well I know I've posted a few things on the topic on other threads and said I would start something separate as I went through the steps of replacing/and/or/improving the efficiency of the underbody.

Its the 2nd weekend I've pulled the car up on ramps to look at things and pull a good chunk of parts off the car to see what I'm working with and where I may go with this project.

I'll pull it up again and actually take pics next time when I start shaping out some templates.

I'll update this as things progress (albeit slowly), but my first thought is this body needs alot of seam welding help.

well heres my first write up

well just an update after inspecting everything. I don't know how different the GDs are to the GE8's. To be honest, I'm not seeing alot of areas to improve upon. I have a base so maybe the rear sport bumper hangs down more and would benifit more from a rear diffuser, that I cannot say. but the stock base one is pretty decent, a bit of improvement could be had making an extension for the passenger side rear, and if you reworked the exhaust a bit could be done with the drivers side.

as far as mid body, the biggest gains for efficiency would be to panel off the passenger side, thats a biggie. not much can be done with the drivers side as the exhaust is routed there. and the center is just a gas tank. If you wanted to be extreme you could pull the tank and drop in a fuel cell, reroute the exhaust straight down the center and flat panel the whole damn thing. But if your going that far, you might as well cut out the spare tire well, work in a replacement brace and you could do a full on gt3 style venturi rear diffuser (not that theres any point to that).

For the front, theres already a good start on the underbody and it looks like there are already factory mounts for paneling over the bottom of the engine. I'm already trying to scheme how much venting and where would be needed to take advantage of this. Also it wouldn't be too difficult to add some brake ducting.

 

its great to see someone thinking like me (i.e more about aero than intakes)! i think we could do much better if more people would take a que from formula one more often and not from the rice-boy mindset. annny hooo.....

 

Good luck. Keep us posted. Several fabricators have tried/failed to make a rear diffuser for the GD's.

 

holy bump batman. I've been in car burn out the past few months ago. I probably won't have much to say on the topic until at least the spring. I have a different project car thats been in the works for many years thats slowly getting to the point I have to get a move on building the underbody and the fit is going to be the test run for that.

like I said, there isn't much practical improvements that can be made on the 2nd gen (after seeing kelso's the other month, I can see why people complain about the underbody on the 1st gens, theres a big difference between the two).

 

I remember seeing an episode of Mythbusters where they took a Ford Taurus and covered it in clay and then cut dimples in it like a golf ball. Because the aero was so much better with the dimples (why golf balls are dimpled to begin with) the fuel economy was greatly improved. Why don't they make full car underbody trays that are dimpled? It seems like if you want the most aero car base the items on the most aerodynamic item you can. I doubt anyone would dimple a roof, fenders, doors, etc but the undertray is a different story.

 

I believe the Prius underbody is done this way.

-Barry-

 

I recently purchased Beatrush under panel for the GE8 and it was a direct bolt on. The mpg went up like 0.1 the stability on the highway increased.

 

where did u buy it? what website

 

I noticed the missing panel when I was under there last month. At least somebody else noticed and I don't have to ask the dealer who took it off.
Now I am wondering which country they ship with the belly pan under the motor, or is it just for their home market?

 

checking with my honda parts guy, the EV undertrays are decently cheap, I think around $200 for the two sides and the middle section. They're plastic, I believe, but not available for sale yet.

 

There is actually a reason besides price that manufacturers choose to leave off underbody trays. They can serve to increase lift and possibly reduce traction at high speeds.

This is not to say this risk cannot be managed with extensive testing - obviously some cars like the Prius have very flat underbodies - but it can be easier (lazier?) to just leave the underbody a little "dirty" and not have to bother with additional high-speed testing. Sometimes it's not dangerous but the car "feels" wrong at higher speeds and they leave it off to increase perceived stability.