Sparky don't care. Twins is twins.
850 twin pipes
- Thread starter RMK-King
- Start date
Sparky don't care. Twins is twins.
So that means with just pipes and clutching alone will be A SOLID 185HP?
Ok on a serious note; I cannot believe for a second that twins will net twice that of a single. No way.
The whole story of tuned exhausts for 2-strokes goes against it. Sorry.
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Spaarky
Well-known member
Sorry... but South Dakota isn’t California. Typically don’t need to do a parts check!!!! I ride a polaris you can assume I like girls.
I suspect with most motors there's more to be gained from twin pipes than a single pipe. That's because you don't have the Y-pipe and exhaust from the other cylinder interfering. Twin/triple pipes tend to be more peaky and need more tuning though. I'd bet SLP is right about the 850 twin pipes making twice the HP of their single, but it'll probably be less of a plug-and-play.
Of course it depends on how good the stock pipe is too – for instance, SLP never made a single pipe for my old 600VES, and I've read that's because there was very little power to be gained over the stock pipe. I have to wonder these days if there's really as much power in aftermarket single pipes as is often claimed. Obviously it's possible to take a motor and tune it to the ragged edge with your parts and post those gains. Not saying that's what everyone's doing, but I have to wonder why the OEMs would leave 8-10 HP on the table year after year. Weight differences are another story, obviously.
Of course it depends on how good the stock pipe is too – for instance, SLP never made a single pipe for my old 600VES, and I've read that's because there was very little power to be gained over the stock pipe. I have to wonder these days if there's really as much power in aftermarket single pipes as is often claimed. Obviously it's possible to take a motor and tune it to the ragged edge with your parts and post those gains. Not saying that's what everyone's doing, but I have to wonder why the OEMs would leave 8-10 HP on the table year after year. Weight differences are another story, obviously.
This chart shows the old 800bb twin pipes hp was approx. double that of their single over stock.
Not sure how accurate it is though.
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Biggest reason po or any manufacturer leaves hp on the table is usually meeting epa requirements. aftermarket does not have to meet any set rules & regulations
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snowmobiler
Well-known member
dont stick a piston.
RMK-King
Super-Moderator
"SLP twins Q&A
Q-Price?
A-We aren't at the point in development where we can announce prices, we will keep everyone updated as we progress.
Q- What kind of power gains are you seeing?
A-We are very pleased with the gains we are seeing but testing and development aren't done at this point in time, we will keep everyone informed as development progresses. We are confident that the twin pipes will at least double the horsepower that we have been seeing in our single pipe sets.
Q-Video
A-No videos at the moment but we have lots of videos planned for this winter to show off the awesome products we have!
Q-What about twin pipes for the 800?
A-We feel our 800 stage kits, especially stages 3 & 4 are at a very high level of performance for dollars spent, and we don't believe that we will gain more performance with 800 twin pipes than we have with the stage kits.
Sounds like some fueling changes will be necessary."
Q-Price?
A-We aren't at the point in development where we can announce prices, we will keep everyone updated as we progress.
Q- What kind of power gains are you seeing?
A-We are very pleased with the gains we are seeing but testing and development aren't done at this point in time, we will keep everyone informed as development progresses. We are confident that the twin pipes will at least double the horsepower that we have been seeing in our single pipe sets.
Q-Video
A-No videos at the moment but we have lots of videos planned for this winter to show off the awesome products we have!
Q-What about twin pipes for the 800?
A-We feel our 800 stage kits, especially stages 3 & 4 are at a very high level of performance for dollars spent, and we don't believe that we will gain more performance with 800 twin pipes than we have with the stage kits.
Sounds like some fueling changes will be necessary."
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Ok, well that makes more sense then. I do wonder what EPA requirement makes them have to stuff it down that much, but if anyone can dream up a buzzkill, it's them...
Thanks for pointing it out, I was actually reading about that setup just now. They still list it on their website, FWIW. I could only find a couple actual reports, and none indicated a noticeable power gain, but the weight savings is significant. They give 112HP for a stock 600 VES, but some say that number is low. So maybe their claim of 122 is accurate, but the gains aren't as big. I would like to try the SLP twins. They claim 10HP, and that may actually be conservative. I even read of 20+ with porting. Only trouble is, I'm not sure I could live with the noise. I used to run their can, but was too loud for me (older, noisier tech than their newer cans); also, I measured just under 5 lbs weight difference, where they claim 8.
Anyway, getting back to the 850, I wouldn't plan on a quiet riot there either. Was just looking at the description in their flier: it'll have glasspack silencers, and they describe it as a competition series product. Hopefully it's not one of those love to hate products – big power and even bigger noise. Hard telling until they release it, of course.
This is an old song and I don't see much that has changed to effect the pipes part in it. Power from an 800cc twin is not better than it has been, and it seems they will still top out at around 175Hp with porting, head and single pipe. Some more on top with twins, but at the cost of response, sensitivity to temp/altitude and width of powerband.
