The aero mods have begun........

[fotomoto]

Matt,

 

FWIW, the Volt has an aggressively low air damn and it well know for scrapping on everything.   GM even offers a shorter one in the accessory catalogue with a lower fuel economy disclaimer.   I took the el cheap approach and simply removed mine.  

 

Anyway, I still have it laying about if you'd like to try adapting it to the CMax.  It comes in three pieces (front, left corner, right corner) that snap together and is held in place by several plastic screws into the underside of the front fascia.

[mtb9153]

your making me very jealous, I have only dreamt of doing the same to my SEL.  Just don't know how to begin with limited garage tools

[ScubaDadMiami]

I would perhaps consider a kit that I could take to someone for installation.  Let's see what's out after the C-MAX is on the market for a while in North America.

[Recumpence]

I am on the road going from Chicago to Minneapolis. I am driving 70mph average with AC on averaging 49mpg! :)

 

I love these aero mods!

 

Oh, I may be interested in that Volt chin spoiler. PM me your info and we can talk. :)

 

Matt

[Jus-A-CMax]

We need new pictures of the car overall with the lexan cover and your stealthy grill replacment covers ;)

 

Sure you don't want a black matt paint job, Matt? :drool:

[Recumpence]

Hey Guys,

 

Here is an overview of my entire trip with my observations and some cool experimantal data;

 

First, the trip total was 900 miles. It consisted of 800 miles of interstate driving and 100 miles of through town driving. 

 

My total mileage ended at 46.7mpg for the entire trip. The last time I made this trip was totally stock and I averaged under 42mpg (38.9mpg up there and 42.2mpg coming home). So, my aero mods have increased my mpg around 4 to 5mpg on the highway and around 3mpg in town.

 

I did some expermentation with mixed EV (under 63mph) driving and engine only running (over 65mph) and these are my findings for my car with aero mods;

 

Above 65mph with the engine running 100% of the time, my mpg (coming home) on the expressway was averaging 44.5mpg (I had a stiff headwind coming home that was not there when we went up). However, once I dropped the speed to 63mph to allow the car to run EV occasionally, my mpg immediately shot up to over 48mpg and that was consistant over 100 miles of driving. This was through Wisconsin. It may not be consistant through flat states. However, at least with my car in hilly terrain, the EV with engine off helped my MPG tremendously. My theory on that is the engine volumetric efficiency sweetspot. That is the point of power output that achieves the highest efficiency (power per unit of gasoline versus friction and RPM). According to my Scangauge, this appears to be somewhere around 45hp. So, running the engine at 45hp results in the best efficiency. Under accelleration, that normally equates to roughly two bars on the power graph. This seems to figure correctly as most of us have found that is the accelleration sweet spot. For cruising, if the engine is running all the time, the power output was on the lower 20s (horsepower in the lower 20s) to sustain expressway speeds. However, when running under 63mph, the engine would shut off for a time, then start up. When the engine started up, it would draw around 45hp driving the car and charging the pack up. I believe this 45hp is where the engine is most efficient. So, that means the engine was running at its sweet spot whenever it was running. Then, obviously, when going downhill or on a flat with the battery relatively full, the engine would shut off and run in EV. So, the only time the engine ran was at its power output sweet spot of roughly 45hp.

 

I hope that makes sense.  :)

 

Matt

Edited July 7, 2013 by Recumpence

[obob]

http://www.aerocivic.com/

 

I found this article interesting and related to this thread.

 

Though it is more of a research project for I wouldn't want to have to parallel park that car.

 

Basically the guy gets 95 mpg (gas without the alcohol) in a civic going 65 miles/hr with all sorts of mods.

Edited August 3, 2013 by obob

[Recumpence]

Yes, that is one of the fugliest cars I have ever seen!

 

That is a typical ultra-hypermiler vehicle (though a lot uglier).

 

I am a member of teh Ecomodder forum. That is a great resource for all things related to MPG.

 

Matt

[mtb9153]

Very interesting to say the least.  If someone wants to go to that much trouble to make their car air streamlined?  Why not make it look more professional?

[salsaguy]

recump, how will all these mods be affected negatively when you go in for the FE update?? won't the update make doing this worse??

 or cancel out the benefits of the fe update?

 

btw, nice job on the mod. brave one for sure to be the first to cut up their car so much without a sure thing not knowing how much it would improve mpgs, or not...

