"4-mix"?

[max2cam]

Where did this term "4-mix" come from when describing the 4-stroke (Otto cycle) engine?

I've been seeing it used on this forum by knowledgeable guys, but it sounds kind of wacky to me. The only "mixing" I can think of refers to the oil you mix with gasoline for the 2-stroke engine.

4-stroke, 4-cycle maybe, but "4-mix"?

Can somebody PLEASE explain the logic behind this term and where it came from?

 

[Lobo]

I think the ''4-Mix'' was coined by Stihl for their new EPA compliant engines.

I guess it is because the engines are like 4 strokes or 4 cycles if you prefer with 2 valves to reduce emissions, but you still mix the gas and oil as you would mix for a traditional 2 cycle.

 

[sedanman]

It is a 4 cycle engine with no oil in the crankcase, fuel mix enters the engine through a hole in the intake port, it lubes the valvetrain and the crancase and then is pushed back through the hole in the intake port to be metered by the intake valve. For this to work the crankcase must be sealed like a 2 cycle engine. If you vented the crankcase, put oil in the crankcase. and sealed up the hole in the top of the intake port, you would have a conventional 4 cycle engine.

 

[max2cam]

I think the ''4-Mix'' was coined by Stihl for their new EPA compliant engines.

I guess it is because the engines are like 4 strokes or 4 cycles if you prefer with 2 valves to reduce emissions, but you still mix the gas and oil as you would mix for a traditional 2 cycle.

For a second I thought you were joking, but I guess not.

Sounds like the worst of both worlds: valves to break or wear out and to adjust, yet with the lingering oversight of using straight gas with dire consequences.

Thanks

 

[max2cam]

It is a 4 cycle engine with no oil in the crankcase, fuel mix enters the engine through a hole in the intake port, it lubes the valvetrain and the crancase and then is pushed back through the hole in the intake port to be metered by the intake valve. For this to work the crankcase must be sealed like a 2 cycle engine. If you vented the crankcase, put oil in the crankcase. and sealed up the hole in the top of the intake port, you would have a conventional 4 cycle engine.

Hmm....interesting.

Is it a Stihl invention like Lobo thought?

And just at a time when the modern 2-stroke chainsaw IMHO had just about reached perfection of power, lightness, and (gasp!) reliability.

Thanks

 

[max2cam]

Must be a Stihl invention; at least Stihl has trademarked the term "4-mix." Sorry if I'm just catching up on what the rest of you guys already know....

Stihl WEBSITE:

The STIHL 4-MIX® engine puts you in first place with exceptional power, unparalleled performance and high fuel efficiency.

With the introduction of the STIHL 4-MIX® engine, STIHL unveils the outdoor power plant of the future. This patented engine design includes the best of 2-stroke and 4-stroke technologies combined. The new STIHL 4-MIX® engine offers more horsepower, more torque and less vibration than its 2-stroke counterpart.

Products with the
STIHL 4-MIX® Engine


* FS 100 RX Trimmer
* FS 110 R Trimmer
* FS 110 RX Trimmer
* FS 110 Brushcutter
* FS 130 R Trimmer and FS 130 Brushcutter
* HL 100 (0-90°)
Hedge Trimmer
* HL 100 K (0°)
Hedge Trimmer
* HL 100 (0-90°)
Hedge Trimmer
* HT 100 Pole Pruner
* HT 101 Pole Pruner

Built with the patented STIHL lubrication system, it runs on standard 50:1 fuel-mix, thus eliminating the need for a separate oil chamber. Its compact design with fewer parts, creates less frequent service needs than a typical 4-stroke engine. And also weighs less then the typical 4-stroke engine.

The STIHL 4-MIX® not only meets the Environmental Protection Agency (EPA) “Phase 2” emissions standards effective January 2005, but also measures up to the regulations set forth by the California Air Resources Board (CARB).

Professionals will appreciate the fast acceleration, pleasant sound, high torque and fuel efficiency with fewer “pit” stops. So, when the day is done and the work complete, you'll finish in first place with the STIHL 4-MIX® engine.

 

[sedanman]

Stihl and Shindaiwa had parallel development of nearly identical engines and both deny that they were in cahoots with each other. I have a 4-mix trimmer and the torque is unbelievable! My FS-110 is powerful, fuel efficient and quiet, I would buy a 4-mix saw in a heartbeat.

 

[sedanman]

At Stihl silver school we were told that a 4-mix trimmer would take 30 tanks af straight fuel before grenading, assuming it was previously run on 50:1.

