Torque ratings - I'm bored

[BlackCatBone]

I'm bored too....

For those interested:

We all have seen the equation P=T x rotational speed (not rpm!!!)

To work with this equation you must:
1. Convert HP to ft-lb/s by multiplying by 550 (1 HP=550 ft-lb/s)
2. Convert rpm to radians/s by multiplying by 2pi and dividing by 60
3. Made sure your torque value is in ft-lbs

....and for those who are really bored

That weird 5252 number we always see:
=(550 x 60)/ 2pi

 

[chrispy6822]

It may very well do just that, if the 4 cylinder one is a Turbo.....

True but then again we get into the power band issue and how flat the curve. Even more so with the inherit narrow powerband of the turbo. But in general speak a max 200hp V8 has a lot flatter curve.

That is of course unless you get into German cars where the small motors are engineered for better torque then HP ratings. Germans love high torque and low HP for some strange reason. LOL

 

[BlackCatBone]

That is a pretty common one, but wrong imo - as many saws have useful power way above the max hp rpms, while others fall off pretty fast above that rpm number.

To judge what performance to expect, we really need the complete curves, not only the peak numbers - and then a lot of other factors enter the picture as well - so it really is a lost case..........

Precisely Troll. We would need to look at area under the curves to really see who is the paper champ

 

[chrispy6822]

I can believe that - and as for the outrunning of a 4cyl, I guess it depends on how quick revving and light the car was, but I'd put money on the V8...
Just so long as it was light and unlayden.

Correct weight being a major deciding factor. But that is usually a non-issue with the extra drag these kids put on their 4cyl front wheel drive cars with the 3 decker rear wing. Well that and the 40lb 5" chrome exhaust tip.

 

[harrygrey382]

Correct weight being a major deciding factor. But that is usually a non-issue with the extra drag these kids put on their 4cyl front wheel drive cars with the 3 decker rear wing. Well that and the 40lb 5" chrome exhaust tip.

yeah - and it's worse in europe. Thing that makes me feel all warm inside is that those motors will be shot by 50 000...

 

[Dibbs]

saw hp/rev lb-ft(Nm)/rev

041av 3.7/7500 5.2(3.8)/5000
051av 5.8/7000 8.0(5.9)/5000
075/076 7/7000 9.2(6.8)/5000

Your lb-ft and Nm seem to be back to front.

saw hp/rev lb-ft(Nm)/rev

041av 3.7/7500 3.8(5.2)/5000
051av 5.8/7000 5.9(8.0)/5000
075/076 7/7000 6.8(9.2)/5000
070/090G 6.5/7000 5.7(7.7)/5000 (The 090G will double the torque with the gears)
090 8.5/7000 7.0(9.5)/5000

 

[harrygrey382]

Your lb-ft and Nm seem to be back to front.

saw hp/rev lb-ft(Nm)/rev

041av 3.7/7500 3.8(5.2)/5000
051av 5.8/7000 5.9(8.0)/5000
075/076 7/7000 6.8(9.2)/5000
070/090G 6.5/7000 5.7(7.7)/5000 (The 090G will double the torque with the gears)
090 8.5/7000 7.0(9.5)/5000

yes, back to front they were - holy cr4p, the 070 has SHEDLOADS of torque - it wipes the floor with the 076, and is 0.1Nm less than the 088... You didn't do a typo did you? I might have to find me an 070!

edit: ah - i see the confusion, you didn't swap them, you converted! how about this:
041av 3.7/7500 2.8(3.8)/5000
051av 5.8/7000 4.4(5.9)/5000
075/076 7/7000 5(6.8)/5000
070/090G 6.5/7000 4.2(5.7)/5000 (The 090G will double the torque with the gears)
090 8.5/7000 5.2(7.0)/5000[/QUOTE]

which, hang on, still isn't right - surely the 090 is higher than the 088, and the 070 higher than the 660...

 

[harrygrey382]

ok, in case any of you are as sad as me - here's a rough chart. Stihl are orange and grey (suprise!), husky red, dolmar blue. trinagles torque, squares HP

I only put the 3**xp huskies on cos I don't know much about them (put the 262xp on there, 5hit - it's pretty hot), dolmaer 7900 and 6400 made it on - you'll find them per cc.

Unfortunately I couldn't find specs on the 3120 or 395xp (only 394xp - differences?)

 

[SawTroll]

Good job!

....but no surprises.....

 

[harrygrey382]

Good job!

....but no surprises.....

yeah - no suprises, certainly not for you I'm sure! Actually I was slightly suprised how close they look like that - and the old ones don't do too bad, and there's the odd good one (7900, 262xp, 361). I'll keep working at it, any other resources for torque you know of? I want the 3120 up there, and can someone double check the 070 and 090 figures, they seem low...

 

[Dibbs]

yes, back to front they were - holy cr4p, the 070 has SHEDLOADS of torque - it wipes the floor with the 076, and is 0.1Nm less than the 088... You didn't do a typo did you? I might have to find me an 070!

edit: ah - i see the confusion, you didn't swap them, you converted! how about this:
041av 3.7/7500 2.8(3.8)/5000
051av 5.8/7000 4.4(5.9)/5000
075/076 7/7000 5(6.8)/5000
070/090G 6.5/7000 4.2(5.7)/5000 (The 090G will double the torque with the gears)
090 8.5/7000 5.2(7.0)/5000

which, hang on, still isn't right - surely the 090 is higher than the 088, and the 070 higher than the 660...