Edited August 3, 2013 by salsaguy

[RaPieR]

Thanks for the info on the engine sweet spot.

 

Hey Guys,

 

Here is an overview of my entire trip with my observations and some cool experimantal data;

 

First, the trip total was 900 miles. It consisted of 800 miles of interstate driving and 100 miles of through town driving. 

 

My total mileage ended at 46.7mpg for the entire trip. The last time I made this trip was totally stock and I averaged under 42mpg (38.9mpg up there and 42.2mpg coming home). So, my aero mods have increased my mpg around 4 to 5mpg on the highway and around 3mpg in town.

 

I did some expermentation with mixed EV (under 63mph) driving and engine only running (over 65mph) and these are my findings for my car with aero mods;

 

Above 65mph with the engine running 100% of the time, my mpg (coming home) on the expressway was averaging 44.5mpg (I had a stiff headwind coming home that was not there when we went up). However, once I dropped the speed to 63mph to allow the car to run EV occasionally, my mpg immediately shot up to over 48mpg and that was consistant over 100 miles of driving. This was through Wisconsin. It may not be consistant through flat states. However, at least with my car in hilly terrain, the EV with engine off helped my MPG tremendously. My theory on that is the engine volumetric efficiency sweetspot. That is the point of power output that achieves the highest efficiency (power per unit of gasoline versus friction and RPM). According to my Scangauge, this appears to be somewhere around 45hp. So, running the engine at 45hp results in the best efficiency. Under accelleration, that normally equates to roughly two bars on the power graph. This seems to figure correctly as most of us have found that is the accelleration sweet spot. For cruising, if the engine is running all the time, the power output was on the lower 20s (horsepower in the lower 20s) to sustain expressway speeds. However, when running under 63mph, the engine would shut off for a time, then start up. When the engine started up, it would draw around 45hp driving the car and charging the pack up. I believe this 45hp is where the engine is most efficient. So, that means the engine was running at its sweet spot whenever it was running. Then, obviously, when going downhill or on a flat with the battery relatively full, the engine would shut off and run in EV. So, the only time the engine ran was at its power output sweet spot of roughly 45hp.

 

I hope that makes sense.  :)

 

Matt

[obob]

Yes, that is one of the fugliest cars I have ever seen!

 

That is a typical ultra-hypermiler vehicle (though a lot uglier).

 

I am a member of teh Ecomodder forum. That is a great resource for all things related to MPG.

 

Matt

 

Matt, your mods look awesome - looks like a prototype for C-Max Sport.  I think your C-Max looks better than the stock C-Max.

[salsaguy]

recump, did you do a elevation plot of the trip to see how the hills and down slopes affected mpg? you can use the Apple app ski trails or Android app gps essentials to record a track and see the plot of change in elevation.

[salsaguy]

so regarding your 45 hp sweet spot, what does that translate to us normal folks? what is the end lesson to learn and now apply to the car? only accelerate to just under 2 bars and let go? 

[Recumpence]

recump, how will all these mods be affected negatively when you go in for the FE update?? won't the update make doing this worse??

 or cancel out the benefits of the fe update?

They will positively affect the new FE update. The reason is, the new updates affect EV use on the highway. EV has far less power available than with the engine running. So, if the air drag is reduced, the EV will have a better chance of keeping the car going at the higher expressway speeds. Therefore, rather than negating the new updates and their affects, I should see a slightly better increase than the average user.

 

Matt

[Recumpence]

so regarding your 45 hp sweet spot, what does that translate to us normal folks? what is the end lesson to learn and now apply to the car? only accelerate to just under 2 bars and let go? 

Personally, I accellerate at just OVER 2 bars. What I did is to train myself to accellerate as hard as I can while maintaining a positive battery charge. So, watch the charge arrow. Accellerate at the highest degree possible while keeping the charge arrow pointed up.

 

Matt

[Jus-A-CMax]

Personally, I accellerate at just OVER 2 bars. What I did is to train myself to accellerate as hard as I can while maintaining a positive battery charge. So, watch the charge arrow. Accellerate at the highest degree possible while keeping the charge arrow pointed up.

 

Matt

In total agreement with my fellow hypermiler. Predominanty 2 bar user here but I do dwelve into 1 bar or 3/4 barwhen I  want a compromise between quick run and more charge but YOU - da driver - has to call this as each street and traffic is different.