+Steve Matchett Just about as efficient as any other engine if you treat it wrong. Ever notice the ones that spin a bearing or throw a rod are doing donuts or are really low on oil? Take care of it and it lasts forever. Or don't take care of it and it won't last long. True for any engine.
These videos are great! I'm a Mechanical Engineering student, I want to design forced induction systems, and watching these videos is a great 1,000ft view of all the different systems used in modern autos. (Not to mention I'm also a huge Subaru fan)
This diagram is wrong. Non turbo Subarus come stock with equal length headers. The only reason for unequal length headers is the other header/exhaust meeting to the turbo manifold on the right side on the engine. You're an idiot and don't even know your own car.
+Stirling Moss No - that's not the only reason for it. Subaru has sold the EJ series motor in Japan for years with EL headers... so if they wanted to go that route, they could.
I´ve watched this video many times! This channel is great as one can come back to videos. Thanks for all the videos and the helpful info. I´m very motivated by the passion you put in all your videos. I'm now obsessed with the STI more than ever, that sound makes me want one very bad.
Nothing like owning a car with an engine that sounds like it has at lease one cylinder that isn't firing and is prone to problems with its own rotating mass... BRILLIANT!
Best explanation by far on UEL and EL headers and the boxer rumble. I think it's funny when people complain that the new WRX doesn't have that boxer rumble and they should have kept UEL on it. But they don't realise that they would be sacrificing so much beneficial efficiency and power by trying to run UEL with a twin scroll turbo... Also, a Corolla can replicate the same exact sound as a Subaru if one of it's cylinders are blown. Look it up it's hella funny.
This is a good one. What I would like you to explain also is the science behind the change in exhaust note or tone between fresh and "broken-in" exhaust pipe/system and the different materials used for different systems.
Part of that iconic Subaru sound is the piston slap, and don't forget rod knock on the really well broken-in ones. I've been driving a 2006 Subaru now for about 10 years, and I'm not getting rid of it until it totally impossible to repair. I've already put a new engine in it at 190,000 miles, and I'm up to 225,000 now (about 35k on the new engine so far), and everything is going great so far.
+Dominic Bradley Honestly I didn't know who this was so I googled it. After watching a few of his UA-cam videos, I actually admire the way the guy thinks. Do you own research, do your own tests, learn about what's best for you, and do it. Forums are great, but they can often be misleading. Honestly all the same info applies just as well to car culture as it does bodybuilding.
+Engineering Explained He puts out some great information in my opinion but people lately just like to make fun of him and his name in the comments of his videos now. I can't believe it's spread into a channel about car engineering/reviews.
This is a good explanation. I came across this because of the ecoboost mustang 4 cylinder engine being criticised for it's normal 4 cylinder sound. I always wondered why the 4 cylinder Subaru engine sounds so good, almost like a V8. So to resemble this, you would have to produce two seperate exhaust manifolds with unequal lengths, but at the expense of power. I guess the power is more important to most! This would be difficult to achieve on an in line 4 turbo anyway, due to limited distance avaiaible between the cylinder exhaust outlets and the turbo. The turbo needs to be as close to the cylinder head as possible to avoid lag etc. On a V or boxer layout it would lend itself however.
+Zack Richmond Yeah, I've always thought that the MS3 had one of the most underrated exhaust notes. Especially with a nice quality aftermarket exhaust that isn't too loud.
You should hear an Volvo 140 series, with the B20, 2 litre, short stroke I4. They sounded as gurgly as the old Subaru. The motors were almost as oversquare too. The twin sidedraft carby models with the C cam(mildly lumpy, factory camshaft) sounded best!
Not as "UEL" as the Subaru but will a UEL design, I had a Mazdaspeed 3 gen 1, removed the two resonators, kept everything else stock, and I loved the sound! Had some drone but not too much, the sound was deep
Thanks for finally making an explanation of this Subaru sound that made sense. Been trying to figure it out for a year now, but the explanations usually didlle and get stuck on the firing order. Cleared that up with your explanation of the pressure fronts. Do some more car review videos. Either way looking forward to more good stuff from you man
it is like watching paint dry these videos, but for me personally this is as good as watching anything else. I work in a garage but this guys knowledge astounds me every time! I love Scoobies but I know nothing compared to this guys keep it up
Another positive to the EL headers is that you can run the same timing both sides as with UEL the short side ends up running hot, and creating a scenario in which promotes detonation and thus ringland failures. Though you can just lower the timing per cylinder and avoid it that way. Killer B make absolutely amazing 'Holy' headers.
Really love your videos! Watched a BUNCH of them on the STi and other cars you reviewed. Ended up with the STi, partly influenced with understanding more about it and driving it and your videos!
