Moon discs

[thommysgarage]

I know that Moon discs have been used by most racers for many years, but I have noticed that some record setting cars don't have them. I am building a 77 firebird for altered class. Are the Moon discs really helpful on a car like this?

[Joe Timney]

Here is the link to the wind tunnel test on discs:
http://www.hotrod.com/techarticles/body/113_0703_car_aerodynamics/photo_02.html
Click on the Moon Disc picture and read the caption.

[SaltRat]

It seems we want less turbulence?  Whether there is a measurable difference? Dunno.

Then there is the car (wife) phenom I call the oil change/wax job (pat on the ass/box of chocolates) effect.  Ever notice the old hot rod (wife) seems to run better w/ fresh oil (box of chocolates)?  Sometimes some sharp hub caps help . . . . . [1]

cheers,


[1] Once upon a time, an old lady stopped me at the gas station and told me she hadn't seen "those hubcaps" (moon discs) since her husband had that hot rod before they were married!

[mitchell968]

 

[mitchell968]

i sure do like the marianis spin on moon discs. they look very aero friendly.

[Rex Schimmer]

I agree that the Mariana's wheel covers are probably the best I have ever seen for really getting the air by the wheel/tire with the least disturbance. The draw back is that they were made by Troy Trepannier so they are probably about a grand apiece!! but it doesn't mean you couldn't do a copy that might not be as expensive. I have a couple of thoughts using standard Moons adapted to using the additional "skirt" that sets against the tire.

Rex

[tauruck]

Rex, I'm doing a few sets of my own design for a few of my friends.

You've just given me a wonderful idea. Thanks.

[Sumner]

I've considered disc's like above for a number of years for their obvious aero advantage over traditional moon discs but wondered about their legality since they do go up onto/into the tire area and don't just cover the wheel itself.

Has something like this been run on a vehicle that set a record and gone through impound successfully?

I'd also wondered how to overcome the problem of having some flex in it to deal with the changing shape/profile of the tire during a run to avoid any possible damage to the tire?

Sum

[Stan Back]

I've wondered the same things as you, Sum.  But I think the safety concerns may (or may not) have been addressed in Inspection, not needing to get to Impound.  Anyone out there have any answers?

[Seldom Seen Slim]

That IS the Mariani roadster, isn't it?  The team pitted next to us at SW '12 and I had many chances to look at their stuff -- including those wheel discs.  Sharper in person than by camera -- and they look great in a photo, too.  Anyway -- don't I remember that the car did make it to impound - twice?  I guess I could go back and look at the record book, but then I'd spend too much time looking and trying to figure out those darn car classes.   Somebody else do it, please.

[Stan Back]

You can make it to Impound and get a record and not make the Record List.  See Rule Book Section 1.J.

[Stainless1]

Stan, I tell folks that all the time, but until today I did not know where to find it in the rulebook 

[Sumner]

That IS the Mariani roadster, isn't it?  The team pitted next to us at SW '12 and I had many chances to look at their stuff -- including those wheel discs.  ..

I looked at the 2013 results.  Looks like they were car number 46 running as D/STR.  The record in the 2013 rule book is 185 by the Barbee Boys in '97.  The 46 car ran what looked to be a qualifying run of 201 on the 13th but I can't see any other runs after that so don't know if they went to impound or had a car problem??  Maybe someone has an answer?

I do see that a Mariani Farms car has the E and F STR records set in '08 and '10 but don't know if it was the same car and if it had the wheel covers in question.  Someone knows  ,

Sum

[Stan Back]

Different car.

And I think you're looking at El Mirage records.

[mitchell968]

when i spoke with dennis in their pit, he wasnt giving up much, but if i remember right , all their cars were broke. i think this was tuesday. i rapped my knuckles on one of the covers , heavy pieces. when i contacted billet specialities on these  " wheel covers ", they said these " wheels " were a one off for the marianis and troy .  not available to the public. doesnt mean the design car be tweeked a bit, but still bound to be expensive.  i hadnt thought of the legal thing , but the possible pressure on the side wall was a concern for my pea sized brain.   mitchell