GT550 3 into 1

[Vintageman]

Best of all worlds, reeds, 3 into 3 into one silencer........ https://www.youtube.com/watch?v=RoqgP4vTAYk" onclick="window.open(this.href);return false;" onclick="window.open(this.href);return false;

+1 Although not off the shelf item.
Funny I am liking four strokes more with separate pipes https://www.youtube.com/watch?v=vLUCjKaTnWgand" onclick="window.open(this.href);return false; and 2 strokes combined

A triple is very different to a twin in terms of pulse timing. Twins have a lot more time to complete a cycle, where triples interfere with each other much more seriously.

True. why I included the video of the Yamaha VMAX 700 single pipe triple video. Triple 2 stroke sleds have been no more since early 2000s only twins left. No sure if any one offered and improved version over OEM. That single pipe version was a decent setup stock and people just changed the can.

[tz375]

What is really interesting to me is that sled and PWC manufacturers and places like SLP and AAEN have done such a good job of making 2 into 1 and 3 into 1 pipes that rev over 8,000 in some cases.

None of the software I have used comes close to predicting power from a 3 into 1 pipe. Wizard claims to generate a 3 into 1 pipe but all it does is increase the diameters to make the pipe larger after the collector but makes no adjustment for the collector length. It's not such great software but it doesn't cost much either.

What I don't know is how the best of the best pipe designers design a 2 into 1 or 3 into 1 pipe. Some seem to prefer a short header and others like long headers. Some are tapered and some are parallel. the Koenig that Kim Newcomb raced in the seventies was a 4 cylinder with two chambers and two short Y pipes.

Jollymoto uses long tapered headers. The others are just dump tubes that create all manner of spikes and don't really operate like a chamber at all. No wonder they lose power. But sled guys seem to do a pretty good job. I'll have to drive up to Racine again and see if I can get Olav Aaen to reveal all his secrets. I think I have a better chance of winning the lottery.

I'll stick to single pipes I think.

[Alan H]

I think the reason a 3-1 doesn'r allow top end revs is just that 3 inlets and one outlet causes a restriction to the exhaust gases. Not so much pulse degradation/mismatching as pure plain restriction, which in turn causes back pressure which is the last thing you need in any exhaust. I'll see how the 3-1 performs on mine when I get it done (hopefully) in the next few weeks. I can compare it against the 550K I have for starters. Then possibly get some Abbeytune 3-3 pipes made locally. I don't want a standard exhaust on this one for a few reasons.

thread details for anyone interested

[Vintageman]

Hmmm… if you use a stinger outlet the same size as a single pipe designs that would be a problem. Single pipe you have a long pause in between exhaust period versus closed. So 3 into 1 needs a stinger outlet 3 times larger. Then you need fat pipe so stinger is negligible or maybe exist in the middle of pipe.

When 3 cylinders pulse not much time in-between them to get the chamber timed to pull and push before the next one interferes. Cyls are 120 degrees a part but, exhaust remains opened nearly 16x-180 degrees depending on tune. You have to center the chamber pull and push effect to be complete in less than 120 degrees and centered well with in exhaust cycle. I can see why a single pipe can use more of the full exhaust cycle even 2 into 1 pipe can be near ideal as well. Well what I just said I am only thinking out loud and my math may be wrong

But a 3 into 1 chamber should be better than stock pipes (that are not tuned that is... I suspect stock pipes are tuned somewhat)

3 cyl engines that do this well do all seem to have short collectors before chamber, fat chambers and I’ll have to pay attention as to what outlet looks like.

If someone figured this out you could sell a couple or just be Mr. cool

Fun Stuff

[tz375]

The math is fairly simple even though we are are talking about time as a factor. The stinger design on a single pipe is very small compared to the header because it acts as a pressure bleed . For example 45mm headers use 22-25mm stingers.

Collector design has changed dramatically over the years on 4 strokes. It used to be about the pressure wave generated from the change in section at the collector, but now it's about flow through the collector. Current collector design is all about merge collectors where flow disruption is minimized.