 

[max2cam]

At Stihl silver school we were told that a 4-mix trimmer would take 30 tanks af straight fuel before grenading, assuming it was previously run on 50:1.

That sounds very positive.

How will the 4-mix® engine compare with regard to price?

 

[bwalker]

Sedan, Wasnt the Shindaiwa four mix type trimmer out a few years before the Stihl? IMO the shindaiwa has the better designed engine, but in the trim/size the offer it in its on the anemix side.

 

[max2cam]

Sedan, Wasnt the Shindaiwa four mix type trimmer out a few years before the Stihl? IMO the shindaiwa has the better designed engine, but in the trim/size the offer it in its on the anemix side.

Just as Harley-Davidson had to seek help from Porsche for new engineering, it wouldn't be surprising if Stihl had to go to the Japs....

 

[bwalker]

Max, In actuallity the two designs are much differant. The Shin design uses two read valves. One at the intake and on in the crank case to actually provide air to the intake valve at a higher than atmospheric pressure. Much like a two cycle does through the transfers. The stihl sytem on the other hand is just four cycle that runs on mixed fuel. I also highly doubt that a four mix will run any longer than a two cycle on staright gas as the pistons and bearings are of the same type.
Also of note is the fact that redmax is phasing out their four stroke trimmers because there compliant two cycles are much better in regards to emmisions, weight and power. Interesting times in regards to the two cycle engine.

 

[Lobo]

Just as Harley-Davidson had to seek help from Porsche for new engineering, it wouldn't be surprising if Stihl had to go to the Japs....

Harley also got help from either Suzuki or Kawasaki, I don't remember which one however.

 

[bwalker]

Harley needs all the help they can get........

 

[sedanman]

Ben, If you ever decide to come to a get together bring your 2 cycle string trimmer. We'll run our trimmers on raw fuel and the first one to puke has to pay for all the damage. The reason the 4 mix runs so muck longer on raw fuel is the relatively small amout of air passing through the crankcase. and it's all following the same path, all the way up to the top of valve cover, The oil can fall out of suspension and linger in the crankcase longer. I'm willing to BET on it.

 

[Lawn Masters]

Well, it sounds like a good design then. Now I'm thinking I might want to try one.

 

[max2cam]

If the Shindaiwa has reed valves, does the Stihl 4-Mix® have them too or regular "poppet" type 4-stroke valves?

A saw that doesn't seize-up on straight gas would be awfully nice. Does that also mean air leaks and over-lean mixtures wouldn't kill a 4-Mix® either?

If you guys hold that contest between the 4-Mix® and the Shindaiwa can the rest of us watch and place bets?

I have come to like the simplicity of the modern 2-stroke chainsaw engine. They have gotten very reliable it seems to me. Easy to work on. I rebuilt my 024 holding it on my lap like a baby. That simple, valve-less cylinder is a marvel! I used to HATE 2-strokes, but I have been converted....

As to Harley-Davidson, I never heard that Suzuki or Kawasaki helped them, but there are plenty of Jap-made components on them. The Porsche connection is real enough as Milwaukee didn't have the necessary expertise to design a "modern" Jap-type engine.

Funny, but Harley-Davidson now has a greater worth as a company than General Motors! Strange but true. Gotta think that one of them is either over-valued or under-valued....

 

[Sylvatica]

I'm bringing this topic up again hoping that the people who have been operating the 4 Mix units for a while can give me their opinions.

I am thinking about buying a couple of trimmers-on-a-stick, namely the Stihl HL 100.

So, what is the word on the Stihl HL 100 ??? (And the 4 Mix in general.)

Thanks

 

[Lakeside53]

Ben, If you ever decide to come to a get together bring your 2 cycle string trimmer. We'll run our trimmers on raw fuel and the first one to puke has to pay for all the damage. The reason the 4 mix runs so muck longer on raw fuel is the relatively small amount of air passing through the crankcase. and it's all following the same path, all the way up to the top of valve cover, The oil can fall out of suspension and linger in the crankcase longer. I'm willing to BET on it.

Makes perfect sense to me, and although I'm not going to bet, I'd sure like to watch

Also, for those that think 4-mix is a crazy term, it's much better then calling it a "4 stroke" .. most people associate 4 stroke with straight gas, hence "4-mix..." I'd guess Stihl did a lot of end user market research on this topic before deciding what to do...

ps. I love my BR600 4-mix.

 

[THALL10326]

Looks like that one guy there really like's those 4-mix engines, he got a bunch of them and they are indeed great. As for alittle history on Stihl's 4-Mix I don't think ya really wanna know where they got the idea from, I think Lake knows what I'm referring too..