Miata Aerodynamics

Do you have a copy of the rule book?

What's allowed?

I'm assuming that you'll be trying to run in G/GT (G = up to 2.0l), and my rule book is at home right now. You are going to be stuck with certified gasoline, which will be supplied on site- but even with that, you can be darned liberal, since they have really good gasoline available.

IF you are allowed engine changes (and I think you are in GT, but not as many in Production), what can you afford? With the altitude and available fuel, you can crank up the compression a LOT- 12:1 would be safe. And cams, baby, cams. And exhaust.

Oh, more weight = better.

If there are any factory spoilers, or if you can add one- do it- less air under the car makes it a lot more stable.

Here's a picture of our car the morning we broke the record and set it to 230mph in G/BGMS http://www.autocomponenti.com/bonneville_photos/SpeedWeek_2009_album/slides/waiting_to_run1532s.html

Eric

mad machine wrote: "Yea.. I once coaxed one of my Fiat spiders to almost 105 (indicated) with the top down... it was a white knuckle affair with the beating I got from the wind coming over and around the windsheild."

is it really that bad? not that i am sure we will hit 105 in the thing on a 1/4 mile strip..... but hearing that i am not sure i want it to!

Light short wheel based cars at triple digit speeds, will increase the value, you place on your life. It's not for the feint of heart.

alfadriver wrote: Here's a picture of our car the morning we broke the record and set it to 230mph in G/BGMS http://www.autocomponenti.com/bonneville_photos/SpeedWeek_2009_album/slides/waiting_to_run1532s.html Eric

There's an Alfa in there?

That's an amazing accomplishment. The Alfa doesn't exactly have a long wheelbase.

Ypu don't have the body molds for that, do you?

Also found on Eric's link:

http://www.autocomponenti.com/bonneville_photos/SpeedWeek_2009_album/slides/Super_Bird690s.html

kreb wrote:

alfadriver wrote: Here's a picture of our car the morning we broke the record and set it to 230mph in G/BGMS http://www.autocomponenti.com/bonneville_photos/SpeedWeek_2009_album/slides/waiting_to_run1532s.html Eric

There's an Alfa in there? That's an amazing accomplishment. The Alfa doesn't exactly have a long wheelbase. Ypu don't have the body molds for that, do you?

Shockingly, most of the body is stock. Hood isn't, tonneau is not, from lights (stock duetto covers) forward is not, and bottom side is by far not. Stock 88 in wheelbase.

And an Alfa Twin Spark with lots 'o boost.

(hopefully, you get to read about it)

On that page you linked- I took many of those pics this past year, but some (like the chute open) were taken over the past 10 years.

ok, looking through the 2009 rule book I have- you are pretty much limited to the GT class, and not the PROduction class.

What's allowed- cams induction head (assuming a 4V head) final drive (assuming original layout stays) trans ratios (ditto) exhaust alternator may be removed Engine swap is allowed as long as it's a Mazda.

wheel openings can be radiused for tire clearence factory optioned air dams

If it matters, the G/GT record is 157.9 mph.

But to make sure, you should contact SCTA. (www.scta-bni.org)

Eric

itsarebuild wrote: mad machine wrote: "Yea.. I once coaxed one of my Fiat spiders to almost 105 (indicated) with the top down... it was a white knuckle affair with the beating I got from the wind coming over and around the windsheild." is it really that bad? not that i am sure we will hit 105 in the thing on a 1/4 mile strip..... but hearing that i am not sure i want it to!

well.. I am going from memory here.. that was 15 years ago on a two lane road.. and I had long hair then too.

The car itself was pretty well planted.. maybe if I had rolled the windows up I would not have gotten so beaten up.

alfadriver wrote: ok, looking through the 2009 rule book I have- you are pretty much limited to the GT class, and not the PROduction class. But to make sure, you should contact SCTA. (www.scta-bni.org) Eric

He's doing the "World of Speed" event. Not Speedweek. He needs the USFRA rulebook, not the SCTA book.

They're a little more liberal about required safety equipment and have a few more stockish classes. From his post, it also sounds like he doesn't want to modify the car beyond safety equipment or simple, reversible, aero aids.

In reply to modernbeat:

Based on their website- http://www.saltflats.com/ it's pretty hard to tell what's going on. They do use a rule book, but the one they sell is the SCTA-BNI rule book that I have (this is the link to buy a rule book- at the bottom is the one USFRA sells, which is the one I have- http://www.saltflats.com/cgi-bin/store/agora.cgi?cart_id=2814487.15756*Qp8_L7&xm=on&product=Books-N-Stuff)

It's hard to tell what rules they use... But even the SCTA's rules for sub 150mph cars are more liberal than the faster ones.

For the GT class, mods are pretty limited anyway- aero is realistically limited to things the factory sold as dealer installed options- anything else is not allowed.

Eric

Also from Alfadriver's site:

Bellytanker!!!

http://www.autocomponenti.com/bonneville_photos/SpeedWeek_2009_album/slides/bellytank_lakester1497s.html