Aerocivic - how to drop your Cd from 0.31 to 0.17

[Cd]

Thanks for the reply Mike. It's late and I'm spaced out and tired and not understanding you very well.
So are you saying that you get 95 MPG without hypermiling or with?

If you were to take a trip in which it was all highway speeds of 65 MPH for several hundred miles, and you used cruise control and never used E.O.C. or other tricks, would you actually get a 95 or so MPG average at the end of the trip ?

I have the same car as you, but mine is a '93 automatic DX hatch. It has the same engine that you were getting the 95 MPG with.

If I replicate your aero mods on my car, what kind of mileage can i expect if I currently get 42 - 45 MPG highway and i take a trip like i described above ?

I too have a SuperMID and the data readings fluctuate constantly every couple of seconds. How are you getting a constant reading ?
I gave up using it because the data changes so often, and by such large amounts that it is almost useless to me.
I ended up just using it to estimate the averages of a trip versus the instant MPG.
I wonder if the Scan-Guage and MPGuino display the same behavior.

Lastly, I'd also like to ask about the Lexan back window that you have. Are you finding that it is more scratch resistant that Plexiglass, because Plexi seems to scratch extremely easily. ( and is horribly brittle )

Thanks !

[comptiger5000]

I think he's saying it'll get 95 mpg at a steady 65mph on dead flat ground. Add in hills, wind, etc. and it will vary.

[MetroMPG]

... oh, and also acceleration to get to that speed.

Originally Posted by Cd

If I replicate your aero mods on my car, what kind of mileage can i expect if I currently get 42 - 45 MPG highway

As Mike suggested, a closer approximation for you would be to apply the same % increase to your base figure that he initially got (before switching to the lean burn motor).

He saw a 45% increase (from 47 to 68 mpg) in his average MPG following the aero mods (mostly highway driving I assume).

So if you're starting from 42 mpg highway: 42 * 1.45 = 60.9 mpg.

You'll have to accept it's just a guesstimate though.

[tiderfish]

I have to hand it to you Basjoos. This is the stuff dreams are made of! This car looks great and I find myself wanting to experience the coast down "speed decay", or lack thereof.

One question. You stated you removed the rear hatch and fabricated a new one into the boat tail. Do you have problems with rain water leaking in?

Great work! You have inspired us all!

[Cd]

Thanks for the info Metro !

[QUOTE=Cd;212864
If you were to take a trip in which it was all highway speeds of 65 MPH for several hundred miles, and you used cruise control and never used E.O.C. or other tricks, would you actually get a 95 or so MPG average at the end of the trip ?
![/QUOTE]

Sorry for repeating myself, but I'm dense. So if you were to fill up your tank with gas, accelerate onto the freeway and then use the cruise control set at 65 MPH, a trip that would have very little to no wind, and no hills would net you 95 MPG when you pull into the gas station at your destination several hundred miles away? ( Let's assume you wouldn't have to accelerate to get to the station. )

Thanks !

( BTW, What about the Lexan vs Plexi question ? Based on the images from your wreck, the stuff doesn't shatter at all like Plexi does and looks really strong. But does it scratch easily like Plexi ? )

[basjoos]

I got the 95mpg on a 2 mile stretch of flat road. I would set the hand throttle for 90, 95, or 100 mpg and see how well it maintained speed going both directions on that road. I used the 2nd km/l line on the SuperMID (the line that averages over the past 5 km) to get the mpg reading over the 2 miles. Using the hand throttle allows me to get a mostly constant reading on the SuperMID's instantaneous readout.

I haven't had any problem so far with scratches on the Lexan. When I was rear ended, the Lexan cracked and a small section broke off, but it didn't shatter.

The only leakage problem I had with the rear hatch was a slight leak at the top front where the Lexan attached to the hinged remnant of the stock hatch, but a little caulk fixed that.

If I had the ideal situation of a flat, dry, smooth road, with temps in the 80-90 F range, with no wind or traffic, and I accelerated up to 65 mph, maintained a constant speed/throttle setting using the hand throttle, then engine off coasted back to 0 mph at the end of the trip, I could get 95 mpg.

[3-Wheeler]

Maybe to add a little more perspective to the ultimate mpg's achievable....

Last summer on the way to LaCross on a hot summer day at 95°F here in Wisconsin, the Insight without the tail, averaged 87 mpg on mostly flat 55 mph roads over 150 miles.

I honestly don't think the car is capable of 95 mpg at 65 mph in it's current form, but I typically don't drive at those speeds either.

Now that the tail is on the car, and with the temperature at let's say 100°F, tires at 55 psi and again at 55 mph, I highly anticipate that the car could get over 95 mpg in those conditions. Flat, smooth road with no stops.

At the turtle speeds I normally drive on the back roads, to/from work, I expect to hit 130 mpg or so when it gets toasty hot this summer. This 130 number includes the normal stops and such, so the straight line numbers are much higher. This will be the first summer that the car is out of the garage and not having a major project done to it.

Jim.

[MetroMPG]

YouTube interview...

http://www.youtube.com/watch?v=-q6SLDYhK0k

[basjoos]

That was made when I was stopped at a roadside vegetable stand. I didn't know he was recording so it was a totally candid interview.

[3-Wheeler]

Originally Posted by Cd

... I too have a SuperMID and the data readings fluctuate constantly every couple of seconds. How are you getting a constant reading ?
I gave up using it because the data changes so often, and by such large amounts that it is almost useless to me.
I ended up just using it to estimate the averages of a trip versus the instant MPG.
I wonder if the Scan-Guage and MPGuino display the same behavior.....

Hi Cd,

You should be able to get much better results with the ScanGauge II.

I originally used one on the 1996 Chevy Cavalier when I started eco-driving back in 2007.

The ScanGauge was great...

1) Get to a steady speed
2) Hit reset on the total MPG display
3) Drive over several miles
4) As the miles accumulate, the display gets more steady, since it's constantly averaging the results
5) Write down your numbers and get ready for another trial

Look up the specifications for the ScanGauge, since it has a lot of options.

Now I use it for keeping track of throttle position (TPS), water temperature (radiator block), air intake temperature (hot air mod), and 12V battery voltage.

It's a nice unit, and even comes in handy if you want to read scan codes.

Jim.