GTC-200 wing, smaller wing or no wing at all?
 

So I need to get a new setup on the car. I'm wearing the outsides of V730s in about 5 hours and the insides are at 80%. No idea what happened, but it's both sides and there is a lot of negative camber.

While I'm getting a setup done, I'm debating removing the rear wing entirely or just going to smaller one (if that's possible). I see ARP has deferent side plates, but they dont state how much of a difference they make. If it's a big difference, for $120, I'd start there (they also dont tell us the difference between the old, the new and the euro side plates)

It just pushes too much as it is, and I can't get much, if any, rotation on braking.

As far as running ST5, or similar, what is the general consensus for a wing- if there is one?

What’s the whole setup on the car? My biggest problem adding a splitter and wing(gtc200) was my suspension was no longer up to it.

Did you end up changing your suspension to accommodate it?

It has a small splitter, but I doubt it does anything. It's not low enough.
Suspension is is fine. Stance coilovers.

Yeah, future prof’d it when I did.

What did you end up doing? I ask because I just did the UCW wing and splitter from Verus. I'm running Shaftworks USA coilovers with 6k/9k springs and all spherical bearinigs. I'm hoping that's enough.

What are your rates? Alignment Settings, Swaybars etc. Coilover aside, something seems incredibly wrong on the setup side of things to be having this type of wear.

Sideplates won't change anything drastic what you're looking for. APR is notorious for having wings that produce too much DF for our cars in particular. They're draggy.

Well the dampers themselves should be fine... Worst case its new springs and a revalve.

I would be curious what John says about your setup. 6k/9k is pretty common for non aero builds. But maybe its more slicks and aero that require stiffer springs than just aero alone

I am on Annx CSP’s on 10/12k setup now. I was on older T2’s on a 6k flat setup. I was bottoming the fronts a lot and the car didn’t want to rotate.

Good to know. Thanks everyone.

Looks like my 6k/9k setup needs to go to 8k/9k. Thanks to a couple of key resources for that info.

What is your current complete setup?

Front
-.10* toe (total)
-3.72* Camber
5.71* Caster

Rear
.12 total toe
-3.02 Camber

Stance coilovers (I know... they came with the car, they're honestly not that bad and my track is very smooth so its not a big deal)
gutted/caged/etc
small splitter
V730 tires
and obviously, the wing

Is that rear on both the front and rear or just the front?

Stance coilovers are fantastic, is there a sentiment that they are not?

So multiple things...

Nowhere near enough front camber for 200TW tires if you want to optimize the setup. I've got -5 degrees up front. Rear is... fine?


What spring rates? What swaybars?


Also, the misconception that "my crappy shocks are fine because my track is smooth" is totally ignoring what shocks do. Their primary job is to control what happens to the tires when there are driver inputs and track smoothness is mostly irrelevant for that.


That said, Stance coilovers are "fine" valving wise.

I agree, but it's a lot worse on bumpy tracks.

I dont really know the spring rates - I would very much assume they are whatever the off the shelf XR1 Stance coil overs are for the BRZ.
Whiteline sway bars (adjustable, dont recall where they're set) and a front strut tower brace.


That is wear on the front. Similar on both front tires. Rear is wearing nicely.

I wouldn't say fantastic. I think the sentiment is they're a good cheap shock.

I'm sort of going all in on spec miata because of the number of them here locally and that an 86 isn't very competitive in WRL due to fuel tank/mileage otherwise I'd get coil overs that match the rest of the car. It's got a great cage, very good brakes, solid motor, upgraded trans, great cooling, great seats, etc. Shocks (and data logger) are the only place it sort of cheaped out.

They are what came with the car when I bought it 5 years ago. If it was me, I would have gone with nicer coil overs. But otherwise, the car was awesome and the right price, and (knock on wood) it's been very good to me.

I doubt I'd be any faster on $5k KWs, but I love a good set of coilovers. It was the first thing I did to the Viper and C7 (well, just the DSC controller as the springs were fine). The Viper came with Eibach lowering springs so I basically had to "fix" it. With the big aero on it, it needed more than OEM spring rates so stock wasn't an option, nor was just slapping super stiff springs on stock shocks.

Do you have any pyrometer data on the tires?

Try reducing angle on your wing for the time being and/or raising the car as a whole (and re corner balance).

remember, a higher leading edge on the wing doesn't mean it's positive AoA against the air flowing on the wing.

Is there anything stopping you from removing the wing and splitter to test the balance without aero?

No data, but I'd strongly assume the outsides are very hot, lol

It's set to minimum A0A.

The rear would be loose as ever living hell. Feels like the rear is driving in rain without the wing and the splitter there, let alone removing that too. I doubt the splitter does anything measurable. It's like 4" long and 6" off the ground. I know Kelsey and Silvio did some testing with and without it. Maybe @Kelse92 can chime in.

What splitter do you have? Have you checked the angle of it, if it's mounted to the bumper there is a chance it's pointed in the wrong direction.

APR. It's pretty flat. A 4" splitter just isn't going to do much at relatively low speeds. And it's certainly going to less than the wing at AoA as speeds increase.