The equal length headers were known as "Extractors" in Australia(possibly else where too).. also heard it referred to as "tuned headers" or "tuned exhaust" at some point. Extractors were fitted mostly to improve fuel economy more than anything back in my youth. They did make some difference. Like with not tuned headers, they had the advantage of removing heat away from the cylinder head more rapidly too than the cast iron manifolds could. Not sure how much of a difference it made for standard road use though..... There was the performance improvements that could be had too from the fitting of extractors.
So much more that goes into the boxer rumble. Different metals have different tones and sounds. Also resonators and mufflers and stock cats as well as catless + high flow all have different sounds. Another huge factor is piping diameter. Bigger the diameter, lower the tone.
If I am right, the stock subaru headers are 4-2-1 UEL headers: the "4 to 2" lengts are equal at all of the cylinders, and the length differences are between the "2 to 1" lengths. Now, measure / count out that length difference. So if we design a 4-2-1 header for an i4 engine where the cylinders nr. 1 + 2 are connected, and cylinders nr. 3 + 4 are connected (the pair of cylinders next to each other - as the cylinder banks of the boxer engine), and the "4 to 2" pipe lengths are equal for the i4 engine, close to the subaru stock header's "4 to 2" lengths, then let's say, the "2 to 1" length for the cylinder 1 + 2 will be the shorter, but not matters the length, and for the 3 + 4 cylinder will be longer with the difference measured/counted out on the stock subaru header, then there will be the same exact ruble on that i4 engine? I mean, not the whole sound because of the totally different exhaust system, just the rumble...
banpeinet on less built cars (stock heads/cams/turbo) there's maybe a 5-10whp difference. The benefits of the design though help the turbo spool quicker and it equalizes cylinder pressures/temperatures. On your NA honda, the power difference will probably be negligible.
you could but the exhaust wouldn't sound the same, it would be a higher pitch due to different exhaust piping size, and different bore and stroke sizes
+DevanH87 Any N/A application was suffer a lot more from inefficiency than a forced induction car. If he took the NA motor and introduced a poor header design the power loss would be much more significant than if the HP loss of an sit going to an equal length header
with that diagram and drawing, 2 and 4 actually have the longer runners, and this is why many believe cylinder 2 and 4 always seem to have ringland issues.
The vintage VW air-cooled engines used in the Beetle, Karmann Ghia, Type3, the type 2 bus and the vanagon from 1983-1992 which is a waterboxer all produced the boxer rumble depending on the exhaust system used. as the Subaru engines are a popular conversion for the water cooled vanagons, as the early vanagons from 1980-1983 were air-cooled.
I'll take the rumble of my '14 WRX over the whine of the new ones any day of the week! Are the ELHs a better design choice as far as power goes? Yes, I cannot deny that. But, there's more to driving/owning a car than performance and numbers. I would much rather drive a car that I actually enjoy the sight and sound of than one with slightly increased performance. Anyway, great explanation as always! Keep the information coming!
An idea for another video: Exhaust back pressure vs scavenging. What helps scavenge/back pressure and what doesn't. How to calculate exhaust tube diameter for engine size/power for optimal exhaust gas speed.
Love that iconic boxer rumble. I'll gladly trade some power and efficiency for dat sound. I had an aftermarket UEL on my N/A 2.5L back when I owned a Subaru Legacy LOL.
i have EL headers the rumble is still there its just more cleaned up and more WRC sounding also its important to note that your Up Pipe and down pipe and even exhaust shape and diameters all play a role in the acoustics of your exhaust
Good video. A tiny bit disappointed that you didn't mention or show anything to do with the thumbnail for this clip, which is an aircraft flat-four engine.
It sounds nice, i wonder why does the frs, brz and 86 have such a horrible torque dip? Great videos man this is my 3rd time rewatching this vid, keep up the great work !! 👍🏼
In a turbo Subaru running unequal length headers , cylinders 1 & 3 have the shortest distance for the exhaust pulse to travel. the diagram on the left is backwards.
Finally, someone explains this simple fact to the masses. I actually hate the sound of Subarus because people who tune them tend to flaunt that throbby exhaust note and make it very loud. In general, I think that four-cylinder engines, while good for making reliable, cheap power, will never sound very good.
Hi Jason. Over the years I've heard many a debate from many people about the differences between a straight 6 engine compared to a V6 engine such as which one makes more torque at lower revs and which one revs quicker and harder and which one is more fuel efficient. Would it be possible to make such a vdo describing the advantages and disadvantages between the two of them ?
