Aeromodded Civic VX 72mpg (image heavy)

[Superfuelgero]

Originally Posted by The donkey CRX

Thanks for the offer. I guess I was not thinking about the mods costing me power. The main reason I want to aero mod the CRX is it has more torque at lower speeds than the VX while in lean burn. I think I will wait til I can test the CRX with aero mods before I try any engine mods. But I will not give up on the idea that engine mods will help.

Based on driving both the CRX and VX prior to any modifications, I think the CRX has the potential to beat the VX by about 5 MPG. So my goal would be to get to tank MPG of 85 in the summer and 75 MPG in the winter with the completed CRX.

The stock motors are very good BSFC out of the box, there is no magic bullet. The only ways to improve it is to:
1) update materials/technology beyond what honda had available (not much).
2) upgrade on what Honda was willing to spend (not much either),
3) narrow the usable power band (cut high rpm and load) beyond what Honda thought customer would accept.
4) Reduce total power, which requires a total package (aero, friction and rolling resistance)
The last two are examples of where your WAI fits in by effectively reducing displacement, and also air flow conduits (effective intake and exhaust size) reducing power band (shifting VE towards the low end) and power levels.

The first two areas are much harder and expensive. You won't see many examples here, and I've yet to dive deeply into a build for it. When used in combination, they could have large gains, but you have to live with constant lower level of performance.

An overview would be to build more as a stationary motor (fixed rpm and load) than a gas powered car (wide rpm, wide load). This designing for narrow band is where increased efficiency can be built in. It is also why you view your HF as a higher efficiency motor, since it is a more narrowly focused engine. This can be done to the D15z1 with either more mpg, power, or power band depending on which way you lean.

So plan starting at #4, and we can work it backwards to get everything lined up. Just remember, the further you go, the less the ROI and the more you have to just view it as a hobby/challenge.

[The donkey CRX]

Wow! Thanks for all the detailed information. This will give me a lot to consider.

I like your final advice and will wait until I have all the aero and rolling resistance items completed and then consider engine mods based on how the stock engine reacts to these mods.

I have read on EM that it is hard to predict how your current engine and trans gearing will perform when powering a totally different car after extensive aero mods.

So far, the red VX engine seems to really work better with the reduced drag of the aero mods we did. It has produced better MPG's because it takes less torque and throttle to produce better MPG. At least that's the way I perceive it

Thanks again for all this valuable info.

[EcoBill]

just went thru this whole thread. very impressive.
I will be using some of your ideas on my Xa. I just hit 38.4 mpg. Looking to break into 40 and possibly hit 50.

[NeilBlanchard]

You should be able to do that. My manual '05 is averaging ~46MPG year round, and peaking at 55MPG+. Driving helps - and aero like shown in this thread is also very important.

[ECONORAM]

Originally Posted by Xist

How easily can you cut a straight line in the air dam material? I need to figure that out for my lawn edging when I redo mine, but that stuff very well may look better!

What I have done in the past is used an uncut sheet of 1/8" ABS as my straight edge, if I have to make a long cut. Pine 2x4s usually have too much warp to give you a good straight edge. A piece of finished oak could also be used.

[edit] I forgot to mention that I have found using a box cutter knife works well on ABS sheet. Mark it, get your straight edge and run the box cutter along that line a few times to get a groove started, slowly increasing pressure after the first few times. Once you get most of the way through the ABS, you can stop and literally bend it on the seam and break the piece off clean!

[The donkey CRX]

I have had the best luck using a large (12 inch handles) pair of tin snips to cut straight lines with the 1/8" HDP that I used on the air dam for the red VX.

[ECONORAM]

Originally Posted by California98Civic

I could understand that it would do that, but won't doing so produce a lot of downforce? How would it interact with the rest of the car? I would imagine with more air going over the car from the nose, that the back end matters even more. True or a mistake? What do you think?

This might be akin to the bulb nose you see on the front of ships. The bulb that sticks out starts the water moving to avoid the ship and reduces drag (I'm paraphrasing, of course, but I think that's the jist of it).

Originally Posted by johnlvs2run

Basjoos, what is your opinion on this? I'm planning to have the same type of nose as Aerohead & The donkey CRX. I'm thinking to cut the plastic at 7 or 8 inches from the ground, but wondering if 6 inches would be better.

I tried using a lowered air dam on my truck and it didn't help. My guess is because of the additional frontal area, but I don't know. What I do now is I have a splitter that protrudes about two inches, then the belly panel descends maybe an inch lower as it travels back about a foot then stays level... I have a picture in my garage that might help clarify.

@ The Donkey; nice work. My mule won't reach those numbers, and I'm paranoid about drilling holes in it...but I do see a couple of ideas to pursue. Thanks for sharing. [edit] I didn't think of using adhesive vinyl. Nice application. I use 0.100" LEXAN sheet and double-sided velcro for wheel covers. 550 cord also works to hold them on. [edit] It occurred to me I should add a picture. This one shows a wheel cover w/550 cord, front splitter, belly panel sloping down to cover front suspension, and side skirt behind the nerf bar.

[Planckl1]

Can you layout the dimensions and material used for your car so I can order it please? I'd like to mimic it or pm me please doing this to a 1997 metro! Thank you!

[The donkey CRX]

Not sure what part you are referring to. I have listed all materials used for each aero mod in this thread. Please be more specific and I will be glad to supply any additional information I can.

Thanks

[Planckl1]

What I want is the parts you used for your aero mods listed in a message so I can use it as a list at the parts store. If you could include a good store to go to as well I'd greatly appreciated. Thank you sir!