4 into 2 Vs 4 into 1

What is the different from the 4 into 2 exhaust vs the 4 into 1? Does it change the torque power curve? Or do people do it for the weight saving?

SATSFYD wrote: What is the different from the 4 into 2 exhaust vs the 4 into 1? Does it change the torque power curve? Or do people do it for the weight saving?

And some folks prefer the more "balanced" appearance provided with a muffler on each side.

Good Fortune!

The theory is that a 4 into 1 will give more top end power where the 4 into 2 will give more midrange........in saying that i highly doubt you'd notice the difference & different pipes will give different dyno curves so IMO its not worth worrying about..........go with what you like the look of or ties in with your bike's style.

[quote="Patton"
And some folks prefer the more "balanced" appearance provided with a muffler on each side.

Good Fortune! [/quote]

That would be me, plus You don't have to lose the center stand.

JD

Patton wrote:

SATSFYD wrote: What is the different from the 4 into 2 exhaust vs the 4 into 1? Does it change the torque power curve? Or do people do it for the weight saving?

And some folks prefer the more "balanced" appearance provided with a muffler on each side.

Good Fortune!

+1

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internal comustion engines are essentialyy an air pump. the freeer the air gets in and gets out the more horsepower you produce. exhaust is only one componet and usually the cheapest mod. if you put bigger carbs, valves, port the heads coming in you have to be able to get it out.

with that said the back pressure from the pipes (ie diamiter of pipe bends in tubing size and shape of collecter)tune the torque curve and over all over hp @ a given RPM

Generally speaking you will notice a modest gain in torque and performance with a 4 into 1 swap. but this is only 1 component in increasing overall performance

I think dual is quieter from a noise pollution testing standpoint. If you can scatter sound in more directions, any one direction will be quieter. That probably weighs in on factories using dual, in addition to the other factors.

Weight is a pretty huge factor, though, when you campare a full factory chrome dual to an aluminum canister Kerker.

What about a 4-2-1 compared to a 4-2, does the 4-2 still give more midrange or are they more or less equall?

Mookachacka wrote: What about a 4-2-1 compared to a 4-2, does the 4-2 still give more midrange or are they more or less equall?

Interesting discussion. I would love to see someone put a properly tuned totally stock KZ on a dyno then swap out only the exhaust and re-tune the bike for the new exhaust and dyno it. I think it would be great to see a true apples to apples comparison of the two powerbands - one with stock pipes and one with 4>1 without other mods (other than properly tuning the bike for the pipe) as this would reveal the strengths and weaknesses of each system. Ed

that would be great. I know on the comarisons I have seen on newer bikes the 4 into one is a couple horsepower throught out the rpm range over stock and a few less in the midrange with a more exotic 4 2 1 or tri y designs or whatever they call em

loudhvx wrote: I think dual is quieter from a noise pollution testing standpoint. If you can scatter sound in more directions, any one direction will be quieter. That probably weighs in on factories using dual, in addition to the other factors.

Thats very true Lou, at our trackdays we are noise tested over here & its very hard to get a true reading of a dual exhaust bike according to noise testers. The rules state that a bike is tested at a given RPM (7000 for 600's & 5500 for 1000's) at a 45 degree angle, 50cm away from the exhaust exit height. They cant test the dual exit's correctly especially if thay are either side of the swingarm. I've seen & heard many times of a big bike passing the noise test & then being louder on track than a single pipe bike putting out similar DB. They have now started to introduce 'drive by' testing to read differently.

ramtough_63 wrote: that would be great. I know on the comarisons I have seen on newer bikes the 4 into one is a couple horsepower throught out the rpm range over stock and a few less in the midrange with a more exotic 4 2 1 or tri y designs or whatever they call em

Also true. I'm involved in the road racing here in Northern Ireland & i've seen dyno sheets to prove that a 4-1 has slightly more top end power on a modern sports bike than a 4-2-1, or a 4-2. Im sayig that some of the 4-1-2 systems work well on a GSXR1000 like the Leo Vinci


You commented about header pipe shape.......Micron used to do a 'Serpent' header pipe that was supposed to improve torque but i didn't ever see data to prove that, if it worked they probably wouldnt have went out of business & everyone else would have copied i reckon. The 1st curve on the headers looked like a cobra ready to attack