AFTERMARKET PIPES FOR TURBOS

Yes, but stinger/silencer size is not really an option for most turbo kits. So that brings us back a turbo specific pipe? Can't really see a market for a turbo specific pipe for the polaris when the stock one works so well. Maybe if they came up with lighter weight one the would hold up to the boost but even then I don't see you having any "noticeable" performance gains relatively speaking compared to the added performance of the turbo and justifying the cost. mountainhorse not quite exactly sure what your point is in regards to a turbo pipe?

whittaker727 said:

Why can't you alter stinger or silencer size? Most kits require a pipe to be cut and re fitted anyhow, so why not alter the diameter or length of the pipe to optomize torque or revs? As far as the silencer goes, there are already different size exhaust being used depending on if you do a side exit, tunnel dump or shock tower set up. You could pick your set up based on what you want the system to do if that info was available with real dyno result numbers.

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Yea, I guess that's true. I thought that most kit don't run a silencer because of the lack of room?

Kawgrn... what you are doing is changing the backpressure...

shadow.... My question is simple and put above... and for the Makers of the pipes..

I'd like to hear what specifically makes it better for a turbo or at least what the Mfg is trying to achieve with the pipe.

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The different character of the 2 stroke expansion chamber (aka "pipe") is tailored by many factors in its design.

A good turbo pipe needs to hold up to the pressure and not split...but that is not the only criteria.

A stock pipe is desinged to work with, as a tuned exhaust, the character of the Naturally Aspirated 2 stroke engine it was made for. Put that pipe on a turbo and you are certainly not running an optimized system.

Changing the head pipe size/lenght, Diffuser taper/length, Dwell section volume and the converging cone plus the stinger will change the character of the way the engine runs.... Heck... even insulating the pipe will change the way it performs.

The pipe is still stuffing back air and fuel into the motor even when the turbo is making considerable boost.

I'd like to see a Turbo pipe that would help to improve bottom end throttle response and still work well when the turbo making full boost. I believe this an area where turbo pipe design can be refined....and make the turbo kits give more predictable power for the consumer, making a broader power band.

Twin scroll/twin pipe designs seem like a perfect canidate for 2 stroke sleds as well... keeping combustion temps down and allowing the turbo to work more efficiently. Maybe even making boost at/near idle...I wonder who is going to be first with this one?

... I hope we see continued innovation in the design of Turbo kits for our 2 stroke sleds that will improve the function and flexibilty for the end user!

All too often I have read on the forums and talked to people that say things like... "My Race Gas T-800 makes 270 hp and climbs like no other...I can boondock it as well as any other machine out there"... In reality... I find that hard to believe.. Kind of like saying that your Funny Car makes a good rally car.

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Then you need to jump on a machine with a proper race gas set up. It is possible. Our goal has always been to have the best of both worlds, or the turbo would go bye... bye.

The biggest gain IMO would be a stronger pipe. I have seen some claims of 20-30hp gain with a turbo pipe. I highly doubt it, unless you combine it with some proper porting.

I have had a few experiences that proved to me the pipe design does not mean near as much in the turbo world, as the n/a sleds.

This entire issue is far more complex than it may seem at least on the surface. The presence of a turbo and the roll it plays in this use scenario creates a number of conundrums. After having built a pile of turbo specific pipes and having suffered multiple failures, its amazing how many times I scratched my head and thought "Now why didn't that work??" or conversely "Why did that work???" One thing has become evident almost none of the conventional thought processes applied with respect to ratios, angles, volumes and tension seem to apply. With that in mind the question of stinger alterations (length, diameter, internal or external, shape, etc.) is slightly more predictable however affords far less margin for error, the consequence of being even slightly too tight results in some pretty surprising mid section pressures. All of which have consequences effecting the sound waves ability to effectively do its job. Anyway it suffices to say that with the myriad of relevant variables, and the recent upsurge of two stroke turbo popularity, new pipe technologies will continue to be explored and will no doubt produce an extremely efficient and effective result.

I have had a few experiences that proved to me the pipe design does not mean near as much in the turbo world, as the n/a sleds.

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IMO... the Current offerings in pipe design would hold that comment true... Which to me simply means there has not been much engineering in the Turbo pipe designs.

I have been on some pretty amazing turbo machines... I'm not saying that I'm a great rider... cause I'm not... I have had the chance to throw a leg over some pretty well done Turbo sleds in the last few years though.

Race Gas and pump gas are more a philosophy than the actual fuel used... Race gas setups are designed, usually, with large volume intercoolers/charge tracts and larger turbos (eg on a RG 800 3071 compared to a PG 2860)...

