You have to check out this exhaust!

[2STROKECAFE]

Backyard engineering at its finest.
http://www.youtube.com/watch?v=yrwNq04E3PU

[Barry S.]

What is that, a jet ski exhaust??

[tz375]

Snowmobiles regularly use 2 into 1 and 3 into 1 exhausts. Sure they can make even more HP with separate pipes, but you would be amazed at the power they can make with that type of pipe.


With a simple Y pipe header into a single chamber, a 700 twin has no problem making nearly 140HP at about 9100rpm.

[two-stroke-brit]

hey guys on this note, do the 3 into 1 chambers work either fo the buffalos or is it best to go with indevidual chambers.
thanks mark

[Suzukidave]

For pipes made here in the US get some 3 into 3 Jemco's http://www.jemcoexhaust.com/

[tz375]

generally accepted practice is that individual pipes can make more top end power than 3 into 1s.

Over time a whole series of myths and urban legends have risen with a few interesting anecdotes to support the argument.

To the best of my knowledge, non of us as actually seen an objective Dyno test of stock versus 3 into 1 versus chambers.

Some of the old 3 into one pipes had good reputations (Strader and Bromlech for example) and some had terrible reputations (Piper in the UK for example). But none of us has seen comparative data.

That said, the easiest way to go is to buy a set of Jemco pipes. We have not seen them tested back to back either, but results so far seem to suggest that on a poeted motor they can make around 65-80HP.

Tommy Crawford of TCE has made a few really interesting 3 into 1 GT750 pipes which seem to get good reviews, but no back to back data to know how they work.

In the US the choices are limited and Jemco's are the most cost effective. In the UK you could try Gibson (Allspeeds) or Swarbrick, and JollyMoto still make a 3 into 1 that costs a small fortune.

But unless you are after a huge performance gain, why not try a modified Snowmobile triple pipe and we'd all love the read your results. It's time to add facts to the old myths.

BTW I'll try a Strader 3 into 1 on mine if I get it finished

[Suzukidave]

I think the snowmobile's get away with the 2,3,4 into 1 pipes as they can be tuned to run best when the clutches lock up and then i bet the thumb throttle is to the bars most of the time and even those guys switch over to the separate chambers for better performance . What i have read on this and other lists about the 3 into 1's is they cut off a bunch of weight , sound cool but seem to always cut off RPM's at around 6000 so if cruseing around is what you mainly do a 3 into 1 might do the job .

[rngdng]

Tommy Crawford of TCE has made a few really interesting 3 into 1 GT750 pipes which seem to get good reviews, but no back to back data to know how they work.

The TC pipes look great and are well-built, but both Gordon and Wayne have reported that they shut down at about 6K. My bike doesn't start accelerating well until about 7K, so that's not for me.



Lane

[Craig380]

Lane,

with Blueboy's mods, where does the power start to fall away? Do you have a 'safe' rev limit that you use?

Is the crank / rods / bearings all stock too?

cheers, Craig

[Suzukidave]

The TC pipes look great and are well-built, but both Gordon and Wayne have reported that they shut down at about 6K.
Lane

[rngdng]

Lane,

with Blueboy's mods, where does the power start to fall away? Do you have a 'safe' rev limit that you use?

Is the crank / rods / bearings all stock too?

cheers, Craig

Blueboy drops power at just above 8000, which is safe for a GT. It doesn't really hit really hard until 6000, however, so it's not what you'd call a broad powerband. It pulls OK down low, but at 6000, it comes to life.



Lane

[ja-moo]

Over time a whole series of myths and urban legends have risen with a few interesting anecdotes to support the argument.

To the best of my knowledge, non of us as actually seen an objective Dyno test of stock versus 3 into 1 versus chambers.

It's simple acustics. The sound wave has to be timed to push the mixture that's in the header pipe back into the cylinder. When in the powerband, a 3 into 1 is sending 3 acustic waves back to the cylinders, and 2 are way off timing wise. This basically kills the stuffing action in the pipe.

And this has been shown in use, as 3 into 1's usually "die" when the powerband hits.

[water cooled]

Lane,

Do you think it drops off above 8000 due to the JEMCO chambers? When I ran the dyno pulls, mine did the same thing not too much over 8000.

[tz375]

Ja-Moo, so true but that's only part of the story. I once sat down and worked out when all the pulses return in a three cylinder system with interference header design and plotted the pressure waves at different engine speeds, the results were interesting.

Just below tuned rpm ie resonant length, the thing actually works quite well (in theory) but at the tuned length of the pipe, pulses do in fact start to arrive at the wrong time, but their amplitude is much lower than with a 3 pipe system.

By designing the system to resonate at a slightly higher RPM than stock it is possible to stretch the power curve quite well without sacrificing too much power anywhere else.

Obviously that will never give the same peak HP as three chambers, but below peak it can be made to make more power/torque. Snowmobile pipes are a little different and they join the 3 pipes as soon as possible and I suspect that reduces both the positive and negative effect of the pipe.

What people like SLP and HTG and AAEN seem to be able to do is to get a fairly broad powerband from those single pipes from say 6,000 to 9500. There's enough examples out there to look at and so far those are the only dyno charts I have seen. The rest of it is just use speculation and rationalizing.

Of course the real reason to run a 3 into 1 is, a/ because you have one and b/ because they weigh a whole lot less than stock.

[ja-moo]

Of course the real reason to run a 3 into 1 is, a/ because you have one and b/ because they weigh a whole lot less than stock.

Don't forget, some guys really like the sound.........