itsnoe30

this guy gets better mileage with his SC than I do, so I can't help but believe him

As for the staying in fifth vs sixth, John is largely correct when referring to highway cruising. Assuming stock gearing, the stock ECU's AFR is more rich at 70 mph than at 80mph. A member tested this and did indeed have higher MPG numbers at 80 than at 70, despite the increase in resistance. By staying in 5th, you are able to maintain the difference in RPM from 70 to 80 mph, without the increase in resistance or risking police intervention.

zippity

So you guys are saying to stay in 5th gear below 70 mph?

rrounds

Oh GOD no, I got my best mileage when I was sightseeing @ 50 mph in 6th and got 32+ mpg.
If I go faster the mileage goes down and I've cruised at 85 for 3 hours and got 24.8 mpg on that tank of gas.
Mine is a stock '06 with 225/255 tires.

ROD

shadowcoder

I've been averaging 18mpg with mostly city - a far cry from my CR-Z's 30mpg, although I have been driving rather spirited since getting the s2k.

If I'm not accelerating, then I'm always in 6th.

zippity

So some of you guys cruise around at about 3000 rpms with AP1's?

bmms8

i agree with posters who said shifting at 4 rpms is best. first off theres no power under 4 anyways, and its smooth ar 4+, not jerky at all. i havent cruised in 5th at highway speeds, always kept it in 6th. in fact i rarely keep it in 5th, i have a tendency to put it into 6th right after 5th. can someone confirm being in 5th at highway speeds is beneficial, or am i reading wrong?

takeshi

Depends on the situation. Shift as is appropriate for conditions.

Mistman

Interesting topic. Been driving mine since '05 and reported early on that my MPG was better cruising @ 70 mph (6th) than @ 60. I'm now turboed and have digital coolant temp and AFR guages. When cruising in 6th @ 60 mph my AFR's are around 14.2ish, if I shift into 5th they go up to 14.7ish (~4k rpms). Also, wathcing my temp guage, steady 60 mph in 6th I run around 187 ish, if I shift to 5th, I'll drop it to ~185ish, not much but it shows to me that it's running more effficient at the higher RPM's. My commute is roughly 55 miles 1 way, almost all hwy and I average high 25's mpg, or about 250 miles per tank. Without the turbo I used to average about 270-290 (best ever was ~32 on a 600 mile trip). It's a GT35 w/10.5 lbs of boost and 410 whp and I always boost/vtec it when driving at some point, I couldn't be happier w/my MPG considering I can stomp a bunch of cars that can't even get close to that kind of mileage.

zippity

Very interesting...So i gather that, if an AP2 is running more efficient at slightly higher rpms (~4k) than I would have to think this would hold even more true for an AP1 which has a larger rev range. Does this make sense to anybody? Is it ideal to rev to about 4k rpm all the time or just on the highway?

JLUDE

I do all the time...My engine seems to love sitting at 3,000 rpms around town as long as I'm not going upgrade. If you are going up a hill you want to be closer to 4000rpms.

I've heard before that flooring it up to 4K in each gear is supposedly better than light throttle (which makes no sense to me)....but I get 26-27 mpg commuting and 33 mpg highway keeping it out of VTEC and <50% throttle and shifting at 4000 in normal driving....can't see that getting much better.