Not sure if this has been posted previously: AutoSpeed - Real World Measurement of Drag and Lift

It's a bit hard to tell from the pics but might the fenders/deflectors be a bit wide/high - I feel like they may be pushing air out further and creating a wake larger than is necessary to hide your wheels (I'm just thinking about tire tests where going from a 9"/225 tyre to a 10"/245 tire has made a difference of a second or two due to the extra frontal area.

Something else to consider would be an open top/middle on the fenders to allow wheel bump travel when necessary but lower their frontal height to reduce the area?

 

I saw you running the car at AMP on Monday. Wondering if any of your changes helped overall times or not. I was in the red turbo Miata running Intermediate.

 

Small world!

Short story: Aero had had a significant impact. Probably more in down force than drag reduction. Harder to test and I assumed since track top speeds are impacted heavily by corner speeds at AMP.

Longer story:
Aero Update: New design and track tested results.

New design is is a lot more frontal area but gets the air off the wheels and showed interesting results with front downforce and some improvement in top speed.

I had the opportunity to run at AMP with the SCCA Track Night crew.

The new aero caused heat buildup that cooked my electronic boost controller so speeds and times aren't a direct comparison to last season but I did get same day back to back testing which is probably better anyway. The conclusion is that with the big aero package and windshield it had way too much front down force. The rear got loose between T5 and T6 and I had some uncomfortable passes through T16.

Removing the windshield helped balance things out. Still a tad too much front down force but close. Also learned that no windshield isn't nearly as nice as running with one. Also fount that the front aero (or perhaps simply the extra 20 lbs) helped with turn in on the auto cross course as well.

Finally ran without windshield and no aero in the last session. Drove the wheels off the car despite a bunch of push (not enough front end downforce).

(All of these run at 4 psi of boost (down maybe 30-40 HP from usual)
Top speed with aero and windshield (100mph) 1:36
Top speed with aero and no windshield (105 mph) 1:35
Top speed with no aero and no windshield (97 mph) 1:37
(previous best was 1:32 with windshield and no front aero and a whole lot more power)


Highest recorded speed with windshield but no aero - 112mph (could be bad data or could have been drafting) typically about 106-108mph on a sub 1:35 lap.

So....way down on power, similar top speeds and aside from a few laps channeling Aerton Senna, I was doing the same time with aero and no windshield but down 30-40 HP. I'd call that a win.

Corner G forces were notably higher with front aero installed.

Definitely needs more testing but showed some improvement. Not so much on drag reduction but the added front down force is very nice.

 

Has anyone done (or found benefit) in rear wheel spats? Skimmed through this thread and didn't find much on this

 

If I remember right Keith noticed a pretty decent difference with wheel spats after he installed his splitter. It may be in his targa build, but I do remember him saying it was a positive difference

 

Lincoln Logs did some rear spats, his build thread is on cr.

Lincoln Logs NA6 Track Build - Page 3 - ClubRoadster.net

 

Yep and they worked great. Only reason they were removed eventually was we originally made them from dibond and they got chewed up from when Sean would get all dorifto at the autocrosses and side-slap cones.

 

I made a new wing, it's as wide as the MX5, and has a 300mm/one foot chord. I am testing it on my Holden Commodore race car this weekend as I am waiting on the cage to be built on my MX5.

 

That's a bunch of camber!
On a Miata at least, I'd consider that a mid speed wing for over 250whp cars. N/A builds need not apply.

 

I found that people's opinions and what I read about wing angles/camber etc, and what actually works in real life can be different. Just out of curiosity on my old red NA8B I ran the wing at a very high AOA and the car went even faster (lap times, not speed). That was a similiar but not as wide. Fastback might be helping with a steady flow of air. It's actually the main element of a dual element wing, so plenty of scope for extra downforce. I will hopefully get to test it on a N/A Miata in a few weeks at a high speed ~ 2:00 min track. I am coming over there in a few weeks for Sema, and take the kids Disneyland for Halloween. I will see if I can get to the shop while I am there.

 

any details on how those were mounted?

 

Figured I'd add in my most recent creation to the thread

Dollars spent: ~$250 (including purchase of eBay GV rep lip)
Hours spent: ~6
How effective: TBD. Car is much more planted than before from initial impressions on street driving
Materials used: Tire Spats (0.100" HDPE), Splitter (1/2" Birch Plywood), 3mm Galvanized Wire, Misc Stainless Steel Eyelets/Washers/Nuts, Stainless Swageless Wire Fork Terminals.
Bracket location: To Rails and Bumper Crash Beam
Tracks tested on: N/A at this point. Still have yet to test on anything but street use
Race/TT class built for: HDPE Events / AutoX

 

V1.0 on Creampuff back in 2013 -




V2.0 on Morpheus last year -

 

V2 looks stunning; besides the actual aero effects

 

It's my favorite feature in overall looks of the car.
We transferred it onto Creampuff a few months ago, looks great too

 

I love your aero, but can't get over your open top with all those bars hanging out like they do. Have you considered some kind of fastback for Creampuff? On a high speed 2:00 minute track my car was 2 seconds slower with no roof.
or maybe you could make some kind of cover like this.

 

If you look closer you'll see the covers

 

Does your car have a windshield?
Also, it's hard to see but there's an aero fairing on some of Creampuff cage as Harry said.

 

Not really an aero modification, but certainly one that is related to it.
I got tired of dicking around with the jack every time I need to lift the car with the *rather low* flat bottom, so I welded a stub to the cage with a removable pad on an extended arm, all that I need now is just to drill a hole through the door and it's a done deal -

 

You stole my idea! I was gonna do this when I built the cage this winter. Nicely executed, as always.