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

[porsche965]

Correct me if I'm wrong but doesn't both AT and MT sample rpm and throttle position and adjust accordingly?
Be nice if they had one more input like a o2 sensor.

Or a pyometer.

 

[bwalker]

O2 would be better and I say that based on having had EGT probes and a Race pack on several two strokes.

 

[nitehawk55]

Do "those guys" own M-tronic type systems? Or fully modded M-tronic saws?

I fully trust those engineers with the AT and M-Tronic systems better than myself with that little orange driver.

How many out there go to great lengths to buy an old truck or car with a carburetor?

Do "those guys" own M-tronic type systems? Or fully modded M-tronic saws?

I fully trust those engineers with the AT and M-Tronic systems better than myself with that little orange driver.

How many out there go to great lengths to buy an old truck or car with a carburetor?

Seems the MT and AT systems work fine in a stock saw , it concerns me a lot if any mod will be causing an unknown issue and I would have to include overly rich oil mixtures with this too....anything richer than 40:1 included .
With these systems sensing temps , load , fuel mixture , altitude , load...etc. I would have to think changing something could mess with any of this and change how the system is working .

A car with a carb ? , I sure love the old ones and loved tearing a big 4bbl carb down and rebuilding it back in the day and doing the idle tweak to the idle mixture screws to get them just right
I was a mechanic before and during the change from point ignition and carbs to solid state ignition and throttle body/sequential injection systems with your ECM controlling it all . It was a somewhat difficult time for the auto tech !!

 

[porsche965]

I've never a problem with AT or Mtronics thus far in ported saws.
Trusting in the process at this point.

 

[nitehawk55]

I've never a problem with AT or Mtronics thus far in ported saws.
Trusting in the process at this point.

There may not ever be any problems but I'm old school and always felt if it ain't broke........

 

[porsche965]

Nice to play with both!

 

[Ron660]

Correct me if I'm wrong but doesn't both AT and MT sample rpm and throttle position and adjust accordingly?
Be nice if they had one more input like a o2 sensor.

I'm sure it adjusts for ambient conditions such as temperature but I wonder if it can adjust for altitude?

 

[bwalker]

I'm sure it adjusts for ambient conditions such as temperature but I wonder if it can adjust for altitude?

If you think about it, any system that adjusts for temperature would also adjust for altitude as they have a simular effect on tuning. Forget about temp, altitude, humidity, etc. AT doesnt care. It's just holding rpm to a set point in relationship to throttle position. Unless my understanding of the system is way off.
What would be a cool is a strato saw with no rev limiter and a tunable carb or better yet a O2 sensor tied in with AT.

 

[blsnelling]

MTronic simply samples RPMs and adjust the H needle accordingly. It'll pull a little, then see how that affects RPMs, and vice versa. By this manner, it accounts for all conditions, but it fuel, temperature, altitude, porting, muffler mod, etc.

 

[blsnelling]

What would be a cool is a strato saw with no rev limiter and a tunable carb....

That's called a MS441. The early ones had no rev limiter.

 

[bwalker]

That's called a MS441. The early ones had no rev limiter.

Tunable carb too?
Wasn't that saw a dog?

 

[bwalker]

MTronic simply samples RPMs and adjust the H needle accordingly. It'll pull a little, then see how that affects RPMs, and vice versa. By this manner, it accounts for all conditions, but it fuel, temperature, altitude, porting, muffler mod, etc.

That's strange it only samples one parameter.

 

[porsche965]

So the viscosity is the variable in which the M-tronic cannot compensate for ? This would explain a lot if so.

What if Stihl deliberately made their saws to run best on Ultra @ 50:1? Talk about a marketing coo. That would make Amsoil look pretty much like beginners lol.

So an oil with a profile like Ultra would produce the best results performance wise? Viscosity included?

 

[blsnelling]

Tunable carb too?
Wasn't that saw a dog?

Yes, tuneable carb. Stock they weren't as strong as the MS441C. After porting, they ran fantastic, just as a MS441C does.

 

[SCHallenger]

That's called a MS441. The early ones had no rev limiter.

How about the early MS261. I do remember you saying you ran into it somewhere "north of 15,000 RPM", but, for all practical purposes, this does not count for much since it shouldn't come into play?!

 

[blsnelling]

I'm trying to remember if the MS261 was rev limited or not. If it was, it was way high where it didn't really matter.

 

[Andyshine77]

So the viscosity is the variable in which the M-tronic cannot compensate for ? This would explain a lot if so.

What if Stihl deliberately made their saws to run best on Ultra @ 50:1? Talk about a marketing coo. That would make Amsoil look pretty much like beginners lol.

So an oil with a profile like Ultra would produce the best results performance wise? Viscosity included?

We are still dealing with bad information on this whole oil test BS. I know others want to say this, but don't want to cause an uproar. A lot has been said behind the smoke and mirrors. Until the test is preformed by someone who is competent, this meandering thread will continue.

 

[porsche965]

Test away Andre'

 

[bwalker]

We are still dealing with bad information on this whole oil test BS. I know others want to say this, but don't want to cause an uproar. A lot has been said behind the smoke and mirrors. Until the test is preformed by someone who is competent, this meandering thread will continue.

I said this 100 pages back...

 

[porsche965]

The real smoke and mirrors is testing a stock saw with 32:1 in a video and then later testing the same saw ported with 32:1 and finding 30% gain. Test the stock saw with OE oil at 50:1 and see what the difference is when it isn't gargling with too much oil, more than it was designed to use.

That's real smoke and mirrors IMO.