661 Oil Test 32:1 vs 40:1 vs 50:1 ?

[weedkilla]

what about tuning for time?

I spent a lot of time messing with the MM084 and TM880. In the end I settled at 12,500 on the 36" bar. I got a lot of comments that they sounded too rich. But that is where they cut the best. I tried 12k, 12.2k, 12.5k, 12.7k, 13k. 12.5k was the best times.

Then what about the 361 oil test? For a stock saw I tuned each ratio to the called for idle (think it was like 2800) and then top end for the called for 14,000 wot. I'm sure the best ratio would be different for a different oil. Probably closer to 32 or 40:1.

But look at the times and temps. The fastest times are right around where the coolest temps are. Same with the 660 test (see attached).

Seems to me it would be a lot easier to just figure the fastest cuts for each bar and note the RPM used. Then just tune to that RPM.

Obviously double check make sure by ear your not to lean...seems very unlikely.

Thoughts on this approach?

Essentially that's how you tune on a dyno. You are tuning for max power in the band of revs that you cut in. Id say that's perfect.
The fact that you are using a simplistic temp measurement to back it up is great. I only say simplistic, in that it's not reading exhaust gas temp before the muffler with a high sample rate.
The same approach could be used to optimise ignition timing.
You still need to make sure you don't introduce a problem at other points in the power band - like stumbling as you hit the throttle for instance - but you have a baseline that you don't want to go leaner, or more advanced.

 

[Ron660]

True, the majority of the fastest times are the cooler temps.

 

[Ron660]

My last timed tests with my 660 I considered retesting using different tach readings such as 13200, 13500, and 13800 just to see what would happen. Size of wood would definitely matter.

 

[weedkilla]

If I ever build a Chainsaw dyno, the first thing I'll do is adjust the high screw while it's loaded. I try to do it in a log, but I'm not even as accurate as redbull's tined cuts. I just go on feel, and check its 4-stroking when I lift.

 

[one.man.band]

base my opinions on reference material, all of it is not found here. right/wrong/whatever.

references: eric gorr has good info on reading piston burn patterns using cht and egt temps; blair, reher-morrison, race car engineering on chamber/wet flow design characteristics; efficiency % was calculated by me from published bsfc and hp/tq data; motor heat data from blair.

.....the egt's are nowhere near those of any kind of performance motor. bsfc's are pig rich. if you care about evening out transfer flow, maybe burn patterns will help you.

......and the brake dyno will show you nothing other than what was discussed 100's pages back...........the proper tune varied with load.

and i don't see anything wrong with using the 4-ST method of tuning saw motors, no matter what anyone says. safe tune. these motors are what they are.

edit. spelling

 

[bwalker]

The fourstrokes method is pretty subjective and in many cases results in a overly rich saw..
All moot as future saws will not have screw adjust carbs.

 

[one.man.band]

The fourstrokes method is pretty subjective and in many cases results in a overly rich saw..
All moot as future saws will not have screw adjust carbs.

all good.

here are some ways these zama electric screwdrivers work: (may not be what you think). there are many variations of the same theme.

donut magnet on diaphragm or air bleed types.

https://www.google.com/patents/US7264230
https://www.google.com/patents/US6581916
https://www.google.com/patents/US6702261
https://www.google.com/patents/US20090145399

ingenious inventions they are.

goes good with a beer. warsteiner oktoberfest hits the spot. maybe the old milwaukee of germany for all i know. but tastes fine.

 

[Ron660]

The fourstrokes method is pretty subjective and in many cases results in a overly rich saw..
All moot as future saws will not have screw adjust carbs.

Fuel injection would be better...lol

 

[bwalker]

Fuel injection would be better...lol

If two strokes are to survive it will have to be direct fuel injection and not some half azzed attempt like Stihl did with that cut off saw.

 

[KG441c]

If two strokes are to survive it will have to be direct fuel injection and not some half azzed attempt like Stihl did with that cut off saw.

Wonder if they have anything in the works?

 

[bwalker]

Wonder if they have anything in the works?

Its already been done for years with different applications. Would just need to be scaled down to fit a saw. Bombardier etch system is pretty dam simple in that the injector is a simple voice coil.

 

[redbull660]

had a member PM me a question. I think my reply is applicable to the thread so I am posting it.

"what would you burn the HP2 at in stock saws ?..does it burn ok at heavier ratios ?"

----------------------------------------------------
my reply:

This is 32:1 on a brand new 661 after 3 tanks. (see attached pix)

guess I'm not sure if ratio is dependent upon saw size or not. I know a guy who swears that his 362 and his 661 like different ratios. He says the 362 liked a little bit less oil than the 661.

