Grabbed some scales from a buddy to try and get the car corner balanced. I was also really curious to see what the weight of the car was. The last time I weighed it was over a year ago before I added the turbo kit, wing, rebuilt the engine, etc...

This was a "good enough" attempt. I used a string and level to make sure the scales were roughly level with each other and surprisingly they were spot on. I didn't have ramps, so I had to use a jack to lift the car onto the scales. Gave each corner a little shake, climbed in the driver seat and boom, 50.1% cross weights with no adjustments.
https://cimg1.ibsrv.net/gimg/www.mia...12091e90d5.jpg


Now, this isn't perfect, considering there were a few things left in the car like my tool bag and the fire extinguisher I keep in the glovebox, but I'm going to say it's good enough for autocross. A nice sanity check, and now I know that the car with around a 1/3 tank of gas is at 2353 pounds. That means that if I wanted to, and could find a way to, I could take about 185 pounds out of the car and still be class legal.

I'm not planning to try to hit that, but I bet I could get pretty close with the following

• Remove soft top and hard top
• Remove AC
• Remove PS
• Replace battery with a lightweight unit
• Change out steel intercooler and piping for aluminum

At that point the car would be much less enjoyable as a daily for me, so I don't see that happening. I could also try to lose ~185 pounds but that would put my personal weight around -20 pounds, so that's not much of an option either.

I have very rarely seen a RR corner heavier than the LR on a Miata. