Quote:
Originally Posted by THE EVIL TW1N
Post your dyno sheets then, show me these lower gear run's that you've done.
you don't know how most dyno's even work. 
dyno's DO NOT read tq and factor in HP. it's the opposite. Otherwise a car with better rear end gears would always dyno higher. and that is not the case. If you leave off the ignition source to read RPM, the dyno will still pick up what the HP is, it just can't calculate tq, and will print out an HP graph based on speed (MPH).
another example is if a car reads 300 rwtq on a 1:1 ratio, then if the dyno really did go off of rwtq, a gear ratio of 1.4:1 would read 420 rwtq. I don't see any dyno graphs being anywhere near that off. Do you? if so, please post.
4th gear or whatever 1:1 is is generally used because it has the least parasitic losses (higher rwhp) and it also gets the best reading. |
I'll get them scanned in...
but in third gear, my car dynos just over 276rwhp, in fourth, it's 269. Almost a 10hp gain, by shifting down. On a different dyno, it did 263rwhp in 3rd, 245rwhp in 4th, almost 20rwhp difference. Torque numbers were closer, at about 5lb-fts difference.
My understanding of the dyno is just the way I explained it. That even if the rpm reading is missed, the computer still can't truly measure horsepower, but rather does calculations based on drum speed and gives a horsepower reading. Maybe I'm wrong on how it works, but in my experience, I'm not wrong in the end result.
Of course, to go along with that, it's my understanding horsepower can't truly be measured. Torque can. Horsepower is a mathmatical number derived from torque. Gimme a few minutes, I'll go see if I'm wrong. Or you can post up something that says so, other then just you words.