floor pan under rear of car

[Skelly]

Hi all apex members
I am looking at putting a flat bottom floor on the back of my car, but not sure how far i can go back?? I help would be great.

Thanks
Sean
99 VD Honda

[S Lathrop]

Back to the rear axel center line. That is not disputable in the rules

I think you can go back further than the axel C/l but you need to check that carefully.

[Skelly]

Thank you for the clarification on this. Will start getting the dimensions i need.

Sean

[R. Pare]

You can go back as far as you want, but once past the rear tire rear edge ( or the axle centerline - I forget which) there is a maximum width - 16 iches if I remember correctly.

Easy enough to look up in the GCR for the right answers.

Just went back and looked at it myself. It is Bodywork that cannot be more than 16 inches wide once back past the rear edge of the rear tires - the floorpan has no limitations.

However, any undertray under the engine and gearbox will most likely be deemed as being "bodywork", so I would play it safe and stick to that 16 inch limitation.

[teamwisconsin]

"Diffusers and undertrays shall not exceed a maximum width of 95 cm (37.40"). No part of the diffuser or undertray shall extend beyond 80 cm (31.50") behind the centerline of the rear axle nor exceed in height a horizontal plane 90 cm (35.43") above the ground with the car as qualified or raced with the driver on board."

That's on page 284 from LAST YEARS GCR. I don't have this years handy, so you're on your own there Sean like Richard said, not too difficult to look up.

Good luck buddy, get that car done soon! Love to see it out and see you back running again!

[alangbaker]

"Diffusers and undertrays shall not exceed a maximum width of 95 cm (37.40"). No part of the diffuser or undertray shall extend beyond 80 cm (31.50") behind the centerline of the rear axle nor exceed in height a horizontal plane 90 cm (35.43") above the ground with the car as qualified or raced with the driver on board."

That's on page 284 from LAST YEARS GCR. I don't have this years handy, so you're on your own there Sean like Richard said, not too difficult to look up.

Good luck buddy, get that car done soon! Love to see it out and see you back running again!

Just a few paragraphs on; 6.i (Aerodynamic aids) to your 4.d (Bodywork):

(Formula F only) No part of the bodywork is allowed to have any down-turned fences or intermediate strakes. Undertrays are allowed, but any portion within the reference area (B.5) must comply with the reference area measurement rules. No bodywork below the horizontal centerline of the differential and to the rear of the rear tires may be wider than 16 inches.

So you can go back to the maximum rear overhang for a ford (1 meter behind the rear axle), but once your undertray goes beyond the rear of the rear tires it can only be 16" wide.

[Skelly]

Hi Ethan
Where did you get the one for your piper. It is a very nice part. Actually your whole car is amazing!!!! Hope to be out on track soon. Not much time this last year with work and 2 year old at home..

Sean

[R. Pare]

One other thing - for your piece to be legally defined as a floorpan, I believe that it would have to be attached in the manner described in the Frame section. If it is a removable piece, that would pretty much make it an undertray, which would be controled by the Bodywork rules.

[teamwisconsin]

Hi Ethan
Where did you get the one for your piper. It is a very nice part. Actually your whole car is amazing!!!! Hope to be out on track soon. Not much time this last year with work and 2 year old at home..

Sean

I had Ian Burnham of Burnham Composites make me a vacuum bagged, foam core fiberglass sheet of something like 36"x 40" and .125" thick. I then trimmed it to a legal size, fit it to the car and drilled my holes where I was going to install the tethers, and (on the leading edge) the camlocs. I gave it back to Ian and he sealed the edges and made hardpoints in the spots where the tethers and camlocs would mount so they wouldn't deform when tightened. Then I used a piece of 3/8" aluminum wicker on the trailing edge to give it some stiffness (so it would pass the 1" deviation rule) and that was that. I think the whole shebang cost me around $200. Burnham Composites is located here in Petaluma, I can give you his number if you'd like. But any composite shop could make you a foam core fiberglass flat panel pretty easily. Or just get the materials from TAP Plastics and do it at home. Me, I hate doing composite work if I can avoid it... good luck!!!

Oh, one more tip. You can (as has been discussed above) make your floor/undertray fairly long. But on my DL7 I made it so it was juuuust shy of the split in the carrier. So when I changed gears I wouldn't have to: A. remove the undertray or B. fill my undertray with gear oil when I pulled the gears.

[provamo]

that last 16 inches of width could be interesting