torque vs. speed graphs 2.0 vs. 2.2
Joined: Oct 2000
Posts: 1,921
Likes: 0
From: Lisbon
Great post Gregg.
Can I suggest you plot thrust in your y axis on the speed charts? Just divide your calculated wheel torque by the arm length (in ft), that is, the tyre rolling radius, and you get pounds.
We could compare it with the original chart that Honda published on their jdm site (although they actually plot useable thrust, that is, they subtract rolling and drag resistence).
And, please, update those charts when we get dyno runs from "consumer" cars.
Can I suggest you plot thrust in your y axis on the speed charts? Just divide your calculated wheel torque by the arm length (in ft), that is, the tyre rolling radius, and you get pounds.
We could compare it with the original chart that Honda published on their jdm site (although they actually plot useable thrust, that is, they subtract rolling and drag resistence).
And, please, update those charts when we get dyno runs from "consumer" cars.
Registered User
Joined: Feb 2001
Posts: 2,895
Likes: 1
From: You wish
Gregg,
You can get pretty close approximations for the rolling and aero drag either by measuring (AP22 or other tool) or by approximating until your simulation provides estimates close to real world results.
In the analysis (its coming I promise) we did, I went out and did the interval acceleration testing for both cars, then came back and ran the simulation. The absolute numbers in the sim were off by a couple tenths of a second for both cars (about 5% error), but the _differential_ between the two cars very close to what was predicted. The difference between the measured and calculated advantage for the 04 was under 0.05 seconds, which was less than the standard deviation in the measured data.
Now, we just need to see if other 04's make the same power as the one we tested.
UL
[QUOTE]Originally posted by Gregg Lee
You can get pretty close approximations for the rolling and aero drag either by measuring (AP22 or other tool) or by approximating until your simulation provides estimates close to real world results.
In the analysis (its coming I promise) we did, I went out and did the interval acceleration testing for both cars, then came back and ran the simulation. The absolute numbers in the sim were off by a couple tenths of a second for both cars (about 5% error), but the _differential_ between the two cars very close to what was predicted. The difference between the measured and calculated advantage for the 04 was under 0.05 seconds, which was less than the standard deviation in the measured data.
Now, we just need to see if other 04's make the same power as the one we tested.
UL
[QUOTE]Originally posted by Gregg Lee
Joined: Oct 2000
Posts: 1,921
Likes: 0
From: Lisbon
[QUOTE]Originally posted by Luis
...
Can I suggest you plot thrust in your y axis on the speed charts? Just divide your calculated wheel torque by the arm length (in ft), that is, the tyre rolling radius, and you get pounds.
...
Can I suggest you plot thrust in your y axis on the speed charts? Just divide your calculated wheel torque by the arm length (in ft), that is, the tyre rolling radius, and you get pounds.
Registered User
Joined: Jul 2003
Posts: 819
Likes: 0
From: Portland, OR
Wow, the new one drops out of Vtec on every shift. Thats Gotta really be ungratifying to drive. Every time I've shifted at 8000 instead of 9 on semi hard acceleration it's always met a frown to not find vtec on the shift. BOOO. Silly mistake by honda in my mind.
ron
Registered User
Joined: Feb 2001
Posts: 2,895
Likes: 1
From: You wish
Gregg, just to clear things up, I own the dyno that TOV uses. Additionally, TOV sells nothing to any end user (oh, well, you can buy a t-shirt if you like). No membership fees, nothing. Nor does TOV receive any funds from Honda/Acura. The only money changing hands is between advertisers and TOV. AFAIC, this is an independent dyno test, in fact we went so far as to change ECUs (w/o Honda's knowledge) to see if they gave us a ringer.
The dyno measures output at the wheel hubs. The wheels are removed and the dyno is bolted directly to the hubs. The gear ratio is inputted and power and absolute hub torque are measured. Then the lower torque number is calculated by dividing hub torque by the gear ratio.
I do a variety of product testing for a number of companies that pay good money for consistent, repeatable results and analysis. Chassis dynos are not particularly useful for deriving an absolute hp number for the engine, but they are exceptionally useful (when operated correctly) for measuring differences between various configurations, modifications, etc.
UL
The dyno measures output at the wheel hubs. The wheels are removed and the dyno is bolted directly to the hubs. The gear ratio is inputted and power and absolute hub torque are measured. Then the lower torque number is calculated by dividing hub torque by the gear ratio.
I do a variety of product testing for a number of companies that pay good money for consistent, repeatable results and analysis. Chassis dynos are not particularly useful for deriving an absolute hp number for the engine, but they are exceptionally useful (when operated correctly) for measuring differences between various configurations, modifications, etc.
UL