mjheathcote
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Lots on the Internet, this is quite a good description:
http://www.carid.com/articles/are-2...pes-the-best-type-of-dual-exhaust-system.html
Although according to Larini, the X is louder than the H....
Whats In My Back Boxes, Suggestions Please?
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Lots on the Internet, this is quite a good description:
http://www.carid.com/articles/are-2...pes-the-best-type-of-dual-exhaust-system.html
Although according to Larini, the X is louder than the H....
mjheathcote
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I believe tone and loudness, more loudness if no H or X.
Emtee
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Don't forget if comparing to stock that the stock CC is muffled, so tone would change AND the volume would rise, as neither the Larini H nor X are muffled.
mjheathcote
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Yes.
I always struggle to understand that the larini X is louder than the larini H, the difference I see is the improved gas flow with the X, which is only a small percentage increase over the H. Can't see how this can change the loudness, but apparently it does.
mjheathcote
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Yes the replacement X or H pipe are insane prices.
It's not the price of the stainless steel tube, we use thin wall stainless tube in our industry and a 6M length of 2.5" polished tube in superior 316 grade material costs less than £100, and you would not use all of it, about half of it.
Emtee
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High R&D costs across all their range and especially their ongoing race work, divided by short production runs aimed at a small targeted audience equals high unit costs. On top of that they know they can charge a premium as their past trading and reputation have proved. The H and X sections are a snip compared to their sports cats!
stradaman
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X, H, S T, what ever shape the pipe, is restrictive. The gasses have to slow down, and change course, its simple science. This will build up back pressure, further up the pipe, around the cats, and secondary manifold pipes.
A straight pipe, with no silencers, will make most power, every time.
You want good straight through, talk to Power Flow. Always had good readings , from their pipes, on RR. Good prices too.
X pipe dear, and not expensive to produce, because of the Maserati name, attached, i can assure you!!
Andy
A straight pipe, with no silencers, will make most power, every time.
You want good straight through, talk to Power Flow. Always had good readings , from their pipes, on RR. Good prices too.
X pipe dear, and not expensive to produce, because of the Maserati name, attached, i can assure you!!
Andy
Fat Arnie
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Right, lets discuss different exhaust configurations and aural effects and why we have an X-Pipe.
The first thing to make a difference on how your car sounds is the crankshaft. V8 crankshafts can be flat plane as on a Ferrari 355/360/430 or they can be cross plane like all American V8's
In essence a flat plane V8 is like two 4 cyl engines running 90 degrees (the angle of the V) out of phase.
You get an exhaust pulse every 90 degrees of crank rotation, but the flat plane crank fires each cylinder in each bank at even 180 degree intervals. (remember the engine revolves twice to complete one 4 stroke cycle - 4 x 180 = 720 deg)
On all the mentioned Ferraris the exhaust manifolds merge the exhaust pulses together at once - a "4 into 1 manifold".
So on a flat plane he exhaust pulses on each bank are even. This means bank 1 fires at 0, 180, 360, 540 and bank 2 at 90, 270, 450, 630
On a cross plane crank the exhaust pulses on each bank are uneven. This means bank 1 fires at 0, 90, 180, 450 and bank 2 at 270, 360, 540, 630
So moving to Maserati.
The 3200 engine and its V8 ancestors have a firing order of 1 - 8 - 4 - 5 - 7 - 3 - 6 – 2
TYhe 4200 and the 4.2/4.7 litre engines in the QP and GT are all derived from the Ferrari F430 engine, though they share only a very small number of common parts. Importantly the crankshaft is cross plane, not flat plane and has a firing order of 1 - 8 - 4 - 2 - 7 - 3 - 6 – 5 This gives uneven exhaust pulses on both engines.
So why do they do this?
Cross plane cranks are better balanced - much lower 1st harmonic resonances. The engine is better balanced and idles more smoothly.
Downsides?
The cross plane has additional counterweights which make it heavier (which improves torque) but means it is reluctant to rev due to increase rotary inertia.
So a Maserati V8 has slower pickup and a deeper exhaust note, all down to a few basic design characteristics.
Now, fitting an H-Pipe balances the uneveness of these exhaust pulses and makes the car quieter and more refined. Think what a Rover V8 powered TVR sounds like and you get my drift. (A TVR has no H-Pipe). Same for most Yank muscle cars.
The lack of the H-Pipe also makes the exhaust note much deeper.
