PMS kit going to the dyno

KJAssault · Dec 7, 2011

hey guys been doing a lot of reading about flashes on pms kit. i just wanted to let you guys know that my assault is gettin strapped to the dyno on tuesday dec 13th to get her tuned in. setup going to the dyno is,
PMS KIT, 12.5 PA HEAD, AAEN PIPE, HPS CAN, PCV, AND PINK EXHAUST SPRINGS. elevation is about 2000ft. hopefully get pixs and post numbers when its done. :rockon:

akrevrider · Dec 7, 2011

KJ,

Seen your PM and sent you a PCV Fix Kit base map to try out on the dyno. My suggestion is to have a laptop handy so you can switch between maps to see which one runs the best. My sled has the 08 fuel map & 08 head, the Fix Kit and an Aaen single pipe with stock can.

When I load the PCV maps I recalibrate the TPS from closed throttle to WOT IAW with the instructions from Power Commander.

Good luck,

akrevrider

KJAssault · Dec 8, 2011

got your pm i got the dyno for eight hours so we are gonna tune it good the place im going only uses dyno jet stuff so the know what their doing will take my lab top for that very purpose i'm pumped for this.

Stewy · Dec 8, 2011

Keep us posted, Im betting your in the 163 range with fuel management.

KJAssault · Dec 8, 2011

im hoping for 170hp but ya expecting 160hp at the track. hell lets have some fun you guys see my setup post your guess on hp we'll see how it comes out:face-icon-small-ton

St0rm77 · Dec 8, 2011

i'm in for 165.3 ..... looking forward to seeing if there is a valid difference

pura vida · Dec 8, 2011

not at the track. 160 might be at the crank. but keep us up to date as we are all interested.

pv

byeatts · Dec 8, 2011

KJAssault said:
im hoping for 170hp but ya expecting 160hp at the track. hell lets have some fun you guys see my setup post your guess on hp we'll see how it comes out:face-icon-small-ton

not even close , Maybe 110 at the track

KJAssault · Dec 8, 2011

byeatts said:
not even close , Maybe 110 at the track

now that just being a pessimist haha hope your wrong

pura vida · Dec 8, 2011

sorry he isn't. my guess, trying to be conservative, was going to be 100hp at the tracks. like any machine, lots-o-loss through the drive train. all hp numbers are reported from off the crank.

pv

thefullmonte · Dec 8, 2011

Little off topic, but yes. The snowmobile drive system is painfully inefficient. This is where the secret lies. We all like to see big HP numbers at the crank. The big question is how much are you really transferring to the track. Lets break it down.

Engine produces power. Primary clutch must transfer power through the belt to the driven clutch. Here is the first HP loss through belt slip. This is why many after market clutch weight companies claim 12% HP increase to the track.

Secondary must then transfer power through jack shaft to drive sprocket. More belts slip and loss through twisting of shaft etc...

Drive sprocket must then transfer power through the chain to the driven sprocket which finally gives power to the drive shaft. Even having a jack shaft or drive shaft not centered with the bearing can rob HP.

When you think about all the moving parts that the energy must transfer through and all the motor movement and parts flexing it is easy to see how much power is being lost. I have heard figures around as much as 40% power loss or in that range. You don't want to do the math on that. In comparison a motorcycle only looses about 15%. The secret is in drive train efficiency. I've said it before. The company that can design a better drive system is going to change snowmobiling.

Look at how much a snowmobile motor twists and flexes. Why is there not an upper motor mount? High performance motorcycles had this figured out years ago. Why are we still using the same basic clutch design from the late 70's early 80's? How old is that dang P-85 anyway? Lol. Seriously though, there have been no major advancements in primary clutch design since.

Just some food for thought.

pura vida · Dec 8, 2011

and you missed the biggest hp sap of all, that big rubber belt that we spin around and around. unfortunately that what makes us go... actually for sled purposes cvt clutches are the best option. mototcyles are more efficient b/c they have gears, that wouldn't work on a sled. Plus out of all the primary clutches the p-85 is pretty much considered the best. (although i don't know much about the yamaha clutch) not that i'm saying improvements aren't possible by any means but as inefficient as it is, it is the by far the best option available. i do agree an upper engine mount sounds like it would make sense...

pv

KJAssault · Dec 8, 2011

Great stuff guys keep on teaching

akrevrider · Dec 8, 2011

My guess is 160 at the crank and 120 at the track for a 40hp loss thru the drive train system.

Have you cleaned both primary & secondary clutch sheaves, wash the belt (use a new one if possible), adjust the chain & track tension.

Let them dyno numbers roll after all the adjustments & fuel map tweaking..

akrevrider

KJAssault · Dec 9, 2011

akrevrider said:
My guess is 160 at the crank and 120 at the track for a 40hp loss thru the drive train system.

Have you cleaned both primary & secondary clutch sheaves, wash the belt (use a new one if possible), adjust the chain & track tension.

Let them dyno numbers roll after all the adjustments & fuel map tweaking..

akrevrider

yep new primary clutch, weights and spring emery clothed the sheaves. new washers in secondary. aligned the clutches new oil in chain case and set tension. new belt. new springs in exhaust valves. and cleaned um. thats what i have done. if i missed something tell me i will do it.

Angermangement890 · Dec 9, 2011

Having friend that dyno'd his 1200 WC on a load cell track dyno and he made 120 HP to the track. I'm guessing. 160 crank HP, 75 HP to the track.

PAT2 · Dec 9, 2011

You should see if you could find a Dyna Port pipe to try, or a stock BMP mod pipe. Those 2 made way more hp than any other pipe on my motor. I did have a lot of porting done. It was like 8 hp difference from dyno port to a slp or aaen.

pura vida · Dec 9, 2011

PAT2 said:
You should see if you could find a Dyna Port pipe to try, or a stock BMP mod pipe. Those 2 made way more hp than any other pipe on my motor. I did have a lot of porting done. It was like 8 hp difference from dyno port to a slp or aaen.

wow. that is pretty impressive. wonder how much of a difference the porting made in that whole setup?

KJAssault · Dec 9, 2011

i did have this pipe dynoed by jim at dyno tech. he told me it made 2 to 3 hp more on 2 different motors. over slp and bikeman. i dont know anyone with slp or the bikeman mod to even take along sorry.

volcano buster · Dec 9, 2011

I'm not sure how much dyno time you'll have but I would find it interesting if you had different brand belts for your sled to slip on and try. Stock 1115 Polaris belt, XS809, plus whatever else you might have. We hear that different belts allow more slippage, or that they hook up better. I realize that the purists are going to point out that you would want to reshim the primary, but who does that all the time?

Might be interesting.

PMS kit going to the dyno

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