Aerocivic - how to drop your Cd from 0.31 to 0.17

[euromodder]

Originally Posted by ECONORAM

I'm almost afraid to ask how you manage this. With my full-size RAM, brakes are a necessity!

1) Your RAM is an automatic, they're not as good on engine braking as manuals.

2) The sheer weight of your RAM means it'll carry more energy, meaning it'll be harder to shed the excess energy (though that's partly compensated by your RAMs higher drag).
Start coasting sooner if you still need the brakes.


3) basjoos might well be more committed to saving fuel , and be a more extreme hypermiler


102K miles on my brake pads so far, yet I've been known to brake hard.

(It's better to shed more speed early in the stopping game and relax when the road situation improves; rather than be relaxed about stopping and then stress out when the road situation takes a turn for worse. Nothing is as useless as wasted stopping distance. )

[basjoos]

I try to plan my coasting so I rarely have to do more than 25mph worth of braking. I drive my Ford F150 4X4 in the same manner (although its coasting performance is well below that of the Aerocivic).

[lowglider]

Hey basjoos. The other day I was observing highway traffic and listening to the swooshing sound each passing vehicle makes and a question popped in my head. Has it ever been measured how much noise a passing Aerocivic makes in comparison to other vehicles? Even if not measured yet, is there a noticable difference if you listen by ear?

Makes me wonder if the improved aerodynamics reduces not only gas pollution but also noise pollution.

[basjoos]

Reduced wind noise would be the main difference, although the enclosed wheel wells might also reduce tire noise a bit. I haven't measured the noise level either inside or outside of the car, but the aero mods resulted in a very noticeable noise reduction inside and I can't hear any wind noise when driving. People have mentioned that the car is very quiet when I pass them on the road and when the aerocivic passed by on the Carolina Traveler video, it was very quiet.

[HydroJim]

Do you have any pictures of the radiator venting system and how it is vented into the wheel wells?

[basjoos]

I don't have any photos as it is nothing special. The air coming off the radiator enters the engine compartment and then, since the underside is paneled and it can't exhaust there, uses the existing openings that are there to allow for suspension movement of the FWD drive shafts to exit into the front wheel wells. A smaller amount of air passes down the paneled central exhaust tunnel to cool the exhaust pipes and cat to empty into the right rear wheel well.

[AaronMartinSole]

Sorry for this newb question, but what screws are you using to attach your wheel skirts and stuff like that? Are there like some sort of suction window type of attachments or something, and what are they called? I want to eventually down the road make a kammback, but I want to do it non-invasively without drilling holes into the body. And a front air dam, which I'm toying with using zip ties, as you can see on my Corolla 'Insight'.

[1993civicVX]

Originally Posted by martae

Great job Basjoos, but why didn't you start with a civic VX instead of a CX ? It was the high mileage model. Feather light aluminum wheels. Wider ratio transmission with a higher final drive ratio (2000 rpm at 60 mph). Variable valve timing with a twist. In this engine only one intake valve opens below 2500 rpm. Since there is only one intake valve open more of the pressure drop between the atmosphere and the cylinder is across the valve rather than the throttle plate. This gives a more turbulent fuel air mixture which allows a leaner fuel/air charge, greater torque at low engine speed, and no predetonation . The use of a very sensitive oxygen sensor (unique to the VX) allows more precise control of the FA mixture making a very low idle possible. On a warm day mine idles at about 500 rpm. The practical effect of these engine tweaks is high torque at low RPM sort of like a diesel. As I'm sure you guys know, the great weakness of the Otto cycle (the spark igniton gasoline engine is an Otto cycle engine) are the large pumping losses at part load caused by sucking the FA charge past the throttle plate. The ability of this engine to deliver good torque at low RPM (and thus lower pumping losses) is the secret to the high fuel economy this car delivers. The CX and the VX share the same body, but the CX is listed at EPA 42/46 and the VX at 47/56. The VX also offers higher power since the engine has the same displacement, but four valves per cylinder (92 vs 70). I bought mine new in 1992, have put 208 thousand miles on it and still average 45 mpg to work and around town. When the car was new 52 or 53 mpg was not unusual on a long road trip. The fact Honda could do this with the technology of 15 years ago shows what a bunch of liars the auto companies are when they squeal about a 35 mpg average fuel economy rule.

Someone should really donate a good working VX motor to Basjoos. His car would get 100+ mpg all day long with the D15Z1.

Originally Posted by lowglider

Hey basjoos. The other day I was observing highway traffic and listening to the swooshing sound each passing vehicle makes and a question popped in my head. Has it ever been measured how much noise a passing Aerocivic makes in comparison to other vehicles? Even if not measured yet, is there a noticable difference if you listen by ear?

Makes me wonder if the improved aerodynamics reduces not only gas pollution but also noise pollution.

Only makes sense. The basjoos mobile has less turbulent air flowing over it. Surely more turbulence equals more noise.

[MetroMPG]

He's got the VX motor.

From Aerocivic - Honda Civic modifications for maximum gas mileage - aerocivic.com

Update (Feb 2010): lean burn engine installed for more MPG

In the late summer of 2009 at 512,000 miles my engine and transmission were wearing out, so I had a lightly used transmission and lean burn (VX) engine installed in my car.


So far, the new engine is averaging 7 mpg better than the old engine. This engine doesn't get the same mileage over a broad speed range that I saw with the previous engine, but instead shows the steady decrease of mileage with increasing highway speed typical of most cars. In the summer on a level road the new engine gets 100 mpg at a steady 60 mph and 120 mpg at 40 mph. It has tank averages in the upper 60's in the winter and upper 70's in the summer. I have had it remain in lean burn on a level highway up through 91 mph and estimate that it should be able to remain in lean burn up to speeds slightly above 100 mph.

[1993civicVX]

I just saw this on his site! I was just about to edit my post but you beat me to it. I've been wanting him to make this upgrade ever since I first learned of the project way back when. Admittedly I haven't checked in on this site in a long time and only just now discovered Basjoos' new (and very nice) website. Cheers!