That's good for us because 2 strokes are about the right changes in cross sectional area at the right places in the exhaust. So a modern 3 into 1 would have a decent merge collector design. Typically collector outlet is sized at 1.57 - 2.0 times inlet area of one pipe.

For sure a 3 into 3 baffle size would be undersized for a 3 into 1 but no need for anything larger and that should give us an idea of what size stinger is required.

[ja-moo]

Physics still can't be ignored, the return pressure wave has to return at the correct time, to have any perceptual supercharging effect. With 2 out of three coming at the wrong time, and the 3rd correct reduced to 1/3 there is very little effect. There is no way around that. And a 3 into 1 is not rpm limiting in it's design, it's limit is in effectiveness.

A friend has been doing a lot of pipe testing on his modded H2. And the 3 into 1 averaged a 20 to 30 rwhp loss over different 3 into 3 pipes.

[Vintageman]

I don't think any one is expecting a 3 into 1 to out perform a 3 into 3. But I don't think we expect a 3 into 1 to kill power versus stock.

And, there are real world examples in the late 90s into early 00' where 3 into 1s work well. Ultimate perfromance is 3 into 3 of course, but 3 into 1s were on very sprrty machines

Again i am not sure how Omar performs, but seams like other similar design prove worst that stock

Check this out ->

And I quote web site

"2 INTO 1 & 3 INTO 1 EXPANSION CHAMBERS EXTENSIVELY TESTED FOR VERSION 5!"

http://www.buildandclick.com/html/tuned_pipe.html" onclick="window.open(this.href);return false;

and the "Dual Power" convergent code design seams promissing as well

http://www.buildandclick.com/html/duel_power.html" onclick="window.open(this.href);return false;

Fun stuff

[tz375]

That software does not generate 2 into 1 or 3 into 1 exhaust systems despite what it says. To put it politely it us pretty much useless for anything more than a simple pipe IMHO and even then it tells you nothing about the how it compares to any other design. I have versions 4 and 5 and they are both pretty basic and the 3 into 1 is a myth.

I would not go as far as to suggest that all 3 into 1 systems make less HP than stock but a stock exhaust system is like an expansion chamber with a flat end that generates really odd short stuffing waves. I am yet to see a 3 into 1 with a good collector design to optimize the overall pipe.

What we need is a rich benefactor willing to test every available combination and share the results. Until that day comes we'll all just choose what we want and facts be damned.

[ja-moo]

I guess it all depends on the output you are looking for. You were looking "compared to stock", which is at the lowest level of performance, so there will be a bit of advantage with the weight reduction, and some performance gain.

[tz375]

One would hope so, but it ain't necessarily so.

[diamondj]

Found this while watching the other GT550 3 into 1 video. It's 3 individual chambers entering into one muffler. Got to wonder how well these work with the varying lengths:

https://www.youtube.com/watch?v=9Dey7bKSnhM

Supposedly the Reimo customs that had 3 into 1's worked well although I've never met anyone that had one to verify this. There is a video of a Reimo on the GT750 and another of a GT380 that is Reimo equipped running through the gears:

https://www.youtube.com/watch?v=PW1DZVfCprM

https://www.youtube.com/watch?v=58qt_ZTa-oc

[Vintageman]

https://www.youtube.com/watch?v=dq3v5uX3Jyk" onclick="window.open(this.href);return false;

Yes that must be the best exhaust for the GT550 in the world!

Several including me previously asked where he got the exhaust… no reply

What country / language is he speaking? Maybe I need to translate my request

[tz375]

That's easy. Check out his rear license plate. It has PL for Poland

[Vintageman]

I got lucky and located a Strader 3 into 1 for my 1973 GT550 and swapped out my 3 into 3s. It has a single and radical looking chamber section (not just straight piping). It adds a lot of boost low to upper mid range rpms. I see no no loss in top end (ability to rev high that is) but not boosting at 6500 - 8500 like it does from 3500 - 6500. To address the extra boost especially from 3750-4750 while cruising ( ~1/8 to ~ 1/5) throttle). I had to increase the fuel to air ratio else pinging.

