Automotive X Prize - would a modded Civic VX make it?

[Krieg]

Is anyone familiar with the "Automotive X Prize"?

Basically, it is an X prize to produce a production vehicle that gets 100 mpg.

Seeing as you all have a lot of experience with some cars that come close or meet that bogey, I wonder if you would critique my idea for an entry.

I'd be starting with a '92 to '95 Honda Civic VX with the manual tranny (44 mpg EPA highway).

If you are familiar with the Import Tuner space, you know that there are a ton of performance mods for this car. I would be applying as many weight saving and efficiency enhancing performance mods as possible.

For example, you can get carbon fiber doors, fenders, hood, spoiler, air dam and hatch for this bodystyle. You can get weight saving polycarbonite windows. You can get weight saving aluminum control arms. You can get springs that lower the car dramatically. Lightweight seat are also available.

On the efficiency front, you can get underdrive pulleys, headers, freeflow exhaust systems, cold air intakes, larger throttle bodies, and freer flowing intake manifolds.

For some more unique items, I would be looking to replace the side view mirrors with backup cams (eliminate the drag due to mirrors). I'd be looking for some other more... unique hacks of the ECU to enable start-stop, cutting fuel on deceleration, and alternator cut out on acceleration.

It goes without saying that I would use low rolling resistance tires and a low drag suspension alignment (those aluminum control arms have a lot more adjustment). Also, some of the tuner items like adjustable fuel pressure regulator and cam phaser would offer more tuning ability.

My question to you experts is, do you think that this would be enough to get in the 100 mpg ballpark? Lighter weight, less drag, more engine efficiency, optimal tuning and setup?

Or would I just be wasting my time?

[SVOboy]

Originally Posted by Krieg

http://www.wired.com/cars/futuretran...6-01/ff_100mpgIs anyone familiar with the "Automotive X Prize"?</a>

Basically, it is an X prize to produce a production vehicle that gets 100 mpg.

Seeing as you all have a lot of experience with some cars that come close or meet that bogey, I wonder if you would critique my idea for an entry.

Welcome to the site. I am indeed familiar with it, and you have some interesting ideas.

I'd be starting with a '92 to '95 Honda Civic VX with the manual tranny (44 mpg EPA highway).

If you are familiar with the Import Tuner space, you know that there are a ton of performance mods for this car. I would be applying as many weight saving and efficiency enhancing performance mods as possible.

For example, you can get carbon fiber doors, fenders, hood, spoiler, air dam and hatch for this bodystyle. You can get weight saving polycarbonite windows. You can get weight saving aluminum control arms. You can get springs that lower the car dramatically. Lightweight seat are also available.

These all sound like they would influence the weight quite a bit, but at a huge cost burden, I would say to hold off on this until the end. Especially the spoiler bit,

On the efficiency front, you can get underdrive pulleys, headers, freeflow exhaust systems, cold air intakes, larger throttle bodies, and freer flowing intake manifolds.

I would be careful before adding any of these things to be honest. You have to remember that a fuel efficient engine does not a fuel economical car make. It's no help to use 20% less fuel per HP if you're making 30% more HP....you'll end up using more fuel in the end.

When working with the vx, it's best to take your design queues from honda, I think.

For some more unique items, I would be looking to replace the side view mirrors with backup cams (eliminate the drag due to mirrors). I'd be looking for some other more... unique hacks of the ECU to enable start-stop, cutting fuel on deceleration, and alternator cut out on acceleration.

It goes without saying that I would use low rolling resistance tires and a low drag suspension alignment (those aluminum control arms have a lot more adjustment). Also, some of the tuner items like adjustable fuel pressure regulator and cam phaser would offer more tuning ability.

It's good that you've thought of removing the mirrors, but that's nothing compared to the whole world of aeromods out there. I honestly don't think you'd make it to 100mpg without tapping most of them a decent amount.

Can you hack the p07 yet? The last time I was on pgmfi.org it was not doable still....

