Straight Exhaust vs. H-Pipe vs. X-Pipe!
This episode of Engine Masters presented by AMSOIL delivers the goods many viewers have asked for as we test the power of straight dual exhaust with no crossover pipe versus using an H-pipe versus an X-pipe. Will the old bench-racing stories come true
Transcript
00:00 Fans ask for this and Engine Masters delivers.
00:02 We will test the power of an exhaust H-pipe
00:06 versus an X-pipe versus no crossover at all.
00:09 (dramatic music)
00:12 (engine revving)
00:18 (dramatic music)
00:26 (dramatic music)
00:29 This is Engine Masters, which is presented by AMSOIL,
00:32 which we generally leak all over the place,
00:35 kind of like this.
00:37 We're also supported by Mr. Gasket
00:39 and Earl's Vapor Guard Plumbing.
00:41 Now this time, we are gonna do a test of the power
00:44 of a full exhaust system like you'd have in your car
00:46 and compare straight pipes to an H-pipe to an X-pipe.
00:51 I've never done this before.
00:53 I'm really curious what's gonna happen.
00:55 Now the engine that we're using for this
00:57 almost isn't important because essentially,
01:00 it is just an air pump that's shoving exhaust
01:03 so that we can find out what's gonna happen.
01:05 It makes about 350 or 360 horsepower,
01:09 so this should apply to you if you have a V8
01:12 that is making about the same power.
01:15 But I'll tell you exactly what this is.
01:16 It's an LS motor.
01:18 It's a 5.3 and yep, we're running it with a carburetor.
01:22 This thing is completely stock
01:24 with the exception of a tiny crane cam.
01:27 I think it's 224 at 50, I don't recall.
01:30 We've got a 750 double pumper Holley HP up top.
01:34 We're running a one-inch spacer on it
01:36 because we found out that it's easier to tune with that
01:38 with this particular manifold,
01:40 which is an Edelbrock RPM LS1 dual plane.
01:44 We've also got a set of one and three quarter inch
01:46 conversion headers on this deal
01:48 and we're gonna roll it in here,
01:49 sauce it up with some AMSOIL, fire it up,
01:51 and the first test that we'll do
01:52 is gonna be with two and a half inch straight pipes,
01:56 Gibson mufflers, and no crossover at all.
01:59 This thing is completely stock in the bottom end
02:01 and you know, these newer engines
02:02 have tighter bearing clearances
02:03 than the older muscle car stuff
02:05 and so they take lower viscosity.
02:06 In fact, some of the latest things, they can zero weight.
02:09 But for this, our go-to is a 530 Signature Series
02:14 AMSOIL synthetic.
02:15 (upbeat music)
02:18 (whooshing)
02:20 Okay, we finally got this thing consistent and ready to go,
02:25 but our curves we're seeing,
02:27 they just vary by one or two horsepower here and there
02:29 and my opinion is what we're doing here
02:31 might not change stuff more than one or two horsepower.
02:35 So what we're gonna do is run the engine
02:37 three times in each configuration and average the poles.
02:41 - Can I turn on the sound meter?
02:44 - Oh, and Dulcich has got this decibel fixation.
02:47 - Yeah, I wanna know.
02:48 - Is he allowed?
02:49 - If it's gonna make any difference.
02:51 I've gots to know.
02:54 All right, what I have here is the decibel meter.
02:57 It's gonna read how loud the engine is
02:59 through the various muffler and crossover setups.
03:02 So I'm gonna take readings at wide open throttle.
03:05 At idle, the room is noisier than the engine.
03:08 - Okay, so let's fire it up while we got the temp in it.
03:11 - It's running. - It's running.
03:12 - And up. (laughing)
03:13 I'm so quiet, I'm so not used to this.
03:16 It's running.
03:17 This is just straight pipes and mufflers.
03:20 We got no crossover whatsoever.
03:22 So this sounds like Dulcich's truck, except for better.
03:25 - Better, except it's quiet.
03:26 - Yeah, because they're not out each side going.
03:28 (engine revving)
03:29 Sounding like two four cylinders running on three.
03:31 - That's the sound of power.
03:33 - Oh.
03:34 (engine revving)
03:36 (engine revving)
03:39 Looks like that's on target with what we've been seeing
03:59 in our tune-up process.
04:01 All right, we've got our final wrap up here.
04:03 This is the average of three pulls.
04:05 Look how nice and smooth and happy.
04:07 366 pound feet of torque at 4,400 RPM,
04:11 and pretty similar to that all in here.
04:13 And up at the top, we got 6,100 RPM and 362.3 horsepower.
