• We are no longer supporting TapaTalk as a mobile app for our sites. The TapaTalk App has many issues with speed on our server as well as security holes that leave us vulnerable to attacks and spammers.

Stock Phazer Dyno'd - HP/Torque.

rs-yam

Newbie
Joined
Mar 12, 2006
Messages
16
Location
MN
Stock 07 Phazer 500: 78 hp at 11500 rpm and 37 lbft torque at 9800 rpm.

This was from the MC-xpress turbo article.
 

Is that torque # before or after the gear reduction?????? Personally I would guess that # is without gear reduction. And if that is the case I think that 60 lb/ft would be a safe guess?
 
PowerValve-700 said:
Wow, I expected more torque than that. How much torque does a 80HP 2-stroke make? Say a 98 Formula 500? I think they were around 80HP.

I've got an old Dynotech test of a 1994 Ski-Doo MXZ 470 - Stock: 79.8 hp/57.8 ft/lbs torque.

What's the gear reduction ratio? Since it is built into the crankcases, can they even bypass that with a dyno? I thought the dyno hooks onto the same pto end that the clutch is on.
 
They dont always take the engine out, and by the looks of the mcxpress website they dynoed off of the crank so i would guess those are the numbers from the reduction.

Not impressive to say the least but my turbo will fix that.
 
Not that it makes any difference at all, but those numbers are definitely withOUT the gear reduction.

WITH gear reduction, final torque will be about 49 footpounds at 9800 RPM (because the PTO shaft will really only be spinning 7400-ish).

Power = ( Torque * RPM ) / 5252

Use that forumla to determine that those numbers just don't make any sense at PTO shaft speeds.

Also note when comparing this number to that 94 MXZ posted above that Phazer's CLUTCH SPEED is faster than that 470's peak crankshaft speed, and that the torque difference will be made up by further gear reduction in the gearcase.

Anybody know what the exact gear reduction is on Phazer? I'm using 1.32, but am not sure how precise it is.
 
Why do some of you allways come up with the gear-reduction whenever there are dyno-results? Do you think they can tap directly into the crank-shaft with the dyno-axle? Do you really think they rebuild the entire PTO side of the crank just to dyno it? NO WAY!!! And besides, what would be the point of doing that? You could never run it like that in the snowmobile.
They are all dyno'ed the same way (as far as I've seen), through the tapered PTO axle. :-o ;)!
 
LazyBastard said:
Not that it makes any difference at all, but those numbers are definitely withOUT the gear reduction.

WITH gear reduction, final torque will be about 49 footpounds at 9800 RPM (because the PTO shaft will really only be spinning 7400-ish).

Power = ( Torque * RPM ) / 5252

Use that forumla to determine that those numbers just don't make any sense at PTO shaft speeds.

Also note when comparing this number to that 94 MXZ posted above that Phazer's CLUTCH SPEED is faster than that 470's peak crankshaft speed, and that the torque difference will be made up by further gear reduction in the gearcase.

Anybody know what the exact gear reduction is on Phazer? I'm using 1.32, but am not sure how precise it is.

----

Agreed, this is an engine dyno, this is what the engine outputs, not at the track power, but oddly enough, it must have a very linear torque curve.

As in, peak torque is 37 ft pounds right? Well... typically peak HP is the point were torque is falling off at a rate such that revving any higher will not create more HP.

Well at 80HP @ 11,500 RPM, the sled is making 37 ft lbs of torque, look:

80 = (11500 * Tq) / 5252
Tq = 80*5252/11500 = 36.9

So at 11500 RPM the engine is making 37 ft lbs, and at 9800 its making 37 ft/lbs (which is 69 HP). This means chances are its making 37 ft/lbs for almost ALL its powerband, very nice, and good for mileage in the sense that you dont need to worry about your RPM affecting your mileage so much ;) ...

but continuing this also means that like the R1 motor that it mimicks, which has a 12,500 RPM redline, chances are this motor is still making like 35 ft lbs at that 12500 RPM.

HP=(12500*35)/5252 = 83 HP.

I bet theres a few ponies to be had with clutching and a good Intake/Exhaust setup.

But I digress, the bottom line is that with gear reduction that clutch probably is NOT spinning any faster then 7500 RPM.

11500 / 7500 = 1.53 lets say 1.5 to be safe.

37 ft lbs * 1.5 = 55 ft lbs.

The accelleration will be descent and have a nice linear pull to it, very smooth, almost like an invisible powerband not peaky like a 2 stroke.

-Steve
 
55/35 reduction so it'd be a 1.57 reduction roughly.
 
Phazer

I'm so confused, maybe the dealer will take my Phazer GT back on trade for my 02 SRX, what do you think???
 
The dyno was hooked up to the PTO and includes the gear reduction. See photo from MC-Express who dyno'd the Phazer.

Our dealer said is no way to run the motor without the gear reduction because it's built into the crank cases. The only dyno's he's seen for sleds all run off the PTO tapered end. They record the engine rpm and the dyno records the power/torque on the PTO - the power the clutch sees. It would be very involved to take a part the motor, mount it back in the sled and create some interface to the dyno in order to take a reading without the gear reduction. It's much simpler to remove the clutch and mount the dyno in its place.
 

Attachments

  • Phazer-dyno.jpg
    Phazer-dyno.jpg
    36.3 KB · Views: 501
Perhaps, but it was accounted for mathematically then.

There is no way that engine is only making 22 ft/lbs of torque (37 after gear reduction).

-Steve
 
BV1 said:
Perhaps, but it was accounted for mathematically then.

There is no way that engine is only making 22 ft/lbs of torque (37 after gear reduction).

-Steve
Shouldn't the gear ratio be applied to both the hp and torque?

If 80hp/37t is used in the equation, I would think both hp and torque numbers would be proportional to the gear reduction - not just the torque. The above equation is correct but the motor output before the gear reduction is about 53hp/24t. (assuming a 1.5 gear ratio.) (Tq = 53*5252/11500 = 24)


What does a 500cc twin 4-stroke motorcycle dyno?
 


Back
Top