Ecomodding an automatic '04 Civic Sedan

[westb87]

Originally Posted by mpg_numbers_guy

Same, but we gotta deal with what we have for now! I suppose for now my current tires are just a reminder that I haven't hit a final FE peak yet!

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Started doing some P&G today with success. Since the college portion of my classes are done, my 15-20 mile twice a week commutes where I averaged 48-53 mpg are over; now my commutes are all 5-6 miles where I previously averaged 40-43 mpg.

Well now I've started doing P&G until my engine coolant temperature reaches the minimum threshold for the RPMs to be "normal" (71C/160F). Has definitely been helping a lot, and I've been averaging 46 mpg for this past week, on all short 5-6 mile trips, which means that I should be getting over 50 mpg on any 10+ mile trip without too much effort. Problem is, I don't have anywhere I need to go that's over 10 miles away.

I need a longer commute so I can get better MPG numbers...but that'd mean more gas being used and negative savings with all factors considered.

Still no work resumed on the wheel skirts as I've been too busy lately.

All mods have been holding up perfectly so far. No issues with the self tapping screws/washers on the air dam, and my duct-tape covered cardboard has held up perfectly to 3 rainstorms and multiple foggy mornings so far.

And apparently my signature picture thingy changed since my first tank was over 90 days ago...drat, now it's no longer my lifetime average...and it's still not up to what I'm averaging currently lol. But the numbers do look better on it though.

Woop woop! Your numbers HAVE updated! You're crushing it man. Keep going! I'm right on your heels with my FE!

[mpg_numbers_guy]

So right now I'm plateauing at 46 mpg with my daily commutes. My goal is 50 mpg. I can get 50+ mpg on 10+ mile commutes, but I don't have any 10+ mile commutes, so I'm not getting 50+ mpg. I need a 10% increase in FE. Driving style is probably 90% perfect for my routes now, so there isn't a whole lot I can do there.

Still want to resume wheel skirts. The attachment method was good (thanks California98Civic & MetroMPG!!) but my one test skirt rubbed against the tire, so I took it off.

I sort of have an idea of how to keep the skirts away from the wheels; I just need to do it since it'll take a little bit of effort.

Anywho, right now I'm looking at the following design. Any thoughts or critique?

Blue is the idea, yellow is the optional possibility. All brackets (red) are not held in with screws:



Like what it would look like finished (minus the brackets being visible):



Here's a view from the "top" - wheel spat directly integrated with the wheel skirts and side skirts.



Yea, I know, another radical idea from the MPG guy.. Side skirts would be held on using brackets (similar to the ones from the wheel skirts) on each side of the wheel wells as depicted, and secured with painters tape+duct tape. Wheel skirts would go down lower on the front to be even with the side skirts, and I was considering the yellow addition (in the first picture) or extending it out? What do y'all think?

[California98Civic]

Looks clean and like a spaceship! I think the side skirts behind the tires might be counter productive. Is that aft section open at the bottom facing the road? It will be more like a parachute that way. A rear diffuser more like what was on the circa 2006 Prius would have some of what you seem to want. The whole area behind the rear axle, under the car, it a parachute on a lot of these Civics.

I like the side skirt & wheel skirt integration a lot.

[mpg_numbers_guy]

Originally Posted by California98Civic

Looks clean and like a spaceship! I think the side skirts behind the tires might be counter productive. Is that aft section open at the bottom facing the road? It will be more like a parachute that way. A rear diffuser more like what was on the circa 2006 Prius would have some of what you seem to want. The whole area behind the rear axle, under the car, it a parachute on a lot of these Civics.

The idea was to have them extend back but be open in the back, kind of to extend it in similar fashion to say a tail extension and to keep air from going back under the car where the rear bumper is a terrible parachute. How would it be counterproductive and parachute-like? Not doubting you, just curious.

Originally Posted by California98Civic

I like the side skirt & wheel skirt integration a lot.