Physical reality: that for a given engine... a larger turbo will not spool as quickly or fill the larger intake tract as quickly as a smaller turbo with a smaller intake tract (given that both turbo systems are correctly designed/made).

So... I guess I should have been more clear... by "Race Gas" I'm talking about a large turbo, large intake tract volume. By "Pump Gas" I'm referring to a smaller turbo and lower volume intake tract...

Most people I know with "PG type" setups run at least a mix of race in their fuel... PG sized systems running 12 lbs of boost are at 110 straight for the most part if you want to keep det to a minimum.

But I will hold to my assertions...The large "RG" setups designed to make maximum HP will not have the same throttle character as a Small "PG" system and vice-versa. Large volume systems will not have as good of bottom end throttle response.

I really don't believe it's possible to have the BEST in the "best of BOTH worlds"... max hp and max throttle response/bottom end.

Other things like coming up with something other than the "disco potatoe" designed for generic automotive applications and more along the lines of tailoring to the needs of the 2 stroke turbo world.... regardless of if we are talking about Automotive or Aero turbos... I've seen both systems kick azz on the mountain.

Like I said before... we are in the infancy of 2 stroke turbo design. Can't wait to see what is developed... Lots up the sleeves of some system makers for next season (wink)

So back to the pipes....

I think that more time/engineering/testing/building of exhaust design in 2-stroke turbo systems will help bring them closer to the "best of both worlds" situation than we currently have.

My 2 cents

a pipe that flows better could cause faster spool up and support higher max HP if you were really pushing it. at least thats how it works on cars. id imagine that it would be somewhat the same. but on the otherhand i know a pipe made of thicker metal can make less power, at least on 2 stroke dirtbikes. pro circuit used to make the pipes for the factory bikes super thin for more harmonics through the pipe and they said it would make for a better powerband

a pipe that flows better could cause faster spool up and support higher max HP if you were really pushing it. at least that's how it works on cars. id imagine that it would be somewhat the same.

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Many people have this concept of 2 stroke exhausts... though it is not close to the same thing in practice... 2 stroke pipes are not designed to "flow better" ... they have so much more going on there. (Which is exactly the reason why, often a free flowing muffler will actually reduce power of a naturally aspirated 2 stroke if the muffler does not work with the design of the exhaust pipe as a "system".)

Have a look at this link Expansion chamber for a presentation of what is going on in a typical 2 stroke exhaust.. It may help you to understand more of what is happening.

As Erik (Vohk) points out so well with the turbo 2-strokes, ... all the rules change in design and right now, for the 2-stroke turbos.. a lot of trial and error is going on in tuned exhaust [aka "pipe"] development and needs continued attention... little things like the "port blocking".... pressure wave meets head on with the boost pressure coming out the exhaust... this is part of the reason that pipes split...but other things are happening as well that affect the performance character of the pipe and the turbo system as a whole.

Having a pipe that is designed to compliment the turbo operation as well as enhance the performance when the intake is a negative pressure (vacuum) as it transitions into boost can only make the systems work better. But again... not really much engineering or development YET in this part of the Turbo 2-stroke kit offerings out there right now.

IMO... WHEN the turbo kits evolve into a truly well developed "systems approach in their design and fabrication these machines will have a much better performing, more user friendly character.

the thinner pipes is a big part of why the aftermarket pipes do not last!

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Not necessarily true...
But it is true with the current design and understanding of pipes and how they function in a 2 stroke turbo

Vohk: One thing has become evident almost none of the conventional thought processes applied with respect to ratios, angles, volumes and tension seem to apply. ..... results in some pretty surprising mid section pressures.

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Erik makes the Biggest point here....The way pipes are designed are going to need to be looked at in a whole different light.

The pipes are not holding up because they were never designed to scavenge AND participate with the turbo needs in the SYSTEM. You have the pressure wave coming back from the pipe meeting head on with the boost coming out the exhaust. I dont have the answer here... but certainly, pipe and turbo designers should be able to take us closer to a better system than a stock pipe designed for a stock N.A. motor... "Not the same game... not even the same ballpark... He!!, it is not even the same sport (pulp fiction)"

Wow, a lot of information here! I have an 09 D8 with a boondockers Pump Gas turbo on it including the EBC. I run about 3 gallons of Sunoco 110 in every tank of fuel. I have the EBC set to make about 10.5 lbs. of boost with another 1.5 lbs. of boost on the button. I have the stock pipe. This setup runs very well. My detonation light never comes on with this arrangement. I don't know what would be gained by putting on an aftermarket pipe. The sled makes crazy power the way it is and the throttle response is very linear with imperceptible lag (to me).

I am also running a 163' Camoplast Challenger Extreme 2.5" track. It works well on this sled.