Mate, you're almost there, it's because the cylinders fire from one side first for 2 of them, then the other two on the others side, that is why the rumble exists, it's two lots of pulses in a row, then followed by the other two, if you make equal length headers, the pulses clash which eliminates the resonance, they cancel each other out, the uneven length just allows the characteristics of the Subaru flat 4 to be heard. The flat 4 VW engine is different in the sense that it fires on one side, then the other, then back again and back to again till it finishes 2 revs of the 4 stroke engine, the Subaru fires twice one side for one rev, then 2 on the next revolution for the other side for the 4 strokes.
Glad to see one of the old whiteboard videos! So is the boxer sound produced purely from the UEL? If this is the case, would another engine, like a V type, be able to make the same sound if they had the same exhaust configuration? I'm wondering if the sound is unique because of the exhaust or a combination of the exhaust and the engine itself.
My 05 Legacy GT with completely catless exhaust, up pipe & downpipe sounds so amazing! Its definitely a unique sound. Sure beats that fart can sound from other 4 bangers. Lol
My 93 Probe GT with the Mazda K 60-degree 2.5L V6 sounded like silk thanks to funky equal length fingers underneath the block that forced the oil pan into a pretzel.
1&3 and 2&4 join immediately after the exhaust port. complete different sound when you use a 4 into 1 (the design used). believe the factory set up sounds the best.
Thank you for explaining it so well, easy to understand and honestly my 2015 WRX with an aftermarket exhaust (as I hear online, mine specifically does has the stock) can sound just as sexy so the positives for equal length outweigh the mainly cosmetic (can I use that with sound? lol) or audible benefits of the unequal length headers.
Great video, I'd like to see a video on the awesome sounds of the Audi 5 cylinders and that of the VW R32/36 which all sound amazing. How much of the sound is derived from the engine vs the exhaust
Would it be possible to replicate that sound in an inline 4? Looks like each banks exhaust runners aren’t connected to their companion cylinders. I know there’s more downsides than advantages, but it would be interesting to hear.
+Matthew D Look up some YT videos on the legendary Offenhauser I4 engine that dominated Indy racing for about 50 years until it was rule-booked out of racing. One of the meanest sounding racing engines of all time. Offy's were pure intimidation and the "4 cylinder from Hell" if you were racing against it with any engine not named "Offenhauser", because your butt was already kicked before the race started!
I care for fuel efficiency, and I'm happy with the one on my 2015 WRX, but if the increase in consumption is minimal, I would pay a tuner to loose some horsepower and get the sound of the STi. For how many years was the Evo better than the STi, but in the end, not everybody cared for the lap times, and boxer rumble experience turned the balance in favor of the STi with the people actually purchasing the cars. If it were an option that came with a button, I wonder how many would not use the 𝒊𝒄𝒐𝒏𝒊𝒄 𝒃𝒐𝒙𝒆𝒓 𝒆𝒙𝒉𝒂𝒖𝒔𝒕 𝒓𝒖𝒎𝒃𝒍𝒆.
+Engineering Explained I dont understand why its called a boxer rumble still. You can get this sort of a rumble on any car running unequal length headers. My first turbo car had this rumble. Self turboed a 95 saturn sc2. The manifold I built had very uneven length runners so that I could keep my Air Con (ac pump very near the exhaust manifold area. And for some reason I decided on a top mount turbo...
I would argue the number one reason Subaru went with UEL all this time is not because of wait savings, but because of packaging. Its far easier to fit into the car than an equal length setup. But I highly doubt the UEL will stick around much longer. Subaru has to meet the same fuel economy regulations as everybody else, and an EL setup is better for power and efficiency.
+semiautoriflelover1 they have twin scroll turbos. 2 cyls feed half the turbine and the other 2 feed the other half, to make it simple. equal lenght are needed to do this, more efficient turbo design
Are equal length headers always desirable? For example on a parallel twin or other configuration with an odd firing order, would having equal length headers be best?
I would rather have equal length headers, I don't need the boxer rumble, i like it, but don't need it. I'd rather have the equal length so the turbo works better and has less lag
+Bryan Doherty The question is, can you make them EL till they reach the turbo and UEL at some point after so you get the best of both worlds? Probably wont work, but I'd like to know more.
+Bryan Doherty At the RPM's your turbocharger is spooled up at, there is no measurable difference. At 3000 RPM you have each cylinder firing off 750 times per minute, or 12.5 times per second, so the turbo has no time to loose it's rotational speed, therefore, not losing any power. And realistically, you are only losing about 1-2 horsepower with the unequal length headers, less than the difference between air pressure and moisture caused by different weather.
+Psycho Fourseven that wouldn't work. you have already evened out the spacing so exhaust flow is constant. splitting the piping would just make half of that smooth flow take longer to travel.
