MCX will announce their kit(s) to Viper in Aprill

[Nytro40th]

Here for an example of a stock exhaust manifold on a mustang and a performance replacement. As you can see the performance header has far more bends and increases hp. Enough said on this topic how the exhaust robs power.

 

[Nytro40th]

and the performance header

 

[09nytro]

....so can we move on now that everyone can see this now.....

Thank you Nytro40TH

 

[cannondale27]

Not really. I still believe the reason Viper pipe was designed like it is was for nothing more than the cooling effect a long pipe directly in the snow has. Nothing more.

 

[Nytro40th]

I am not stating why it was designed like that, just that we can not assume it has a power loss due to the bends.

 

[jaydaniels]

The exhaust on the new yz450 is a great example of this. It has a 360 deg bend to increase its length.

http://canadamotoguide.com/2009/10/08/y ... rsed-head/

 

[Alatalo]

And one more example from a 270+ hp MotoGP bike. You think they would design a full circle bend right at the end of the exhaust if this would rob horsepower...?

 

[cannondale27]

Wow look at that! Think of the time and skill involved in making that pipe. Work of art.

 

[cannondale27]

I am not stating why it was designed like that, just that we can not assume it has a power loss due to the bends.

True for sure.

 

[MCDuke]

271 HP on the new SR Viper with turbo.

 

[cannondale27]

Wow

 

[JRT]

271 HP on the new SR Viper with turbo.

I'm guessing that power comes from around 1.1bar (16PSI) of boost. Nytros regularly provide between 270 and 280 horses in that particular dyno with that boost level, 98E pump gas. Mine cranked 277 horses, it was -2C in the dyno room. I believe it is several degrees warmer now in Piteå, so we can conclude that if the boost level was thereabouts, a turboed Viper produces nearly identical power to a Nytro, which was expected.

Regarding stock power, Yamaha has always advertised the engine as Genesis 130, ie it cranks at least 130 horses. I heard of 139hp dyno results. Now if the same engine is dynoed in a different bench with different temperature it will bring a different result. I am quite sure the Viper delivers at least 130hp and there is no significant power loss or gain from the new ECU and/or exhaust. If there is a difference when riding, it is due to clutching.

It would be interesting to see repeated drag results between a Viper and a similarly tracked 7000 cat.

 

[Alatalo]

I do not know any hp numbers from the stock SR Viper prototype that was dynoed by MCX (they are for sure not allowed to talk about this). But I do remember the first FX Nytro produced 124 hp in their dyno. Not the 135-140 hp that some people see with other dynos.

 

[cannondale27]

Sure sounds like if you are happy with Nytro power it wont be a issue with the Viper. Nytro and Viper same dyno same day needs to be done to find that out.

I know I will be interested in the delivery. Modded Nytros seem to have a issue with hesitation when throttle is hit hard. Never really heard why and most can tune most of it out but it is still there. Many suspect the E.B.C. system.

Do you guys know if MCX is using the AC ECU to tune the turbo? Should be possible.

 

[JRT]

Sure sounds like if you are happy with Nytro power it wont be a issue with the Viper. Nytro and Viper same dyno same day needs to be done to find that out.

I know I will be interested in the delivery. Modded Nytros seem to have a issue with hesitation when throttle is hit hard. Never really heard why and most can tune most of it out but it is still there. Many suspect the E.B.C. system.

Do you guys know if MCX is using the AC ECU to tune the turbo? Should be possible.

In the rumoured 180/190 kit this is most likely the way, in the rumoured 270 kit there will likely be 3 additional fuel injectors controlled by MCX's own ECU while the stock fuel line is kept, well, stock. At least this is how it's done in Nytro.

Do note that engines are also individuals of sort, I'm sure that if 10 similar brand new engines were dynoed in the same bench in the same conditions there would be a difference of few hp. Considering this and the fact that different dynos provide. different results it's only a matter of academic debate whether the SR Viper has 130, 135 or whatever hp stock. I bet not many of us would feel the difference of a couple of hp. Again, if it feels slow when riding (compared to a stock Nytro), it's a matter of clutching and gearing. Personally I think that all N/A engines suit lawn mowers and such, a real sled needs boost