My question to you experts is, do you think that this would be enough to get in the 100 mpg ballpark? Lighter weight, less drag, more engine efficiency, optimal tuning and setup?

Or would I just be wasting my time?

I think if you looked more into the aeromodding part of things, you would be well on your way to the realm of possibility.

[Krieg]

The point of the engine mods would be to make the engine more freer flowing. Less drag in the intake and exhaust system. Lighter engine components (how about an aluminum flywheel, for example).

I think that you are right that, without some tuning, this could just increase HP without a corresponding increase in fuel efficiency.

That's where the adjustable fuel pressure regulator, cam phaser, and dyno time come in. You need to do your time tuning the thing on the dyno.

Maybe I mis-spoke by sayiing ECU hack. It could be that these features would be enabled by outboard systems.

Regarding the carbon fiber, no doubt they're expensive parts. The doors along go for $1600. The hood is like $500, the fenders like $600.

One reason to use them is that the vehicle needs to be production ready. To go into the competition with a readily available production car (even one currently out of production) modified with readily available aftermarket parts (no matter how expensive) would give you a huge leg up on some of the competition.

The CF parts do lend a sort of... technogeekishness to the car. That's not for nothing.

Aeromod wise, first pass is the lowering springs, front air dam, mirror delete, and rear spoiler (a small ducklip on the hatch, not a big, stupid one like you see on a lot of the imports). There is a radiator blocker for the VX as well. Maybe an underbody pan (might be moot if the thing is low enough!).

What else is out there for aeromods? Are they really worth the extra weight at 55 mph?

[trebuchet03]

What's the methodology for the X-prize testing? Is it just - throw it on a dyno, then multiply by a scalar correction factor? (which I believe is how the EPA does it - or maybe did it)...

If that's the case - focus only on mechanical, not aero. Yes, I know aero is just as important - but that's not how one wins a competition as this And you know, if the above scenario is the case - the big players will do just this (and might have a cool looking exterior)...

[SVOboy]

I guess I'll echo treb's comment here...it would very much depend on how the testing is done. Can you tell us that?

And if it's done with real driving (ie wind) the extra weight for aeromods will be well worth it.

[Krieg]

There's going to be a road test. Aerodynamics is VERY important.

But... The VX hatch is pretty aerodynamic to begin with. What's its stock CD? 0.25? Something like that?

What would the modifications I'm considering get you? Under 0.2? There are probably diminishing returns to aeromods at some point.

Here's the homepage of the prize:

http://auto.xprize.org/

I've seen the guy on this site that has a heavily aeromodded Civic, with the nose-cone and tail-cone. I can't say that it looks right to me.

And he "only" gets 70 mpg. It's not a VX though.

[Krieg]

http://xprizecars.com/

[SVOboy]

I would actually call the hatch very unaerodynamic. CD is .36, I believe,

[SVOboy]

So it's 100 mpg across country? That could be done with an insight and driving mods...I would think it could be easily accomplished with an aeromodded and otherwise stock vx.

Keep in mind that while cruising on a highway weight is going to mean very little to the feul economy of the car.

[Krieg]

This is a paper from 1992 on the VX

I was wrong, the CD of the VX was 0.31. So aeromoding would do a lot of good, huh?

I was also wrong on the highway fuel economy. The VX was good for 55 mpg!

According to this paper, the VW had a weight reduction of 80 lbs., which was good for a 2.5% improvement in fuel economy. Going from 0.32 to 0.31 on the CD was good for 1.5%.

I think that you could get a pretty significant weight reduction with the carbon fiber, etc.. 100 lbs. would be easy. 200 lbs. might be possible. Would that be good for a 6.25% improvement in FE?

Could you get down to 0.25 on the CD by lowering it, an air dam, mirror delete, and a spoiler? Would that be good for another 7.5% improvement?

Engine mods maybe get you another couple of %. Let's say 2%.

That's a roughly 15% improvement. You'd need a 81% improvement.

Can that gulf be bridged by the electronics mods (start-stop, engine cut off on decel, alternator cut off on accel)? And driving techniques? And tuning?