+Newgenerationisbg you lose quite a bit of power. the average gain when going to equal length is between 10-15whp. that equates to up to 20hp at the crank
+Rome1017 Where did you get this info? When my friend went from UEL to EL headers on his 2.5XT forester, the gain was 5 or 6 WHP. That's less than 2.5% of the power of the car, and therefore pretty much useless. It's still a very quick car, but sounds like a straight 4 now, so he will soon be replacing them for "dat sound". Of course, there are people who would deem those 5-10HP as worth it, so they can do just that. To each their own, it's a free world after all.
It's possible to get dat rumble (albiet, not as intense) with equal length headers. Using a 4-2-1 collector setup instead of a 4-1 collector setup seems to preserve the rumble more. I had guys ask what headers I was running on my RS when all I had was a 3" catback on stock headers, which have the 4-2-1 collector setup. I still have rumble with my 2.25" catback, too, it's just quieter overall. Most aftermarket EL headers have the 4-1 collector pattern. I'm planning on getting the TechWorks Engineering 4-2-1 headers hopefully by the end of next summer, so I'll find out for sure if EL can still have good rumble.
Best sound ever! You can hear a subie coming from a mile away!
word
+Luca Car Mods no you can hear a twin turbo BB coming from a mile away though.
+TeamLowLife Brad i meant recognize👍🏼
+Luca Car Mods Sounds weak compared to a VR6
Not as far as you can hear a honda coming your way!! haha!
Inefficiency never sounded better!
+Joe Dijeaux Also quite efficient at kicking pistons through the block
+Steve Matchett Just about as efficient as any other engine if you treat it wrong. Ever notice the ones that spin a bearing or throw a rod are doing donuts or are really low on oil? Take care of it and it lasts forever. Or don't take care of it and it won't last long. True for any engine.
+Steve Matchett so does mazda and its not uel
+Unbearable Pain disconnect a plug on an older gti/gli with an exhaust and it sounds hilariously similar. SIMILAR.
+Unbearable Pain
LOL, like a screamin demon! (Detroit Diesel 2 stroke engine)
These videos are great! I'm a Mechanical Engineering student, I want to design forced induction systems, and watching these videos is a great 1,000ft view of all the different systems used in modern autos. (Not to mention I'm also a huge Subaru fan)
It's been 7 years are you designing forced induction systems yet?
Engineering Explained logo is actually a boxer engine.
+tokekkk i never noticed that, i always noticed the logo shaped like a rotated gear shift gate..
+tokekkk Haha yesss!
+Engineering Explained secret is out, save the manuals!
This diagram is wrong. Non turbo Subarus come stock with equal length headers. The only reason for unequal length headers is the other header/exhaust meeting to the turbo manifold on the right side on the engine. You're an idiot and don't even know your own car.
+Stirling Moss No - that's not the only reason for it. Subaru has sold the EJ series motor in Japan for years with EL headers... so if they wanted to go that route, they could.
Inline 4's have a tendency to sound like an angry bee in a tin can. I can appreciate the sound Subaru's make.
@Kenny Argueta Ventura that’s not true, just say you can’t afford an sti and move on
I´ve watched this video many times! This channel is great as one can come back to videos. Thanks for all the videos and the helpful info.
I´m very motivated by the passion you put in all your videos. I'm now obsessed with the STI more than ever, that sound makes me want one very bad.
Main benefit of UEL: Sounds awesome
Nothing like owning a car with an engine that sounds like it has at lease one cylinder that isn't firing and is prone to problems with its own rotating mass... BRILLIANT!
Best explanation by far on UEL and EL headers and the boxer rumble. I think it's funny when people complain that the new WRX doesn't have that boxer rumble and they should have kept UEL on it. But they don't realise that they would be sacrificing so much beneficial efficiency and power by trying to run UEL with a twin scroll turbo...
Also, a Corolla can replicate the same exact sound as a Subaru if one of it's cylinders are blown. Look it up it's hella funny.
Bro I've been watching your videos for a while now and I've always thought you were just a 16-17 year old who REALLY knew his stuff on cars
How about rotary brap explained.
+Jsp P5 Taunus I don't think science has an answer for rotary braaap yet ;-)
It's caused by porting the intakes.
Ben Wickham I want V4 burble explained.
because it's a 2 stroke lol
Generic Name Felix Wankel cared.
This is a good one. What I would like you to explain also is the science behind the change in exhaust note or tone between fresh and "broken-in" exhaust pipe/system and the different materials used for different systems.
Part of that iconic Subaru sound is the piston slap, and don't forget rod knock on the really well broken-in ones.
I've been driving a 2006 Subaru now for about 10 years, and I'm not getting rid of it until it totally impossible to repair. I've already put a new engine in it at 190,000 miles, and I'm up to 225,000 now (about 35k on the new engine so far), and everything is going great so far.
Can you do a video on how Rich Piana is so naturally massive?
Rich Piano is my favorite natural musical instrument.
+Dominic Bradley Rich Pantera is my favorite 90's rock band
oil
+Dominic Bradley Honestly I didn't know who this was so I googled it. After watching a few of his UA-cam videos, I actually admire the way the guy thinks. Do you own research, do your own tests, learn about what's best for you, and do it. Forums are great, but they can often be misleading. Honestly all the same info applies just as well to car culture as it does bodybuilding.
+Engineering Explained He puts out some great information in my opinion but people lately just like to make fun of him and his name in the comments of his videos now. I can't believe it's spread into a channel about car engineering/reviews.
I wish you where my science teacher at school 😂 cheers
This is a good explanation. I came across this because of the ecoboost mustang 4 cylinder engine being criticised for it's normal 4 cylinder sound. I always wondered why the 4 cylinder Subaru engine sounds so good, almost like a V8. So to resemble this, you would have to produce two seperate exhaust manifolds with unequal lengths, but at the expense of power. I guess the power is more important to most! This would be difficult to achieve on an in line 4 turbo anyway, due to limited distance avaiaible between the cylinder exhaust outlets and the turbo. The turbo needs to be as close to the cylinder head as possible to avoid lag etc. On a V or boxer layout it would lend itself however.
My Mazdaspeed 3 makes a similar sound, sort of a gurgling, because of our stock UEL exhaust manifolds. Sounds great!
+Zack Richmond Yeah, I've always thought that the MS3 had one of the most underrated exhaust notes. Especially with a nice quality aftermarket exhaust that isn't too loud.
+Zack Richmond Yup, I always wondered why my friend's Speed3 sounded so rumbly. Makes more sense after this video
You should hear an Volvo 140 series, with the B20, 2 litre, short stroke I4. They sounded as gurgly as the old Subaru. The motors were almost as oversquare too. The twin sidedraft carby models with the C cam(mildly lumpy, factory camshaft) sounded best!
Not as "UEL" as the Subaru but will a UEL design, I had a Mazdaspeed 3 gen 1, removed the two resonators, kept everything else stock, and I loved the sound! Had some drone but not too much, the sound was deep
Cylinders are shown back to front (1 & 2 are at the front, 3 & 4 at the back), but apart from that pretty good. Gotta love the boxer rumble!!
Yes, you've got it right on the button. I'm glad to see that I'm not the only person who knows how this works! Good one, dude.
Thanks for finally making an explanation of this Subaru sound that made sense. Been trying to figure it out for a year now, but the explanations usually didlle and get stuck on the firing order. Cleared that up with your explanation of the pressure fronts. Do some more car review videos. Either way looking forward to more good stuff from you man
it is like watching paint dry these videos, but for me personally this is as good as watching anything else. I work in a garage but this guys knowledge astounds me every time! I love Scoobies but I know nothing compared to this guys keep it up
Another positive to the EL headers is that you can run the same timing both sides as with UEL the short side ends up running hot, and creating a scenario in which promotes detonation and thus ringland failures. Though you can just lower the timing per cylinder and avoid it that way. Killer B make absolutely amazing 'Holy' headers.
Really love your videos! Watched a BUNCH of them on the STi and other cars you reviewed. Ended up with the STi, partly influenced with understanding more about it and driving it and your videos!
why do you only have 400k subscribers? phenomenal explanation!!
+tblue3cibm I thought 400k sounded pretty good! :)
Like almost 3M now! (5 years later)
The smile on your face when you mention the sound is great.
you forgot to write G on the "unequal lenth headers"
BMW Technicien atta boy eyes
I actually rewatched the video to see that.
The equal length headers were known as "Extractors" in Australia(possibly else where too).. also heard it referred to as "tuned headers" or "tuned exhaust" at some point. Extractors were fitted mostly to improve fuel economy more than anything back in my youth. They did make some difference. Like with not tuned headers, they had the advantage of removing heat away from the cylinder head more rapidly too than the cast iron manifolds could. Not sure how much of a difference it made for standard road use though.....
There was the performance improvements that could be had too from the fitting of extractors.
tuned exhaust at least to me typically referred to 2cycle rc engines where it really mattered significantly more.
you have one of the best channels on youtube... I'm sure you already knew that though.
I'm making a set of unequal length headers for my dsm, I've always loved that unique trait from Subaru
I'll take a 15hp loss over sounding like any I4.
true words
Dual exhausts matter, too. It's like the difference between listening to "stereo" vs monaural.
@Jimbob and i would watch videos that actually cater to my interests. Go watch videos on v8's, moron.
OR don't drive a 4...
Would you take ringlands over sounding like any I4? EL headers reduce the risk of failure because there's equal pressure on all cylinders.
Crossplane V8 and the Subaru boxer are my favourite engines.
