AFTERMARKET PIPES FOR TURBOS

[mountainhorse]

Anthony... didn't you work out octane (too high) levels After you installed the OVS/SLP pipe? ....didn't you add the wrap and run Jacks new "turbo flash" after the install as well?

Did you try it again after the wrap/octane-adjustment on the stock pipe?

Just trying to figure out if we have a base-line comparison OVS-to-Stock pipes?

 

[Anthony Oberti]

Well.....yes, I did change my octane levels and that improved it significantly. I also did have some others goodies on it as well. However, I know for a fact the bottom end was much improved this year......who knows exactly from what as I changed alot....including the head. I can say this; last spring I rode back to back pump gass 800's, one with the stock pipe and one with the OVS/SLP pipe. The one with the pipe pulled much ahrder on the bottom and mid range than the stock pipe. Everyone that rode the two agreed on that.

 

[mngoat]

Have to agree with Oberti about the ovs/slp pipe. Much better low/midrange pull after swap. No other changes where made at the time. Just the swapping of the y-pipe and pipe from stock to OVS/SLP and pull the rope. Rode the sled stock for a bit then swapped out stuff and did the same pulls with new pipe setup, same pulls same riding place just the time that it takes to swap it out was the only difference. There was a definite seat of the pants difference. This was an 2008 dragon 800 with OVS garrett setup.

 

[mountainhorse]

AO and MnGoat..

Thanks for the feedback on your installs...

Kind of reinforces my belief that an exhaust, specifically designed with a turbo in mind can make a difference... And this is the "first stab" at a turbo pipe... wait till the engineering and testing have more time to come around.

Vohk has been working with speedworks on the AC Turbo exhausts for a while... In a couple of more years, I expect that the Turbos on the 2-stroke sleds will be much more evolved as a system than they are currently.... Pipes designed to do the job will be a big part of that evolution IMO.

 

[whittaker727]

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".)

Not exactly true. How the pipe flows and reacts to back pressure is all part of the pipe design not mufflers/silencers. This is why a two stroke turbo runs fine straight piped just as a mx bike runs no different with blown out packing in the silencer. The only function of that silencer is exactly that, quiet or silence the exhaust. Two stroke pipes are all about volume (area that is) and tuned length.

 

[PMSPOLARIS]

BIG BOOST TURBO by MTNTK

I'm getting ready to start my new build this summer and had a question I can't seem to find an answer to. Has anyone used an SLP or any other brand single pipe for their turbo build, and if so any positve gains or other issues? I have seen for the cats that there are turbo pipes available, just haven't seen anything for the Poo.

You guys should really look into the new kit from Mountain Tek (MTNTK) the big boost turbo is clean and you can take the turbo off your sledd no welding or cutting and return it back to stock for under $125 in parts.
check them out on our website www.pmspolaris.com

 

[Pure Logic Tuning]

OVS does have a turbo pipe and y-pipe for the 800. This pipe is a SLP blank that has been modified in length and stinger size to optimize the torque and hp by changing the operating rpm and torque curve to match the turbo and turbine housing that OVS uses on there turbo kits. If you run the same size turbo and turbine housing you also can benifit from this pipe. This pipe also utilizes compression springs instead of exhaust spring that break constantly.
The pipe is thinner and recommended to be wraped to stop engine harmonics from causing pipe breakage. This pipe will not last like the thicker stock pipe but does perform alot better so it is up to the customer if he wants the extra performance. The pipe on Brad Story's sled is a OVS pipe that is wrapped.

 

[mountainhorse]

I copied this thread here from another section of the forums to see if we could get some more discussion on this great topic.

 

[mountainhorse]

Pure Logic Tuning: The pipe is thinner and recommended to be wraped to stop engine harmonics from causing pipe breakage.

Travis,

Is the pipe breakage issue caused, in your opinion, by simple resonant harmonics or the huge pressure spike created by the reversion wave ramming into the boost pushing out of the exhaust before the piston actually closes of the transfer & exhast ports??

My understanding is that the reversion wave is trying to stuff the exhaust/fuel back into the cylinder (port closing) but hitting the charge pressure generated by the turbo.

The Description that I hear from most people is that the pipes are splitting or "blowing out" not simply cracking. Although I have seen plenty of turbo pipes that have simply cracked at a weld... much of which could have been helped by normalizing the weld line. Radical, rapid temp changes in the pipe mixed with water/snow spray splashed thru venting on the hoods and hitting the pipes places huge stress loads on the pipes.

I have seen signs of precip. hardening of a weld boundary in much of the custom pipe fabrication...not much of an issue in the pressure levels in a Nat Aspirated pipe...but the turbo systems have higher pressure levels and larger pressure spikes. A bit more work after the welding is done can go a long way, IMO.

From my understanding, the primary function of wrapping a 2 stroke pipe is to retain heat IN the pipe for more effective exhaust operation. Is this true?

 

[mountainhorse]

whittaker727: Not exactly true. How the pipe flows and reacts to back pressure is all part of the pipe design not mufflers/silencers.