04:18 Once again, as an average of three pulls.
04:20 That's with straight pipes and mufflers,
04:22 and now we're ready to go put in our H-pipe.
04:25 Now I should tell you about the mufflers
04:29 that we're running during all of these tests.
04:31 It's a Gibson made in USA budget muffler called MWA,
04:36 muffler with attitude, meaning loud.
04:40 The way these work is that the case is completely open,
04:43 except for a straight through pipe in the middle.
04:46 And it's a pipe like this,
04:47 and it's got a couple of rectangular cutouts in it
04:50 and a few smaller perforations.
04:52 It's not louvered, it's just got cutouts.
04:54 The theory being when exhaust is moving slowly at idle,
04:57 it just sort of poofs out inside the case
05:00 and dampens itself and sounds mellow.
05:02 But when you're on it, it goes straight through and shrieks,
05:05 which is pretty true.
05:06 I've got a set of those on a blown big block
05:08 in a roadkill car and I like them.
05:10 Now we're going to go to the test of adding crossover pipes,
05:13 merging both twice pipes together,
05:17 kind of with a common pipe.
05:18 You can do that either with an H-pipe like this
05:21 or with a big X-pipe.
05:24 And guys have different theories
05:25 how each one of these work.
05:27 I really don't.
05:28 I've never done this test before.
05:29 I've run both of these in a car
05:31 and I can tell you that it sounds more mellow
05:34 when you do this,
05:34 but I have no idea what's going to go on for power.
05:36 Tech wise, note that the H-pipe that we're using
05:40 has a full two and a half inch crossover,
05:43 the same size as the main pipes in our system.
05:46 You'll see in some cases where guys will run
05:48 a smaller crossover pipe, but we're doing full size.
05:51 Really the same with X-pipe,
05:52 the whole system is two and a half inch.
05:54 We are making sure that the mufflers
05:56 are in the same position for every test.
05:58 Also the overall length of the exhaust system
06:00 is in the same position for every test.
06:02 There are a lot of theories about where the crossover
06:05 should go in the system.
06:06 And we did make sure that the center line of our X-pipe
06:10 lands in exactly the same place as our crossover here.
06:13 So that's kind of the same.
06:14 Now, a lot of people will say,
06:15 well, the crossover, you know, for optimum torque
06:17 needs to be in just the right spot.
06:19 And they've got a slide rule
06:20 and an abacus telling them all this stuff.
06:22 Here's the deal.
06:23 The real estate under your vehicle is going to tell you
06:25 where you've got to put your crossover pipe.
06:27 And so that's how we've sort of guesstimated it.
06:29 We figured looking at the dyno,
06:31 at the end of your transmission,
06:32 you usually put the crossover pipe just after there
06:35 so it doesn't run into the drive shaft,
06:36 the oil pan, anything like that.
06:38 That's about where we've got it on the dyno,
06:39 very much mimicking what's in a car.
06:41 What's going to happen?
06:42 I don't know, but we're going to start to figure it out
06:45 with the H-pipe.
06:46 (upbeat music)
06:48 So I guess theoretically,
06:54 the firing order shouldn't change the H-pipe,
06:57 pulsation, any of that stuff.
06:59 - No, it won't.
07:01 - We're about to see what it's really going to do,
07:03 which I'm really curious about because--
07:05 - I am too.
07:06 - I want to add an H-pipe in my truck,
07:08 hoping to make more power,
07:10 but I won't bother if we show nothing here.
07:13 - Yeah, what?
07:14 - Oh, nothing.
07:15 I'm kind of itching to go check my decibel meter.
07:18 - It hasn't changed.
07:19 It's been idling the whole time.
07:20 - Yeah, I know, okay.
07:21 (laughing)
07:22 - God.
07:24 (engine revving)
07:27 - Survey says--
07:46 - Boom, ooh, just a tiny, tiny, tiny, tiny, tiny bit.
07:50 Let's look at the overlay.
07:51 We saw 370 pound feet of torque and 360.8 horsepower
07:55 over the average of three curves,
07:57 but this is what's telling.
07:59 Look at that.
08:00 There's actually a difference.
08:01 So the H-pipe is in black.
08:04 No H-pipe is in red, and it did, in fact--
08:08 - Wow.
08:08 - Add some meat below the crossover.
08:11 - Here's something you guys aren't considering.
08:13 If you look at the computational flow dynamics,
08:15 as the velocity of the gas through the pipe increases,
08:19 the amount that crosses over decreases.
08:21 Basically, you've got one pipe like this,
08:23 another one like this.
08:24 The faster the gases are going this way,
08:26 the less ability they have to cruise through here.
