[LoveLearn]

When Toyota first released their then-new Matrix, they called it a "Corolla Matrix," later dropping the Corolla prefix. But the platform and mechanics are clearly Corolla derived as was true of Pontiac's Vibe. Transmissions then offered were 5-speed manual, 6-speed manual but only with the higher-output Yamaha-developed 1.8 liter version which had wider bore, shorter stroke, larger valves, higher compression and other changes which slightly compromised low rpm torque compared to the standard 1.8 liter up to 6,000 rpm, beyond which power boost from valve timing kicks in. Also, on the standard 1.8 liter 130hp rated engine was offered Toyota's A246E 4-speed automatic, which was configured with a very slightly taller top gear cruising throughput ratio than the 5-speed manual. All that background context just describes standard stock configurations.

Some EcoMod discussion participants have talked about alternative strategies to obtain a "taller" (numerically lower) final drive throughput ratio. One strategy was to install a trans from an Echo which has a slightly taller top gear throughput ratio. Another strategy was to swap some gears between the layshaft and the input or output shaft to generate the reciprocal of the original ratio for considerable expense. Interesting but unlikely to fit most modestly funded budgets.

Before I provide my suggestion for consideration, let's briefly consider the stock 1.8 1ZZ-FE engine's torque near 2,000 rpm. According to two published curves, this engine appears able to deliver up to about 38 hp at 2,000 rpm, which is well over double what's required to sustain 65 mph cruising speed. That may not leave much reserve for passing and hill climbing, but that small power-reserve seems a small price to pay for dropping down into a lower engine friction region.

Also, I polled about 50 posts from various web sites claiming to report cruising rpm at various speeds, then converted all those into standard mph/1000-rpm measurement which Road & Track and other periodicals used in hundreds of road tests over many decades. I got a wide scattering of reported values, which I found to be humorous since that value is fixed for any vehicle after it is fully locked up in its highest cruising ratio. Some fellows reported wildly-varying ratios for the same vehicle in the same post, which I found funny. Anyway, I suggest that owners of these vehicles simply set their indicated rpm to precisely show 2,000 rpm, then divide indicated mph by 2 to obtain their vehicle's mph/1000-rpm. I'm seeing 49 mph at 2,000 rpm in an automatic 2003 Vibe. Other 2000-rpm reported speeds would be welcome.

Please consider the following:
Data Suggesting that U250E 5-speed automatic could improve cruise MPG
in VVT-i 1ZZ-FE engine powered Matrix/Vibes and Corollas.

Transmission ratios comparison A246E Through-Put Ratio U250E Through-Put Ratio
1st - 5th Gear - - - A246E - - - - U250E - - - - (Gear ratio x axle ratios)
Axle Ratio - - - - - -2.962 - - - - - 3.391
1st - - - - - - - - - - 4.005 - - - - - 3.943 - - - - - 11.86 - - - - - 13.37
2nd - - - - - - - - -- 2.208 - - - - - 2.197 - - - - - - 6.54- - - - - - 7.45
3rd - - - - - - - - - - 1.425 - - - - - 1.413 - - - - - - 4.22 - - - -- - 4.79
4th - - - - - - - - - - 0.982 - - - - - 0.975 - - - - - - 2.91 - - - -- - 3.31
5th - - - - - - - - - - - NA - - - - - - 0.703 - - - - -- - NA - - - - - - 2.38
Cruise Through-Put Ratio - - - - - - - - - - - - - - -- 2.91 - - - -- - 2.38
MPH/1000-RPM - - - - - - - - - - - - - - - - - - - -- - 24.5 mph -- - 30.0 mph
NA = Not Available
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Toyota A246E Automatic OEM Choice in
2003-2007 Matrix (with VVT-i 1ZZ-FE engine)
2003-2008 Pontiac Vibe (with VVT-i 1ZZ-FE engine)
1994-1999 Celica ST
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Toyota U250E automatic 5-speed version of U241E OEM Choice in
2009– Matrix (2.4 L 2WD)
2009-2010 Corolla (2.4L)
2005–2009 Camry (4 cyl.)
2006–2009 Solara (4 cyl.)

So can VVT-i 1ZZ-FE engines be mechanically-mated to U250E 5-speed automatics without exotic efforts? If the answer is yes, what electronic control modifications would be needed to convert from what I measure to be 24.5 mph/1000 rpm to 30.0 mph/1000 rpm, which would give 60 mph at 2000 rpm with equal proportions for higher cruising speeds.

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It has been a long time since I last posted. I was participating in MPG contests before the average age US citizen (37 years) was born. Like "Big Dave" with whom I exchanged over 200 notes before joining this group a few years ago, I also own a 7.3 manual transmission turbo-diesel Ford pickup with Randy's Ring & Pinion 3.07 differential gear set and other mods that has gotten 28 mpg at 65 mph on long trips carrying over 2,800 pounds in the bed (lathe purchase). DOT don't read this.
John - LoveLearn