Branson 4815C PTO Dynamometer Test Results

[K5lwq]

It would be beneficial to know when the dyno was last calibrated, and what the results were. I worked at a repair shop once, and the dyno was used mainly to test tractor engines under load. The HP readings were not accurate for sure!

I have no idea about when or if it was calibrated. They said they mainly used it to load the tractors as you mentioned so I doubt they calibrate it at all. What I don't know is if it is off, how much could it be? I would think it would be +-2hp or so.?

 

[K5lwq]

Is your 4815 engine a turbo triple or non turbo four? Bransons' web site says it's a triple but the bore, stroke and displacement listed match that of the 4520 which is a four. When I was shopping Bransons they'd just come out with a high HP model of the 15 series (can't remember if it was the 4815 or another one) which had a turbo triple. Of course that was three years ago and they might have changed.

It is a four cylinder non turbo. If you can trust the specs the bore and stroke is the same as 3 cylinder model but displacement higher.

 

[LouNY]

Most of the old pto water bank dynos were +-10%,
they were good for tuning as you were just looking for the change not an exact value.

 

[K5lwq]

Lou, you are correct. I am more interested in the change over a exact value. However, I was hoping to get a decent number for rating as Branson list the same PTO hp for HST and geared tractors. I find that hard to believe.

So if it is +-10%, that would put it around 39hp if it is reading on the low side. Wonder what the HST model would be?

Another thought could be the rating was done on a non DPF model and once the conversion is complete, it will be more in line with the claims.

 

[LouNY]

I would expect the pto hp to be the same as it is a straight thru drive from the engine to the pto clutches.
The transmission HP changes would be on something like the Nebraska test or on a wheel dyno such as a car or truck would show.

 

[K5lwq]

Maybe so Lou. I may have understood incorrectly. :confused3:

 

[sd455dan]

I am not sure about the calibration. Also would be interesting to know what the variances from one dyno to the next. I would think they would be close but not exact.

Torque was difficult to read as it changed more rapidly than the hp did. This is because hp is a calculation of the torque measurement. Hp= (torque x rpm)/5252

The dyno showed hp in whole numbers which is why it was easier to watch. But the torque was in the 345 ft lb range so that would make it around 35.47 hp.

Sorry, The torque # of 345 lb ft. just can't be right- that is more than double most tractors rated at around 50 HP


using a 50 hp tractor as an example -even one that will produce more torque because it is rated at max power at a lower RPM say 2000 RPM the math shows


2000 rpm X 150 lb ft = 300000 divided by 5252 = 57 HP


or using Branson's HP Max rating @ 2600 RPM

35.47 X 5252 = 186,288

186288 divided by rated HP RPM of 2600 = ~ 71.65 lb ft

Obviously that is not the Bransons engines peak torque #- it should take place at a lower RPM and definitely will be higher but not over 250 lb ft higher.


Not trying to start an anything , but 345 lb ft just can't be right.

 

[LouNY]

Sorry, The torque # of 345 lb ft. just can't be right- that is more than double most tractors rated at around 50 HP


using a 50 hp tractor as an example -even one that will produce more torque because it is rated at max power at a lower RPM say 2000 RPM the math shows


2000 rpm X 150 lb ft = 300000 divided by 5252 = 57 HP


or using Branson's HP Max rating @ 2600 RPM

35.47 X 5252 = 186,288

186288 divided by rated HP RPM of 2600 = ~ 71.65 lb ft

Obviously that is not the Bransons engines peak torque #- it should take place at a lower RPM and definitely will be higher but not over 250 lb ft higher.


Not trying to start an anything , but 345 lb ft just can't be right.

Most pto dynos are indicating pto torque to get to your engine torque divide that number by the engine rpm to the pto rpm,
that is going to be around 4.6 to 4.8.
So 345 (pto torque)divided by 4.8 (pto rpm/engine rpm)=71.8 engine torque.

 

[sd455dan]

Most pto dynos are indicating pto torque to get to your engine torque divide that number by the engine rpm to the pto rpm,
that is going to be around 4.6 to 4.8.
So 345 (pto torque)divided by 4.8 (pto rpm/engine rpm)=71.8 engine torque.

AHH, that clears it up.

Now that I think about it, any tractors that run 1000 RPM PTO's would need to be converted to.


My mistake, Sorry about that K5lwq and Great info- thanks Lou

Oh and Congrat's on the New Branson K5lwq it is a Beauty

and when the time comes to purchase another tractor for our property Branson is at the top of my list.

 

[K5lwq]

Thanks Dan and no worries. Thanks Lou.

Once all of this is complete, I will take it somewhere that can print the test results. Maybe it will also be more accurate but who knows.