Highest MPG for Non-Hybrids?

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I just averaged 50mpg on a quarter tank of gas with my '95 Civic EX sedan. That's the highest I've ever gotten, and it's not representative because of the small sample and because that driving was 90% highway,
but I still find it impressive. What other high numbers are you folks getting? BTW, I practice 'Super-Miling' which is just modest, safe steps to increase economy, unlike 'Hyper-Miling,' which can be dangerous. I run the tires at 38psi cold, coast with the engine *on* when possible, and accelerate gently. I also try to 'time' lights so I don't have to stop more than necessary. I generally get about 41mpg in Summer, a few less in Winter. I use midgrade gas because the gearing is so high I need full engine power to get the best economy.
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Leftie wrote:

I regularly get 40mpg on the highway with my 2004 Civic LX automatic. I usually drive about 10mph over the speed limit, and my driving style is moderate but not heavy or light. I have my tire pressures about 2psi over what Honda recommends, and I use regular unleaded fuel (87 octane).
Speaking of tires, I just replaced the horrible Bridgestone Insignia's with a set of Falken Ziex ZE912's, so I'll have to see how much the step up in performance will affect my mileage, if at all.
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Leftie wrote:

It's a shame that hypermiling gets such bad press. I'm doing much the same as you, and get high 30s (city and highway) in an old Accord wagon. Having a manual transmission helps; you can coast in neutral and accelerate with the engine in it's most efficient RPM/Throttle envelope without the transmission downshifting. Back last summer, when gas was 4$, I had a fair number of people ask about my mileage. When I told them, there was often a mild backlash accompanied by the accusation, "Oh, you're one of those hypermilers." I then had to explain that I was a 'good' hypermiler. :) I watch my mirrors, try never to hold up traffic, don't run red lights, etc. I may not get 60MPG, but I'm not tearing up my car or becoming a traffic hazard.
I'd argue that anyone exceeding EPA is a 'hypermiler,' but agree that some of the hardcore techniques do little except alienate the average driver. We've all seen the news segments - "See how Wayne gets 65MPG!" Most people are curious, but react with a giant 'WTF?' when they see one of the HM 'stars' putting down the road trailing a queue of pissed off commuters, turning the ignition off while moving, taking freeway exits at clearly unsafe speeds, pushing the frigging car across parking lots, bragging 'my tires have 70psi,' and engaging in other hare-brained behavior. If HM proponents could keep their ego in check and act in a less OCD fashion they might manage to get somewhere in terms of educating the public. Simply teaching people to anticipate those #$%^ traffic lights will instantly increase Joe Sixpack's city mileage by 10~20%
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Greg Campbell wrote:

Agreed. Slightly higher tire pressure, reasonable acceleration, and some coasting instead of always having one foot pressing a pedal can usually save at least 10%.
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Running your tires at 38 psi may be bad for them and dangerous for you. When you heat those puppies up to 200 F or so (get a pyrometer) you'll probably be around 45. Which is probably near the realistic limits. Also, you are changing the shape of the tire and the wear. And, unless you've changed your struts up, your handling is worse. And don't get me started on wet weather driving.
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Dillon Pyron wrote:

FWLIW, 38PSI cold is about right for my 92 Accord. The factory specifies 32PSI, but that gave me a _lot_ of excess edge wear. Hot pressures are, as you guessed, mid 40s. This is great on the freeway, but firm enough make you watch for potholes and whatnot. Any dirt road travel strongly 'encourages' you to soften things up!
Wet weather performance (resistance to hydroplaning) actually improves with increased pressure.
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Dillon Pyron wrote:

You're mistaken. The tires are rated for 44psi, and while *that* might damage them, I always replace my tires because of age, with lots of tread left on them, running them at 38.
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The tires are stamped with their maximum cold pressures, and the manufacturers give those specs knowing exactly what will happen when the tire heats up.
If the tire is specified to take 38psi or more, then there's no danger. It may go up to 45 or even 50psi when run on the freeway on a hot day; the tire manufacturer has taken all of that into account for you.
My Prius specifies 36psi, for God's sake.
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Exactly the same feeling I am getting.
And for what reason person can torture themselves?
It is for the global warming and to save Mother Earth? :-) Probably not...
It is probably to save 5-6 dollars when refueling the tank and spend it later on a prematurely blown tires or repair and medical bills after a crash on slippery road after rain...
BTW - is there any reason at all for running Civic on mid grade gas? This engine was designed to run on regular, so there is no knoking which can be avoided using higher octane gasoline...
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On 4/24/09 9:02 AM, in article snipped-for-privacy@poczta.onet.pl, "Pszemol"

They all have knock sensors that will make any knocking immediately disappear, probably before you even notice that its doing it, regardless of what gas you use vs. what was actually spec'd for the car.
There was some traffic from Honda several years ago that indicated some of the cars were actually designed for premium fuel and would give better mileage and performance if it is used, but rated for regular and depended on the knock sensor to make it all work.
The way to find out if yours is one of those is to run several tanks of higher octane fuel in it. If the mileage is consistently better then you can benefit from it. If it isn't, stick with regular. AFAIK, all the Civics are designed for regular.
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E. Meyer wrote:

