| Author | Message | ||
| Mark Moon (Enzomoon)
Junior Member Username: Enzomoon Post Number: 133 Registered: 4-2002 |
Mitch: I understand. I think you also must have known that I meant that it calculates rather than "measures" RWHP but I was not trying to be technical. I suggest you be careful who you label as "less educated". I did not post my question to be patronized or insulted or to be given a lecture in physics. I am quite sure that I have as much or more high level education than you do. If you want to teach physics fine but that was not the question I posed nor do I care about spliiting hairs with you over semantics. | ||
| Mitch Alsup (Mitch_alsup)
Member Username: Mitch_alsup Post Number: 831 Registered: 4-2002 |
Mark Moon: the less educated may actually think it measures the RWHP. By showing the the connection from what is measured to what is presented to the user, the reader becomes more educated. It, thereby, does not "obviously measure rear wheel HP" (rear wheel or otherwise), it measures acceleration, plain and simple. It computes RWHP from this and other measurements. Thereby HP is computed, not measured. The distinction is not material in a colloquial discussion, but is in a physics discussion. | ||
| Gary Reed (Gary_reed)
Junior Member Username: Gary_reed Post Number: 126 Registered: 2-2002 |
Willis, Yes, that is correct. The owner bought a set of used 456 Tubis for his car. They are pretty much the same as the 550's except for the longer tailpipe tips. GREAT SOUND!! | ||
| Mark Moon (Enzomoon)
Junior Member Username: Enzomoon Post Number: 132 Registered: 4-2002 |
Mitch: Was that dissertation designed to educate or just to demonstrate your mental acuity? I know full well how it works but the result is in essence what I said....it gives an approximation of RWHP. | ||
| Mitch Alsup (Mitch_alsup)
Member Username: Mitch_alsup Post Number: 828 Registered: 4-2002 |
"I have been playing around with a new GTECH PRO which obviously measure rear wheel HP." No, Gtech Pro measures acceleration. From acceleration and the weight of the car, it can compute thrust. From thrust over a 1/4 mile, it can compute the and gearing. Knowing thrust and gearing, it can them compute engine TQ and from there HP. But it measures acceleration. Driveline loss in a front engined manual transmission car is estimated to be 15%. But this number is only accurate to 2% or so, so the driveline loss could be as low as 13% or as high as 17%, and unless you also strap that engine to an engine dyno you really have no way of actually knowing to an accuracy better than 3% or so. In addition, driven wheel dynos make assumptions about the amount of rotating inertia in the driveline. These dynos are calibrated for typical american V8 applications. If the Ferrari drivline rotational inertia is different, additional inaccuracy creeps in. If you can get a driven wheel dyno graph for all 6 speeds, you can compare the 1st gear TQ curve to the 6th speed TQ curve and actually determine the rotational inertia of the driveline (including clutch, FW, and crankshaft.). | ||
| martin j weiner,M.D. (Mw575)
Intermediate Member Username: Mw575 Post Number: 1056 Registered: 5-2001 |
Mark, Approx 15% loss from flywheel to rear tires. | ||
| Willis Huang (Willis360)
Intermediate Member Username: Willis360 Post Number: 1372 Registered: 8-2001 |
HAHA! Yeah, almost exact words!  That 550 had, if I remember correctly, the 456 Tubi installed. The tail pipes were sticking way out. Sounded pretty good though. | ||
| Gary Reed (Gary_reed)
Junior Member Username: Gary_reed Post Number: 125 Registered: 2-2002 |
Willis, it's fun that you were typing almost the exact same words as I was, at the same time... | ||
| Rob Lay (Rob328gts)
Board Administrator Username: Rob328gts Post Number: 5452 Registered: 12-2000 |
Let, me guess, Gary and Willis were both there?  | ||
| Gary Reed (Gary_reed)
Junior Member Username: Gary_reed Post Number: 124 Registered: 2-2002 |
At our club's dyno day last March, a 1997 Euro 550 cranked out 409 horsepower at the rear tires. | ||
| Willis Huang (Willis360)
Intermediate Member Username: Willis360 Post Number: 1370 Registered: 8-2001 |
Back in March, we had a Dyno session. A 1997 Euro 550 with a Tubi did 409. | ||
| Mark Moon (Enzomoon)
Junior Member Username: Enzomoon Post Number: 131 Registered: 4-2002 |
I have been playing around with a new GTECH PRO which obviously measure rear wheel HP. Does anyone have numbers from a Dyno test on the 550? Also, what is thought to be the percentage driveline loss from the flywheel to the rear wheels? I saw 400 hp on the gtech with a smooth launch. Thanks for any input. |