Also just wanted to put out a big THANKS to the folk on this thread. Been lurking for a while, and learned a lot.

I've autocrossed a friend's Subaru off-and-on over the years, and was blown away by how much it mattered when did some fairly extensive aero. He ran in X-Prepared, which has allowances for something like 8sqft of wing and a huge splitter that extends 6" ahead of the bumper and goes back to the centerline of the front wheels. The biggest difference was in braking.

I wasn't sure what difference it would make to my CSP Miata, which has relatively small allowances for splitters and only allows a spoiler. The spoiler can be 10" off the bodywork, so still pretty large. But the splitter has to be behind the leading edge of the bumper and can only go back to the front of the wheel opening, which results in a pretty small splitter on a Miata. We put together an alumalite front splitter and a durabond rear spoiler on the car a couple months ago, just at the end of the season, and it made a noticeable difference, even at autocross speeds.

Neal

 

Here is my EP bumper. Just the same as everyone else. I haven't made any ducting to the radiator yet because I was limited on time. But I did pick up 5 mph on the straight away at NCM motorsports park with the air dam and under tray. I also made a spoiler like the blackbird one and added a gourny flap but I really don't think it does anything. I have a COT wing also, Im just waiting on my buddy to find time to make the stands.

Dollars spent: 50ish
Hours spent: 2
How effective: 3
0=slower, 1, no improvement, 2 =slightly better,3= big improvement
Materials used: 1/8th inch abs and 1/4 inch HDPE
Bracket location: right beside the tow hooks
Tracks tested on: NCM motorsports park
Race/TT class built for: PTE

 

Finished up the new front aero setup just in time for GTA SLB Finale.

Old:



New:



A few things to add/improve still that I didn't get around to before the event, but performance was excellent even as-is:

 

Your car looks very purposeful. Nice work.
I made a front spoiler buck. Just need to sand and polish it, then take a mould. This design is intended for a street/track car. So doesn't hang down or out too far.
Will upload some better pics when it's done.
I used 20mm foam, and plaster. Then hi fill primer, and black paint.
I will make a carbon fibre spoiler from the mould. This will only fit NB8B 2001-2005. Hopefully have the first spoiler done in the next week.

Also, I made some panels up to block the sides of the radiator opening, reducing the size substantially. Alloy sheet was used. Pics up when it's all done.


photo upload

 

Forgot to upload the finished pics. Will be testing it on a high speed track at the end of the month.






windows 7 screenshot

 

That came out great! Wish I had one for my RX7, very similar look to a number of the European hill climb cars.

 

Ryan, your car has always looked impressive from an engineering perspective and now the paint looks as good as the aero. Nice job. Is the rear still the same what you showed us last?

 

What form of bracing to you plan to implement to support the aero loads?

 

Most likely make a support behind the bumper to the Oem hole where the inner liner and bumper bolt together with the plastic screw. But use a metal bolt and captive nut. And bolt on a small removable alloy strap under the front edge on each side that will wrap around to the top side with a cable attached onto the tow points to support the leading edge.
I have had it to about 70mph as is, with only the Oem plastic screws holding it on.

 

Whether it survives at speed without falling off is a different thing entirely than how much downforce is being lost in flex.

Thank you sir! The pic in my sig shows the rear aero as it is to date; something like v3 or 4 of this diffuser. I've been working on an all new diffuser in my head for a little while now, and that will likely happen during this year, but there are some other big plans that will come first.

-Ryan

 

i'm shocked by the rolls of plastic that summit sells. they all color match oem miata colors...

 

Based on my experience, that air dam/splitter will generate maybe 150-200lbs total load at 100mph. Enough to flex the plastic nose letting the air dam drag the ground. It's hard to image any cantilevered structure under the dame supporting it better than cables to the radiator core or bumper support.

 

And 949 Racing orange

Allstar Performance purchased via Amazon. 4x8' x .100, $56 shipped. Amazon.com: Allstar Performance 22465 4X8 PLASTIC ORANGE: Automotive

Note the self clearancing and crack resistance where it got whacked. HDPE is the ideal material for this.

 

it matches my hexis matte red vinyl.. crazy

 

^ First set of our NC hood louvers in the wild... and they're on an NB

-Ryan

 

I regularly see this comment pop up in aerodynamic discussions and have always kept my mouth shut, but I like this place too much.

The idea that dowforce is lost due to trunk lids or bumpers or other parts flexing is just an old forum wives' tale. Think about trying to compress a spring with your hands. If you push the spring with your right hand, then your left hand has to push back with the same force to compress the spring. Your left hand does not see less force because the spring is compressing. You're putting potential energy into the spring as you compress it, but energy and force are two separate things.

The same goes for body parts flexing under aero loads. If an aerodynamic device is creating a downward force, then 100% of that force is eventually going to end up at the tires. The downforce doesn't just disappear into space when one of the pieces in the middle flexes.

The only way flex comes into play is when it starts changing the shapes of parts and the angle at which air is hitting those parts. However, as Formula 1 has shown recently, that flex can help you just as much as it can hurt you. Without testing, it's just another unknown.

 

Thanks for posting. I have always wondered about this, especially after the RB brouhaha from a few years back (and to some extent Williams this year).

 

What about flexing transferring the direction of the load? Is that possible?

 

Nope. If your wing mounts bolted to the roll bar and your wing was behind the bumper it acts on the car the same as if its bolted to the bumper. What the flexing can do is change the angle of attack or shape of your aero component. So when the air pulls down and on that bumper cover and stretches it out its moving the cow catcher in relation to the ground, and that could change the downforce.

 

Makes sense