Had my Apex on the Dyno

[Macheater]

So this summer I installed a Yamacharger (YC) on my 2006 Apex. I had it on the Dyno at Dynotech Research in Batavia New York this past Monday morning. Jim has been dyno testing snowmobiles for over 30 years and does the testing for all the sleds at the annual Amsnow shootout. My previous trip to his facility in December 2017 showed a peak hp of 162.4. I wanted to not only see how much hp the YC gave me, but, also tune it using the pc3 and ignition box. Here is my dyno sheet showing the hp numbers obtained after tuning.

As you can see the YC lived up to its history of gaining 20hp at peak over stock. But, even more impressive is the midrange increase. At 9,500 rpm it picked up 24.1hp compared to my previous run.
I also compiled a chart comparing a stock 2006 Apex, to my modded 2006 Apex without YC, to a 2012 Apex with YC, PC5, and Bender silencer, to my modded Apex with YC. I'm very pleased with the power I've been able to pick up with the mods I've added. Once again, check out the midrange improvement. All these numbers were generated at Dynotech Research. I'd also like to thank Hurricane performance for doing a great job on my head porting. The comparison between my YC hp and the 2012 is do to the head porting.

This is the gain I saw with my YC modded Apex compared to the other 3 dyno test subjects.

Although the above chart does not show rpm, it mirrors the chart above it with rpm starting at 7,500-10,700.

 

[Macheater]

Some pics of my machine on the dyno.

 

[sideshowBob]

Great work! 30 plus hp over stock @ 20% hp increase.
I am really impressed how your sled has such a flat power curve and makes basically the same hp from 10,000 rpm right up to 10,600 rpm.
Its also interesting that its hp peak is not closer to 10,800.
That is also the first dyno sheet I have seen that shows the improvement head porting makes on the Apex.
Great info.

 

[74Nitro]

Great stuff, but I would love to see these mods done one at a time on the same exact engine.
Your Apex should be pretty strong - a real sleeper.
Thanks for sharing.

 

[trailanimal]

please post results of slaying a stock sidewinder

 

[Macheater]

Great work! 30 plus hp over stock @ 20% hp increase.
I am really impressed how your sled has such a flat power curve and makes basically the same hp from 10,000 rpm right up to 10,600 rpm.
Its also interesting that its hp peak is not closer to 10,800.
That is also the first dyno sheet I have seen that shows the improvement head porting makes on the Apex.
Great info.

Thanks Bob, I was VERY happy with the quality and quantity of hp my sled produced. Even Jim was impressed, and this is from a guy that has dyno'd 1,000+ sled engines.
I too was a little surprised at the peak being somewhat low but, keep in mind that between 9,900-10,600 its only a difference of 1.6 hp. So a few tenths in peak is insignificant. Jim did not test it beyond 10,600 because power production had already started to decline and did not feel the need to stress the engine for an extra tenth or two.
Since we did not plumb a pressure sensor into the plenum box we were not able to measure the pressure change or drop at or beyond peak. We speculated that the compressor may have reached the point of max efficiency (especially with the ported head) and was no longer able to continue producing additional boost. I believe that Dave Marshall even touched on this subject in an older post when he was doing some testing. I was really impressed with the midrange improvements. My clutching is now a little high on shift out rpm. When I nail the throttle it immediately shoots to about 11 grand. Gonna have to throw a little weight at it and bring it down to about 10,400 or so.

I don't want to confuse the issue but Jim used 2 different testing (sweep rates) to test my sled. The 1 shown is the one he typically uses to tune engines. It is a faster sweep rate and loads the engine a little harder just like when the sled first accelerates.

He did a second test where he slows the sweep rate and starts the pull at a much higher rpm. That way the dyno is not accelerating as much and is closer to a step and hold test. Using that dyno pull standard the sled actually produced 183.7@10,400. This is the power the sled makes after the rpm has stabilized much like when the sled is already at max rpm and the clutch is shifting out. I did not want to post that sheet because I didn't want to confuse the issue. And the first test rate is the one Jim posts when testing sleds. So I wanted to have a consistent comparison.

 

[Macheater]

Great stuff, but I would love to see these mods done one at a time on the same exact engine.
Your Apex should be pretty strong - a real sleeper.
Thanks for sharing.

Yes she is a good sleeper. As far as like a stage tune, here's what I can tell you. The Excell head-pipes probably did nothing for hp production. I'm not bashing them, they are a quality piece, and I'm glad to have them, I just don't believe they are a big player in hp production. The silencer definitely improves midrange by about 2-3hp and about 1.5 at peak. In fact the silencer was tested at DTR when they were first constructed. The pc3 does not have as much impact on a near stock sled. Its very valuable to have to tune as you start making more hp. The ignition box is worth a few hp across the range as the Apex seems to like additional ignition lead. The big players are the ported head and of course the YC.

 

[Macheater]

please post results of slaying a stock sidewinder

Yes, it ought to surprise a few lower powered SW's. In fact, after the dyno session, I spent 3 days riding up in Old Forge. I never did have a chance to race a riding mate who was on a new 850 long track Doo. But, based on us chasing each other through the trails, I feel like I had plenty of power on it and could catch or pass him fairly easily.

 

[74Nitro]

If it was mine I would have taken it to the rev limiter.... The blower should continue to add boost the higher it is spun.
I had the MPI trail supercharger on a Nytro I once owned. I originally tried to clutch it for 8500-8700, but soon realized that clutching it as high as possible without hitting the limiter(9200) was the fastest setup. I know that is not an apples to apples comparison, but blowers do add boost the higher they spin.

 

[Macheater]

74Nitro, what you have to remember is that the MPI units are overdriven, where the YC is driven off the end of the crank at 1-1 engine speed. Since it is fixed in volume, its going to have a definite boost/volume limit. That limit seems to be right around 1.7 psi at full revs. Now add less restriction through better flowing ports and exhaust and the boost starts dropping. At 1.7 psi you don't have a lot to work with.

 

[yamhaattakman]

May I ask were u had the head ported. Was thinking of doing my 2012 and shaving it aswell

 

[Macheater]

May I ask were u had the head ported. Was thinking of doing my 2012 and shaving it aswell

Hurricane did the stage 1 porting and also shaved the head 20 thou.
See first post.
It was a very noticeable improvement when properly tuned.

 

[kinger]

Great accountability and testing to see the gains!

 

[Macheater]

Great accountability and testing to see the gains!

Thanks Jess, I have over a grand invested in dyno time alone. But I feel its worth every penny. Not just for the extra performance, but from the info and education that the sessions provide. You have an opportunity to see just how hard it is to make extra hp and what it takes as far as tuning to do it.

 

[yamhaattakman]

Is it worth just shavingbthe head 20 thou lookin tomadd alittle extra for drags