Branson 4815C PTO Dynamometer Test Results

[desertdog71]

looks good.

 

[Slowpoke Slim]

Very cool. Thanks for the update. I look forward to seeing your new dyno numbers.

 

[K5lwq]

I am very curious as well. It might be fun to post the question in Owning/Operating and see if any guesses are close. This all started with a thread I read and the guys were debating emissions control robbing HP. Everything was speculation or seat of the pants comparison. This should give a more accurate comparison.

The weather conditions today are very similar to the day of first test. So I don't think it will skew the results much at all.

 

[LouNY]

I will be surprised if it shows much different, I would have expected that the DOC/DPF wasn't very restricted as you are low houred.
With more hours it might show more improvement.
So I'll say maybe 3 hp more with no pumpadjustments.
I would be tempted to get my dealer involved and have him tune it up a bit to get closer to advertised.
I would possibly even forget to mention I was running a different exhaust.
Good Luck

 

[ptsg]

I will be surprised if it shows much different, I would have expected that the DOC/DPF wasn't very restricted as you are low houred.
With more hours it might show more improvement.

Good Luck

My thoughts exactly. As the DOC gets plugged over time, I can see how it will restrict the exhaust gases and reduce the HP.

 

[K5lwq]

Well unofficial results are in!

Today the tractor held 36HP at the PTO. That is a 1HP gain.

Now is where the unofficial comes in and I will defer to those more knowledgeable than me to explain.

Torque hit 438 ft lbs at the high and was consistently between 415 and 420. I verified unit of measure to be ft lbs. From the previous test I never saw anything close to 400. It was around the 345 ft lbs range. By doing math that would equal a 7HP gain. If you figure on 415 ft lbs that would put the PTO HP around 42HP.

How can the dyno read such a high torque value and not equate to HP?

One other test I did was road the tractor up the small hill on my street in high 4th. Before the mod it struggled to maintain 2000RPM climbing the small incline. Today it held 2800RPM. A noticeable difference for what that is worth.

Any thoughts?

 

[LouNY]

Your power torque curve may be coming in sooner,
so lower rpm more torque same hp.
But that additional torque is carrying you up the hill easier and allowing you to pull more rpm.

 

[ruffdog]

Being that most implements are run at 540 PTO RPM, what were the torque/hp numbers at that speed?

 

[K5lwq]

At 540 it was 35 and 345 before mod and 36 and 415 after. As it was brought below 540 torque increased all the way to 438 at 500 rpms and then it would start to fall.

 

[ericm979]

I wonder if the injection timing was changed when the DOC+DPF was added to better suit it. If so there might be gains to be had from changing the timing.

 

[K5lwq]

Either way I am happy with the mod. After the 50 hour service I probably will take it to another place that can provide the printed graph and results. If it still is low, I will contact dealer and Branson on adjusting the fuel to bring it within specs.

It has plenty of power for what I do but it should at least produce advertised power.

 

[K5lwq]

Your power torque curve may be coming in sooner,
so lower rpm more torque same hp.
But that additional torque is carrying you up the hill easier and allowing you to pull more rpm.

The more I think about this post the more I think it is correct. It would also explain the perceived increase mentioned by others. I still don't understand how the computer on that dyno could show that different of torque values with relatively no change in HP or RPM. I guess what I understood about how the dyno works is incorrect.

Even if you use the high torque number of 438 at 500 rpm it calculates to a little over 41HP. Again very close to advertised output.

 

[ptsg]

Around 42 HP is what I would expect out of a 48HP tractor. But it's a new tractor, still breaking in and the dyno might not be that accurate.

Here is a dyno run of a 4520, same engine as yours I believe, with close to 700 hours and dirty radiator screen, putting out 43HP.

Branson Compact Tractor Owners Group Public Group | Facebook

 

[K5lwq]

Around 42 HP is what I would expect out of a 48HP tractor. But it's a new tractor, still breaking in and the dyno might not be that accurate.

Here is a dyno run of a 4520, same engine as yours I believe, with close to 700 hours and dirty radiator screen, putting out 43HP.

Branson Compact Tractor Owners Group Public Group | Facebook

I would agree. Something very strange with the dyno. If you use the torque values it is more in line with what I was expecting. But who knows if any information from it was correct.

 

[ruffdog]

From what it sounds like, any data from this dyno is questionable. Even high-end dynos the experts use will vary one from another.

 

[K5lwq]

From what it sounds like, any data from this dyno is questionable. Even high-end dynos the experts use will vary one from another.

I agree. The only way to know is duplicate the test on another dyno that can give us the printout. At least then we can see the curves and might understand the change, if any. So maybe we can do that. I need to remove the muffler to paint it. I guess I could put filter back on and try again.

 

[Slowpoke Slim]

Just wanted to say "thank you" for all your efforts "For Science".

 

[Branson Bob]

I agree. The only way to know is duplicate the test on another dyno that can give us the printout. At least then we can see the curves and might understand the change, if any. So maybe we can do that. I need to remove the muffler to paint it. I guess I could put filter back on and try again.

Thanks for sharing all of this with us.