Carpenter dyno # question

Jvheli

Nitrous
Joined
Apr 12, 2016
Messages
1,100
Location
Milwaukee, Wisconsin
Ride
2016 Rocket Roadster
I've been daydreaming about having Carpenter work over my engine after my warranty is up. However, reviewing their dyno numbers leaves me confused: what's confusing is the hp/tq in every dyno sheet I have and the ones I've seen cross at 5250 rpm. So what gives???
 
Hi Jvheli,

The formula for HP is Torque times rpm divided by 5252. The lines will always cross at 5252 because of the formula.

You may as, "Why 5252, why not some other number?" 5252 is determined by the definition of HP (James Watt said 550 ft-lb of work per second equals one horsepower in the 1750's) and a series of Algebraic steps using formulas from a Physics book. If you would like a full explanation, I can provide that.

Later,
Jerry C
 
I'm aware of the formula, I just don't understand Carpenters numbers...or in other words how can you compare one dyno sheet to another unless the same standard applies. Their claimed 240hp is leaving me wonder what it would be SAE .
 

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The 5250 crossover is not obvious when hp & torque values are at different rates on either side of chart.
 
Jvheli said:
The 5250 rpm cross hp/tq will be obvious IF the formula I posted is used.
Click to expand...
But if you are looking at the 240 hp dyno sheet Carpenter has posted on there website, the tq numbers on the one side is not lined up with the hp numbers on the other. If you look where 5250 on each is they do match. It's just not printed like a typical dyno sheet
 
I think what I'm looking at (on Carpenters site) is a before and after HP COMPARISON.
 
Jvheli said:
I think what I'm looking at (on Carpenters site) is a before and after HP COMPARISON.
Click to expand...
Notice the hp numbers on the left, and the tq numbers on the right don't line up. But if you look at 5252 they are both just above 185.
 
I think I would find a better view of the equation then what you posted. Who ever started to break that equation do substitude something else a a unknown. May he did not have the internet qhere he could look it up. At either rate you can find better ones out there that show you how to transpose a algebraic equation wich might help you and others. And yes the early carp graph did not have it overlaid. And really does not need to be unless you want to save paper. Now back to the beer oops I mean union break
 
Like this? Ive spent a truckload of cash tuning stuff on a dyno.....just want to fully understand how the Carpenter kit will perform oranges to oranges so to speak.
 

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