4 into 2 exhaust

I have seen a photo somewhere of an xj with a 4 into 2 exhaust that had cylinders 1 and 4 to one side and 2 and 3 to the other. Does anyone know anything about them, I assume it would make a 4 cylinder sound like a twin, thats if the firing order is 1/4 together and 2/3 together, so far as I know thats the order on my 750. Comments?

 

Check HERE and HERE

 

I have the 4-2 exhaust on my Seca. It sounds awesome! It sounds more like a jet engine than a twin. I have a pic in my album with the new exhaust.

 

I love our Dual exhaust systems. Looks great. I'm a big fan of symmetry. I wonder if there is a 4 into 2 Deeptone for our bikes. I had how i sound like a mosquito from far away
-SLKid

 

Mosquito! Psht...

Everyone at work knows it's me by the sound of my bike.... Jet engine I tell you, Jet Engine!

They also know when my uncle pulls in, his Honda sounds like a lawn mower.

 

I have a mint condition 4-to-1 on my bike, but I also have a re-done 4-2 from my parts bike (completely sanded and painted flat black). I am looking for a more 'throatier' sound as opposed to jet engine/mosquito ;-P

Which would be better? Any chance someone can get a sound clip from their bike running and revving w/ different exhausts so we can hear? (I can do w/ my 4-to-1 if anyone wants).

 

Guys, I do believe he's looking for a different 4-2.

Our bikes run cyl 1+2 and 3+4.

But he is in belief that they FIRE together as well.

IIRC - they do not. One cylinder at a time.

Not the right order, but the idea is:

Cylinder #1 - Intake
Cylinder #2 - Compression
Cylinder #3 - Power
Cylinder #4 - Exhaust

They all fire seperately, so you get

RIGHT PIPE POP (Cyl #3)
LEFT PIPE POP (Cyl #2)
RIGHT PIPE POP (Cyl # 4)
LEFT PIPE POP (Cyl # 1)

I don't know the crankshaft layout or what not, but I BELIEVE this is the right way it fires, not necessarily the correct order though.

 

Yes dpawl31 that is what I was asking,so they don`t fire as pairs? Its not that I`m looking for an exhaust at this time i have a 4 into 1 with a supertrapp muffler (modified collector box myself) just trying to clear up a question i asked myself and then this forum.

 

Unless someone corrects me, they DO come to TDC and BDC in pairs, but the TDC ones are on beginning of POWER and beginning of INTAKE strokes, while the two @ BDC are on EXHAUST and COMPRESSION.

 

So if firing order is 1342 what would have been the point of the 4 into 2 exhaust i saw that had cylinders 1/4 to one side and 2/3 to the other? I don`t remember where i saw the photo.

 

That set-up evens out the exhaust pulses- - the left muffler takes a hit, the right takes a hit, back and forth. That's a rare aftermarket system.

 

Bushy, I believe what you are refering to is the Jardine "Spaghetti" exhaust system. It brought the output from 1&4 to one muffler and 2&3 to the other one. Something about timing the exhaust pulses for better scavenging. They no longer make replacement systems for our bikes anymore, at any rate. Mike

 

Well thanks Mike and Time , thats cleared that up.My other firing order post as well...... Next question... why? Scavenging, (what a wonderful word/action) does this mean it was done for fuel efficiency, if so,did they have the figures to prove it.