The headers make the rumble a lot louder and more pronounced but as you explained, the firing order itself is what actually makes the rumble.
i was just thinking about this earlier today. i really like the way my impreza rumbles. thanks for the explanation.
I now when a Subaru is coming just by sound I don’t even need to think or look, it’s amazing
So much more that goes into the boxer rumble. Different metals have different tones and sounds. Also resonators and mufflers and stock cats as well as catless + high flow all have different sounds. Another huge factor is piping diameter. Bigger the diameter, lower the tone.
If I am right, the stock subaru headers are 4-2-1 UEL headers: the "4 to 2" lengts are equal at all of the cylinders, and the length differences are between the "2 to 1" lengths. Now, measure / count out that length difference. So if we design a 4-2-1 header for an i4 engine where the cylinders nr. 1 + 2 are connected, and cylinders nr. 3 + 4 are connected (the pair of cylinders next to each other - as the cylinder banks of the boxer engine), and the "4 to 2" pipe lengths are equal for the i4 engine, close to the subaru stock header's "4 to 2" lengths, then let's say, the "2 to 1" length for the cylinder 1 + 2 will be the shorter, but not matters the length, and for the 3 + 4 cylinder will be longer with the difference measured/counted out on the stock subaru header, then there will be the same exact ruble on that i4 engine? I mean, not the whole sound because of the totally different exhaust system, just the rumble...
So theoretically I should be able to make my Honda Civic rumble as wel if I add enough plumbing to the header? Mad! :D
Haha! Thanks, that was awesome! :D
I'm just wondering how many HP were lost in the rumble. ;)
banpeinet on less built cars (stock heads/cams/turbo) there's maybe a 5-10whp difference. The benefits of the design though help the turbo spool quicker and it equalizes cylinder pressures/temperatures.
On your NA honda, the power difference will probably be negligible.
you could but the exhaust wouldn't sound the same, it would be a higher pitch due to different exhaust piping size, and different bore and stroke sizes
+Rome1017 and becuase its a honda civic
+DevanH87 Any N/A application was suffer a lot more from inefficiency than a forced induction car. If he took the NA motor and introduced a poor header design the power loss would be much more significant than if the HP loss of an sit going to an equal length header
Very good explanation! although it would be nice having a clip of a boxer with equal lenght headers, to compare the sounds!
Your videos are good but your drawings are even better, Thanks for the info!!!
+SweazyRaskal Haha this time was just rectangles and lines, that I can handle. Glad you enjoyed the video!
i really appreciate the time you take to reply back to your fans...thanks my friend cant wait for you to hit 1 million subs!
This is explained right, except you have the manifold diagram backwards for the STI. 1 and 3 are the shorter pipes and 2 and 4 are the longer pipes.
with that diagram and drawing, 2 and 4 actually have the longer runners, and this is why many believe cylinder 2 and 4 always seem to have ringland issues.
The thing is, a modified sti with equal length headers still has a decent amount of rumble. The motor naturally has a rumbly sound
Best explanation ever, thanks!
The vintage VW air-cooled engines used in the Beetle, Karmann Ghia, Type3, the type 2 bus and the vanagon from 1983-1992 which is a waterboxer all produced the boxer rumble depending on the exhaust system used. as the Subaru engines are a popular conversion for the water cooled vanagons, as the early vanagons from 1980-1983 were air-cooled.
i love my boxer rumble! Subarus are very affordable and generally reliable and very fun to drive.
I'll take the rumble of my '14 WRX over the whine of the new ones any day of the week! Are the ELHs a better design choice as far as power goes? Yes, I cannot deny that. But, there's more to driving/owning a car than performance and numbers. I would much rather drive a car that I actually enjoy the sight and sound of than one with slightly increased performance.
Anyway, great explanation as always! Keep the information coming!
I would love a video on heat wrapping your headed and what are the ture benefits of doing it
I hooked this video up to my trucks Bluetooth so I could hear that heavenly rumble in HD 😂🔥
Thanks. I always wanted to know how they get that awesome sound
that sound at the end made me shiver! :-)
An idea for another video:
Exhaust back pressure vs scavenging. What helps scavenge/back pressure and what doesn't. How to calculate exhaust tube diameter for engine size/power for optimal exhaust gas speed.
Love that iconic boxer rumble. I'll gladly trade some power and efficiency for dat sound. I had an aftermarket UEL on my N/A 2.5L back when I owned a Subaru Legacy LOL.
I really like your channel, very informative. You know your stuff my man, thank you.
i have EL headers the rumble is still there its just more cleaned up and more WRC sounding
also its important to note that your Up Pipe and down pipe and even exhaust shape and diameters all play a role in the acoustics of your exhaust
Could you do a video on the explanation of different types of turbocharging....
parallel turbochargers,twin scroll turbochargers,etc.