Trying to find a way to minimize the transition to the skirts since the bottom of the skirt will have to extend about an inch out from the car to clear the wheel.

[19bonestock88]

You should look at the wheel skirts on the MPGiata build thread for a transition... my wheel skirts just curved out and around the tire, kinda like a bubble, and slowly transitioned to the rear bumper cover (on the Malibu)... you gotta keep in mind how you’re gonna take this thing off should you end up with a flat tire...

[California98Civic]

Originally Posted by mpg_numbers_guy

... How would it be counterproductive and parachute-like? Not doubting you, just curious. ...

I appreciate the regard, but doubt that is methodical and not personal is way cool in my book.

If it is open in the back, then the parachute comment does not apply. Instead look up the rear wheel strakes on the back of a Prius circa 2007. Like yours it sorta extends the side skirt to the back bumper, but it also creats a strake behind each tire, reducing drag induced by the back of the tire itself, I presume. All of it is integrated into a rear diffuser assembly. Always have admired and wished I could buy and install that part on my vehicle.

[California98Civic]

Oh, but the parachute thing refers to how the area under the trunk is often open on these civics, making a giant parachute out of the rear bumper cover. A rear diffuser can fix that.

[mpg_numbers_guy]

Originally Posted by 19bonestock88

You should look at the wheel skirts on the MPGiata build thread for a transition... my wheel skirts just curved out and around the tire, kinda like a bubble, and slowly transitioned to the rear bumper cover (on the Malibu)... you gotta keep in mind how you’re gonna take this thing off should you end up with a flat tire...

Just read the whole thread. Lot of good info in there I didn't think would be applicable at first (hence why I haven't digested the thread before). After all, what applicable information could be found in a thread ecomodding a two seat roadster? But I was wrong!

Originally Posted by California98Civic

I appreciate the regard, but doubt that is methodical and not personal is way cool in my book.

If it is open in the back, then the parachute comment does not apply. Instead look up the rear wheel strakes on the back of a Prius circa 2007. Like yours it sorta extends the side skirt to the back bumper, but it also creats a strake behind each tire, reducing drag induced by the back of the tire itself, I presume. All of it is integrated into a rear diffuser assembly. Always have admired and wished I could buy and install that part on my vehicle.

Originally Posted by California98Civic

Oh, but the parachute thing refers to how the area under the trunk is often open on these civics, making a giant parachute out of the rear bumper cover. A rear diffuser can fix that.

So something like that could possibly work, but only if I had a belly pan and rear diffuser installed to stop the parachuting?

[California98Civic]

Originally Posted by mpg_numbers_guy

... So something like that could possibly work, but only if I had a belly pan and rear diffuser installed to stop the parachuting?

Toyota seems to think it can work when a diffuser is incorporated into it, and they have some of the best aero engineers in the world, I am sure. But you do not want a race diffuser, designed for reduce lift. That will also induce drag. You want a design angle that is quite a bit gentler. On my Civic coupe that meant 4* rise from behind the rear axle to the rear bumper cover. I cannot prove it works. I just know the science says it probably does, if I executed it well enough.

[mpg_numbers_guy]

Originally Posted by California98Civic

Toyota seems to think it can work when a diffuser is incorporated into it, and they have some of the best aero engineers in the world, I am sure. But you do not want a race diffuser, designed for reduce lift. That will also induce drag. You want a design angle that is quite a bit gentler. On my Civic coupe that meant 4* rise from behind the rear axle to the rear bumper cover. I cannot prove it works. I just know the science says it probably does, if I executed it well enough.

I'll keep that in mind. The belly pan won't happen until late June though since my busy schedule doesn't allow me for more than a few hours of ecomodding at a time, and this is my daily driver so taking it off the road isn't practical.

So right now I'm planning on revising the wheel skirts, adding incorporated side skirts and wheel spats, maybe a trunklid extension and some gap sealing. That with as much P&G as possible should hopefully get me up to 50 MPG. We'll see.