08:28 - Yeah, and that's why we're seeing less there and more.
08:32 - Okay, that was better than I thought, so now what?
08:34 X-pipe?
08:35 - X-pipe.
08:36 - Let's go do that.
08:37 - Just a little trimming.
08:38 Drop right in, cool.
08:39 - All right.
08:40 - I'll try not to cut the pipes in the wrong place again.
08:42 (laughing)
08:43 - Should I erase all the magic marker lines on the pipe
08:46 and give Steve only one to deal with?
08:48 - Yes.
08:49 - Okay, perfect.
08:50 - I like that.
08:51 - Let's clean them off.
08:52 (upbeat music)
08:54 It's definitely quieter with the X-pipe.
09:08 - So far, I mean, we'll see when we get it up to some speed,
09:11 but it's funny because we're sitting here
09:13 and you can't hear the motor.
09:14 - I hear the manufacturing of fish tanks next door
09:18 more than the engine.
09:19 - That's our neighbors through the wall.
09:20 We can hear their routers
09:21 and we can't hear the motor sitting right here.
09:22 It's amazing how quiet it is.
09:24 - But more than just quiet, to me, it's smoother.
09:27 You don't hear like any pulses.
09:29 It's just like a vroom.
09:31 - Yeah, it's like a tone rather than a brr-brr-brr.
09:34 - Let me ask you guys something.
09:35 As you've gotten older,
09:35 have you started actually enjoying quiet exhaust?
09:39 - No.
09:39 - No!
09:40 (laughing)
09:41 - We're about to do our very first pull with the X-pipe.
09:44 (dramatic music)
09:47 (engine revving)
09:49 - I'm gonna go with it sounds better than the H-pipe.
10:09 The X-pipe is cooler sounding at wide open at RPM.
10:13 - It sounds like 7,500 instead of 65 to me.
10:15 - Once it starts to get to that tone,
10:17 it really sounds like there's some engine speed.
10:19 A lot of it's perception.
10:20 We talk ourselves in and out of some things,
10:22 but it does sound cooler.
10:23 - It's pretty clear.
10:24 - Can I go in and check my decibel meter?
10:26 What?
10:29 - We have OCD, anxiety, and depressive.
10:34 We have all of the emotions.
10:37 (laughing)
10:39 - God, that's so close to being real.
10:41 - It is!
10:43 We looked at 369.9 pound feet of torque at 4,300 RPM,
10:47 essentially within a tenth of a horsepower,
10:49 identical to the H-pipe.
10:51 And in the horsepower, 362.1 at 6,000,
10:55 which is up almost two.
10:58 - We're ready to look at the H-pipe?
11:00 - I'm ready for the overlay.
11:02 Ready?
11:03 Ooh!
11:04 Basically doesn't care.
11:07 The H-pipe is lower above peak torque.
11:11 - Yeah, the X-pipe's a touch better.
11:14 - Yep.
11:15 - Want me to zoom in on that?
11:16 'Cause it's basically identical in here.
11:17 - So what we're seeing is that this right here
11:20 can be the start of the dyno pull
11:21 and how the carburetor is carbureting.
11:23 This I would look at as not data.
11:25 I would start looking at it from 3,500 RPM
11:28 to 4,800 RPM, really identical.
11:33 But let's zoom in and have a look at everything
11:35 above 5,000, like right there.
11:39 Now you can get a better look at the fact
11:41 that the X-pipe is making a tiny bit more power
11:45 than the H-pipe.
11:46 So the H-pipe proves to be better at lower RPM
11:50 and the X-pipe not as better at higher RPM.
11:54 - You know, they're both better down low.
11:56 I mean, that's a given.
11:57 There's five or six pound feet that I think is verifiable.
11:59 We're looking right here,
12:00 when we start looking at these spreads,
12:02 we're looking at 60.8 versus 62.
12:06 We're looking at a horsepower and a half, two horsepower.
12:09 - Yeah, to give you scale on this,
12:10 the difference between these two lines
12:11 is like one to two horsepower.
12:14 So we're really talking minutiae here.
12:17 - I can really zoom in on that.
12:19 - Yeah, and it makes it look like something.
12:20 - And that is 155, for instance.
12:25 - 355 versus 357.1, 2.1 horsepower,
12:30 which for the record, you will never feel in the car ever.
12:36 So basically it's a wash.
12:40 - I like the sound of the X-pipe.
12:42 - I do.
12:43 - But I wonder how much more difficult the X-pipe is
12:44 to get in a chassis, in a frame.
12:46 - Yeah.
