Any Guesses to HP Loss With Emission Control?

[K5lwq]

I thought this might be interesting to see what others think.

Tractor is a Branson 4815C with a claimed 48HP engine and 40HP at the PTO.

I had it put on a PTO dyno and it was producing 35HP at PTO.

I replaced DPF with a turbopack style performance muffler. Today I am having it tested again.

Any Guesses on the HP change?

 

[CobyRupert]

What do we win if we guess right?

36.8hp

 

[Stan B]

I replaced DPF with a turbopack style performance muffler.

Hold up. How'd you do that without the computer throwing a code?

 

[K5lwq]

Coby, lunch on me next time I see you!

Stan, Branson does not have a computer. It uses a data logger that you simply unplug.

 

[Thunder chicken]

if it sounds louder, it ought to have at least 5 more hp and go 10mph faster!..... at least that's what the local kids think on their snow mobiles.

on a side note, i removes all the emissions (dpf and egr) from my VW tdi, with a computer retune have +40hp, +80ft/lbs torque, 10-15% better fuel mileage and am doing 20,000km oil changes vs 15,000 as the oil stays cleaner without that pesky EGR.
i think you're lucky to have that passive DPF on the branson rather than an afterburner like a lot of other vehicles. you can take yours apart and clean it too if you ever need to.

 

[CobyRupert]

if it sounds louder, it ought to have at least 5 more hp and go 10mph faster!..... at least that's what the local kids think on their snow mobiles.

...but did he put a Flowmaster or Magnaflow (or whoever made muffler) sticker on the tractor? It's a well known fact in car & truck modifications that "Each sticker adds 5 hp, so you do the math"

 

[K5lwq]

The answer is 1HP gain. But there is more to the story as torque increased by 70 ft lbs. That makes zero sense to me. But that is the results from the dyno tests.

 

[RickB]

Well if the observed hp increased that was caused by either an increase in torque or shaft speed, or both.

 

[jaydee325]

Unless the tractor was dyno'd before and after mod, the results are meaningless. Original torque values were not provided in the original post, only HP values. We have no way of knowing how much torque changed.

A 1 HP change is within the margin of error. You could dyno it again on a different day with different atmospheric conditions and have less HP.

 

[RickB]

Unless the tractor was dyno'd before and after mod, the results are meaningless. Original torque values were not provided in the original post, only HP values. We have no way of knowing how much torque changed.

A 1 HP change is within the margin of error. You could dyno it again on a different day with different atmospheric conditions and have less HP.

And if the shaft speed isn’t monitored and exactly the same when the hp value is recorded, all bets are off. We know nothing about the dynamometer’s capabilities. There are a lot of dynos at dealerships with a 4” analog gauge for output and a smaller gauge for shaft speed.