View Single Post
Old 08-18-2010, 04:52 AM   #19 (permalink)
Custom User Title
Join Date: Jul 2008
Location: Bozeman, MT
Posts: 248

Daily Driver - '02 Pontiac Grand Prix SE
90 day: 18.45 mpg (US)
Thanks: 1
Thanked 6 Times in 5 Posts
I recently borrowed my friend's manual Infiniti I30t for a trip (my AC was broke, and 12 hours with a wife at 90*F is a no go). Fun car, sucks fuel. It'll do 25mph in 5th, at 1000rpm. Cruising on the highway at 75mph (I-90 limit in MT) its around 3200rpm. On a 8% grade, I can still accelerate uphill at that speed, or back off to say 60% throttle to maintain. Over 2300 miles it average 27mpg. If it had at least 500rpm decrease in 5th I'm sure it could break and hold 30+mpg. If I hadn't left it in cruise 95% of the time, maybe coasted down the passes, I could have reached 29mpg on some legs of the trip.

Some cars just weren't built for mpg, they were built for fun. The motor has plenty of power to be geared for mpg as well as mph. I'm sure it has a crappy top speed because of the short 5th ratio. Don't worry, its never been above 110mph (to my knowledge).

Random rambling aside, I pretty much let the cruise manage the throttle up hills and mountains (1500-3000ft elevation gain). Most the time it would push it to what felt like 60-80% of total throttle, as I still had room left to accelerate uphill. Only once, at 60mph, 6% grade, did it completely floor it to 100%. Because of the short gear ratios, 99% of the driving this car did, does, will do--never needs downshifting, the engine makes enough power because of the higher rpms. 5th gear at 2000rpm is 51mph. In my GP I'm doing 70mph at 2000rpm. hmmmm...
  Reply With Quote