Looking for both speed and consistency? Rear end feeling a little unstable when you’d rather it not? A rear wing might be the answer you seek.
While we still use our Triple Threat Miata project as a time trials weapon and take it out for weekend country drives, it’s primarily bec…
Nice to see the balance is good front-to-rear with this application. Meaning, you didn't then have to start chasing an unintended consequence at the front.
Great data! How much drag does this add to the car? Would it reduce your top speeds on a fast track like Watkins Glen?
Nine Lives does nice work and it always seems to be functional. I'd still prefer the look of something less "park bench" like for a streetable car though but I know the large wing is the key to getting the useable downforce.
In reply to CrashDummy :
Pretty much any wing is going to add drag, and that means it'll affect top speeds at fast tracks. The trick is not to lose more speed on the straights than you gain on the corners - keep adding more wing until the lap times stop dropping and start going up :)
Note that the "effective yet inexpensive coil-over kit from RedShift" is no longer available.
CrashDummy said:Great data! How much drag does this add to the car? Would it reduce your top speeds on a fast track like Watkins Glen?
I haven't done an A/B at COTA, nor will I likely do so since the ND is an exercise in frustration there due to low power and low top speed.
But there is zero divergence of the speed trace at Harris Hill.
You can't tell me that's not Pikachu coded.
But does it have to be so ugly?
ARrotard said:But does it have to be so ugly?
No, but the swoopy CF version would probably be a $3k wing.
In reply to theruleslawyer :
More importantly, if it were further forward you wouldn't be able to open the trunk. Material isn't that much of a factor. This is not a pure race car part because this is not a pure race car.
In reply to ARrotard :
Yeah, apparently my "Function over Form" has a limit
In reply to Coniglio Rampante :
I would be interested in determining how much does drag by inducing a moment lift the front end vs pure DF doing the same by being behind rear axle. Thinking being, the down force moved forward by moving wing forward would reduce that front in lift but retain much of the DF, and by raising wing DF might increase ( or be more efficient) by being in much cleaner air, but with the downside of creating a larger moment by simply having a longer higher wing strut mounting.
350z247 said:In reply to ARrotard :
Yeah, apparently my "Function over Form" has a limit
Same. And I have to add that I'm disappointed to see both GRM and 9 Lives Racing deleting and hiding critical comments questioning the appearance and practicality of this wing kit on FB and Insta.
6 bolts and remove for street use.
Any thought to testing the flat under body panels and rear diffuser available out there?
Ando said:Any thought to testing the flat under body panels and rear diffuser available out there?
I don't expect them to make much of a difference on such an underpowered car.
In reply to Andy Hollis :
Seems to me a reduction in drag would be even more important on an underpowered car.
Keith Tanner said:In reply to Andy Hollis :
Seems to me a reduction in drag would be even more important on an underpowered car.
Sure. But drag is proportional to speed, and it's not linear. So you need quite a lot of speed for it to be significant How do you get that speed in an underpowered car?
For a track where you never slow down much (e.g. Willow Springs), it might be worth something. But most tracks have slower corners before longer straights, which dominate the difference between underpowered cars and excess power cars. My two local tracks, COTA and Harris Hill, both are like that.
I've done some fun analysis overlaying speed traces of the ND vs the 720 vs the CRX. It's almost comical. The cornering speeds don't change much. Most of the time delta is in the accel zones.
Here's a recent foray down the COTA back straight in the ND. Speed trace with longitudinal G overlayed.
As speeds increase, drag effects should bend the speed curves in each gear downward, and it appears that is the case. But...it's doing it even at lower speeds, indicating the dominating factor there is the torque curve being non-linear.
To wit:
Now here's some significant drag reduction: top up vs top down at COTA. Just under 3mph difference by the end and worth about .5 seconds. Note how it really only affects the accleration above 100 mph.
I am skeptical that adding a few underbody panels is going to get anywhere close to this level of change. The entire engine bay area is already well covered and the center of the car only has a few openings. The rear might be the biggest opportunity, since I have replaced the stock muffler with the GWR Super Street. So there's some void there.
And here's one of the aforementioned comparisons of the 720 vs ND...a demonstration of how power-to-weight is such a dominating factor. The ND handles a little better, but the accel delta is monstrous.
re: drag
generally downforce is probably worth 2-3x as much as any drag reduction.
the original data trace:
looks like it indicates a cornering improvement at 80mph... but I'm not seeing a speed benefit in the 60mph or 70mph corners shown.
is there more data to compare with more familiarity of if the benefit is mainly at 80mph+ for the wing? or perhaps a subjective "I feel it working at 'n' speed and above"?
re: drag / underpanels
NB
https://www.automobile-catalog.com/model/mazda_usa/mx-5_na_2gen.html#gsc.tab=0
ND
https://www.automobile-catalog.com/model/mazda_usa/mx-5_na_4gen.html#gsc.tab=0
diggin in, the ND has a Cd of 0.35 to the NB's claimed 0.36; when one accounts for Ax of ND at 19.27 square feet to 18.4 square feet...
that maths out to a Cd*Ax of 6.75 sqft for the ND and 6.62sqft for the NB. I kind of expected better... but there may be limits to what a soft top can do, drag-wise. Considering a BRZ has a Cd of 0.27 (claimed {I think 0.29 is more realistic}) and an Ax of 20.6sqft, thus a Cd*Ax of 5.57... there might be some room for performance benefit with respect to drag reduction on an ND. But, that would take some work/study to execute, I think.
sleepyhead the buffalo said:
the original data trace:
looks like it indicates a cornering improvement at 80mph... but I'm not seeing a speed benefit in the 60mph or 70mph corners shown.
is there more data to compare with more familiarity of if the benefit is mainly at 80mph+ for the wing? or perhaps a subjective "I feel it working at 'n' speed and above"?
If you go back to the original story, what I was trying to fix was a light rear at higher speeds, especially on entries. All stock Miatas do this. The small wing indeed fixed that, in the places where the data shows it. Feel and data lined up exactly. Slower turns did not have enough rear lift to have a problem needing correcting.
Of note, I have since built up the confidence and precision to now do that first turn flat out, so the speed trace keeps rising now up until the braking zone. W/o the wing, the car would try to kill me if that was attempted. Offs in that corner are...exciting.
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