12:47 - 'Cause it looks like it takes more than a lot.
12:49 - All you need is a straight piece of pipe
12:51 and you can make an H-pipe by yourself.
12:53 - Yeah, H-pipe's certainly less expensive,
12:55 easier to install, takes up less room.
12:58 - H-pipe, X-pipe sounds cooler.
12:59 - X-pipe sounds cooler.
13:01 - Yeah, and they make the same power
13:03 and they're both better than straight pipes.
13:05 (whooshing)
13:08 - Well, Steve-O, I think we can agree
13:10 that you were right and I was chump.
13:12 - Really?
13:13 - Yeah.
13:13 - Why?
13:14 - Remember I said zero was gonna happen
13:15 and you said there was gonna be power to be had
13:17 and there was.
13:18 - Yeah, I know, a little bit of torque down low.
13:20 - It was microscopic though.
13:22 - Well, you know, it was measurable and significant,
13:25 I'd say.
13:26 - It was measurable, I don't know about significant.
13:27 But the real question in conclusion is,
13:30 are you an H-pipe guy or an X-pipe guy?
13:33 - I don't know, I kinda like this guy.
13:35 That's why I'm holding it.
13:36 So simple, just one straight pipe between banks, boom.
13:40 You've got a crossover.
13:41 - I can't deny it, I'm ultimately an H-pipe guy too.
13:44 And really for the same reason,
13:46 it's simple and it's cheap.
13:48 These are more expensive.
13:49 I've tried to install these on cars, I've had them on stuff
13:53 and there's just more angles and curves and junk
13:56 to deal with and getting in the way of your drive shaft
13:58 and safety loop and trans pan.
14:00 The only one I've ever had that fit good
14:02 was a complete hooker kit for an LS swap
14:05 on the Crusher Camaro.
14:06 - But I found the guys on the internet always say,
14:08 these things sound way better.
14:10 And you know what?
14:12 I'll have to say, I'll give it to the internet on this one.
14:14 - I definitely have to give it that.
14:15 These things sound meaner.
14:18 It shrieks.
14:18 - What was the answer on your DB meter deal?
14:21 Well, you know what?
14:22 Oddly enough, this was the quietest.
14:24 They were all pretty loud.
14:25 I mean, the meter goes to 130
14:27 and the straight pipe was almost 129.
14:30 - Okay.
14:31 - And then it went to 128 and that was 127,
14:33 basically if you round off.
14:35 - I don't know what the scale is on DB,
14:37 whether that's really audible to you in the car or not,
14:40 but I'm just gonna go ahead and say that doesn't matter.
14:42 They're all the same.
14:43 - Besides volume, sound quality, this was the best.
14:46 This was probably second best.
14:47 And it was a little burbly with the separated banks.
14:50 - Yeah, absolutely.
14:52 The other thing that I got to bring up for the audience
14:54 is I know that when people see the episode,
14:57 they're gonna look and realize we did all of our testing
15:00 just with the mufflers open on the end,
15:01 no tailpipe whatsoever.
15:03 And you know that there's gonna be people who are going,
15:05 your intestines invalid because you have to have
15:07 a tailpipe on there for the wavelength.
15:10 - What an invitation of the internet.
15:12 - Did I sound like a keyboard commando?
15:13 - Oh yeah.
15:14 - Oh, I know.
15:15 It might've been a little over the top.
15:16 But regardless, I mean, a lot of people believe
15:17 you gotta have an extension behind the muffler.
15:20 And so we were like, you know what?
15:21 We better check it out.
15:22 And off camera, Brulé found an 18 inch length of pipe
15:26 and we put them on the ends of the mufflers
15:28 and we ran our whole test regimen again,
15:30 same way as we did with the crossover pipes.
15:33 And the answer is zero.
15:36 Zero.
15:37 - Nada.
15:38 - At least in this particular application,
15:40 the tailpipe behind the muffler did zilch.
15:43 And I don't think that result would be any different
15:45 if we were running it with straight pipes
15:47 or with or without a crossover.
15:48 It just didn't matter.
15:51 And we were only dealing with like two to five pound feet
15:54 rather in this episode.
15:55 I hope next time we can get back to more violence
15:58 and horsepower, 'cause that's what we're all about
16:01 on Engine Masters, which is presented by Amsoil
16:04 and supported by Mr. Gasket,
16:06 Senior Gasket.
16:07 - Senior.
16:08 - And Earl's Vapor Guard Hose.
16:11 - Hello!
16:14 - What?
16:19 I never wanna see that again.
16:21 What?
16:21 (laughing)
16:24 (dramatic music)