APR. It's pretty flat. A 4" splitter just isn't going to do much at relatively low speeds. And it's certainly going to less than the wing at AoA as speeds increase.

Thanks for the mention.
My data may not be super beneficial. I’ve compared the car with the same tire and suspension setup/mods with and without a wing, but did realign the car each time to compensate. The with-wing setup was faster.

I also tested for considering potentially adding a splitter, but never ended up mounting it.
My test was mainly on 200tw tires in the ruleset vs Hoosiers as the wider 200’s at the time would have afforded adding a splitter vs my setup on a Hoosier. But the lap time slow-down from the 200’s for me just in back-to-back testing (1.5-2 second delta) didn’t seem like adding a splitter would overcome that lap-time difference so we never finished mounting it.

There are people who have had good success with splitter and wing combo on non-Hoosiers, I just didn’t think it was worth the points on my particular car for TT5 and the tracks we drive

Thanks!

I may take it off and see if there is any noticeable difference one day.

I bet you can go "more" minimum.

You literally want the leading edge to be slightly higher. Give it a shot, maybe 2 degrees negative.

don't the v730s wear in a weird way due to the tread pattern. I only have -4 camber up front and -2.6 rear and have not had any issues with my v730s over several events

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honestly that's your problem. My setup is very similar to you. Very similar camber/caster specs, same tires and I feel my car is very planted even without aero. My guess the suspension is over sprung (to high of spring rates) Just because the track is smooth don't mean shit... I made the mistake of getting some custom coils and went for high spring rates made for 200TW or slicks, full aero etc... Without it the car was miserable to drive sadly. Rear felt exactly as your describing

Digging this one up a bit cause I haven't seen closure yet and trying to help a lil.

Can you post photo of the wing mounts/adjuster?

on both of the APR wings I've owned, the hex tube adjuster was too long to get to the correct AOA, so I had to trim it down a bunch. I think I cut 3/4" off the universal bracket kit on my 240SX, and maybe 1/2" on the one for my FRS and I'm just now about +1 or +2deg AOA.

Been running APR since 2017. Ran both the 300 and 200 rear wings. The 2D with gurney flap was marginally faster (2/10 at Dominion) but hard to decipher the difference.

The 2D wing can go down on AOA by the way. My best result was -3 degrees but since they are chamfered and will still produce downforce.

Past 5 years have been on the 2D wing running 0-degree AOA with a gurney flap. Standard side plates that came with the kit. Hope this helps.

Lutfy

Another thing that comes across my mind is ride heights and roll center. Any pics of your car on track? how's the body roll?

If you are still on stock control arms and have the car lowered enough, you put the roll center below the car's center of gravity and then it leans like a pig in the turns. all that negative camber goes away when the whole car is leaning.

https://i.imgur.com/ofMSOgN.jpg

For the roll center, what is lowered enough in your opinion?

There are hard numbers for all this, but I'm just an electrical engineer and play with security systems, not CAD and geometry. it's not that hard tho.

essentially, look at the angle of the control arm inner pivot to the pivot in the ball joint. if that is past horizontal and pointing "up" from inside to outside, then you have roll center problems. with most street cars, that's roughly around 1-1.5" lower than stock, but I've never actually done the measurements and maths on a Twin. it's likely that some of the more academic racers have done it.

I just knew my car handled like crapola and was understeering with tire wear issues and I couldn't get enough camber in the car to reduce the front wear. Sooo I put on a set of SPL arms with roll correction about the same vertical offset as my lowering, then reset the bumpsteer. next race I went 2 seconds faster on the same track and had WAY better turn in response and tire wear.

can't help with much more specifics than that cause it was 2 yrs ago.

Had the same issue with mine. Can’t remember what I trimmed off of them.

Below 140mm front pinchweld to ground, per 949

Soon I should have APR GTC Wing on, Verus Splitter, end plates and dive planes installed with track spec hood vents. Springs will be 7K front/8K rear on RCE T2s. I will report progress and performance at a variety of tracks

FWIW V730s are known to like less camber than a traditional setup due to their super stiff sidewall. I forgot where I read that specifically, but to me it is apparent because I have so much wear on the inside and very very little on the outside. Camber was -3.5 front and -2.5 rear, rear was fine but going to -3 front this year.

My setup consists (at that time) TRD lip, skirts, canards. Verus UCW (mid to full AOA), hood vents, diffuser, spats. APR splitter (for the TRD lip) that is properly flat. AST 5100 suspension with 6k/6k Swift springs. TRD RLCA, toe arms, trailing arms. I have a few other things to predominantly reduce drag too, but that isnt as important in this discussion.

By no means am i a specialist in any of this, this is just what I have concluded based on what I have found and what I have experienced.

Man, I'm nowhere near wearing the inside of my 730s before the outside with the same -3.5

That is what is strange and what makes me think you might have a different issue. I daily the car so I understand there would be more wear on the inside, but to the extent I have it is clear I am running too much camber for the setup. 5k miles, three track days, and two autocross events and the fronts are toast on the inside. Rear at -2.5 looks like almost perfect wear to me

What's your toe? Inner edge wear is almost always from toe and not camber.