This will make YOUR exhaust sound AMAZING. Custom exhaust builders share fabrication secret!

Order megaphones pre-built by yours truly here: fluidmotorunion.com/product/exhaust-megaphone/

Imagine buying a $120,000 v12 sport car and it sound like a Toyota Avalon.

Having made a few DIY exhausts on my driveway with the car on jackstands, I know how much work goes into it and how tricky it can be to get it all done perfectly. You guys are very inspirational

That exhaust sounds more like a Hellcat than an actual hellcat. What a demonic scream that things got. That exhaust fits that engine perfectly! Amazing work

This is why a triumph motorcycle sounds so good it’s the cone exhaust that all the flat trackers run.

Expansion chambers are what we always called them. Been a thing on 2 strokes since the late 70s. You explain them quite well.

"brands of oil to never use in your engine" 😂😂

Dude is BRILLIANT yet refreshing in a sense that those I’ve met who purport brilliance try and convince you they’re just that, seemingly always breaching that condescendence. O.J. obviously strives to teach and does so in a humbled manner. Cheers to O.J. and his FMU family—literally his family!

I haven't been to school in 20 years. Watching this video felt like the first day off school. I'll be watching this video 3xs a week . Great video

Wow. The education here is unmatched. Well done!🎉

Anyone who understands anything about sound waves or even built a custom tuned subwoofer box should be able to understand what the diameter and the length of that vent can do to the sound.

Megaphones obviously made a difference. Early in the video "truck exhaust" was mentioned and I believe not positively. If I had to give a one word description of how this exhaust ended up sounding was like a truck, maybe the best sounding truck but still a truck. Like a big block with big cams not a Pagani exotic or exotic in general. Regardless of the result the information packed in this video is excellent and really appreciate the detailed breakdown.

Factory exhaust is cheap ,is restricted and lacking a good sound. However the entire reasons for factory exhaust is to meet production cost , epa standards and federal dot safety standards. It’s not that they don’t care it’s that they have only so much room legally to get 600 horsepower on to the highway. Like a hand gun . Can’t buy it with the extended mag . That’s a customer option 😉

Just a few notes... The results you got are great 👍. As a muscle car guy I was afraid of it sounding like an open wheel indy/f1 being that it would have even firing banks and so many cylinders. This is actually better than what I was expecting. But if you wanted an exotic f1 sound or to harmonic tune the engine it would be easy without megaphones which the math of those seems to be a guarded secret. On 2 strokes they are often regarded as sound wave reflectors but when glossed over in automotive exhaust literature they talk about sound wave timings extensively but then some may say megaphones don't follow the same mathematical model and require testing. Not sure why that would be but darin Morgan who designs intake systems that also use sound wave reflections talks about angles as part of the rpm range so perhaps the reflections aren't a function of the average length to the cone and just happen when acoustic impedance sufficiently changes so I don't have enough acoustic knowledge to speak on that. But I do know how you would typically tune collector extensions and primary header pipes when megaphones are not involved. Sometimes the path to the best x or H pipe placement is blocked but because it's harmonic there may be subsequent locations down stream. These down stream locations may be lower in pitch so if an f1 type sound is desired you may need to pinch a harmonic (ask a guitar player about string harmonics) to make it high in pitch if you so wanted to. To do this you could add a stepped pipe or an H or x at a half or third or quarter point in the path getting to the tuned point. A typical location for a x would be around 33" behind the end of the primary header pipes for a 6500 rpm engine, it depends a bit on gas speed (the back wave might be delayed in time more than the forward wave time is decreased by gas flow changing the exact length a bit from standard organ pipe math) and temperature. But if that's obstructed by the transmission or transfer case or cross member you could go around 67" with an H at 33" or 16.5." the x on many cars would actually be better placed near the rear universal than as soon as it fits by this math. Shorter for an 8000rpm engine and longer for a 5000 rpm engine like a stock cam or a long runner efi manifold like Ford and Chevy used in the 1980's on tpi and 5.0/5.8l engines. Those numbers are for 8 cylinder engines, the numbers for 12 cylinders may be shorter. The more pitch you want you would divide the distance to the x by larger whole numbers for additional reflection points. A guy who built a 5.0 Ford (yes classic 5.0 not Coyote) powered BMW for budget racing built a 180 degree header to get equal pulses and a super car sound. It worked but this type of build often forces you into primary pipes that are too long. It might work on a 5.0 because the intake is also very long. But it's not always best. So he then replaced the hand built headers with equal tuned length headers and used a triple x pipe to get the super car sound. So he had a pushrod V8 with odd firing banks not known for that high pitched howl and extracted that sound from it on a full length sedan simply by pinching harmonics using redundant x pipes ! Long pipes tend to mean lower pitched rumble but it can be manipulated easily by causing intentional reflections at equal interval lengths.

It took me 13 minutes to realize this is mark rebillet’s older, smarter brother. In all seriousness, thanks for explaining things in the way you do 👍

What a difference OJ, kind of like hitting the bricks in the gym. The more you structure your workouts(and yes to some, increasing the weight), the better the outcome(insert: OJ Lopez's physique). Hence, the more you fine-tune your 'custom' exhaust, the better your baby is going to sound(and yes increasing horsepower along the way). Side note: your delivery is getting more natural for the camera, damn good job all the way around.

Just changing the outlet tip can make a difference. I have a 2000 silverado with flowmasters. It had dual 2.25 outlets. Changing them to an oval changed the tone. Megaphone of a sort.

This channel melds gearhead knowhow, with the intricate disciplines of raw science. Your oratory presentation was quite polished, & professionally articulated. Great video!

Years ago I had a 5.0L V8 with a single 2½" pipe. It had an expansion chamber near the transmission (very similar to a Catalytic converter that had it's insides removed), then a straight through pipe through to a rear muffler. It sounded OK, but I started experimenting and hole sawed another hole next to the muffler tailpipe into the Helmhertz chamber at the back of the muffler. This hole lined up with the internal perforated pipe inside the muffler, and I inserted another short pipe into the hole and attached it to the existing tailpipe with hose clamps so that it could be adjusted to insert into the muffler chamber by different amounts. My mate and I took turns driving WOT and the other listening as we drove by. We adjusted the length of the new tailpipe until we got the best sound, then welded it in place. The results were amazing. Not super loud but more like a sub woofer effect, especially at idle. I guess it may be due to two out of phase sounds being produced? Strangely blocking either pipe had the same effect at making it quiet to about the same noise level. I had many people ask me who built the exhaust. So my question to @FluidMotorUnion is, have you tried placing the megaphones in each pipe at different locations to each other. ie, one close to the engine and one further to the rear. Or, placing them at close to the same length, but making a sliding connection on one so you can adjust it along the pipe by a few inches and move it slightly to experiment with different positions along the pipe while ethe other one remains in the same place. Please tag me if you try this, as I would be very interested... even though my revhead days are pretty much behind me.

Probably the best sounding Merc v12 Biturbo I’ve ever heard.