Hi! Is this possible?
 

I'm new to this community, but want to say hi! I've challenged myself to put together a car in the next year that will exceed 57 mpg at 65 mph over a fairly long distance on an interstate.

Can this be done without modifications to the body of the car? Can it be achieved without drafting behind 18 wheelers? I'd be curious to get people's thoughts in this.

Dave

Welcome to ecomodder, Dave !

If you want that done without mods you'll be rather limited in the kind of car you can get.

Take a look here
EcoModder Fleet list - EcoModder.com
scroll down to below 100mpg to weed out the electric conversions etc. and see what you can get from which vehicle.

First column is the vehicle, if you click on it, you can see what mods were done to it.

Just about everyone's car here is modded in some way or another ;)

Probably. You'll want to look at a 1st gen Honda Insight.

Probably need an old (first generation) Insight & then hypermile the crap out of it. Whoa, wait - you said 65 mph...... yeah, maybe a first gen Insight. .... maybe....

Cool! I just started looking at 2000 - 2006 Insights on AutoTrader and they all have 130K miles. Are they ok at higher miles? I don't mind if I have to completely rebuild one but I'd be concerned about the batteries / battery cost.

The battery may or may not be an issue. Honda has issues with their packs where other mfgs don't seem to have any. The warranty on the battery I believe is 10yr/150k, so keep that in mind. There are also write ups on this site to refurbish your battery. Also, the car can be driven without the battery and it still gets amazing fuel economy. If you're doing highway driving the pack is used very little anyways.

Wouldn't a first gen Insight with a manual just about do it without any mods?

I'll also throw the hat in for a Mk4 VW diesel, either a Golf or a Jetta. Not sure what specifically you consider a "modification to the body of the car", but with a grill block and some under-body aero treatments and a few other non-body mods, I average about 60mpg at 65mph (several occasions where I got 60+mpg tanks on cross-country trips).

Plus I can run 100% bio in mine too (currently run a 20% blend since that's easily available).

Hi, Dave,

Can it be done: maybe. You're pushing the envelope pretty hard with the 65mph stipulation. Making it harder yet, you specify both no drafting and a long stretch of Interstate. That's hard to hypermile. You can do high speed P&G, but you'd need to add some gauges inside to keep a good eye on engine loading.

Just a few small aeromods will take an Insight deep into the 57 @ 65 range, I'm pretty sure. Not that an Insight isn't already pretty well idealized in the aero department, so most of the low-hanging fruit has already been plucked and served up.

+1 on the diesel recommendations. I'm reminded of the old VW Caddy pickup, and I specifically remember Popular Science printing the little pickup's fuel economy: 57mpg at 45 mph. A simple bellypan and a nice aerocap would probably make 57 @ 65 a completely achievable goal. Of course, you'd have to accept a 0-60 time best measured with a calendar, but them's the breaks.

My subaru 360 (which has lots of air in the tires and is well tuned) would return about 53mpg @ 65mph but did 65mpg around 50mph

Oh and the subaru automatically did DWL since it couldn't go much faster.

They are hard to keep running perfectly correct though.

Since the Mk4 VW's have a turbo, they're a bit more fun than the old non-turbo diesels. My mods include larger injectors and a performance tune, which not only made the Jetta a LOT more fun to drive, but ALSO improved my FE... one of those "have your cake and eat it too" deals... :thumbup:

That's one of the reasons I'm no longer driving my VX... with the Jetta I can load it to the gills with people and luggage and average 60mpg per tank in comfort, over the Sierra Nevada and Rocky Mountain ranges. With the VX, I may not even make it over the first mountain range... :turtle:

The bodyshell of a 1st-gen Insight is a nice base for such project. There was a guy who fitted one with an Euro-spec 1.2L 3-pot Volkswagen TDI and was getting close to 100MPG even with the IMA disabled.