Jason...I know where you are coming from and I used to have the same impression. Until the pressure in the pipe goes to atmospheric... the muffler or turbo is still part of the exhaust pipe and affects the back-pressure and effective design of the stinger and pipe overall. The 2010 Polaris factory 800 updates show that 2 stroke exhausts ARE sensitive to back-pressure.

If you burn out the packing in a MX bike... it still has the same pipe size... just no way to absorb the resonant "noise" in the exhaust.... Look at any good slip on... they come with different "chokes" for the muffler... that Definitely changes the way the engine runs... just like changing stinger size does.

I see many of the turbo designers going to a very large short pipe directly out the side of the sled... this brings the exhaust pressure very close to atmospheric directly after the turbine. This makes it easier to tune the turbo package as you are removing one variable in the system... Will this run better than a muffler in the system... not necessarily... but as presented above, there really has not been much research/design/testing/refining of tuned exhausts for the 2 stroke turbos. When there is, IMO, there will be improvements in flexibility, reliably, throttle response, lower octane requirements for a given boost level and probably better fuel economy.

The turbo pipes that are out there now are a step in the right direction, but as VOHK suggests above, there is a lot more to learn and a whole different set of requirements for 2 stroke turbo exhausts. The WAY we think of 2 stroke turbo tuned exhausts is changing, but, IMO, with the direction of the EPA, I doubt that there will be any big money poured onto this engineering challenge. In fact, I don't know of many applications of turbos to 2 strokes outside of the sledding world... You just wont find FMF/Pro-Circuit kind of money poured onto the issue, so development is going to be slow, IMO.

 

[hypnotoad]

a very interesting read, but would love to here more on the subject from the turbo developers themselves

 

[Tonysnoo]

...........................I doubt that there will be any big money poured onto this engineering challenge. In fact, I don't know of many applications of turbos to 2 strokes outside of the sledding world... You just wont find FMF/Pro-Circuit kind of money poured onto the issue, so development is going to be slow, IMO.

Maybe the next step is to talk about what has worked and what didn't.

For example, Volk talked about using an internal stinger on another thread. He probably tried a number of different sizes and lengths. So what didn't work, what did.

Someone else, might share some data about shortening or lengthening a pipe and share that data.

Now granted pipe scenarios, depend on many many outside factors, but if folks layed out enough data about their experiences, I'll bet a pattern would show.

 

[SnowDevil]

Tony, you know the answer why there is no information on this. The few people that develope the pipes are trying to make money at it so why would they publish there research? The bit of information that I have heard on pipe development is probably harder to understand then clutching!

 

[Pure Logic Tuning]

OVS has just finished the testing and dyno results of ther new M-1000 and M-1200 turbo pipe. This pipe offers 24 more foot ponds of torque than the original pipe. The pipe also shows more HP than the original pipe. The y-pipe is made from 14 gauge steel and the pipe is hand built out of 16 gauge steel. This pipe uses the OVS sping system to keep the pipe sealed under high boost. This pipe was dyno tested and field tested for maximum HP and torque for the turbo sleds. It also so was built very thick to stop breakage under boost. If you would like more info contact OVS at 801-940-7777.

 

[Tonysnoo]

Tony, you know the answer why there is no information on this. The few people that develope the pipes are trying to make money at it so why would they publish there research? The bit of information that I have heard on pipe development is probably harder to understand then clutching!

I know what you're talking about as far as kit builders goes. I assumed there were a bunch of dorks like me running around that would share some of the things they learned. I think that concept is what started this forum...LOL

PS: Hey Travis, are you building a heavy duty y pipe for an M8?

 

[Pure Logic Tuning]

Yes we are the M-8 is on the dyno as we speak and this is both models pre-2010 and 2010 model also.

 

[mt st helens]

Yes we are the M-8 is on the dyno as we speak and this is both models pre-2010 and 2010 model also.

So how about us poor old M-7 turbo owners!

 

[sledstew]

Travis,
I currently have a 1400 WC based triple that is EFI and boosted ,running it with slp stamped triple pipes,what boost would you say those pipes can take before they split ,maybe 4-6psi???? Wondering if you have some idea since you have been testing different pipe setups.
Thanks,
Jake

 

[dubbs]

Hey, I have the new OVS turbo pipe on my 07 M8 Tial kit with the OVS intercooler. Got it out for 1 ride did some tuning ect. Seems to be working really good. I had to add fuel all over the place so that must mean it's using more air... Seems to be happier at WOT now than it was with the stock pipe... It must flow better, It seems stronger.

It already spooled up really nice in my opinion but really seems to make boost easy even at 1/2 throttle. Was also the first day with the intercooler... I think the new pipe even with the intercooler spools up better than it did last season. Only played with it for one day and am comparing to my stock pipe from last season so not really the best comparison... Would be cool to bring the stock pipe out one day and compare between the 2... Will that ever happen tho?? Ya prob not.

Would be cool to hear other peoples experiences with the pipe... Getting out 2 days this week maybe I'll be able to post with some better info after that.

 

[lt1bird]

The folks in the banshee world have the same questions...always about pipes, turbo lag etc...... I still have not found anyone that has done a ton of real reaserch on turbo two strokes. Im still thinking that straight pipes would work better, spool a larger turbo quicker. I have not seen anyone try straight pipes(no expansion chamber) for big boost......