Went to Rome New York on Saturday for "dyno day" at Magnum Motorsports. $80.00 gets you two runs on the dyno. My sled is a 2005 Polaris Fusion 900. The motor is stock with 550 miles on it. The only changes I have made is a Dubbs air box. I wanted to see what my peak hp and tq were and at what rpms. First run was with a Stock pipe and a Dynoport can. At 7000 rpms she hit 127.8 hp and 96.0 tourque. So we took the Dynoport can off and put the stock can on. Run #2 was the same. :banghead:

Was the operator wearing a Arctic Cat Jacket ? LOL.

Here is the issue with dyno's - no two are exactly the same and no two operators are the same.

What was the correction factor and what was the weather info inside cell ?

air temp 29
relative humidity 87
barometrir pressure 30.31
sae temp factor 0.971
sae humidity factor 1.007
sae barometric factor 0.988
final correction factor 0.967

I worked in dyno's for 12 years at one of the big 3 auto companies. Dyno's need to be calibrated. Was that raw numbers or
corrected numbers. What correction factors were used? Rich Daley(Dynoport) and Rob(HTG) dynoed Fusions when they first came out. They seen anywhere from 142 to 145 hp stock. spam seen mid 140's also.

It says Dyno-max sae corrected power curve.

What other sleds were dynoed? And what kind of #'s did they pull?

tc, was this track dyno or crank?

My typo error. I ment DynoTec not "spam".

crank

how long of pulls did they do? did they get the pipe good n hot? also what kind of dyno? also curious what some other sleds did.

Many Dyno's had issues with the Fusion....The DET sensor played havic with some...The motor will make 145+ at all correct dyno runs..

I think the fusion makes the peak power between 7400-7500 stock.

Well, a correction factor of .967 means your "raw" hp was 132.16. I'm not surprised, after that many miles the cylinders in my 05 900 were junk, scored everywhere. My stock 03 BM 800 would beat my 900 and that was rated at around 135hp, makes sense to me. I think brand new they may lay down a lot more but there's tons of threads about how the power in these sleds drop right off with miles.

TC, it seems that you aren't running high enough rpms... We had discussed a little while back on what rpms you were running and I remember you saying that Don from White Lake was saying to run at 7,200rpms. Looking at SLP's dyno, their dyno chart is showing approx 136hp at 7,000rpm and not reaching peak until about 7,550rpms.

I am looking to dyno my sled hopefully soon as I'm considering running the slp reflash with stock pipe/can which we had discussed as well.

according to dtr on the dyno shhet on there it made peak hp at like 7200

I asked a question prematurely - here's the first one I should have asked.

What is the SAE standard's for a snowmobile ?

FWIW- I saw a post on amsnow that said the # were short by 5%. This was posted by the shop owner andconfirmed by the dyno operator. The post is under the racing fourm.

Yes he told me his dyno was off by 5%. We ran it up to 7400 rpms. At 7400 rpms the sled was at 115.8 hp. The clutch kit has nothing to do with the dyno run because the dyno was at the crank.

I PM'd Twitchford with the same (More detailed) info I am posting here.

If you have a qualified service technician that is properly trained on digital-wrench, they have the ability to download that dyno-run from the sleds ECM and playback all the running parameters of that engine to determine what was happening. They could easily see if the DET sensor was pulling timing or adding fuel, RPM's, water-temp, throttle percentage, and every other thing needed to diagnose why the numbers were low.

Now, the trick is finding a tech that knows how to do this.

TC- just for grins and giggles disconnect the hose for the ves solnoid then run it again. If have seen and fair share of solnoid that were bad.

dtrain- where is the hose?

There is 1 hose per ves valve. the 2 hoses connect to getherat a t-fitting and the solnoid is attached the left hand shock tower, if i remember correctly. just pull the hoses of the ves valve bodies and see if that makes a difference.

Knock sensors and engine dyno's typically do not play nice together. I run an engine dyno for DCX and almost all of our engine dyno calibrations have the knock sensors disabled within the calibration to eliminate false knock and the subsequent spark timing retard. A hot pipe and coolant temps at or below 125°F are also required for max HP readings. You can try removing the knock sensor, wrapping it in rubber, and tying it off somewhere the next time you dyno. Also make sure you have 91+ octane fuel.

I still had gas from last year. lol

my stock fusion 900 06 hit 151.4 hp at 7400 rpm and 109 torque at 7200 rpm

now i have a dragon with about 92 torque but 50 pounds less. i think the performance are vey similar.

tiluc-did you have your fusion dynoed? how do you like the dragon compared to the fusion?

running old fuel during a dyno run????? WTF???

you are lucky you still have an engine!!!


problem solved!!

yes it was my dyno test.

the dragon is much better than fusion for handling, trail riding...
but for drag... i don't know yet?? no test yet on dragon ( 300miles) very close out of the box

Well said!

I doubt it would have blown an engine with knock retard. But it may have been seeing knock and that explain's the loss of power.
Does anyone know how much timing it pull's when it see's knock? Also where is the sensor located? There are way's to de-sensitse the sensor's so they don't get false knock.

the DET sensor is attached directly to the head. Some have found that taping it to a rubber coolant hose will keep it from activating, and they use this trick for diagnostic purposes only. Do not ever run this sled without the det properly in place.

that is just asking for trouble IMHO, this DET sensor is relied upon heavily by the ECM to determine the initial mapping of the fuel and ignition curves. This is how the ECM determines what grade of fuel you are running and it picks the highest performing mapping for the conditions being reported by this and the other sensors.

Do you guys remember the old 650 RXL injected sleds? The only time I have ever personally seen one burn down is from people running old fuel.

The ECM will keep pulling timing and adding fuel until the knock is gone. With the pump fuel we have available to us these days, 1 month of storage is beyond safe limits. I cannot imagine this sled even running worth a shit on 6 month old fuel. I am surprised that thing even dyno'ed out where it did!!
You must have one hell of a strong motor to show those numbers on that old stale fuel!

Automobiles that are equipped with knock sensor's, pull a set amount of timing. I would assume that a ks on a sled would be the same. I also don't think the pcm on a sled is advanced enough to pull timing AND add fuel. I think it just pull's x amount of timing. At least that's how every other set-up work's.

The Fusion's sequential fuel injection system not only retards the timing on only the cylinder that is knocking it also only adds extra fuel to the cylinder that is knocking as well. Technology is a beautiful thing.

That's awesome. I wish someone would make tuning software for these thing's.

It is not needed! every possible fuel and ignition mapping option needed is already in that ECM for a stock sled to hit that 120 MPH top-speed mark that is programmed into the ECM. the polaris race dept. has the tools to remove the speed limiter. But other than that you should not need to change a single thing.

What you need to do is verify the ecm is getting the correct signals from all the sensors so it can apply the correct mapping for the current conditions.

For instance, if the TPS is slightly off, this sled will never perorm to it's fullest!!

$546.00 USD will get you the digital wrench software and interface cables. Then you'll need a tps testig tool with a nice digital multimeter.

That is everything you will ever need to get this sled to run at it's very best. Oh BTW, run fresh fuel with a minimum octane rating of 91-93 :banghead: Right? TC!