DOMINION

I think this is part of the "Tech and Performance" thread. But I was looking at the first picture of the RX-8 under body. It looks very flat as the 8 sits low close to the ground. This should helps with the air current(s).

DOMINION

In these next 2 pictures they have close the upper under carriage of the RX-8. I think this is to help with the aerodynamics of air flow under the vehicle.
I have seen this to in the Nissan Skyline. But it was used towards the back near the exhaust/gas tank.

RXE16T

When I hit 200+kph, I'll let you know how effective the underbody is in generating downforce........

DOMINION

This is the only other car that I know of that has this feature. Saleen S7R

hfalex

We did it also 'cause the car is so low that it needs a sumpguard for rally use...
Ciao.

DOMINION

OK I do apologize for the lack of clarity after all its very early, but what I ment to say is the Saleen S7R has a complete close under carriage/case. Would this benefit the RX-8 in any way? is what I was trying to figure out.

Reaper Man

that's actually what I thought it was:D

I had a skidplate and diff protector for my subie for those kind of situations, wouldn't believe how much it was "used"

DOMINION

OK I found one of a Skyline.

DOMINION

Looks good but would can we mount something like this on our cars?...

Straight8

The 91 MR2 had a sealed, flat underbody right up to the back wheels.

DOMINION

Quote:

The R34 GT-R V-spec

More.

wakeech

yeah, this was what i was suggesting for the first body kits years ago. the first problem is that engineering a good diffuser is difficult without knowing how the rest of the underbody is shaped (different folks with different exhaust systems or having mudguards or not, or side skirts, etc). then modifying the one design of the diffuser then ruins what you were trying to do in the first place, so no one would really bother using one (other'n exclusively in a rice application, just like an APC wing or some such).

another issue is simple practicality: getting a peice to fit as tight as a body panel, really work, and clear the ground enough that it makes the car no less streetable is nearly impossible to do. the vanes on a diffuser are quite thin, and would get busted up even with a little bit of gravel.

the biggest issue, really, is cost. making a quality peice out of aluminum (for durability, functionality, and weight) would be a little tricky, and pretty darn expensive. a composite piece (like carbon fibre and plastic resins) would be too flexible and rather weak unless manufactured with extrodinarily high tech processes (which builders in F1 and supercar manufacturers use, but your average aftermarket rice shop wouldn't) using an autoclave and super high tempurature and hardness resins.

but back to the question, there's no reason you can't. underbody aero is something that most cars deal with to some extent these days (Vipers, Z's, even Lexuses). it's more effective than a wing, and is just one of those little things you can do to mildly enhance the look of your car while helping on track performance a lot.

RX Renesis

alot of cars have their under covered completely... suh as the ENZO, Carrera GT1, F1 cars.... anything that goes fast usually have the whole under body covered

DOMINION

I like the sound of that a lot. Thanks.

RXE16T

Further to what wakeech posted and you quoted, just look at the Enzo, you don't see any huge GT wings or the like, do you?

The whole design of the car is based on the intakes working in conjunction with the underbody diffusers to generate the necessary downforce to keep it glued to the floor.

DOMINION

Well I dont wont to get too out of hand (IE:F1) after all this is no F1 car. But I wonder if I can get the front and rear closed in like the Skyline if that would help.

wakeech

you bet it would, it's tricky to get the design right (not impossible, almost common sense really when you're familiar with the theory), and then to actually make it or have it made for cheap is really tough.

i'll resuggest you go for aluminum sheet or if you're feeling rich stainless (of varying thicknesses, check around in scrap yards 'cause buying new is rediculous these days... thanks china :P).

taking a second look at that picture you posted of the R34 dominion, i think you could do a whole lot better than those peices on the bottom of the skyline (in terms of potential to make grip). that saleen race car picture you posted i think has just a plain, flat bottom, which isn't going to be beneficial and horrendously expensive, messy, and annoying to try and reproduce yourself (but the road car probably has some pretty good undercar aero).

DOMINION

Thanks, I'm looking into it.

Murray16

Most modern ferraris have completely covered underbodies. Starting with the 348 I believe.

DOMINION

Yea see I never knew that till now. I would like to have that done on the 8.

RXE16T

It's interesting that Ferrari are the only manufacturer who adapts a lot of their Formula One technology into their roadcars.

Everything they release has tricky aerodynamics built into the bodywork.

NomisR

And those cars are all MR or RR instead of FR like with the Rx8. I think it may be difficult to have the Rx8 undercarriage fully covered, at least the exhaust would need to be exposed due to the heat although I may be wrong on this.

wakeech

there are plenty of front engined race cars with flat bottoms or contoured bottoms, you can always ventilate things and one would hope that you'd have enough sense to construct your undertray of something resiliatn enough that it could take the very mild radiant heat of a street motor exhaust.

the tricky bits are around the suspension and areas that need a lot of space for bumpin' around, while leaving yourself some ground clearance without raising the car.

DOMINION

Good ones. Thanks.