An X-Pipe is a different proposition altogether. The X-pipe does not address the imbalance of the exhaust pulses bank to bank, it merges the pulses, so each outlet emits all 8 exhaust pulses.
The effect of this is that it makes the engine sound higher pitched ( a flat plane V8 starts to take on the harmonic like a V12) and this gives the impression of it being louder.
On a car with a cross plane crank, the effect depends on the firing order, but ultimately the exhaust note pitch will increase and it will sound louder.
On a flat plane engine an X-pipe will not help cylinder evacuation, hence why they are not used in F1. On a cross plane, it might help a small amount but the improvement is again down to the firing order .
Hope this helps.
The first thing to make a difference on how your car sounds is the crankshaft. V8 crankshafts can be flat plane as on a Ferrari 355/360/430 or they can be cross plane like all American V8's
In essence a flat plane V8 is like two 4 cyl engines running 90 degrees (the angle of the V) out of phase.
You get an exhaust pulse every 90 degrees of crank rotation, but the flat plane crank fires each cylinder in each bank at even 180 degree intervals. (remember the engine revolves twice to complete one 4 stroke cycle - 4 x 180 = 720 deg)
On all the mentioned Ferraris the exhaust manifolds merge the exhaust pulses together at once - a "4 into 1 manifold".
So on a flat plane he exhaust pulses on each bank are even. This means bank 1 fires at 0, 180, 360, 540 and bank 2 at 90, 270, 450, 630
On a cross plane crank the exhaust pulses on each bank are uneven. This means bank 1 fires at 0, 90, 180, 450 and bank 2 at 270, 360, 540, 630
So moving to Maserati.
The 3200 engine and its V8 ancestors have a firing order of 1 - 8 - 4 - 5 - 7 - 3 - 6 – 2
TYhe 4200 and the 4.2/4.7 litre engines in the QP and GT are all derived from the Ferrari F430 engine, though they share only a very small number of common parts. Importantly the crankshaft is cross plane, not flat plane and has a firing order of 1 - 8 - 4 - 2 - 7 - 3 - 6 – 5 This gives uneven exhaust pulses on both engines.
So why do they do this?
Cross plane cranks are better balanced - much lower 1st harmonic resonances. The engine is better balanced and idles more smoothly.
Downsides?
The cross plane has additional counterweights which make it heavier (which improves torque) but means it is reluctant to rev due to increase rotary inertia.
So a Maserati V8 has slower pickup and a deeper exhaust note, all down to a few basic design characteristics.
Now, fitting an H-Pipe balances the uneveness of these exhaust pulses and makes the car quieter and more refined. Think what a Rover V8 powered TVR sounds like and you get my drift. (A TVR has no H-Pipe). Same for most Yank muscle cars.
The lack of the H-Pipe also makes the exhaust note much deeper.
An X-Pipe is a different proposition altogether. The X-pipe does not address the imbalance of the exhaust pulses bank to bank, it merges the pulses, so each outlet emits all 8 exhaust pulses.
The effect of this is that it makes the engine sound higher pitched ( a flat plane V8 starts to take on the harmonic like a V12) and this gives the impression of it being louder.
On a car with a cross plane crank, the effect depends on the firing order, but ultimately the exhaust note pitch will increase and it will sound louder.
On a flat plane engine an X-pipe will not help cylinder evacuation, hence why they are not used in F1. On a cross plane, it might help a small amount but the improvement is again down to the firing order .
Hope this helps.
Great post, I love people who talk the talk!
I am going to get a guy who makes custom exhaust pipes to make me a x-pipe and see what happens.My R&D will happen when I drive it!
Today I took out the flap and butterfly arrangment from the back box, migged it back together and went for a drive.
The tone was deeper at idle and a far more impressive tone, deeper and muscular, on acceleration. It also seems to have a smoother accelaration and more 'umph'.
Looking at the flap/butterfly, it is clear that when it is even fully open, it still restricts the flow to a considerable degree.
A very cheap and pleasing mod, all for about e20 worth of discs and gas. Glad I did it, sorry about the Mig welding, I was **** at it!
The welded side faces up, so you cant see it.
I am going to get a guy who makes custom exhaust pipes to make me a x-pipe and see what happens.My R&D will happen when I drive it!
Today I took out the flap and butterfly arrangment from the back box, migged it back together and went for a drive.
