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Istas · 06-08-2009, 08:10 PM

Well, the default engine efficiency that the calculator lists is 22%. I don't have any idea on what my engine efficiency is (or the drivetrain efficiency, or 'parasitic overhead'), but when I put in the other numbers I have a rough idea for (weight, Crr, Cd, A), the gas mileage seems to be a bit higher than what I find I get. So I adjusted the engine efficiency down a tad to make the estimates more in line with my observations.

I'm also assuming some loss due to inefficient driving tactics, as I don't yet have an MPG readout to help train and guide my foot on the gas pedal. I'm intimidated by working with Car's wiring, but I'm going to get an MPGuino and try it out.

I have read basjoos's Aerocivic thread and website, and I find it amazing. I never would have thought somebody could get away with doing something like that to a vehicle. His efforts are instruction and inspiration wrapped together. (so is AndrewJ's boattail, also very nice looking)

Hmm, you did standardized, instrument-backed testing and the AC belt removal didn't help at all? In that case I think I'll put it back on. (I hear that having it not rotate for an extended time can harm the compressor)

I'm still a bit leery about doing the aerotabs without having a way to quantify testing them, but I'm going to just take a leap and assume (until I can test them) that having just enough of them to reattach airflow to my rear window will do more good than harm.

The flat sheetmetal ledge spoiler will look interesting, and be easy to do. Your words are encouragement. A multi-spoiler would certainly be interesting.

If I do decide to go for a boattail, at least I have this advantage: the back edge of my car is already lower than the back edge of a hatchback.

I look over those two stickies every once in a while, re-evaluating what I'm willing to do as my boldness waxes and wanes. I better order the rollers for the front wheel skirts now, so I have them in time to work with them before the trip home.

I also am working on getting some CFD software working on my computer. I have a start, but it's tough diving into programs that are so complex and powerful... Overload of information to deal with. It would be excellent to test the trunk spoiler(s).

06-08-2009, 08:10 PM	#20 (permalink)
Istas is not covered in bees. Join Date: May 2009 Location: Seeley Lake, Montana, USA Posts: 207 Honda - '05 Honda Accord EX 90 day: 27.16 mpg (US) Insight - '00 Honda Insight w A/C 90 day: 66.55 mpg (US) Thanks: 53 Thanked 51 Times in 26 Posts	Well, the default engine efficiency that the calculator lists is 22%. I don't have any idea on what my engine efficiency is (or the drivetrain efficiency, or 'parasitic overhead'), but when I put in the other numbers I have a rough idea for (weight, Crr, Cd, A), the gas mileage seems to be a bit higher than what I find I get. So I adjusted the engine efficiency down a tad to make the estimates more in line with my observations. I'm also assuming some loss due to inefficient driving tactics, as I don't yet have an MPG readout to help train and guide my foot on the gas pedal. I'm intimidated by working with Car's wiring, but I'm going to get an MPGuino and try it out. I have read basjoos's Aerocivic thread and website, and I find it amazing. I never would have thought somebody could get away with doing something like that to a vehicle. His efforts are instruction and inspiration wrapped together. (so is AndrewJ's boattail, also very nice looking) Hmm, you did standardized, instrument-backed testing and the AC belt removal didn't help at all? In that case I think I'll put it back on. (I hear that having it not rotate for an extended time can harm the compressor) I'm still a bit leery about doing the aerotabs without having a way to quantify testing them, but I'm going to just take a leap and assume (until I can test them) that having just enough of them to reattach airflow to my rear window will do more good than harm. The flat sheetmetal ledge spoiler will look interesting, and be easy to do. Your words are encouragement. A multi-spoiler would certainly be interesting. If I do decide to go for a boattail, at least I have this advantage: the back edge of my car is already lower than the back edge of a hatchback. I look over those two stickies every once in a while, re-evaluating what I'm willing to do as my boldness waxes and wanes. I better order the rollers for the front wheel skirts now, so I have them in time to work with them before the trip home. I also am working on getting some CFD software working on my computer. I have a start, but it's tough diving into programs that are so complex and powerful... Overload of information to deal with. It would be excellent to test the trunk spoiler(s).