About that new Viper Exhaust. . .

[sledhead23]

So, by having the exhaust still cool in the tunnel and covering it with aluminum then dumping it out the side allows yamaha to have a shorter pipe (to increase power) and keep the cooling affects of the tunnel. Sounds like this may actually increase power.

 

[ruffryder]

I am not a professional but I have spent alot of time on the dyno testing exhausts on the Cannondales which also have a rear exit exhaust.Extra length does not produce power.We found a stepped pipe of the shortest length possible produced the most power period.Problem with that is the heat.The heat is the reason for the longer pipe.Without it the silencer would not last or cook the sled.If you look at the biggest power producing YZF's that is also what you will find.Short straight pipes.Yes length does make broader power but who cares if you are looking for the MOST power and we snowmobilers can easily clutch to keep our machines in the power peak.Heat is the reason.

I would disagree with trying to compare the exhaust of a multi-cylinder engine with a single cylinder engine, especially over 2 cylinders..

 

[ruffryder]

So, by having the exhaust still cool in the tunnel and covering it with aluminum then dumping it out the side allows yamaha to have a shorter pipe (to increase power) and keep the cooling affects of the tunnel. Sounds like this may actually increase power.

I don't think cooler equals more power, at least for the exhaust...

 

[cannondale27]

I am not a professional but I have spent alot of time on the dyno testing exhausts on the Cannondales which also have a rear exit exhaust.Extra length does not produce power.We found a stepped pipe of the shortest length possible produced the most power period.Problem with that is the heat.The heat is the reason for the longer pipe.Without it the silencer would not last or cook the sled.If you look at the biggest power producing YZF's that is also what you will find.Short straight pipes.Yes length does make broader power but who cares if you are looking for the MOST power and we snowmobilers can easily clutch to keep our machines in the power peak.Heat is the reason.

I would disagree with trying to compare the exhaust of a multi-cylinder engine with a single cylinder engine, especially over 2 cylinders..

Definitely you are correct.Not the same with multi cylinders since scavenging does help low end power.But the Phazer which is 2 cylinders dynoed the best with true dual exhaust which eliminates all scavenging effects of single on 2 cylinder also.So I believe the results of one cylinder when applied to multiple are valid if looking for MAX HP.

 

[dudester4]

my dealer went and rode the viper and said its down on power compared to nytro yamaha agreed and said there working on fixing the exaust to get the power back up.

 

[blueironranger]

my dealer went and rode the viper and said its down on power compared to nytro yamaha agreed and said there working on fixing the exaust to get the power back up.

I hear exhaust driven fans work pretty good! engine powered intakes help too!

 

[vsmpowered]

X2^

 

[Ak Yammy]

Who cares about max power up top with out decent midrange or low end. The curves and longer pipes help to get a better power curve=linear power. If all we cared about was top end than yes short straight pipe the thing like a drag bike or sled. Also same result with EXUP. Valve closes down at lower RPM to help out low end power. I can speak from personal experience on this as I removed my SET (Suzuki version of EXUP) valve on my GSX-R and lost some low end power.
Also the go fast guys will turbo it anyway so who cares.

Don't think we need Allen Ulmer in here to tell us that.

 

[F7 Racer]

my dealer went and rode the viper and said its down on power compared to nytro yamaha agreed and said there working on fixing the exaust to get the power back up.

Hence why they havent said a single word about H.P. numbers...........so remind me again how this is so much better than the 125hp 1100 Cat motor ? ?

 

[cannondale27]

Who cares about max power up top with out decent midrange or low end. The curves and longer pipes help to get a better power curve=linear power. If all we cared about was top end than yes short straight pipe the thing like a drag bike or sled. Also same result with EXUP. Valve closes down at lower RPM to help out low end power. I can speak from personal experience on this as I removed my SET (Suzuki version of EXUP) valve on my GSX-R and lost some low end power.
Also the go fast guys will turbo it anyway so who cares.

Don't think we need Allen Ulmer in here to tell us that.

Would normally make alot of sense but you shift your Zuk with your foot.A snowmobile has a clutch that shifts for you and with a 4stroke and its very broad power even in a high state of tune it is very easy to take advantage of max hp especially with help of Ulmer.You are correct though at the extremes.We are not talking extremes though.In all the testing I have done where gains were made in max hp never was there a loss in low end just less of a gain than top.I will say it again.The exhaust design was done that way to keep the exhaust as cool as possible to avoid it melting things around it.

 

[Ak Yammy]

Don't want anyone to think that I am insulting Ulmer or anyone else was just addressing some basic things and answering the member who said we need an expert in here as none of the info given is valid.

Cannondale I do not agree that the example I gave is not valid because the engine is run through a gearbox vs. clutches sorry. Low end power is low end power no matter what drive system it's run through. Also why would they bother to add EXUP to the Apex if you didn't see any low end gains because it is run through clutches and a belt? Otherwise I think we are pretty much on the same page and I agree on the heat thing. Also the original point to all of this was to say that a bend in the exhaust will not be a power robber like everyone thinks. I think people are hearing the proto's are not as snappy and are quick to jump on the exhaust bend when in fact it sounds like they are putting the finishing touches on the fueling.

Last post for me on this thread Allan where are you?

 

[cannondale27]

AK we will agree to disagree.Exup on bikes was intended to make them easier to race/ride.Therefore faster.Just like the Crossplane.But remember what I said about extremes.A Apex even stock is much closer to Extreme than a Viper is.That whole exhaust design can be improved alot.I suspect Ulmer is doing just that and is probably to busy to go on internet much.AK I think one persons view of perfect power is very different from another and all should get whatever makes most fun for them.Thats where aftermarket helps since factories cannot hope to please everyone.Thanks for not taking my opinions personally

 

[Ak Yammy]

AK we will agree to disagree.Exup on bikes was intended to make them easier to race/ride.Therefore faster.Just like the Crossplane.But remember what I said about extremes.A Apex even stock is much closer to Extreme than a Viper is.That whole exhaust design can be improved alot.I suspect Ulmer is doing just that and is probably to busy to go on internet much.AK I think one persons view of perfect power is very different from another and all should get whatever makes most fun for them.Thats where aftermarket helps since factories cannot hope to please everyone.Thanks for not taking my opinions personally

 

[jdinny]

That exhaust looks real turbo friendly to me

 

[2BLUE4U]

I wanna know how much additional weight can be saved by removing that large suitcase? I'm guessing 15-18?