5th generation civic hatchback - improving aerodynamics

[gildo4realdo]

Thanks for the replies. I figured that was the case. I've tried teaching myself the techniques like you've discussed (low speeds, coasting to lights, etc.) but I'm also doing tank to tank averaging. I've thought about the scangauge but just haven't justified it yet, but definitely agree it's probably the best tool for learning techniques.

Metro, thanks for the link to your breakdown, I had seen it before but some of it never clicked. I think 8% increase with pulse & glide engine on is interesting. I'd like to get a scan gauge and repeat with my car. One thing is for sure though, I'll never do the engine off stuff. I understand it's all opinion and I'm not trying to stir up trouble but I think even with a competent driver, there's nothing safe about turning off power steering and brakes. We can agree to disagree here but I didn't realize that P&G works with engine on as well so I'll give that a shot. Also, I noticed you mentioned you pop the clutch when doing the P&G.... how often do you have to replace a clutch? (or next weakest mechanical link) I just flinch when I think about having to pop the clutch every 16 seconds. I figure using the starter is probably even worse. I'm just curious.

I figured there were some non-normal driving techniques going on here so I wanted to add to this thread so noobs like me don't come in here and think you automatically get 30%+ gains by just doing the mods alone and maybe just driving 65 instead of 70 on the interstate. (which is about all I do as far as driving style goes)

I've all but convinced myself to get the scangauge but I'm cheap. btw Larry, I am an engineer, but I have a hard time convincing myself to stay disciplined to these driving techniques so early in the morning... especially since I don't drink coffee. Anyways, happy hypermiling and I hope I helped add to this already extremely awesome thread which outlines what everyone needs to know about hypermiling.

[larryrose11]

gildo4realdo,
another engineer to the mix huh? Welcome!
Perhaps I shouldn't generalize. We are all wired differently. Hell, I KNOW Im a wierdo. I came to engineering as a shortcut to a job in the sciences. I graduated form HS with an emphasis on Art, mostly jewelery and metal work.

On clutches: I have yet to relace a clutch once I learned ho to drive a stick. I replaced 1 clutch on my firs car, when I was 17 and just leaning a stick. Since then, I haven't replaced a single one. Ive been doing this type of engine off. bump start for 6 years now. It takes practice to make it smooth, but so does everything right?

I don't have power steering, so there is no loss of function there.

I can get about 3 good stops with the stock vacuum reservoir. I probably will upgrade to a larger one soon. Again, If you drive conservatively, then the panic stop situations decrease dramatically.

Larryrose11

[Daox]

gildo4realdo,

I initially thought the same as you about all these things. One day a member of another forum invited me to a hybrid club meet and they offered driver training. With a little instruction I had at least made up my mind that it wasn't hard to do. After I filled up the tank there was no going back. The techniques work and done properly you will be a safer driver than most on the road.

However, with your Civic HX and its learn burn ability you are probably better suited to not do continuous pulse and glide. I would suggest accelerating up to speed at roughly 80% engine load (scangauge tells you this) or around 1/2 to 3/4 throttle is a good guess. Once you are up to speed, you basically want to keep your foot as still as possible on the throttle. What kicks your car out of lean burn mode is changing throttle position. So, hills will be your biggest obstacles.

If you are looking for the scangauge to estimage your mileage for you then you may be disappointed. It does not calculate properly for lean burn mode and will not show correct mileage when in lean burn. However, it is still a great tool for monitoring all the other sensors on the vehicle.

[MetroMPG]

Daox - good point on the leanburn + ScanGauge. The MPGuino does not have that problem - its design works fine with lean burn.

[instarx]

Just read this post from start to finish - very interesting and informative. Great writing AndrewJ. What I like most about Andrew's work is that all the mods look so professional and well done.

I don't want to hijack the thread from Andrew's work but you might be interested to hear a historical tidbit about disconnecting alternators. In the late 60's there was a factory option for Pontiac GTOs that allowed belt-driven accessories to be turned off from a switch in the dash. It used an electric clutch to disconnected everything belt-driven, including the fan. Of course it was for racing, but it is interesting how things can come full circle. Now, 40 years later AndrewJ is working hard to recreate what you could order for $100 in 1968 as a drag-racing option!

I think ironic is the proper word to describe this situation!

[MetroMPG]

That's a very neat tid-bit about the GTO.

[Vince-HX]

sorry about continuing to highjack

Originally Posted by Daox

However, with your Civic HX and its learn burn ability you are probably better suited to not do continuous pulse and glide. I would suggest accelerating up to speed at roughly 80% engine load (scangauge tells you this) or around 1/2 to 3/4 throttle is a good guess. Once you are up to speed, you basically want to keep your foot as still as possible on the throttle. What kicks your car out of lean burn mode is changing throttle position. So, hills will be your biggest obstacles.

I have found that in city pulse and glide is much more efficient than leanburn cruise. On the highway its vice versa. IMO trying to drive only in leanburn mode is pretty rough without the help of a capable wideband controller hooked up to another L2H2 sensor. The DWL technique will help quite a bit.

MPGuino

I got to get off my lazy butt and build one for my lean machine


I really want to delete my alternator also pretty soon. I would love another 10% to tack on

[BrianAbington]

very interesting work...definatly gratifying results. The doubling in fuel economy probably will help to justify keeping the car with the wife whenever you need a major repair.

Looking forward to trying these things on my Mirage

[rcpmac]

Originally Posted by instarx

J there was a factory option for Pontiac GTOs that allowed belt-driven accessories to be turned off from a switch in the dash. It used an electric clutch to disconnected everything belt-driven, including the fan.

This would be the same as a pulley clutch on a typical automotive AC compressor. Shouldn't be hard to adapt one... or should it...?
In any event, does anyone have data on how much load is created when the alternator is spinning but with out electrical load?
And perhaps the easiest solution is putting a switch on the field windings.

[randomthot]

i realize this might drain more power than you want, but why not hook up a LED array from your gauge to list your mpg instantaneously while driving! I think that might be worth the electricity!