I have a whole playlist! :) ua-cam.com/play/PL08CEA57427415959.html
I loved this video because I'm a Subaru junkie and I own a n 04' Wrx Sti
I think your definition of sounding phenomenal is vastly different than mine.
I just love the sounds of JDM EJ20 Turbo LGT with ELH and STi Genome exhaust! UELH never sound that "tight"
+Mika Veijalainen JDM EJ20 LGT ELH STI UELH
Woah
Good video. A tiny bit disappointed that you didn't mention or show anything to do with the thumbnail for this clip, which is an aircraft flat-four engine.
It sounds nice, i wonder why does the frs, brz and 86 have such a horrible torque dip? Great videos man this is my 3rd time rewatching this vid, keep up the great work !! 👍🏼
Boxers and rotary sounds are the best imo
Hopefully this will be in the aftermarket scene soon
Always loved that boxer rumble...
In a turbo Subaru running unequal length headers , cylinders 1 & 3 have the shortest distance for the exhaust pulse to travel. the diagram on the left is backwards.
man you have built quite the Channel! you have a crap load of subscribers. is content creating your full time job?
Yep. Creating crap loads of content for crap loads of people is the goal!
I really appreciate your work man. You the number one go to guy when I don't understand something about my car. I have a 2013 BRZ.
Finally, someone explains this simple fact to the masses. I actually hate the sound of Subarus because people who tune them tend to flaunt that throbby exhaust note and make it very loud. In general, I think that four-cylinder engines, while good for making reliable, cheap power, will never sound very good.
Dat sound is beautiful. Thanks for explaining it.
Good video, but it would of been nice to hear a 'Rex with equal length headers at the end as a comparison.
Hi Jason. Over the years I've heard many a debate from many people about the differences between a straight 6 engine compared to a V6 engine such as which one makes more torque at lower revs and which one revs quicker and harder and which one is more fuel efficient. Would it be possible to make such a vdo describing the advantages and disadvantages between the two of them ?
Mate, you're almost there, it's because the cylinders fire from one side first for 2 of them, then the other two on the others side, that is why the rumble exists, it's two lots of pulses in a row, then followed by the other two, if you make equal length headers, the pulses clash which eliminates the resonance, they cancel each other out, the uneven length just allows the characteristics of the Subaru flat 4 to be heard.
The flat 4 VW engine is different in the sense that it fires on one side, then the other, then back again and back to again till it finishes 2 revs of the 4 stroke engine, the Subaru fires twice one side for one rev, then 2 on the next revolution for the other side for the 4 strokes.
Glad to see one of the old whiteboard videos! So is the boxer sound produced purely from the UEL? If this is the case, would another engine, like a V type, be able to make the same sound if they had the same exhaust configuration? I'm wondering if the sound is unique because of the exhaust or a combination of the exhaust and the engine itself.
YES
SOMEONE GOT THAT IDEA (to make a video explanation) TOO!!! I AM NOT ALONE
And thank you for the sound
My 05 Legacy GT with completely catless exhaust, up pipe & downpipe sounds so amazing! Its definitely a unique sound. Sure beats that fart can sound from other 4 bangers. Lol
The H.O. Quad4 is another small engine with a nice NA sound. Problem is finding one in good condition is fairly rare these days.
Recently bought a 2009 Outback Sport 5MT, not very fast but it sounds beautiful.
My 93 Probe GT with the Mazda K 60-degree 2.5L V6 sounded like silk thanks to funky equal length fingers underneath the block that forced the oil pan into a pretzel.
"I promise my car is not broken" - me to anyone who rides with me
"This is just what peak Subie sounds like" :p
Jason draws the best crappy diagrams.
Wobbly lines and what not, but so clear in their illustration.
1&3 and 2&4 join immediately after the exhaust port. complete different sound when you use a 4 into 1 (the design used). believe the factory set up sounds the best.
Thank you for explaining it so well, easy to understand and honestly my 2015 WRX with an aftermarket exhaust (as I hear online, mine specifically does has the stock) can sound just as sexy so the positives for equal length outweigh the mainly cosmetic (can I use that with sound? lol) or audible benefits of the unequal length headers.
Awesome video, please continue to educate us!
thanks, always love your vids!
Great video, I'd like to see a video on the awesome sounds of the Audi 5 cylinders and that of the VW R32/36 which all sound amazing. How much of the sound is derived from the engine vs the exhaust
the sound is the only redeeming factor!
Would it be possible to replicate that sound in an inline 4? Looks like each banks exhaust runners aren’t connected to their companion cylinders. I know there’s more downsides than advantages, but it would be interesting to hear.
The boxer 4 is the only 4cly engine that sounds good to me. And boy do they sound good with the right pipes.