Believe me, I started using midgrade reluctantly. This car has freakishly high gearing, and I first started using it so I'd be less likely to stall it starting out in first on hills. (And no, I'm no newbie to standard transmissions. Between the tall gearing and the idle being set at 600, the car really is touchy.) It worked, and I also noticed a 10% increase in economy. Since midgrade gas was/is only about 5% more expensive, it made sense to keep using it. The thing about knock sensors is they only stop knocking - they don't increase performance. In fact, they are there so the engine can run a more advanced timing curve when you use higher octane gas. This Civic is the only car I've had that got better MPG on midgrade.
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Your car has identical low gearing and final drive to all other Civics prior to it. But your 4th and 5th are in fact higher than they used to be, probably to help improve Honda's CAFE numbers. (I do very much wish _my_ 4th and 5th were higher than they are...)
If you DON'T have the D15Z1 engine, no-load idle of 600rpm is too low.
Pump octanes have zero effect on whether an engine is more or less easily stalled at lights. If there is any effect at all, it's a perceived one, not an actual one.
Boosting the octane rating of gasoline serves only one purpose: to prevent the tendency of a fuel/air mix to self-combust all at once in the absence of a controlled flame front. Self-combustion is what's known as "knocking". On its own, higher octanes have no other meaningful effect on engine performance.
Engine control systems are only capable of increasing performance with higher octanes if they are designed to do so. Your Civic's is not. The Civic is designed for 87 pump octane. Its engine management is not capable of advancing timing past designed-in limits that do not take higher octanes into account, but can only /retard/ timing if knocking is sensed.
Your knock sensor is intended to decrease the tendency to knock, not /specifically/ to prevent engine damage, but to decrease emissions of nitric oxide (NO) while still maintaining the best power and mileage that can be achieved without engine damage.
I've conducted my own fairly extensive tests of different octanes. Given that testing of any meaningful length of time necessarily involves seasonal temperature changes, my results were inconclusive. If anything, I got a very slight /reduction/ in mileage with 91 pump octane versus 87.
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Tegger wrote:

Interesting. A few points: I had a problem with stalling when starting off going up inclines, not at lights. That has improved, possibly just from the midgrade cleaning the injectors. As for the increase in fuel economy, that's real. And there is a white line across my tach right at about 600 RPM; it's obviously there to tell owners that the low idle is intentional. What's the D15Z1 engine? I suspect I may have it. Finally, I wouldn't mind having two overdrives (4th and 5th) but *third* is also way too tall. Trying to accelerate up a hill in third, even after revving the bejesus out of it in second, is discouraging. My 91Hp series one Si would kick this car''s 126hp ass on the dragstrip. Still, as long as it keeps getting 40+mpg in Summer, I'll live with it.
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wrote:

No, that's not why they're there.
Knock sensors are there so that when you use a gasoline that does NOT have the anti-knock properties that are called for in the gasoline--let's say you used a lower octane gas--then the engine doesn't detonate.
But when the engine is already designed for 87 octane fuel, and if you're using a proper 87 octane fuel (not piss water), then the knock sensors don't come into play at all. (I am ignoring the effects of age and bad maintenance causing carbon buildup inside the combustion chamber, which would lead to knocking with 87 octane fuel, which means that a higher octane fuel will help. Rather, I am discussing a properly maintained and clean engine.)
Again, the knock sensors don't come into play at all. You can put all the higher octane gas you want in, and the knock sensors don't move the timing around to keep the engine just at the point of knock. No, the knock sensing system is designed to work with fuels lower than what the engine was designed for. The system was NOT designed to advance timing in the presence of higher octane fuels that are beyond the octane rating specified by the engineers.
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Elmo P. Shagnasty wrote:

well, the truth is between the two of you. knock sensors allow the motor to run the most advanced curve it can without knock, regardless of fuel. at the edge of the envelope, knock can vary tank to tank, rainy days, vs. non-rainy days, cold, hot, etc. if you can figure out where the knock point is, you can move timing accordingly. if you don't know, you just have to set it back, and leave a safety margin. that means very slightly less power and/or fuel economy. in this day and age of powerful engine computers, there's no reason not to pursue that marginal improvement.
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Elmo P. Shagnasty wrote:

There is a contradiction being promoted here: that my car is designed for 87 octane gas only, and that it has knock sensors in case I use gas below 87 octane - below Regular grade. Perhaps Honda doesn't respect American gasoline? BTW, my Civic Si also did better power-wise on midgrade (but with worse fuel economy), and IIRC it noted that higher octane gas was preferred in the manual.
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Not quite. It is possible to have gas that's nominally 87, but is contaminated, of substandard quality or has degraded with age.
In any case, the primary purpose of the knock sensor is EMISSIONS, not engine damage. Protection against engine damage does allow the computer to advance the timing as far as it can without risking detonation, but it can only go up to its designed-in limits, which are configured for 87 octane.
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Tegger wrote:

not necessarily true. the more advanced, the more NOx because combustion temp is higher. but the trade is better fuel economy and/or power. thus, in an ideal world, you want the ignition as advanced as possible for any given day, and the only way to determine the max limit is to use knock detection.

modern ignition timing algorithms, for want of a better word, are highly advanced.
http://www.google.com/patents?id=DtobAAAAEBAJ&dq=5,038,736
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<rimshot>
Thank you, thank you. He's here all week, folks.
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wrote:

Is there an intermission? I'm out of popcorn.
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