The tone was deeper at idle and a far more impressive tone, deeper and muscular, on acceleration. It also seems to have a smoother accelaration and more 'umph'.
Looking at the flap/butterfly, it is clear that when it is even fully open, it still restricts the flow to a considerable degree.
A very cheap and pleasing mod, all for about e20 worth of discs and gas. Glad I did it, sorry about the Mig welding, I was **** at it!
The welded side faces up, so you cant see it.
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stradaman
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Also Arnie, depends which manifold pipe, joins which, and the length of the pipes. Any downward restriction, will push the spent gases, back up the wrong pipe, and then poor cylinder filling. This can be cut down, by having a manifold, that joins pipes together, that eliminates poor scavenging.
Also depends on valve lift, and duration. Manifold tube size, length of pipe. Sometimes, the pipes are unequal length, but mainly equal, with cylinder matching. Sometimes, the manifold, has a step, at the head, to induce speed.
Manifold and exhaust design, is an art, and most production cars, are rubbish.
Andy
Also depends on valve lift, and duration. Manifold tube size, length of pipe. Sometimes, the pipes are unequal length, but mainly equal, with cylinder matching. Sometimes, the manifold, has a step, at the head, to induce speed.
Manifold and exhaust design, is an art, and most production cars, are rubbish.
Andy
Fat Arnie
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Galway Girl - You could grind the welds back to make it look prettier. Being as your name suggests, a girl, and seeing as you weld, I a forced to ask if you have acetylene legs?
Stradaman, you are of course correct, but any decent exhaust manifold will have equal length primaries. Not relevant on a 3200 as there is the turbo between the primaries and any X-pipe, and looking at a 4200 it looks to me that the primaries are equal length. An x-pipe is not restrictive in any significant way,so long as it is reasonably downstream.
4:2:1 maniflold configurations would only generally be used to create back pressure, which boosts torque, generally in 4 cyl applications.
Generally, as I stated earlier, V8's don't have fancy manifolds. They rely on firing order to create back pressure if crossplane, and if flat plane they are built to rev to give top end power at the expense of torque. Current F1 engines being the ultimate example of this.
Its a science, and you are quite right. Wrong pipe sizes and valve diameters/lift/duration can mess things up. A good example of this is the F355 engine. If you have owned one of these, you will know that at high revs the exhaust gas around the outlets stalls, and it is this, accompanied by manifold vacuum controlled fuel pressure which causes these cars to consume exhaust manifolds (they melt them) at an alarming rate.
My exhaust knowledge has come from deigning the system for my P4 replica, which uses F355 running gear. I'm after noise (it has no silencers) and an x-pipe to get it sounding a bit like the V12 in the real $20m thing.
Stradaman, you are of course correct, but any decent exhaust manifold will have equal length primaries. Not relevant on a 3200 as there is the turbo between the primaries and any X-pipe, and looking at a 4200 it looks to me that the primaries are equal length. An x-pipe is not restrictive in any significant way,so long as it is reasonably downstream.
4:2:1 maniflold configurations would only generally be used to create back pressure, which boosts torque, generally in 4 cyl applications.
Generally, as I stated earlier, V8's don't have fancy manifolds. They rely on firing order to create back pressure if crossplane, and if flat plane they are built to rev to give top end power at the expense of torque. Current F1 engines being the ultimate example of this.
Its a science, and you are quite right. Wrong pipe sizes and valve diameters/lift/duration can mess things up. A good example of this is the F355 engine. If you have owned one of these, you will know that at high revs the exhaust gas around the outlets stalls, and it is this, accompanied by manifold vacuum controlled fuel pressure which causes these cars to consume exhaust manifolds (they melt them) at an alarming rate.
My exhaust knowledge has come from deigning the system for my P4 replica, which uses F355 running gear. I'm after noise (it has no silencers) and an x-pipe to get it sounding a bit like the V12 in the real $20m thing.
stradaman
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Read this, about X Pipes. Pretty accurate, in my book.
http://speedtalk.com/forum/viewtopic.php?f=1&t=22988
Andy.
http://speedtalk.com/forum/viewtopic.php?f=1&t=22988
Andy.
Parisien
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Great thread, it seems x-pipes are as much a triumph of marketing as a triumph of engineering....
adam01
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The marketing blub when the GS was released attributted the extra 10bhp (wow) over the std.coupe primarily to the X pipe.
Kinda supports your statement