+Matthew D Look up some YT videos on the legendary Offenhauser I4 engine that dominated Indy racing for about 50 years until it was rule-booked out of racing. One of the meanest sounding racing engines of all time. Offy's were pure intimidation and the "4 cylinder from Hell" if you were racing against it with any engine not named "Offenhauser", because your butt was already kicked before the race started!
EL HEADERS FTW! Sounds so much better with them rather than the UEL, a lot smoother and you don't sound like a beetle.
Too bad for my H6 with EL headers.
At least it sounds brutal, though.
I care for fuel efficiency, and I'm happy with the one on my 2015 WRX, but if the increase in consumption is minimal, I would pay a tuner to loose some horsepower and get the sound of the STi.
For how many years was the Evo better than the STi, but in the end, not everybody cared for the lap times, and boxer rumble experience turned the balance in favor of the STi with the people actually purchasing the cars.
If it were an option that came with a button, I wonder how many would not use the 𝒊𝒄𝒐𝒏𝒊𝒄 𝒃𝒐𝒙𝒆𝒓 𝒆𝒙𝒉𝒂𝒖𝒔𝒕 𝒓𝒖𝒎𝒃𝒍𝒆.
Iconic Subaru boxer sound: "Knock-Knock, got some oil?"
+Engineering Explained I dont understand why its called a boxer rumble still. You can get this sort of a rumble on any car running unequal length headers.
My first turbo car had this rumble. Self turboed a 95 saturn sc2. The manifold I built had very uneven length runners so that I could keep my Air Con (ac pump very near the exhaust manifold area. And for some reason I decided on a top mount turbo...
I would argue the number one reason Subaru went with UEL all this time is not because of wait savings, but because of packaging. Its far easier to fit into the car than an equal length setup.
But I highly doubt the UEL will stick around much longer. Subaru has to meet the same fuel economy regulations as everybody else, and an EL setup is better for power and efficiency.
Enjoy your videos, I noticed you spelled "length" wrong in the boxer side.
Very well explained, if I this were a restaurant i would time you a blue bill.
wait. so does that mean the iconic Subaru sound will be gone with EL headers?
+Joe Espo yes sadly :(
+Joe Espo equal length on a subaru doesn't sound like a honda by any means.
+semiautoriflelover1 they have equal length because they are twin scroll. More efficient at making power and spools the turbo much faster.
look at the wrx, it's already gone
+semiautoriflelover1 they have twin scroll turbos. 2 cyls feed half the turbine and the other 2 feed the other half, to make it simple. equal lenght are needed to do this, more efficient turbo design
Are equal length headers always desirable? For example on a parallel twin or other configuration with an odd firing order, would having equal length headers be best?
Great just answered my question to u on a earlier video.
I would rather have equal length headers, I don't need the boxer rumble, i like it, but don't need it. I'd rather have the equal length so the turbo works better and has less lag
+Bryan Doherty The question is, can you make them EL till they reach the turbo and UEL at some point after so you get the best of both worlds? Probably wont work, but I'd like to know more.
+Bryan Doherty At the RPM's your turbocharger is spooled up at, there is no measurable difference. At 3000 RPM you have each cylinder firing off 750 times per minute, or 12.5 times per second, so the turbo has no time to loose it's rotational speed, therefore, not losing any power. And realistically, you are only losing about 1-2 horsepower with the unequal length headers, less than the difference between air pressure and moisture caused by different weather.
+Psycho Fourseven that wouldn't work. you have already evened out the spacing so exhaust flow is constant. splitting the piping would just make half of that smooth flow take longer to travel.
+Newgenerationisbg you lose quite a bit of power. the average gain when going to equal length is between 10-15whp. that equates to up to 20hp at the crank
+Rome1017 Where did you get this info? When my friend went from UEL to EL headers on his 2.5XT forester, the gain was 5 or 6 WHP. That's less than 2.5% of the power of the car, and therefore pretty much useless. It's still a very quick car, but sounds like a straight 4 now, so he will soon be replacing them for "dat sound". Of course, there are people who would deem those 5-10HP as worth it, so they can do just that. To each their own, it's a free world after all.
just heard one yesterday, I was like dude that's what God's car must sound like
It's possible to get dat rumble (albiet, not as intense) with equal length headers. Using a 4-2-1 collector setup instead of a 4-1 collector setup seems to preserve the rumble more. I had guys ask what headers I was running on my RS when all I had was a 3" catback on stock headers, which have the 4-2-1 collector setup. I still have rumble with my 2.25" catback, too, it's just quieter overall.
Most aftermarket EL headers have the 4-1 collector pattern.
I'm planning on getting the TechWorks Engineering 4-2-1 headers hopefully by the end of next summer, so I'll find out for sure if EL can still have good rumble.