found this in my exhaust

[jmdaniel]

Found this in my exhaust. Hmmmm....

 

[Tek]

Hey exhaust geniuses...
As has been pointed out, this exhaust is 4 - 2(briefly) then 1 - 2. Wouldn't there be a low end torque advantage to putting a divider in the big plenum that forms the "1" part when removing those nasty cat guts. So it would just be a 4 into 2 exhaust.

So long as you aren't using the O2 sensor anyway that is...

I've heard the opposite from people complaining about the lack of cross-over pipe on the Holeshot headers. They say that a cross-over pipe would improve low-end torque.

Does anyone know the purpose of the cross-over between the pipes for cylinders 2 and 3 on the stock header?

As for the O2 sensor, I think hope it's safe to assume that the average of 2 cylinders will be close enough to the average of all 4:

As far as the linking of the two sides of the exhaust, I believe that is supposed to help balance out the exhaust pulses and increase the scavenging of the combusted gasses. (Which is why you see many aftermarket automobile header/exhaust systems that have a "H" or "X" pipe installed between the two exhaust banks.)

Tek

 

[UselessPickles]

Hey exhaust geniuses...
As has been pointed out, this exhaust is 4 - 2(briefly) then 1 - 2. Wouldn't there be a low end torque advantage to putting a divider in the big plenum that forms the "1" part when removing those nasty cat guts. So it would just be a 4 into 2 exhaust.

So long as you aren't using the O2 sensor anyway that is...

I've heard the opposite from people complaining about the lack of cross-over pipe on the Holeshot headers. They say that a cross-over pipe would improve low-end torque.

Does anyone know the purpose of the cross-over between the pipes for cylinders 2 and 3 on the stock header?

As for the O2 sensor, I think hope it's safe to assume that the average of 2 cylinders will be close enough to the average of all 4:

As far as the linking of the two sides of the exhaust, I believe that is supposed to help balance out the exhaust pulses and increase the scavenging of the combusted gasses. (Which is why you see many aftermarket automobile header/exhaust systems that have a "H" or "X" pipe installed between the two exhaust banks.)

Tek

But all 4 cylinders already come together on the stock header (just before splitting into 2 again where the cats are); what's the point of connecting 2 and 3 so close to the exhaust outlet on the engine?

 

[Fred W]

Hey exhaust geniuses...
As has been pointed out, this exhaust is 4 - 2(briefly) then 1 - 2. Wouldn't there be a low end torque advantage to putting a divider in the big plenum that forms the "1" part when removing those nasty cat guts. So it would just be a 4 into 2 exhaust.

So long as you aren't using the O2 sensor anyway that is...

I've heard the opposite from people complaining about the lack of cross-over pipe on the Holeshot headers. They say that a cross-over pipe would improve low-end torque.

Does anyone know the purpose of the cross-over between the pipes for cylinders 2 and 3 on the stock header?

As for the O2 sensor, I think hope it's safe to assume that the average of 2 cylinders will be close enough to the average of all 4:

As far as the linking of the two sides of the exhaust, I believe that is supposed to help balance out the exhaust pulses and increase the scavenging of the combusted gasses. (Which is why you see many aftermarket automobile header/exhaust systems that have a "H" or "X" pipe installed between the two exhaust banks.)

Tek

But all 4 cylinders already come together on the stock header (just before splitting into 2 again where the cats are); what's the point of connecting 2 and 3 so close to the exhaust outlet on the engine?

It has got to be something to do with wave fronts and timing. I'm not smart enough (or industrious enough) to figure it out, but the idea is the the passing high pressure wave from one cylinder puts a slight vacuum on the cross connected pipe. That vacuum will better scavenge the cylinder if the timing is correct.

Same idea as an expansion chamber on 2-smokes, but just with another cylinder creating the vacuum effect. However, I suspect that, just like on those oil burners, the effect is fairly limited to a particular RPM band (hence the two stroke terms "power band", and "peaky") depending on the length of the pipes used and the wave propagation and reflection / vacuum) rates.

 

[RTSR1/FJR]

The chamber before the Cats is similar to an X chamber used on cars and helps balance the exhaust pulses and aid scavaging the other cylinders. I run a Bassani X pipe on my Mustang. Seemed to improve low end and the sound is great too! Blends both banks together.

 

[dcarver]

Nice job - beyond my skills...

Whooo ............. News Flash!!!

This from the guy who can't flush a toilet without directions :dribble:

:haha: :haha: :haha: Yer Killin' me carver

:jester:

Toilet? What's dat? You must be a high class poooping falooting hi tech redneck, eh? :****:

Honestly, guys, will you ever realize the .5 hp increase on the road for all this?

Oh, I see, it's a matter of why not?

Now I get it.

 

[Big Sky]

All this reminds me of the time about 21 years ago when I was doing a little light wrenching on my old SL 350 Honda - the "scrambler" with the upswept exhaust. My two-year-old (now 23-year-old) was hanging around, watching, commenting, "helping" as he always did. When I went to put the tools away, I was missing several sockets. Looked high and low but could not find them. Very curious. Anyway, when I went to start the bike, the missing sockets shot about 20 or 30 feet to the rear out of the mufflers. The kid had decided, with his two-year-old logic, that the sockets belonged in those little holes. This is referred to as a "fond memory." Still makes me smile today.

 

[RockiesRider]

Found this in my exhaust. Hmmmm....

Let me guess...you ate both those hand fulls and... SHIT CORNUTS!!! :lol2:

HAHAHAHAHAHAHAH

Oh man, I crack me up.

 

[Bustanut joker]

Nice job - beyond my skills...

Whooo ............. News Flash!!!

This from the guy who can't flush a toilet without directions :dribble:

:haha: :haha: :haha: Yer Killin' me carver

:jester:

Toilet? What's dat? You must be a high class poooping falooting hi tech redneck, eh? :****:

Who you callin redneck ya ball licker.. :lol:

we got's real shitters here..

yep! odots bedroom..

:jester:

 

[XJRGUY]

This usually makes it easier to get "anything" out of your "exhaust".

:dribble: