Chad whipped the 4Runner into a total of five acceleration runs. The first three runs were with the transmission in "Drive" (overdrive allowed) with both straight and brake-torqued launches, while the latter two were with the tranny in the overdrive-disabled position. The overdrive runs ran an identical 15.8 seconds @ 87mph, while the non-overdrive dropped to 15.6 seconds at 89mph! The 4Runner was dead-nuts stable and would click off identical runs one after another, largely since its weight and traction meant launches were a simple affair of plastering the accelerator down and waiting 16 seconds.
With a girth of over two tons, even the 270bhp V-8 in the 4Runner was only able to post a 0-60mph time of 7.6 seconds. However, that is fast enough to beat out four of our previous G-Tech testers, including Eric's Saab 9-5 Turbo! Sorry, Eric...
Of the runs from today, the best run yielded a measured (uncorrected) 197bhp @ 5000rpm and 232lb-ft of torque @ 4100rpm . Using the brand-spanking-new v1.2 of my correction spreadsheet, that roughly calculates out to 260-267bhp and 312lb-ft torque at the crank. Not bad, since it's rated at 270bhp @ 5400rpm and 320lb-ft torque @ 3400rpm! This is using my new methods of calculating driveline losses, including a different loss figure for an AWD driveline. The above figure is with the spreadsheet set to AWD, since Chad's 4Runner will only run in AWD mode.
Again, since Chad's transmission didn't have a manumatic mode we couldn't truly to a dyno-style power graph, so his torque figure is probably slightly off since the acceleration run restricts the RPMs tested. Also, you can see some roughness in the RPM graph. When the G-Tech was plugged into the power plug in the 4Runner it was unable to use its automatic RPM detection, so it went to the new fallback modes and we selected one of its secondary profiles. This is a nice improvement because in the previous firmware rev it probably would have failed to display RPMs reliably at all, but overall it did a nice job of catching them.
Well, this won't take a long time! Since the 4Runner is rather heavy and has very good traction (it always is in AWD mode), there wasn't much we could do. Brake-torquing and normal launches proved identical in results, so we gave up on the former and just had Chad mash the pedal.
Our next changes were in the transmission department. Since his transmission doesn't allow any direct manumatic mode we couldn't really control the RPMs the tranny shifted from one gear to the next. However, Chad dropped it into the "no overdrive" notch and just that change alone reliably dropped his quarter mile by 0.2 seconds, and increased his trap speed by 1 mph! Yeah! I get strange feelings of satisfaction in these moments...
Taking apart the G-Tech data to see the why of it is a bit more difficult. Looking at the acceleration (Gs) and RPMs recorded over the whole run show no real visible difference. However, when dissecting the shiftpoints in first, second, and third gear show minute differences in RPM levels in the non-overdrive setting. The 4Runner essentially shifts between 50-100 RPM later, and a close analysis of the 1st-to-2nd shift shows that the shift is marginally faster overall, and the clutch re-engagement happens just a bit quicker. Even so, a two-tenth difference in ET and 1mph higher trap speed is an impressive result given such modest changes!
Corrections and Other Factors:
As I mentioned before, I have a brand-new (v1.2) spreadsheet which includes a lot of changes to the power calculation, but relatively no changes to the correction factors for atmospheric and aerodynamic factors. Chad's correction spreadsheet gives the following results in original and corrected form:
|Recorded Data||Corrected Data|
|Best Run||0-1/4 mile in 15.6 secs @ 89mph||0-1/4 mile in 15.4 secs @ 90mph|