70cc class Dyno day

[cuinrearview]

You husky guys are giving yourselves headaches trying to justify the 572. Give it a rest

Don't make me play the sideways balance card..

 

[huskihl]

Don't make me play the sideways balance card..

572 has an inboard clutch, so..

 

[dustinwilt68]

I DNT think anyone here has to justify anything they pay for with their $$$.

 

[huskyboy]

I think the dolmar takes the cake after it’s ported as far as torque goes. The torque curve is quite amazing on a ported 73/79’er and they’ll pull a much longer bar than the av or oiler is realistically capable of handling. The muffler hurts them stock imo. They are still a go getter for an aging design, they were a little ahead of there time back then.

 

[Deets066]

I DNT think anyone here has to justify anything they pay for with their $$$.

What if you didn’t pay for it with your own money. What then?

 

[srcarr52]

What if you didn’t pay for it with your own money. What then?

You’re the one who’s going to have to explain it to your sugar daddy. Not my problem.

 

[dustinwilt68]

What if you didn’t pay for it with your own money. What then?

More variables.... Always variables.

 

[sawmikaze]

This is gettin funnier

Keep going

 

[Deets066]

You’re the one who’s going to have to explain it to your sugar daddy. Not my problem.

I thought choo was gunna be my sugar daddy!?!

 

[srcarr52]

I thought choo was gunna be my sugar daddy!?!

I got 99 problems and you ain’t one.

 

[Deets066]

I got 99 problems and you ain’t one.

Your loss

 

[P.M.P.]

 

[srcarr52]

Your loss

Said your last sugar daddy when you bought the wrong saw.

 

[P.M.P.]

 

[00wyk]

What if you didn’t pay for it with your own money. What then?

Grind off the serial numbers, I guess.

 

[Wolverine]

You husky guys are giving yourselves headaches trying to justify the 572. Give it a rest

Sheit, I’m just haven’t a lil fun..

 

[Red97]

I think the dolmar takes the cake after it’s ported as far as torque goes. The torque curve is quite amazing on a ported 73/79’er and they’ll pull a much longer bar than the av or oiler is realistically capable of handling. The muffler hurts them stock imo. They are still a go getter for an aging design, they were a little ahead of there time back then.

They port well. Most hp I've seen from the class other than the 1 hybrid. But they lack the tq of some of the other ported saws. 500i, 461 some of the hybrids. Even the 372 was close, maybe a bit more tq than the dolmar.

I was pretty surprised at those results. None of the "long" stroke saws really add tq.

 

[Sawrain]

I was pretty surprised at those results. None of the "long" stroke saws really add tq.

Some evidence of the stroke doesn’t dictate torque output conversation from the main dyno threads.

Port layout and general design will effect torque output more than Simple bore/stroke ratio for equal size two strokes, good volumetric efficiency makes good torque, long or short stroke.

If you are designing a high torque engine you most likely aren’t designing a lightweight high rpm unit, chances are it’s somewhat industrial, so service life, reliability and thermal efficiency are high on your list of needs.

Long stroke can help achieve these requirements, long stroke engines have lower surface area to volume ratios, so less heat lost to cylinder walls (good fuel efficiency) and Lower comparative big and little end bearing loads, good for bearing life or to allow reasonable bearing loads at lower rpms than short stroke units of comparable output.

High torque engines are often long stroke due to general design requirements that just often go hand in hand with each other, they aren’t high torque as a direct result of having a long stroke, it just so happens that if you want high and reliable torque output you will probably be long stroke, a bit of chicken or the egg.

 

[pavel408]

Please vote for the post with results ( https://opeforum.com/goto/post?id=1145577 on page 4) as a Best answer by clicking https://opeforum.com/posts/1145577/best-answer
Then this post will be readily visible on the thread first page.

 

[Woodpecker]

Please vote for the post with results ( https://opeforum.com/goto/post?id=1145577 on page 4) as a Best answer by clicking https://opeforum.com/posts/1145577/best-answer
Then this post will be readily visible on the thread first page.

No need to go to that extream. I'm sure when @Red97 gets time he'll post that info up in the dyno numbers only thread.