Why Horsepower Does Not Matter

http://honda-tech.com/zerothread?id=2285023

Ok people, I was asked by someone on another forum to make a thread about this topic. I think I have done this before but oh well. More search material.

First of all, a dynamometer's primary use is a tuning tool for tuners to view the GRAPH and see what changes are seen on the GRAPH when there are changes made to fuel, ignition, cam gear settings..etc. Another is its use as a tool for someone to test parts to see where a certain part gained power to a prior setup and what changes need to be made to net the graph that is needed for a particular setup. These tests need to be done on the same dyno for the most consistent results.

Also, you can use the dyno to determine shift points at the drag so you land (in the next gear) in a portion of your chart that gives you the most momentum. Momentum is what keeps a car going. If you land in an area of low torque, your acceleration drops and your ET's suffer.

It's purpose is not there, like many think, for someone to go and see what kind of numbers the engine puts out and cry about the numberical output because they are "low". If you are worried about the output, do a compression or leakdown test. Preferably leakdown because in my opinion it is a more accurate. If those tests come out good, then check your cam timing and maintenance items. Then do research on the parts you have on your car and determine if they are what is keeping the motor from making power.

There is much more to understanding a graph than looking at the peak output. IE: peak rpm power, peak rpm torque, vtec crossover, how long the torque plateau's, where the torque drops off. Here is a good article by Jeff Evans on why Horsepower does not matter: http://www.evans-tuning.com/techarticle_horsepower.html

This is a little comparison to show how dyno's read differently:

first, this is a dyno of my stock h22a with bolt ons and tuning on the local dynojet in tallahassee

second, this is an older dyno with the same mods and same tuning software. Also on a dyno, but this is on the velocity trends dynojet in jacksonville

If i remember correctly, these dyno's were done in similar climate conditions as well and we even converted the lower graph (STD) to SAE and the differences were negligible. 2whp difference IIRC. The graphs are roughly the same however there is a 11whp and 11ft lbs discrepancy between them.

so what does this all boil down to and why am I blabbering on about nonsense that most will likely still disregard?

answer: dyno's do not accurately display how "fast" or powerful a motor is. One engine that makes 180whp/150ftlbs on one dyno could get wooped by the same engine that makes the same power on a different dyno. This is why the most accurate way of displaying how "fast" a car is to go to the drag strip and see what you trap, the MPH. The numbers dont tell you anything other than what the dyno reads. The number the dyno gives you do not describe your car as slow and it does not describe your car as fast until you go to the drag strip and prove it.

Go to the dyno, go to the track. Compare. No more crying. Go drink a beer.