Calculating new shift points
Using my recent FI dyno plot I extracted rpm vs rwtq and multiplied them by the gear ratios:
RPM -- RWTQ ---- 1st ---- 2nd ----- 3rd ---- 4th ----- 5th
3000 -- 258.4 -- 638.2 -- 480.6 -- 379.8 -- 258.4 -- 193.8
3500 -- 262.0 -- 647.1 -- 487.3 -- 385.1 -- 262.0 -- 196.5
4000 -- 256.7 -- 634.0 -- 477.5 -- 377.3 -- 256.7 -- 192.5
4500 -- 247.2 -- 610.6 -- 459.8 -- 363.4 -- 247.2 -- 185.4
5000 -- 232.6 -- 574.5 -- 432.6 -- 341.9 -- 232.6 -- 174.5
5500 -- 213.9 -- 528.3 -- 397.9 -- 314.4 -- 213.9 -- 160.4
6000 -- 185.4 -- 457.9 -- 344.8 -- 272.5 -- 185.4 -- 139.1
1st speed 2.47:1
2nd speed 1.86:1 (2.47 * .75)
3rd speed 1.47:1
4th speed 1.00:1
5th speed 0.75:1
However, I realized that the previous gear multiplication method is invalid because the vehicle speed doesn't change during an upshift. The engine speed will only decrease according to the gear ratio separation.
For example, shifting from 1st at 5900 rpm results in a 2nd engine speed of 4480 rpm. Assuming that maximum acceleration occurs at maximum mechanical advantage (torque * gear ratio) then the shift should occur when the value in the lower gear drops below the value in the next gear. The optimum engine shift speed can be determined graphically using the gear ratio vs vehicle speed plots and the torque * gear ratio plots.
Interpreting the plots:
1A represents shifting 1st @ 4650 (599 product) which results in 2A (2nd @ 3500 and 488 product).
1B represents shifting 1st @ 5600 (513 product) which results in 2B (2nd @ 4200 and 470 product).
1C represents shifting 1st @ 5750 (492 product) which results in 2C (2nd @ 4370 and 463 product).
1D represents shifting 1st @ 5900 (471 product) which results in 2D (2nd @ 4480 and 460 product).
1E represents shifting 1st @ 6000 (459 product) which results in 2E (2nd @ 4500 and 459 product).
From the graph the optimum 1st to 2nd shift point is 6000 rpm because the product for 1st has decreased to the product for 2nd.
Interpreting the plots:
2A represents shifting 2nd @ 5600 (387 product) which results in 3A (3rd @ 4430 and 365 product).
2B represents shifting 2nd @ 5750 (372 product) which results in 3B (3rd @ 4550 and 361 product).
2C represents shifting 2nd @ 5900 (354 product) which results in 3C (3rd @ 4700 and 354 product).
From the graph the optimum 2nd to 3rd shift point is 5900 rpm because the product for 2nd has decreased to the product for 3rd.
Interpreting the plots:
3A represents shifting 3rd @ 6000 (272 product) which results in 4A (4th @ 4060 and 257 product).
3B represents shifting 3rd @ 6200 (253 product) which results in 4B (4th @ 4240 and 252 product).
From the graph the optimum 3rd to 4th shift point is greater than 6200 rpm because the product for 3rd has not decreased to the product for 4th. This is due to the wide spacing between 3rd and 4th. However, the rev limiter is set to 6250 and the engine may rev at least 50 rpm during the upshift. I prefer to set the shift point at 6200 rpm instead of raising the rev limiter.
Interpreting the plots:
4A represents shifting 4th @ 5750 (199 product) which results in 5A (5th @ 4280 and 188 product).
4B represents shifting 4th @ 6000 (186 product) which results in 5B (5th @ 4470 and 187 product).
From the graph the optimum 4th to 5th shift point is 6000 rpm because the product for 4th has decreased to less than the product for 5th.
With my current axle ratio (3.73:1) I don't anticipate ever experiencing a WOT 4th to 5th shift (even on the dyno) since the vehicle speed would be 137 mph and my tires are only rated for 118 mph.
Comparing the stock values to my torque multiplication method:
------- Upshift ------------- Stock -- Revised
Trans WOT Shift RPM 12 -- 5500 ---- 6000
Trans WOT Shift RPM 23 -- 5500 ---- 5900
Trans WOT Shift RPM 34 -- 5800 ---- 6200
Trans WOT Shift RPM 45 -- 5800 ---- 6000
Comparing the NA baseline dyno plot to the initial FI dyno plot illustrates that the FI torque decreases with rpm at a lower rate (smaller slope) than the NA torque.
I think that supports an advantage to delayed upshifts which adds some credibility to my torque multiplication method. It will be interesting to compare different FI shift points on the dyno in time to speed tests.