Firesice18

: : Feeler thread : :

I've started researching underbody panels to reduce the drag coefficient of a vehicle and a few things that I have noticed is that this is a VERY quickly growing concept on newer model vehicles. They Nissan Skyline has them. Audi uses them. The Honda Insight has them...

Audi engineers claim that 40 - 50% of the total drag on a vehicle is in the underbody and the wheels and wheel wells.

If you could reduce the amount of drag on your vehicle by, realistically, 30% with a full underbody kit how much would you expect to save on gas mileage?

How much would you be willing to pay for a full underbody kit that was a direct bolt-on and reduced your total drag by 30%?

What kind of value would be needed to peak your interest into purchasing an underbody bolt on kit?

There would be other positives to an under body kit, of course. Things like top speed increase, increase in acceleration, smoother ride (less shake) at highway speeds... all additional positives.

More than likely it couldn't be a single panel, so would it be of less interest if it were two panels? three panels? four?

Something like this:

MadMax07SL

I don't know that reduction in underbody drag is going to give you that much gain in MPG's. Add to that, a lowered car will probably give less resistance than anything you could add to the underbelly.

I could see this application intended for high speed vehicle stability more than anything else. But we're talking needs in the 100mph and above arena, not so much between 60-80. So, track application sure. But not for efficiency...

Just my thoughts.

Firesice18

As an example, it has been proven that gains of 5-10% in MPG can be obtained by making the outer face of the rim on a vehicle completely flat.

Sure, lowering your vehicle will absolutely give you a large impact. But what if your car is lowered? Where do you go next? What if you don't want your car lower and have to deal with scraping everywhere you go?

OE Manufacturers do not waste money when they are developing vehicles. If something is designed a certain way, it is for a direct purpose. It costs a lot of money in R & D, tooling, and wind tunnel testing to develop something such as an underbody panel for a production vehicle. They would not go to that extent for no reason. Nissan, Honda and Audi have embraced this as a next step in car evolution...

Firesice18

Does anyone have a detailed image of the underbody of a 6th gen maxima?

HMAX08

Interesting, I am keeping an eye on this thread, though i have not mechanical insight to share. I would be interested however COST will be a big factor for most.

MadMax07SL

Right now your 5-10% is unproven without at least one link to some form of scientific experiment. But I'll agree, smooth flat wheels should yield marginally better MPG's. But two things stand in the way, aesthetics, and brake cooling.


And lowering with a proper front lip will eliminate most of the drag, and the need for anything underneath, within reason of course. Now, for the vehicles that sit higher up, SUV's come to mind, I get what you're saying, it could be beneficial to highway miles if they could properly channel air under the car without drag...and what better candidate then a vehicle that gets in the sub 20MPG's and below...

cfr94

PM me your personal email addy. I've got what you need 6.5 gen.

Firesice18

Possibly overcited, however still a viable option. Please visit:
http://ecomodder.com/forum/showthrea...-6-a-4368.html
for real, tested results.

Apollos2

iTrader: (16)

I think it's a good idea. I think we get a lot of drag from the rear bumper.

cfr94

+1

Firesice18

cfr94 - Thanks for the images. I believe they will help.

I am looking for, however, a better shot of the underside of the engine compartment from the front bumper to behind the front wheels. Also, if anyone has any detailed shots of underneath the rear section, from in front of rear wheels to rear bumper, with an aftermarket exhaust system. This will aid in making a design that will fit more application than stock exhaust.

I have done a bit more research and have a few noted pages from guys that have designed underbody panels for other model vehicles and have significantly increased MPG, about 10-15%, and noticeable handling differences. I can't promise anything right now, of course, but this is exciting moving forward.

Thanks.

cfr94

Firesice18I appreciate it. Give me some time and I'll see what I can do. I don't have an aftermarket exhaust but I am sure you might be able to just make the 'dip' of the underbody panel a few inches deeper to accept a bigger or thicker muffler.

Deviation

Interesting idea. What about weight of the panels cancelling out MPG gains? The panels would have to be fairly lightweight yet durable. At least the fornt panels woud need to come off easily or have an access port for oil changes.

Firesice18

Absolutely, I agree. It would definitely be very lightweight as to not take away from potential gains. Sheetmetal was an option but I feel even that may be too heavy. I have seen corrugated aluminum sheets and/or Coroplast which are good materials for this type of thing. I am also thinking about being REALLY innnovative and making one out of vinyl, pulled very tight, that can easily be unsnapped and removed for oil changes (and yes I have thought about heat dissipation). I am still in the baby steps of this thought process but it seems that interest is increasing...

Firesice18

So, after looking around underneath the front of my max I realize that the front bumper is a little higher than than racingline y-pipe I have installed. I think this type of grade percentage would actually cause lift instead of downforce.

Does anyone have any dimensions as to any of the aftermarket bumpers vs stock? Do they hang lower in the front than factory bumpers? An aftermarket bumper may need to be installed in order to get the proper angle in order to produce downforce instead of lift. Please let me know.