I think a 2.0 slide cut vs 2.5 would be best, but can't find. larger pilot helps, but not enough. I ended up run the later size gt550 orifice size (P-0 vs O-5) needle at 4th clip, It solved it nicely. Not sure what my mpg is yet, think mid/low 30 mpg ( was about 40 mpg). The bike is very enjoyable to ride. Throttle response is immediate. Sounds amazing (if you like 3 into 1 sound) or at least very unique.

I also have/ran 3 J&L (i think) 3 into 3s and those are mid range pipes too. I had similar ping problem but not as much boost l midrange. I think the Strader adds more power over all than J&L's.

I had replaced the J&L with Ocelots 3 into 3s. The Ocelots tuned length is ~8 inches shorter than J&L . The Ocelots don't boost low to mid-range RPMs and they are tuned to come on at about 5500 and up and extend your upper RPM. Nothing radical, still nice street pipes. Sound incredible as well

Ocelots are awesome pipes too (I need another gt550). The Strader low to mid range torque is very addicting. I found strader by luck and swapped out my Ocelots (for now).

I have always had a hard time get my 73 GT550 to want to go 8000 RPM without thrashing it. It runs out of breath. I have even messed with cylinder porting, such as raising EX port, still no go. ( I run stock cylinders, Ex widened some not raise now)

What I found is that the early GT550 airbox rubber boot has very long rubber tubes inside per carb, that get maybe within an inch of the back of boot, seams restrictive. On, the later GT550 they only go half way. I ended up removing the tubes altogether, I shortened (inside section) the rubber snorkel providing atmosphere air into air box (without it it was too load on my ears) . I could have done more optimizing plastic bits of box, but concerned about too much intake noise. This mod woth with Strader on I get and easy additional > RPMs. I just climbs that much higher without trying/pushing it. That is why i Stated 8500 rpm. I would like to now go back and try Ocelots... I need another GT550!

I also put a Zen Shin 3 into 1 on my 1975 GT750. Its not like the one on Oldjapenesebike.com. It has a very aggressive, somewhat shorter tuned length (vs Jemco 3 into 3s). Pipe is amazing. they add that infamous torque al says, but pulls nice top end too, someone di drtesting in this design in Japan. Can't see going back to Jemcos, which are nice, but not like this Black Beauty 3 into 1 Zen Shin. Paid over $1000 usa, where $300 was shipping). I did not have to change any jetting vs stock ( i think I went one size up on mains when I put Jemcos)

What I have seen is 3 into 1s with true chamber sections do add very noticeable power over stock pipes.

And, most 3 into 3s I see for today for gt550 and gt750 have long tuned length that compliment the current bikes power band I think. I think 3 into 3s , should be tune to help pull you higher in RPMS a little vs carving your Ex port height... fast(er) street able bike!

in New Hampshire /Vermont I am sad that riding vintage Japanese two stroke motorcycles is just about over for 2019. God willing I will be riding again April 2020.

Fun Stuff

[jabcb]

Pic of 75 GT750 with Jemco 3-into-1. The bike was modified by the PO. Not sure what he did to porting, but it had no bottom end with the 3-into-3 aftermarket exhaust. Has a strong bottom end with the Jemcos.
GT750-1975_0583 by jabcb, on Flickr

Have Jemco 3-into-1 for the 72 GT550 cafe build. Am just about finished with that build, so results are TBD.

Suzuki improved the cornering clearance for later model years of the GT380 & GT750.
The GT380 frame bolt location for the exhaust was changed. Higgspeed has early & late versions of their GT380 exhaust.
The issues of fitting late-version Higgspeeds on an early GT380 are covered in my GT380 cafe build topic: viewtopic.php?f=21&t=13036
Don’t know how the GT750 changes impact the exhaust. Higgspeed only shows late-model pics on their website.

Would like to see pics of those Zen Shin 3-into-1. Also, how/where did you buy them?