3” resonator that does NOT neck down (I checked) and it goes as far back as the stock IP – i.e., past the rear suspension.

With the Works IP on the car and the stock muffler (probably will sell the ABM, though it certainly looks nice), I now have the Magnaflow 14x6” round 3” muffler feeding into a 3” IP, through a long 3” resonator (fits perfectly due to the excellent quality of the Works piece) and into the stock muffler at the very end. *I drove this combo today for the first time. *All I can say is AHHHH…finally! *Stock-like quiet even with my turbo and cams. *This set-up is QUIETER than the stock catback and test pipe that I ran earlier this year briefly. *There is no resonance at all around 2000 rpm and the car stays quiet even at WOT.

Only step left now is to add the boost-actuated cut out to the very rear of the car. *Stay tuned for that. * I’ll eventually post pictures and video when it’s all done. *Thanks for reading!