Can anyone explain engine firing order and how it impacts the engine sound?

[Todd03Blown]

I have been told by a few people since I was very young that engine firing order impacts the sound of an engine? I have seached the internet and found a few things but nothing that really puts my mind at ease or to the point that I fully understand it.

Anyone care to help or point me to a good link?

 

[virginiafiveo]

the sound of an engine has to do with alot of possible differences, cam, compression, timing, flat plane, cross plane, boxer, rotary, stroke, headers, exhaust, heads, valves, rockers, there is quite a few things that would affect the sound. what is it you are specifically looking for? ferrari's sound the way they do because of being a flat plane crank vs a typical cross plane.

 

[Domingo]

It's simple. Listen to a '99-04 Mustang V6 exhaust (even firing order) vs a '99-'04 gt/cobra.

 

[virginiafiveo]

he is talking about the difference between V8s I believe. chevy to ford probably.

 

[thomas91169]

has more to do with how efficiently air enters and exits the motor, as well as compression, amount of air (displacement), and a shitload of other things.

im sure timing order does play a role, especially with unequal length manifolds or header design.

 

[oilwell1415]

he is talking about the difference between V8s I believe. chevy to ford probably.

The two traditional GM and Ford firing orders are the same. The only reason they look different on paper is because they number the cylinders differently. Even if you look at the two different Ford firing orders, they sound the same. How the engine sounds is a function of all the other different things mentioned in the thread, and all of the "new" engines sound different than their traditional counterparts. IMHO, this is mainly because of emissions requirements. Small bores have better emissions that big bores. Small bores also have less room for valves. Smaller valves dictate smaller ports, and smaller ports mean port efficiency has to be better. Efficiennt ports sound different than junk ports.

 

[todd4566]

The term flat plane crank was new to me, so I searched on it and found this article, which makes mention to exhaust note variables:

"Now, the exhaust note of an engine is related to the manifold design, which is related to the firing order, which is related to the cylinder layout and crankshaft design - therefore the sound of flat-plane V8 is usually somewhat like a pair of four-pot engines screaming simultaneously, unlike the rumble of cross-plane V8s. There have been comments like "It doesn't sound like a V8" aimed at the V8 Esprit... but this should really be "It sounds like a Racing V8!" for the reasons explained here. "

Flat Plane Crank

 

[thomas91169]

good info.

 

[Chris _Scott]

Kinda like why Vipers sound so weird..

Their exhaust never crosses over..so you are essentially listening to two inline-5 cylinder motors

Atleast this is what I have heard

 

[oilwell1415]

Vipers sound so wierd because you can't build an even fire V-10 in a 90 degree block.

 

[astrodudepsu]

Vipers sound so wierd because you can't build an even fire V-10 in a 90 degree block.

You say weird, I say poop.

 

[oilwell1415]

You say weird, I say poop.

I agree with you, I was just using the same term as the person I quoted. If I was charged with designing a high end performance car I would go out of my way to make sure it didn't sound like rhinocerous diarrhea, even if that meant we had to come up with a new engine instead of stealing something off of the truck program shelf.

 

[astrodudepsu]

I agree with you, I was just using the same term as the person I quoted. If I was charged with designing a high end performance car I would go out of my way to make sure it didn't sound like rhinocerous diarrhea, even if that meant we had to come up with a new engine instead of stealing something off of the truck program shelf.

:lol::lol::lol::lol:

Original and totally true.

 

[Ironhand]

Good info. But I also wonder why most V configurations are at or around 90 degrees...?

 

[Fire Pig]

The new Mustang GT sounds like crap compared to my stock 5.0.
TBH I bought my Mustang mostly for the sound...and the looks of course.

 

[thomas91169]

Good info. But I also wonder why most V configurations are at or around 90 degrees...?

because saying "Vee Eight" just sounds way cool.

i know i read somewhere what the angles and everything does when concerning opposing cylinder locations, but i forgeted it.

 

[oilwell1415]

Good info. But I also wonder why most V configurations are at or around 90 degrees...?

There are a lot of things that have to be considered to get to the 90 degree number. With a V8, 90 degrees works well because a cylinder fires every 90 degrees. This allows for a smooth running engine. It also allows more room for the cam in the valley. A 90 degree V also prevents the bottom portions of each cylinder from interferring with each other. Other considerations are width vs height. 90 degrees typically produces the best compromise without making the engine either two tall or too wide. It all boils down to physically needing to fit all the parts of the engine in it while not using up any more space than needed.

 

[Chris _Scott]

I figure it would also help with vibration/dampening effects

 

[James Snover]

The Viper does not have a 72-degree block? If it is a 90-degree block, then no, it cannot be even-firing. A v-10 (dumb), in a 90-degree block (dumb for a v-10) and odd-firing (dumb but unavoidable if it is a 90-degree block) = dumb engine.

OP: the entire engine design is driven by the firing order. Change the firing order, change the various components to suit the new firing order and it sounds different. Because it is now a different engine.

A firing order is necessary to make power efficiently and increase the engine's longevity. There are many possible firing orders for any engine, but only a few are used as most of the others are inefficient, or make less power, or tear the engine up. The Chevy small block for instance, usually came with a 90-degree dual plane crank. But it makes significantly more power with a 180-degree single-plane crank. The single plane won't last as long, however, due to stresses on the crankshaft. The primary benefit of the single plane crank is that the intake and exhaust design can now have evenly-spaced pulses that reinforce each other to the best possible extent. But the 90-degree is what you saw on the street because it made good power and lasted much longer.

The best firing order is with a 60-degree block V-12 with a 120-degree crank. Silky smooth, beautiful sound and they last forever. All the V-12 fighter planes of WWII were in this configuration _except_ the Rolls Royce Griffon which, for some reason, had an odd-firing crank.

A good example of an odd-firing engine which was mass-produce and had great longevity is the Chevy V6 from the '80's and '90's. It was a 90degree block with an odd-firing crank. As much as I hate odd-firing configurations, those old lumps of iron lasted forever.

Jim Snover

EDIT: and vibration! A firing order can be determined to control or mitigate vibration. How could I forget?

Vipers sound so wierd because you can't build an even fire V-10 in a 90 degree block.

 

[deadpres]

The Viper does not have a 72-degree block?

It took me about 10 minutes to figure out why you posted this lol:bash: I finally understand now :beer: