Front Undertray / Diffuser

[Chris L]

G'day All

Just curious, has anyone out there fiddled around with undertrays/Diffusers for these cars ?. If so can they put up a few pics. I have seen a few with modified front splitters and rear wings, but without messing with the lines of the car too much are there some advantages to be had by 'playing' with the bottom of the car, front & rear ?
I think Ash Bright mentioned he used an undertray at Bathurst this year, and at 250kph down the chute im tipping it helped somewhat combined with a very large set of 'pills'.
I also believe Mr Murphy has engineered his car from memory to be very flat underneath and could quite possibly stick a sheet under her without too much drama.

Cheers
Chris L

[Aussie Mike]

I've cut some alluminum pannels to fill in the gaps between the chassis rails and the sill area to smootha that out. I've been thinking about cutting one to go under between the rails under the drivetrain.

the fuel tank is made to give a smoother transition at the rear and I may add a diffuser later.

Phil N has built a nice aluminum front splitter setup for his car. Hopefully He will post some pics.

Cheers

[Gav]

Yep Mikes car is awesome,
It has never gotten light in the nose irrespective of what part of the shed it is parked in

[sambo]

A few ideas from various places...

[Aussie Mike]

Originally Posted by Gav

Yep Mikes car is awesome,
It has never gotten light in the nose irrespective of what part of the shed it is parked in

I dunno Gav, It get's pretty light in the front end from time to time. In fact right now it's so light that the front end is 3 feet off the ground. (We'll ignore the fact that it's got no front suspension attached and it's on the hoist).

[boxhead]

My feeling on the "lightness" a Cobra experiences at higher speeds, I believe has a lot to do with "stuck" air at speed.
I think more flutes in the top rear (if race car only) of the front guards to help air get out from under bonnet would help, Or raising the rear edge of bonnet a few inches to allow air to escape.
I say this after recently driving my car and the bonnet locks not being closed, all was fine until approx 180kph, then the rear of bonnet just gently lifted to allow the air an escape path.
So having a more permenant way for the air to get out, would possably help.

Just a thought.

[xlr8tr]

One thing I dont think i have seen on a cobra set up for the track is serious venting of the front wheelwells/fenders: here is a comment from Fran Hall from RCR Race Car replicas: "Getting the air our from under the front fenders/wheel wells is incredibly important in creating aero balance...and front downforce...which is every race cars nemesis". They run a large vent at the back of the wheel, and louvered vents on top of the front fenders on the race version of their SL-C which is a serious racing machine.

[spookypt]

Backdraft have done alot of different aero stuff. As you can see from the pics they aren't afraid to have a crack at front splitters and spoilers, rear duck tails, rear venting, bonnet venting, guard venting... in different configurations etc

My car (Oz No:6 without hardtop) has rear duck lip, rear difuser, front splitter and spoiler, vented bonnet and boot. How much difference "I notice" it makes is hard to quantify. Certainly for a race car it looks the part LOL. I enjoy the tinkering part of making it work and look right but some may argue that I'm not succeeding in the look right department. From the feedback I get from BDR USA any larger rear duck lip gives the car way too much front lift even with the front aero aids. A hard top accentuates this also. The larger letterbox opening bonnet scoop on the bonnet increases lift so the vent holes or reversed opening makes a big difference as well.
Spookypt

[Chris L]

Thanks to all for the replies, its good to see the different interpretations and read peoples comments.
Cheers
Chris

[Aussie Mike]

Your car looks fast standing still Spook. Love the hardcore racecar looks.

Got any gold wheels for it?

Cheers

[spookypt]

Originally Posted by Aussie Mike

Your car looks fast standing still Spook. Love the hardcore racecar looks.

Got any gold wheels for it?

Cheers

For old times sake!

[Aussie Mike]

Don't tell anyone but I actually liked the gold wheels. We'll just keep that between you and me.

[xlr8tr]

sweet jesus Spook, nice work! who cares about traditional looks: you would likely not be all that competitive if you looked traditional!

[Towmaster]

A photo of my 250kph front spoiler........

[xlr8tr]

That actually looks quite unobtrusive. And 250kph: way bigger balls than I have especially with your head above the roolbar!!

Originally Posted by Towmaster

A photo of my 250kph front spoiler........