Aftermarket underpanel on Honda Fit

[wdb]

Thanks everyone for all the interest in my first post to this forum. My omnibus reply to various questions follows.

You can't see my pictures? Funny, I see them...

Beatrush markets the piece to racing enthusiasts as an aerodynamic aid, NOT as a skidplate. It's quite sturdy; mine has survived a few roadkill hits with no damage. But it's not sturdy enough to protect against, say, flying through the air and landing on a rock.

"Beatrush" is a trade name for a Japanese company called Laile. They make lots of stuff including undertrays for other cars. Here is a link to their English language website.

Interesting comments about the VW pieces - the Fit has an aluminum oil pan as well! I had not considered that aspect of it. This panel definitely adds a significant measure of protection under most normal circumstances.

Sure you can make one cheaper than you can buy one. But while a few people might be handy enough to make their own, a lot more people might not be, and still might want to benefit from having one. At $170 I suspect the Beatrush piece is considerably cheaper than a custom-made one, making it a worthy option for those of us who were not blessed with quite as many handyman genes.

Here is the text from the Kamispeed site:

With year of experience in motor sports, Laile; which manufactures, brands, and operates Beatrush; has collected sufficient data information on the tracks of Japan to produce high quality and functional products. Located in Yokohama, Japan; Laile manufactures most of their product's brands like Beatrush and Arpsports with their high precision machinery. All the unique products developed by Laile offers superior safety and plenty of pleasure both in track and the street, as well to look at.

•Fits 07-up Honda Fit stock bumpers and most after market bumpers
•Air turbulence is significantly reduced, producing a more stable ride at higher speeds and increasing down force by creating higher suction pressures between the panel and road.
•Engine temperatures are reduced and stabilized by removing heat from the engine compartment with specialized slits made to draw out hot air while the vehicle is in motion. This is successfully achieved during the creation of down force, as this negative pressure sucks out the heat and is then swooped out by colder air moving underneath.
•Provides greater protection under the engine than stock plastic panels during heavy track or circuit racing competitions.
•Track tested & developed by Beatrush, Japan.

[MetroMPG]

Originally Posted by wdb

You can't see my pictures? Funny, I see them...

I can't see them either.

You may have hosted them somewhere that only a logged-in user can see them.

If you want, you can post them in this thread as attachments (if they're less than 100kb each, I think).

[CobraBall]

Great looking skid/underbody panel.

The "vents" are called loovers. Many hot rod/custom car builders will have a press than can punch out the loovers. Their width can vary according to punch size. Ask a hot rodder/custom car guy/gal if there is a body/custom paint shop nearby that does LOOVERS.

Here is a 13 photo spread showing loovers, the die and press.
Hot Rod Louver Photo

[cfg83]

wdb and lunarhighway -

I really have no excuse not to make my own.

lunarhighway -

Can you tell me the thickness of the aluminum you used? I know I can get some large pieces at the hardware store.

CarloSW2

[lunarhighway]

I don't remember exactly how thick the aluminum is but it's less than 1mm i think. you can easily bend it by hand and you can punch is with a woodscrew after a light tab with a hammer wich is easyer than drilling... this creates a "volcano" shape in stead of a neat hole but considering the thickness of the material this might actually strenghten the hole and prevent it from ripping trough . some nuts and bolts wich washers seem to do their job exelent in holding things together.
Another advantage is you can cut it with metal sheers with little effort and bend it to a tight angle over a table edge or a straight piece of metal.
When folding all edges up 90 degrees creating a 1-2 cm lip the whole thing becomes much more rigid than you'd think... it will than only be able to flex along a few lines, so a few well chosen attachement points and perhaps a little brace here and there will transform a floppy sheet into a very rigid construction.

aluminum twise as thick would seem a better choice but it would cost twise as much and you'd need specialised tools like a brake, to work it.
after quite some months on the road the tray still looks in top shape... and it keeps the engine much cleaner too.

i'm not saying these factory made trays are not worth their money... time is money and if i count the hours i worked on this thing at and take research into account, plus the quality of the work on the factory dams than i think the price can be justified. but than again some free time spend in an enjoyble way could yield something that does exactly the same for a fraction of the prise

[MechEngVT]

Originally Posted by trebuchet03

Another downside to the cast aluminum pan.... Steel drain bolt plugs on threaded aluminum... Stupid stupid stupid. Future designers and engineers, never do that - unless it's designed to come off very infrequently. If it must be aluminum, use an insert (helicoil, for example). Steel on Steel for fasteners that need to come off more than a few times.

As an engineer I can appreciate your frustration, but honestly automobiles and many consumer devices aren't designed for metastable indefinite use. Having worked extensively with aluminum on (non-roadgoing) vehicles using steel bolts in contact with the aluminum is acceptable provided the bolts have *VERY* nice anti-corrosion coatings. Automotive manufacturers have pushed the envelope designing these and GM/Ford/Chrysler all have specifications of organic/teflon coatings that exceed 900 hrs B117 salt spray. They will last in aluminum for a very long time even in the presence of water and road salt. I believe most drain plug bolts for automobiles have an autophoretic paint (same as used on half shafts) that IIRC has a B117 salt spray rating between 1400-2000 hrs.

In the inevitable presence of oil as one would have with a drain plug galvanic corrosion will not be a concern within double the design life of the vehicle. Future designers and engineers should be aware that it's not ideal and there are risks, but the value of the benefits vs. the costs needs to be considered.

[trebuchet03]

Originally Posted by MechEngVT

In the inevitable presence of oil as one would have with a drain plug galvanic corrosion will not be a concern within double the design life of the vehicle. Future designers and engineers should be aware that it's not ideal and there are risks, but the value of the benefits vs. the costs needs to be considered.

It's not so much the corrosion, it's steel against relatively soft aluminum. The 'gents at Lockheed throw around the term galling, but I'm not convinced that's the right term given that galling is usually referenced to cold/pressure welding when machining...

[samwichse]

Not to mention the stripping potential!

My Insight's got a magnesium (brittle) oil pan, and every time I took it in for a change, I was biting my nails waiting to hear they'd stripped the threads.

So I got a Fumoto valve (not enough posts to link, but it's the first result on google)

A bit of tubing for the nipple on the end of it, and I don't have to take off the aero plates under the engine to change the oil anymore. In fact, with some careful reaching, you can just throw a shallow container under the car and reach the valve from the top of the engine compartment!

Sam