Got 83mpg cruising down the interstate at 60-65mph
 

Got my best average mileage so far (83mpg) for the interstate portion (I-26 from Weaverville, NC to Flat Rock, NC) of my commute going home. Roads were dry, temp was 75F with no significant winds, and with a moderate amount of traffic. I was running at the speed limit to 5 over for the most part, with the speed dropping a few mph on the uphills and going 5 to 10 over on the downhills (with a Cd of 0.17, I gain speed quickly on the downhill despite driving a 2100 lbs car). I was helped out on this trip by being followed by a panel truck towing a car that was taking the uphills at a leasurely pace which allowed me to drop my speed a little more on the uphills than I normally can given the traffic conditions. I normally get 77mpg on this stretch of highway. Who says you need a hybrid or diesel to get good mileage.

Do you know what the equivalent horsepower for that average would be?

I was thinking of building a highly aero modified VW Karmann Ghia with a 600 CC Kubota Diesel engine that is rated at 12 HP continuous at 1 GPH.

Your CD is fantastic. I would think the horsepower needed would be around 10.


regards
gary

Is the CD back-calculated based upon the observed economy.

How is CD calculated on an altered car? 0.36 is a real drag on the Cavalier

There is an Excel spreadsheet for calculating Cd..

Available here:

https://www.instructables.com/id/Meas...t-of-your-car/

I was already to try this until I realized I had a 1991 Geo Metro...you've already done the work for me! And I was so looking forward to finding a nice assistant on the side of the road to help me (although that would probably annoy my wife...)

Your car is amazing basjoos. Imagine what you'd get if you had a VX instead!

I'm into the best nonhybrid mpg cars too. Might go hybrid in 2010 when they do lithium ion plug in, as I hate Nimh.

I'm still waiting for the day Basjoos puts in a d15z1 in place of his dx motor. It should make a reasonable difference as he will be in lean burn the entire time. He Basjoos, you ever try drafting a truck at 125 feet back? Ridiculous. No harm in getting 100mpg. Only a crime in the eyes of Opec. And if you can get 80mpg without drafting, I don't doubt you can get 100mpg by drafting.

basjoos
PLEASE MAKE US PROUD
drop n the d15z1 lets see over 100 mpg!

Your car remains an inspiration to us all (particularly those thinking of aero mods).

Two days ago I obtained metal flat 'bars', and will be doing the first stages over the boat-tail over the next few weeks (and full rear wheel skirts).

Respect for 83mpg though :) I could get 40mpg in my old bluebird on the highway, maybe about 30mpg in my current one. In my current one, I can just about get 83mpg going downhill with engine idling in neutral :)