Hurricane turbo intake upgrade

[1nc 2000]

Some of us have plated the top of the tunnel from the heat exchanger back after the side braces on the procross chassis.
Stiffing up the drive train area...
Waiting till summer maintenance to install the intake tube...

 

[Turboflash]

Track is for sure the biggest factor and largest power drain.
Not sure what extreme heat would be on ProCross chassis but because the chain case is attached to the engine oil tank, it runs about same temp as engine oil temp. Not to mention both are right behind muffler.
As we've seen, if one wants to make their engine look better on track dyno, bring it with a speed track and no studs. With a "supposed" 320 tune, it will make the same engine seem like it has 25+ more HP.
It would be very interesting to put that engine on an engine dyno, same day, right off track dyno. Answer the question if the engine is that "weak", or is the track (and driveline) that big of a power robber? Is 57% right number, or is that just the right number for a sled that has heavy trail studding (lots of long studs, backers)?
Take exact same sled and change it to speed track with no studs, suddenly the engine has 15-20 more HP? No. So with such a speed track, is the right efficiency factor more like 50%? Or 45? to get close to real engine (crank HP)?

 

[Srxspec]

I suppose the chassis could be loosing out on 7% efficiency some where, plus the fact they are not making the power claimed, which most know to be true. Think about where the power loss could be coming from however. There's only two shafts and a chain case. Typical power loss due to the driveline is in the neighborhood of 10%. The track is the biggest loss on a snowmobile. Could it even be possible there is an extra 7% loss in the winders chain case? Perhaps, you'd think the heat in the chaincase would be extreme if that was the case. I figured back in the day when the 1100 Suzuki turbo was in this chassis it took an added 30-35 HP in it, compared to say a 1200 Doo turbo, so something it the chassis is robbing the power away. I had a 240 Turbo 1200 that would walk away from my buds EVO tuned winder that was supposed to be 265 HP or somewhere in that neighborhood.

I believe it's in the Procross chassis. 3" longer on the center to center distance of the jackshaft & driveshaft, which equals a longer chain and if you study the Procross chaincase compared to the old Yamaha design, the Procross has way less strength in it. I really believe the jackshaft/driveshaft area is really flexing. I may try to setup a laser pointer on the inside of the tunnel with a known reference line and see if we can see movement via a GoPro mounted under there.

 

[1nc 2000]

Have you guys seen the dyno video of a winder where you can actually see the jackshaft flexing forward under load?
The secondary moves forward.
The flex in the shaft is something else.
I don't have the video but it's out there.

 

[DMCTurbo]

Have you guys seen the dyno video of a winder where you can actually see the jackshaft flexing forward under load?
The secondary moves forward.
The flex in the shaft is something else.
I don't have the video but it's out there.

Could explain alot of things.

 

[Srxspec]

I've tested with and without a brace between primary & secondary, back to back runs, that's not where the majority of the loss is at.

 

[DMCTurbo]

I know the reverse gears weight 5lbs. Not sure of the weight difference between an Apex but 5 lbs rotating is alot.