MH is right about most of the riders out there. They just want to ride the damn things. I don't do the maintenance like in his test for us. I love the sled and I have not had to do a thing to it but change the belt and plugs once this season which is far from over in Idaho. It is snowing off and on in Boise today and it is coming down in the mountains. The best riding is in the spring. Deeper snow, longer days and no crowds because the non hard core guys are playing golf or gardening or riding dirt bikes or whatever.

Go ride and don't worry about aftermarket pipes for turbo applications. I cannot believe that you would even be able to tell if it was making more power. However, if you want more power, put in more race fuel and turn the boost up. That would be a lot cheaper than buying an aftermarket pipe and having to mess with a system that works very well the way it is.

RMK935VA said:

Go ride and don't worry about aftermarket pipes for turbo applications. I cannot believe that you would even be able to tell if it was making more power. However, if you want more power, put in more race fuel and turn the boost up. That would be a lot cheaper than buying an aftermarket pipe and having to mess with a system that works very well the way it is.

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Couldn't of said it better!

935VA...I hear what you are saying...for sure.

Aren't you running one of Struthers installs with custom single ring turbo pistons and Jacks custom turbo map?

A pipe wouldn't necessarily be about "making MORE power" ... but how that power is made.... sure you can crank it up.... but what would you say if someone could get the equivalent of your 12lbs of boost on 9 lbs? Or if that power came on earlier. Or better fuel efficiency or less detonation on lower octane?

Hmmm, makes you think...

But the answer of "a pipe doesn't make a difference" is something that will get looked at more closely for sure in the near future.... Especially as the pipe builders "wrap their heads around" a whole new set of requirement in a turbo pipe.

curious if anybody has tried a bikeman pipe mod with a turbo. because isnt that just a stock pipe cut down in the middle and welded back together? i dont know the specifics about the pipe characteristics. im in the want more bottom end grunt group but i also was never able to get mine tuned at all to have ANY bottom end snort

The bikeman pipe mod is for a Naturally aspirated engine setup.

pipes

I have been running a turbo 900 all season . No failures at all 11-12 lbs boost with 100ll and an slp pipe . It has been flawless and extremely fun( approx. 25 rides) . However on the second last ride the slp pipe cracked on the weld about 8-9 inches long.
I put the stock pipe back on for the next ride and noticed no difference what so ever in power or tuning. Stock pipe is definitely heavier and thicker.
So I will be ceramic coating the stock pipe this year. I personally think (no expert) that when you put a positive intake pressure to you motor the hole "tune pipe" thing falls away.

DMJ..... Ceramic coat the stock pipe AND re use the stock heat shield to retain the heat in the pipe.

Or have Paul at Thermal Protection Inc. make you a 2 piece clam-shell wrap for your pipe (much better looking than the heat wrap tapes everybody is using and will hold heat much better)... the "header wrap" tape is not to protect the Sled from the heat.. but to hold the heat in the pipe for more consistent performance.

I put the stock pipe back on for the next ride and noticed no difference what so ever in power or tuning.

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I agree with you on the difference with the SLP (non turbo) and Stock pipe for use with the turbo install... we have yet to see any real development (other than some first try prototypes) in turbo pipe development.

Both of those pipes were designed for naturally aspirated engine... so it does not surprise me that you saw no real difference between the two (I can tell you though that the SLP Pipe on a non-turbo does make a difference)

From what I'm able to gather from talking thru this with some pretty savvy 2 stroke engineers .... Port blocking on the compression stroke is one of the more tricky aspects as well as providing the pre-boost bottom end response. The port blocking aspect is what puts most of the stress on the pipe... it is not over all backpressure, but the rapid pressure spikes that happen as the reversion wave is trying to stuff the exhaust back into the cylinder and the boost is pushing against that pulse....

All of this is going on in a single pipe situation where there is only 90° of separation between exhaust pulses... This is why I believe that a twin scroll turbo with twin pipes will be something that will help evolve the 2 stroke turbos beyond what we have now. Each cylinder having its own pipe will give better wave management properties which might give more power from a given boost level, lower cylinder temps, decrease detonation, increase reed life, improve throttle response and increase fuel economy. Only more testing and true ingenuity in kit evolution will help move this along IMO.

I DO believe that much of the above scenario is possible in a 2 stroke turbo as we come into the 3th year now of consumer kits for turbos that are out there in any significant numbers.

I know the pipe I have is not on OVS's website, but I did get it from them. I was told to wrap it to prevent cracking the welds on the pipe. I will say this, with the new pipe, my sled ran as good, if not better at 12lbs then my sled ran with the stock pipe at 14lbs. I have heard from several reliable sources that in back to back comparisons, the OVS/SLP pipe was the equivalent of 1.5-2lbs of boost on an identical sled and set-up.