Most powerful 372XP

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Simonizer

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I just dynoed one at 8.2HP@14160. No expansion chamber. Stock is 5.4. Doug Herman raced it against a modded 390 and won marginally in a 50" spruce, bucking, 34" 75ga. Fun. Cheers, Simon.
 
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Thats insane :D
good work !!!!
Still 71 cc's, but vented-skirt piston and pretty aggressive porting. I have built about 80 this year, had a half-dozen connecting rod failures, big-end. 3 or so were due to poor quality oil. Doug is a pro-faller and has two of mine both over a year old, both still strong other than usual wear, clutches etc. Is is sad that production on this excellent little machine will stop in 2008. Last year the swedish engineers told me they would be available through 2011, but I guess the emissions criteria folks are really pushing these 575's, (which are a piece of S**t).:mad: :cheers:
 
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Still 71 cc's, but vented-skirt piston and pretty aggressive porting. I have built about 80 this year, had a half-dozen connecting rod failures, big-end. 3 or so were due to poor quality oil. Doug is a pro-faller and has two of mine both over a year old, both still strong other than usual wear, clutches etc. Is is sad that production on this excellent little machine will stop in 2008. Last year the swedish engineers told me they would be available through 2011, but I guess the emissions criteria folks are really pushing these 575's, (which are a piece of S**t).:mad: :cheers:

Sounds awesome!!

So you hate the 575.....what's your opinion on the 441? I realize the mod-ability of strato saws is limited.
 
I just dynoed one at 8.2HP@14160. No expansion chamber. Stock is 5.4. Doug Herman raced it against a modded 390 and won marginally in a 50" spruce, bucking, 34" 75ga. Fun. Cheers, Simon.

Do you find 5.4 to be the average for stock 372's when you test?

Fred
 
I had the same question Simon

Did you dyno the stock 372s on the same dyno as a reference?

Also what type/brand is the dyno?
Water brake?
Electrodynamic?
Mechanical brake?

What calibration standard are you using?

I bet people would love to see some pics of your test set up
 
Probably Inertia or Hydraulic.
Actually torsion-bar set-up. A driven shaft is forced against a load, (tiny disc-brake), the shaft deflection is measured at several different rpm's. Horsepower is derived from 2*Pi*rpm*torque/33000. This gives a very accurate reading as there are no frictional losses to calculate as with a hydraulic or electric dynos. Yes, the stock 372 does deliver 5.35 hp +/- 0.30 hp. Any saw builder will agree with me that there are casting differences and port-height differences as Mahle probably has 25-30 different dies. Cheers, Simon.
 
Actually torsion-bar set-up. A driven shaft is forced against a load, (tiny disc-brake), the shaft deflection is measured at several different rpm's. Horsepower is derived from 2*Pi*rpm*torque/33000. This gives a very accurate reading as there are no frictional losses to calculate as with a hydraulic or electric dynos. Yes, the stock 372 does deliver 5.35 hp +/- 0.30 hp. Any saw builder will agree with me that there are casting differences and port-height differences as Mahle probably has 25-30 different dies. Cheers, Simon.

Do you run any other saws? Looks like you are a Husky man. I would like to see the Stihl and Dolmar numbers.....

btw that 372 is smokin' :cheers: :cheers:
 
Actually torsion-bar set-up. A driven shaft is forced against a load, (tiny disc-brake), the shaft deflection is measured at several different rpm's. Horsepower is derived from 2*Pi*rpm*torque/33000. This gives a very accurate reading as there are no frictional losses to calculate as with a hydraulic or electric dynos. Yes, the stock 372 does deliver 5.35 hp +/- 0.30 hp. Any saw builder will agree with me that there are casting differences and port-height differences as Mahle probably has 25-30 different dies. Cheers, Simon.

A straight mechanical brake dyno

With no friction losses

Now I GOTS to see a picture
 
How much money do you have????? LOL!!!!!

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Simon
It appears you are reluctant to post a pic of your set up.

That is fine with me but again I ask what you are using as a base of reference.

You may either be shorting yourself in actual HP OR you may be using a base calculation that is over estimated by using two different sources of measure.

You are aware that the KW rating of pretty much all saws is not a direct correlation to HP figures are you not?

And you should also know why this is.

No calling out anybody nor bashing or anything of the kind.........

Let us have a true technical discussion.

BTW you have so far been extremely fortunate with the crank failures by your posted numbers.
 
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