I think these are the correct figures:-
Saw_______hp/rev_____________lb-ft(Nm)/rev

041av_____3.7/7500____________3.8(5.2)/5000
051av_____5.8/7000____________5.9(8.0)/5000
075/076___7.0/7000____________6.8(9.2)/5000
070/090G__6.5/7000____________5.7(7.7)/5000 (The 090G will double the torque with the gears)
090_______8.5/7000____________7.0(9.5)/5000

070, 090 Workshop Manual section:-

The 051AV and the 070 are roughly the same while the 075/076 and the 090 are roughly the same.
With the omission of the 056 it seems the 1960s saws were directly comparable to the 1970s ones at the large end of the scale.
I wonder if the 056 and the 066 are comparable?

 

[Dibbs]

Scrap that last post. New info is coming to light here!

 

[Dibbs]

What I know for sure:-
Saw_______hp/rev_____________lb-ft(Nm)/rev

041av_____3.7/7500____________2.8(3.8)/5000
070/090G__6.5/7000____________5.7(7.7)/5000 (The 090G will double the torque with the gears)
090_______8.5/7000____________7.0(9.5)/5000

070, 090 Workshop Manual section:-

041 Workshop Manual section:-

 

[harrygrey382]

I think these are the correct figures:-
Saw_______hp/rev_____________lb-ft(Nm)/rev

041av_____3.7/7500____________3.8(5.2)/5000
051av_____5.8/7000____________5.9(8.0)/5000
075/076___7.0/7000____________6.8(9.2)/5000
070/090G__6.5/7000____________5.7(7.7)/5000 (The 090G will double the torque with the gears)
090_______8.5/7000____________7.0(9.5)/5000

070, 090 Workshop Manual section:-

The 051AV and the 070 are roughly the same while the 075/076 and the 090 are roughly the same.
With the omission of the 056 it seems the 1960s saws were directly comparable to the 1970s ones at the large end of the scale.
I wonder if the 056 and the 066 are comparable?

according to the workshop manual (and I've triple checked this)
the 076 has 6.8Nms(5lb-ft), the 051 5.9Nm(4.4lb-ft)
according to the test reports (reference links) the 088 has 7.8Nm(5.8lb-ft)...
so this means actually the 070 is comparable to the 088, wipes out the 076 and the 090 leaves them all way behind, in torque anyway, hp is different. I'm having problems believing this - the 090 maybe but the 070???

See the graph it's updated with this:

 

[harrygrey382]

I don't understand - unless it's a misprint the 070 is a super torque machine, why is it so much better than the 076 and so close to the 088. Is something amiss here, is my manual wrong? I might get rid of my 076 and get an 070 for milling!

 

[Dibbs]

I'm not up on the world of mechanics but the 075/076 has a larger stroke than the 070 and a similar diameter piston, so, it should have more torque........ unless the exhaust port on the 070 is further down the cylinder, allowing the "power" to be on the piston for a longer period of time along the rotation of the crankshaft inducing a larger torque even though the 070 has less cc than the 075/076.

 

[Dibbs]

Update:-
Saw_______hp/rev_____________lb-ft(Nm)/rev

041av_____3.7/7500____________2.8(3.8)/5000
051av_____5.8/7000____________4.4(5.9)/5000
075/076___7.0/7000____________5.0(6.8)/5000
070/090G__6.5/7000____________5.7(7.7)/5000 (The 090G will double the torque with the gears)
090_______8.5/7000____________7.0(9.5)/5000
088_______8.7/????_____________5.8(7.8)/????

 

[NPKenny]

In the areas with multiple Stihls in a particular CC range, which is which? I am looking at the 60cc's specifically.

The way I read the chart, it would show the 361 to have more torque than the 036, but less hp. Unless, of course, you tricked us and started dabbling in homeowner specs.

I guess what I am saying is, which saws did you use in addition to the ones listed.

 

[harrygrey382]

I'm not up on the world of mechanics but the 075/076 has a larger stroke than the 070 and a similar diameter piston, so, it should have more torque........ unless the exhaust port on the 070 is further down the cylinder, allowing the "power" to be on the piston for a longer period of time along the rotation of the crankshaft inducing a larger torque even though the 070 has less cc than the 075/076.

yes, it should, but it doesn't - by a HUGE margin, and i'm not convinced it's right...

Update:-
Saw_______hp/rev_____________lb-ft(Nm)/rev

041av_____3.7/7500____________2.8(3.8)/5000
051av_____5.8/7000____________4.4(5.9)/5000
075/076___7.0/7000____________5.0(6.8)/5000
070/090G__6.5/7000____________5.7(7.7)/5000 (The 090G will double the torque with the gears)
090_______8.5/7000____________7.0(9.5)/5000
088_______8.7/????_____________5.8(7.8)/????

088_______8.7/8500_____________5.8(7.8)/6750

In the areas with multiple Stihls in a particular CC range, which is which? I am looking at the 60cc's specifically.

The way I read the chart, it would show the 361 to have more torque than the 036, but less hp. Unless, of course, you tricked us and started dabbling in homeowner specs.

I guess what I am saying is, which saws did you use in addition to the ones listed.

yeah, the 60cc range is cluttered, I'll label it tomorrow... 361 is 59cc - more power than 360, but less torque (don't compare hp to torque, they're different units compare it with the the other torque or hp figures). I'll list the others soon, the only non-pro saw I listed was the MS280, but I did list the MS341 (you don't get that right?)...

 

[NPKenny]

I understand the comparisons, even if my post didn't show it. I'll wait for the labels.