Aerodynamic Discussion Thread - Page 21 - Miata Turbo Forum - Boost cars, acquire cats.

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Old 08-01-2013, 10:52 PM   #401
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Quote:
Originally Posted by doward View Post
I assume you mean the front wheel.
So would you place the tabs on the rear edge of the front bumper, so the vortices would smooth flow over the spinning wheel and tire, rearwards.
correct. No, place them behind the wheel, so turbulent flow from the wheel is smoothed out as it joins the flow on the side of the car.
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Old 08-01-2013, 10:56 PM   #402
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Originally Posted by Supe View Post
Only one way to find out. Keep in mind, the Peugot 208 T16 and Monster's Suzukis both used the same setup, no break/outlet in the crevice. If its doing more harm than good, I'll yank it off. Fortunately, I've got somewhere in the neighborhood of 400-450 HP and only see 4th gear a few times, so I've got enough torque and rear gear to offset some drag that I otherwise wouldn't want at a higher speed course.
This completes the picture a little better. I always seem to consider things at my low HP Miata frame of mind.

At 400hp and lower speed courses you should be able to over come some drag.

As the ridiculously powerful hill climb cars do. Though noticing this video shows a Focus where the splitter sills are spaced out at the rear.
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Old 08-03-2013, 09:24 PM   #403
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Here are some flow

LaFerrari



Hennessy Venom GT





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Old 08-17-2013, 12:59 PM   #404
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Any thoughts or photos of radiator duct work sealed to the hood that has side exits?

I'm mocking up my radiator mounts now with the new front frame rail setup. I would REALLY like to be able to run an air cleaner with my motor, and to do so, I need to center mount a forward facing hood scoop. What I don't want is that nice warm radiator air being forced up the hood and right into the mouth of my throttle body, so I'm thinking of making a wire frame and fiberglassing the outlet ducts, so that it dumps more towards the sides of the hood/closer to the fenders.

Any thoughts?
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Old 08-17-2013, 10:12 PM   #405
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That could work... but I find it hard to believe that the only way to run an air filter is with a hood scoop. Hood scoops suck unless they are mounted sky high which is problematic for visibility.

I'd think the ideal solution would be to run a ram air, or at least cold air, hose from the front of the car to your intake rather than trying to suck air from the low pressure area of the hood, an area that is much better suited to exhausting radiator flow.
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Old 08-18-2013, 08:35 AM   #406
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Route the air from the the front somewhere under hte fog lights to the filter, dont waste ur time with a hood scoop. Odds are if you toss a hood scoop it will be from a vacuum area.
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Old 08-18-2013, 10:31 AM   #407
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It's largely a hood clearance issue. I can't fit a bonnet/intake elbow without cutting the hood, same goes for a circular air cleaner. Don't have the clearance with the current firewall setup, fuel rails, and distributor to run a cowl induction setup. I may use the second set of front light holes for some sort of air inlet, but with a v8 and a ton of other underhood crap, space is at a premium.

I'm also beginning to have my questions about the accuracy of that notorious RX7 air pressure diagram. I have a TII hood now, and last time I towed the thing, there was so much pressure at the inlet that I couldn't keep the 3M tape over the mouth of the thing, it kept getting blown in.
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Old 08-18-2013, 12:49 PM   #408
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Can you run an intake to the high pressure air at the base of the wind shield like this but bigger for your V8
http://img470.imageshack.us/img470/9008/pict0393vi8.jpg
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Old 08-18-2013, 07:17 PM   #409
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Can't do it on account of firewall space. Passenger side is occupied by wiper motor, brake lines, ignition coil, fuel rails, EFI harness. Driver's side is fuel rails, booster, clutch master, brake master. I could put a rear facing "cowl" scoop on it so to speak, but would have a heck of a time trying to get it to seal to the TB.

Sadly, I have to have SOME sort of scoop or elbow on my hood. The throttle body sticks up past the hood line, as I have a large single plane intake. Making things even more complicated from an air intake perspective is that I have a strut tower bar that can't be removed (I've removed a lot of material up front, and it also doubles as my throttle return spring mount), so it would interfere with most of the dual snorkel type intakes.
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Old 08-18-2013, 08:56 PM   #410
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Old 08-18-2013, 09:49 PM   #411
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That Mach 1 probably has a Chevy engine ;-)

show us another pic of your engine bay, so we can look at what your working with.
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Old 08-18-2013, 09:54 PM   #412
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Probably going to be a while. Nose/fenders aren't on the car, but I'll see if I can dig up an old one.