One pipe per cylinder is a paperbook ideal, ever since Walter Kaden discovered the use of pressure pulses in 2-stroke exhausts in 1954. But a single has an advantage in two-cylinder engines; the two pistons hav 180degree oposite phases, leaving only the physical design of the Y-pipe as a "fault" in the harnessing of pressure waves. The oposite cylinder is closed by its piston when the first cylinder does its thing together with the pipe and vice versa.
What both cylinders gain from this is a much more stable pressure and temp in the pipe, making conditions for sound wave speeds stable.
On a triple, the gains in pressure pulse efficiency will be great when going from one to three, netting good Power gains. But they also had a tough time maintaining a sweet middlepoint on pipe-temps/pressure.
About leaving Hp on the table.. the OMEs knows more about making power than most of us will ever realise. Count on it. But they need to balanse power with EPA demands, like mentioned, and a wide enough power band/stable power (weather/altitude conditions, rider weight, soft/heavy snow) that stays ON the power with minimum clutching changes.
And of course; idiot-proofing that power.. so that the people whos idea of warm-up is the time it takes to put on gloves and helmet can still be a part of their customer base..
Holy testicle-tuesday!! That was a long one, and stuff I've not typed about in ten years on Snowest.. memory lane right there.
One pipe per cylinder is a paperbook ideal, ever since Walter Kaden discovered the use of pressure pulses in 2-stroke exhausts in 1954. But a single has an advantage in two-cylinder engines; the two pistons hav 180degree oposite phases, leaving only the physical design of the Y-pipe as a "fault" in the harnessing of pressure waves. The oposite cylinder is closed by its piston when the first cylinder does its thing together with the pipe and vice versa.
What both cylinders gain from this is a much more stable pressure and temp in the pipe, making conditions for sound wave speeds stable.
On a triple, the gains in pressure pulse efficiency will be great when going from one to three, netting good Power gains. But they also had a tough time maintaining a sweet middlepoint on pipe-temps/pressure.
About leaving Hp on the table.. the OMEs knows more about making power than most of us will ever realise. Count on it. But they need to balanse power with EPA demands, like mentioned, and a wide enough power band/stable power (weather/altitude conditions, rider weight, soft/heavy snow) that stays ON the power with minimum clutching changes.
And of course; idiot-proofing that power.. so that the people whos idea of warm-up is the time it takes to put on gloves and helmet can still be a part of their customer base..
Holy testicle-tuesday!! That was a long one, and stuff I've not typed about in ten years on Snowest.. memory lane right there.
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Wow... Walter Kaden.... memory lane for me too. I worked for the resurrected MZ factory in Zschopau, Germany in 2010-11 racing Moto2 in the Motogp championship. The two strokes were long gone but the ghosts of Kaden and Degner were still wondering that factory...
That's some pretty good insight. Heat in the pipe is a big player, depending on riding style – I wasn't thinking about that. I've never owned a triple, but the it's pretty easy to see how independent pipes make a much bigger difference than on a twin: the return pulse to the closing cylinder has to deal with two extra branches, plus the opening exhaust on one of the other cylinders. I've heard 20% gains are typical going from a 3-1 to a 3-3. I wonder what the theoretical gain on a 2-2 is. 5, 6% at most? Given the engine is tuned for the same RPM and EGTs, of course. I can see where the power gains may not justify the weight (ideal weight, not vs stock) and heat sensitivity of twin pipes.
With regard to margins for durability/longevity, I'd think there'd be more margin built into the fuel mixture and ignition timing than the exhaust, but I could see the pipe being set up to drop off quickly above peak RPM to help prevent over-revving. Of course there's the possibility that the internals don't have much margin and they're de-tuning for that. Trouble is, you'd think then that turbo setups would eat motors left and right, but it doesn't seem that bad. I don't know, I don't have all the answers; I just love wrenching on and talking shop on motors. You'll know I've hit it big when I have my own machine/fab shop and am making my own parts!
Should be gains similar to those seen with stage 4 kit on the 800HO.
It will be a bolt on kit with a reflash of some kind (bullydog or what not). The advantage is you dont have to do heads, etc... the disadvantage is you have to put the ypipe back on if you take it in for warranty.
Ive known the SLP guys a long time and they are pretty excited about the opportunities the new patriot motor is providing. Same with the turbo companies. Cool tech like the new exhaust valves paired up with beefy crank and PTO bearing gives aftermarket companies lots of possibilities to milk every last pony out of the motor.
Lets hope for a short cold fall with an early start to winter so they can get real world testing done and get these things out before christmas!! My name is on the list to get some.
It will be a bolt on kit with a reflash of some kind (bullydog or what not). The advantage is you dont have to do heads, etc... the disadvantage is you have to put the ypipe back on if you take it in for warranty.
Ive known the SLP guys a long time and they are pretty excited about the opportunities the new patriot motor is providing. Same with the turbo companies. Cool tech like the new exhaust valves paired up with beefy crank and PTO bearing gives aftermarket companies lots of possibilities to milk every last pony out of the motor.
Lets hope for a short cold fall with an early start to winter so they can get real world testing done and get these things out before christmas!! My name is on the list to get some.
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