Snellerized MS461 on the dyno

[stihlaficionado]

Good it's not for sale.

There is always a price point for everyone & everything. It's only a matter of time & circumstance

 

[HuskStihl]

$75

 

[lone wolf]

You guys wondering about break in.

I tend to think the seals do more to drag down the engine than anything else. I'm sure the rings getting bedded in makes some difference, but a new set of seals really makes the crank a lot harder to spin by hand when assembling an engine.

The tight bar groove adds a bit of drag in the small CC saws.

 

[stihlaficionado]

Now I asked Brad about the 461 last year so I'm first in line for the 461

 

[Turbo BBQ]

Most of the time yes. The shop I test in is huge and we have exhaust drop hoses but I find it really hard to capture the exhaust especially on a dual port muffler. I roll the dyno outside the door because the shop gets uncomfortably smokey quickly. I do a lot of cutting in the summertime then my saws sit for awhile till its cold and the ground is frozen. I feel the need to usually retune when its cold. Cold air is more dense so the saw runs leaner when its cold. I've had ported saws that felt like they could have had a larger carb when running it in super cold weather but they run fine when its warm.

Since it has been proven that without loss you can run a modified and tuned saw at peak with the muffler completely removed, build a muffler exhaust adapter for each of the various class of saw you want to run so you can control the run inside on a stand. You'll expunge the fumes, control each run and provide for an additional point to monitor pressure and temperature.....

You must monitor and control all the variables to get a consistent read.

 

[wyk]

Since it has been proven that without loss you can run a modified and tuned saw at peak with the muffler completely removed, build a muffler exhaust adapter for each of the various class of saw you want to run so you can control the run inside on a stand. You'll expunge the fumes, control each run and provide for an additional point to monitor pressure and temperature.....

You must monitor and control all the variables to get a consistent read.

The factory exhaust, or mod thereof, is part of the read.

 

[RedFir Down]

The tight bar groove adds a bit of drag in the small CC saws.

So does a pinched chain.

Nice job fellas, interesting read.

 

[SAWMIKAZE]

Wait a minute....

Good job bradley

 

[Ron660]

.789 increase to be exact. I looked back in the weather archives and found the weather data for the August date when I tested it and yesterdays data and entered it in the calculator. .944 correction brings yesterdays stock 461 max hp to 6.4hp. 8/22/14 has a correction of 1.008 bringing its max hp to 6.04 hp
So with the corrections added my stock 461 gained .36 hp since it was last tested. That could have very well been from a good thorough break in.

What rpms were the saws tuned to at WOT?

 

[Mastermind]

Wait a minute....

Good job bradley

I agree.

 

[chadihman]

Brads 461 was still four stroking nicely at 15,400
Nice thing about the dyno Is I can easily pick up the rpm where it changes from four stroking to smoothing out. This one smoothed out at about 13,300
It's pretty cool to see on the dyno. The torque fluctuates all over the place when it's jumping back and forth at its sweet spot. They don't make power till they smooth out.

 

[Ron660]

Something like 45 degrees difference. I remember that august day being very cool and the archived data shows 76 deg F that day. I'm positive your 660 would pull harder now.

Chad, have you checked your stock 660 recently on the dyno? I'd like to see if there were any changes since the first tests.

 

[Ron660]

Brads 461 was still four stroking nicely at 15,400

WOW that's smoking. Wonder if the dyno results would be different if tested at 14400 rather than 15400? Different torque curve?

 

[chadihman]

Chad, have you checked your stock 660 recently on the dyno? I'd like to see if there were any changes since the first tests.

Nope. It's currently jugless

 

[1 stihl nut]

Since it has been proven that without loss you can run a modified and tuned saw at peak with the muffler completely removed, build a muffler exhaust adapter for each of the various class of saw you want to run so you can control the run inside on a stand. You'll expunge the fumes, control each run and provide for an additional point to monitor pressure and temperature.....

You must monitor and control all the variables to get a consistent read.

If I was going to have a saw dynoed, I would want it done with the exhaust that it was going to wear in the field.

Otherwise it seems you are adding a variable in order to get rid of a variable.

The one you are adding is one the saw will never normally see, and would likely affect the shape of the power curve by operating with unknown flow and backpressure.

The variable you are trying to get rid does not go away any unless you can control not only temperature but also humidity and barometric pressure.

Anyhow. ..great work on the chart , and thanks again! !!

 

[blsnelling]

Brads 461 was still four stroking nicely at 15,400
Nice thing about the dyno Is I can easily pick up the rpm where it changes from four stroking to smoothing out. This one smoothed out at about 13,300
It's pretty cool to see on the dyno. The torque fluctuates all over the place when it's jumping back and forth at its sweet spot. They don't make power till they smooth out.

WOW that's smoking. Wonder if the dyno results would be different if tested at 14400 rather than 15400? Different torque curve?

That surprised me as well. I hadn't run this saw since last fall, so hadn't had a tach on it recently. I was curious Chad, was that with your tach or the one that's mounted on the saw?

 

[chadihman]

That surprised me as well. I hadn't run this saw since last fall, so hadn't had a tach on it recently. I was curious Chad, was that with your tach or the one that's mounted on the saw?

The one on the saw. I use a shaft rpm sensor for my dyno calculations.

 

[blsnelling]

So it matched your dyno? The reason I ask is because I don't trust those like mounted on the saw. I saw them read high and jump all over the place. As long as the tune sounds like you described, that's all that really matters. I suspect the tune was actually closer the 14,500.

 

[Andyshine77]

Awesome work Chad!! Brad your saw ran okay I guess.

I have always been a firm believer, that a well broken in saw is a different animal.

 

[chadihman]

So it matched your dyno? The reason I ask is because I don't trust those like mounted on the saw. I saw them read high and jump all over the place. As long as the tune sounds like you described, that's all that really matters. I suspect the tune was actually closer the 14,500.

Could be it was off. To be honest I was looking at the shaft rpms not saw rpms. It was a little jumpy though before testing. I always put on a 8 tooth Sprocket on the saw and the driven pump Sprocket is a 24 pin. I use it to set the saw rpm not the saws tach. 4333 shaft rpms is 13000 saw rpms 4000 is 12000 and so on.