Transmission options.

[Mista Bone]

With your comment about the longer gears and using less fuel. If the engine is turning more rpm, there fore in a more efficient rpm range, but using the same overall fuel per mile. Shorter squirts, but more of them. The advantage is gained when on hilly terrain (Ohio is not flat!) I'm not lugging or having to downshift for the hills, aka "transient response" as some of the Honda Engineers called it.

Now if there was a 7.5 mile oval that could have been used for near perfect test conditions....like right next to a major automobile production facility....

Digging through old DSO posts....

From 2006.....

http://www.d-series.org/forums/trans...er-tranny.html

[user removed]

After ripping out the 4.11 in my 59 Corvette, I replaced it with a.308 for $25. 65 in first,105 in second, 140 in third, and God only know what in fourth. Evendriving like atool on occasions I still got 21 MPG.

I liked my Z car with a setup that gave me 30-60-90-120-150 at 6k in each gear although the top gear would not reach redline. Got 28 highway in that one without any hypermiling techniques. I did P&G (engine off one time only) when a new fan belt broke at the seam and I had to get back 10 miles without any more than air flow driving the water pump through the fan clutch.

regards
Mech

[P-hack]

Originally Posted by Mista Bone

...
A) I will NOT give up any performance capabilities of the CRX in the name of better MPG, period.

Well, I'm gonna have to start calling you mista bone head then

The crx is a good foundation for efficiency (and no fear mongering from you!) best in the garage reports 68.45 mpg:
EcoModder Fleet list - EcoModder.com

Originally Posted by Mista Bone

With your comment about the longer gears and using less fuel. If the engine is turning more rpm, there fore in a more efficient rpm range, but using the same overall fuel per mile.

More rpm doesn't equate to more efficiency, need to understand the rpm/load bsfc charts for the engine in question. Very very roughly peak bsfc is around 2500 rpm @ 3/4 load in cars.
http://ecomodder.com/forum/showthrea...-got-1466.html

If you lower the rpm for a given power requirement (i.e. cruise), you have to open the throttle more, and there in lies a key advantage of lower rpm (but stay out of enrichment near full throttle).

Originally Posted by Mista Bone

I'm not lugging or having to downshift for the hills, aka "transient response" as some of the Honda Engineers called it.

Soooo... you are a "performance enthusiast", but shifting bothers you. I see...

[user removed]

Engines are most efficient when they have low manifold vacuum. Higher gearing gives you lower manifold vacuum and greater efficiency. Most engine BSFC charts show best efficiency at lower than 3k RPM. Fewer power strokes with greater load equals better efficiency. Here is my 30-60-90-120-150 280Z. 3k in 5th @ 75 MPH. 2k at 50 1k at 25. Very close to the ZX final drive. It had a 3.45 R200 diff which I changed to a 3.90 R200.

With the 3.45 it would do 9 more MPH in top gear at 3k RPM, close to 85 @ 3k in 5th.

regards
Mech

[Mista Bone]

P-Hack, I very much understand BSFC, esp on here where is seems the norm everyone has to lug the motor down at 3/4 throttle, which puts the ECU into a range where it is worried about making power, not efficeient MPG.

68+ mpg goal, challenge accepted depending out how that info is reported. Is it some flash number or the average over several tankfuls? How would the forum like it reported?

Old Mech, I think you've just fell off your rocker. Old carbed motors might have been better with a low manifold vac yet high manifold reading at the carb venturi's to better atomize the low pressure incoming fuel past the metering jets. That is not an issue with todays fuel inject systems.

[California98Civic]

Seems to me that intake manifold vacuum is an issue for any engine--carb or FI--in as much as the throttle plate affects losses of power for pumping air. Higher vacuum means great pumping losses, no? Anyway, if you really wanna do such a challenge, take it on ina new thread that will get new attention specifically to these ideas and importantly can also end up a featured thread on the main page. Folks here can help set the parameters of the challenge. This is an important tuner/ecomodder debate and so a really great testing/building thread on it would a very cool contribution.

[P-hack]

Originally Posted by Mista Bone

68+ mpg goal, challenge accepted depending out how that info is reported. Is it some flash number or the average over several tankfuls? How would the forum like it reported?

That was an average over several tankfuls, including some "learning curve":
1991 Honda CRX HF Gas Mileage (CRX HF) - EcoModder.com

Start by adding your car to the corral and start w/a fuel log I recon.

[pgfpro]

Light load BSFC will be a very technical discussion, and I also feel it needs to be talked about on here. I like the "start another thread" idea myself.

[user removed]

Says the member without a gas log, LOL

regards
Mech

[P-hack]

The GF drives it %95 of the time, I work from home, no point really. But if I were trying to prove an experiment, it would be well documented, or I wouldn't expect anyone to believe it for a second.