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

[basjoos]

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.

[R.I.D.E.]

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

[Mike T]

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

[Hateful]

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

[fumesucker]

There is an Excel spreadsheet for calculating Cd..

Available here:

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

[JoeBob]

Originally Posted by fumesucker

There is an Excel spreadsheet for calculating Cd..

Available here:

http://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...)

[JESSE69]

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.

[1993CivicVX]

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.

[mkiVX]

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

[landspeed]

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

[101mpg]

Way to go basjoos! You inspired me to make the switch to my CRX, which I believe I can also get 100 MPG in, with a D15Z1 and a 6-speed. I've got the CRX (currently an automatic with 42 MPG highway my best so far, getting better with the warmer weather), and will be shopping for the parts for the engine & tranny mods. We know that it's possible with off-the-shelf parts to get 100 MPG - you're getting closer to proving it first!

[1993CivicVX]

Originally Posted by basjoos

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 leisurely 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.

You'd also see much better numbers with P&G and EOC as you can roll for much longer than the rest of us--at 80mpg your engine efficiency to power probably isn't too good. Let's say on the highway at 60-65mph you can probably pulse from 55mph-65mph at 30mpg in a reasonably short amount of time--your glide from 65-55mph should be at least 3x the distance what your pulse would be. Are you doing any form of P&G? Because at .17 Cd you are the best suited for major savings. Have you played much with P&G?

Originally Posted by 101mpg

Way to go basjoos! You inspired me to make the switch to my CRX, which I believe I can also get 100 MPG in, with a D15Z1 and a 6-speed. I've got the CRX (currently an automatic with 42 MPG highway my best so far, getting better with the warmer weather), and will be shopping for the parts for the engine & tranny mods. We know that it's possible with off-the-shelf parts to get 100 MPG - you're getting closer to proving it first!

His aeromods are the reason for his high FE. Only with similar aeromods would you be able to achieve 100mpg. You might get into the 60s with the mods you are planning, but not 100! (Unless you do some hardcore P&G with EOC)

If Basjoos is getting those numbers at more or less steady state with no EOC, then it seems to me he could be in the 120mpg range if he employed P&G/EOC to the max.

[Hateful]

Originally Posted by landspeed

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

yes; it gave me all the excuse I needed to experiment with my Cavalier.It quickly got to the point where there was no use in holding back, after I've heard all the comments from family, friends and fellow posters and getting stared at on the road.

[basjoos]

I plan on installing a d15z1 whenever my current engine wears out.

Drafting isn't worth it with my car, since my Cd is so low that drafting offers only a very minimal improvement in mileage. Also, if there is any sort of downhill, I end up quickly overrunning the vehicle I am drafting and having to hit my brakes a lot, killing any of the slight benefits from drafting. When I drive my car, I am effectively drafting myself, and anybody trying to draft me will get no FE benefit from doing so since I don''t leave a wake behind for anybody to take advantage of.

I'll need to try P&G on a flat road sometime. On the hilly terrain around here I FAS whenever I hit a downhill steep enough to maintain speed on (it doesn't take much of a downhill to maintain speed). Whenever I drive a "normal" car, it feels very draggy, like I am driving down a road covered with a thin layer of mud.

[8307c4]

Fuel Economy Test #4: Driving with Load VS cruise control
http://www.youtube.com/watch?v=QYuZQhpuzfI
No truck...

Originally Posted by basjoos

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.

And why can't you do this normally?
I do hehehe

But it does depend, apparently a very good CC can almost match 'driving with load'
Which, it takes a lot of concentration and one mistake and it's off...
So, cc.

[basjoos]

If you get going too slow on the uphill, you can increase the chances of some inattentive 70+mph driver rear-ending you. I do have an advantage in this regard since my unorthodox rear end tends to catch their attention and knock them out of their driving daze, but there is still an increased safety risk in having too much of a speed differential on the highway.

Don't have CC installed on my car, but do have a hand throttle for driving with load.

[Lug_Nut]

Unfortunately my onboard computer doesn't display higher than 99.9 mpg. Sometimes I'm curious what meaningless three (four?) digit number I could boast if I only counted the middle 6 mile long portion of my morning commute.
Sorry, if I'm not impressed by a 38 mile, net down hill, highway only, one way number regardless of how stratospheric it may be.

[basjoos]

According to Toporoute, that stretch of highway (I-26 from Weaverville to Upward Road near Flat Rock) is 34 miles with a net 0% grade from start to finish. I got 83mpg on that stretch. Once I had dropped to to the base of the mountain into SC and got home, then my trip mileage was at 88mpg, but that included a 1200 foot elevation drop.