The main thing in the test, was to find an oil that stood out from the pack. Then guys can argue about what ratio to run in their saws...the irony of that, is like stated above I think it might vary from saw to saw. Maybe it's the power and displacement of the saw? The power range/band of the saw? I dunno. I know that the 660 liked h1r 40:1 best and the 361 liked 45:1 h1r best. (both stock saws) But it's h1r, so there is that cloud of suspicion hanging overhead that it burns weird. I'd admit I have the same suspicion. I would like to do a test to verify that some other oil does the same thing in two different size saws....and that is another reason I liked the Hp2, because it ran well at 32:1, ran well at 40:1, it ran well at 45:1. 50:1 I didn't care for, but it wasn't THAT bad.


All that said, I think that one could spend a lot of time thinking about it and talking about it. Easier to just do it.

Mix up some 40:1. Mix up some 32:1 maybe a gallon of each or something. Run em each and see what ya think. And I'd really like to know what you find.

 

[KG441c]

The only thing ive seen yet for hp2 in my saws is that it smokes a bit off idle or loads up alil but that could be me running my saws alil rich on the low speed to bring them back to idle quicker. My 440 is tuned at 14900 running 87efree and hp2 32to1 and still 4 stroking and I shut it off at wot. Pulled the muffler cover and its semi wet but not soaking wet. Getting closer to that tune Bwalker keeps talking about that has a more complete combustion. So far the hp2 lubricates well and is burning off in the topend. With a good load I believe she will be spot on

 

[KG441c]

Im looking for complete combustion in an oil and not a saturated system when looking through the exhaust but hp2 will give u that if u tune that way

 

[bwalker]

all good.

here are some ways these zama electric screwdrivers work: (may not be what you think). there are many variations of the same theme.

donut magnet on diaphragm or air bleed types.

https://www.google.com/patents/US7264230
https://www.google.com/patents/US6581916
https://www.google.com/patents/US6702261
https://www.google.com/patents/US20090145399

ingenious inventions they are.

goes good with a beer. warsteiner oktoberfest hits the spot. maybe the old milwaukee of germany for all i know. but tastes fine.

Before snowmobiles went with transfer port or direct injection they used simular methods to create temperature and altitude compensating carbs. Snowmobilers largely couldnt wrap there mind around tuning a carb either...

 

[bwalker]

had a member PM me a question. I think my reply is applicable to the thread so I am posting it.

"what would you burn the HP2 at in stock saws ?..does it burn ok at heavier ratios ?"

----------------------------------------------------
my reply:

This is 32:1 on a brand new 661 after 3 tanks. (see attached pix)

guess I'm not sure if ratio is dependent upon saw size or not. I know a guy who swears that his 362 and his 661 like different ratios. He says the 362 liked a little bit less oil than the 661.

The main thing in the test, was to find an oil that stood out from the pack. Then guys can argue about what ratio to run in their saws...the irony of that, is like stated above I think it might vary from saw to saw. Maybe it's the power and displacement of the saw? The power range/band of the saw? I dunno. I know that the 660 liked h1r 40:1 best and the 361 liked 45:1 h1r best. (both stock saws) But it's h1r, so there is that cloud of suspicion hanging overhead that it burns weird. I'd admit I have the same suspicion. I would like to do a test to verify that some other oil does the same thing in two different size saws....and that is another reason I liked the Hp2, because it ran well at 32:1, ran well at 40:1, it ran well at 45:1. 50:1 I didn't care for, but it wasn't THAT bad.


All that said, I think that one could spend a lot of time thinking about it and talking about it. Easier to just do it.

Mix up some 40:1. Mix up some 32:1 maybe a gallon of each or something. Run em each and see what ya think. And I'd really like to know what you find.

2r ran well across the range also, correct?

 

[Marshy]

Before snowmobiles went with transfer port or direct injection they used simular methods to create temperature and altitude compensating carbs. Snowmobilers largely couldnt wrap there mind around tuning a carb either...

If two strokes are to survive it will have to be direct fuel injection and not some half azzed attempt like Stihl did with that cut off saw.

Cant unless there is an oil injection system for the bearings as well. Polaris snowmobiles is not manufacturing stock snowmobiles that have such technology.

 

[bwalker]

Cant unless there is an oil injection system for the bearings as well. Polaris snowmobiles is not manufacturing stock snowmobiles that have such technology.

True. Easy to do.

 

[bwalker]

True. Easy to do.

Polaris uses transfer port injection...inferior to Ski doo's true Di system.

 

[Marshy]

Polaris uses transfer port injection...inferior to Ski doo's true Di system.

Inferior even though polaris has higher HP?