Handy-man - don't tempt me. I've often thought of putting my drag motor and powerglide in this car. If only I thought the trans would survive the heat from a 2 minute blast...
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Old 08-18-2013, 11:19 PM   #413
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Haha! awesome!

Most of the fast SM hillclimb cars in the north east are essentially drag cars with wide front tires and better suspension
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Old 08-22-2013, 04:36 PM   #414
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I'm not sure I'm much different. Can't drive into turns worth a ****, but I can sure haul *** between them!
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Old 09-16-2013, 03:31 AM   #415
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I've noticed on a fair few race cars lately have the bottom corner of their front bar are "pushed in" then curve back out to line up with rest of the front bar at the very tip of the corner. Like this:
http://cdn.speedhunters.com/wp-conte..._sonoma-33.jpg
Is that to maximize top area of the splitter within regulations or is there more to it?
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Old 09-16-2013, 11:35 AM   #416
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Default CFD data

I've started getting back CFD data from the Catfish. We used the least aerodynamic setup as our baseline, and the open top car with a windscreen ended up having a coefficient of drag that you'd expect from a convertible.

edit--actually the number was about 0.05 to 0.15 better than other open top cars, but still...

The good news is that it creates downforce in stock trim.
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Old 09-16-2013, 12:44 PM   #417
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Quote:
Originally Posted by Vilko View Post
I've noticed on a fair few race cars lately have the bottom corner of their front bar are "pushed in" then curve back out to line up with rest of the front bar at the very tip of the corner. Like this:
http://cdn.speedhunters.com/wp-conte..._sonoma-33.jpg
Is that to maximize top area of the splitter within regulations or is there more to it?
It's also to channel air around the bumper I quess


Quote:
Originally Posted by cordycord View Post
I've started getting back CFD data from the Catfish. We used the least aerodynamic setup as our baseline, and the open top car with a windscreen ended up having a coefficient of drag that you'd expect from a convertible.

edit--actually the number was about 0.05 to 0.15 better than other open top cars, but still...

The good news is that it creates downforce in stock trim.
Cordycord I love you body, how is the drag over the stock body.
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Old 09-16-2013, 01:38 PM   #418
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Originally Posted by 1993ka24det View Post

Cordycord I love you body, how is the drag over the stock body.
You realize how that sounds, right? Thanks, but I need to go on a diet...

The numbers we have on the Catfish are a little misleading, as they are using a windscreen that we haven't even mounted yet. Standard convertibles with open tops are 0.5 to 0.75 Cd (ugly), which is why Spec racers always race with a top. The windscreen used in the simulation is also a custom (made by computer) design. It's more square than the stock Miata, and more drag-inducing.

We've put the stock Miata screen on the car and it looks fantastic. In fact, we're able to rake the screen down to Lamborghini-style angles while still having good sight lines and the car looks even better. The rake would no doubt reduce our Cd, white removing the windscreen completely will cut a huge chunk of drag out and add downforce.
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Old 09-16-2013, 01:45 PM   #419
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Default Moby Dick

Speedhunters has a new story on Moby Dick:

911 TO THE EXTREME: THE 935/78 MOBY DICK - Speedhunters
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Old 09-16-2013, 01:59 PM   #420
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Quote:
Originally Posted by cordycord View Post
You realize how that sounds, right? Thanks, but I need to go on a diet...

The numbers we have on the Catfish are a little misleading, as they are using a windscreen that we haven't even mounted yet. Standard convertibles with open tops are 0.5 to 0.75 Cd (ugly), which is why Spec racers always race with a top. The windscreen used in the simulation is also a custom (made by computer) design. It's more square than the stock Miata, and more drag-inducing.

We've put the stock Miata screen on the car and it looks fantastic. In fact, we're able to rake the screen down to Lamborghini-style angles while still having good sight lines and the car looks even better. The rake would no doubt reduce our Cd, white removing the windscreen completely will cut a huge chunk of drag out and add downforce.
I know how that sounds, I thought it could be funny.

I have been thinking of buy the Exocet kit and designing some aero to help the air flow. Like these off of the Caparo T1

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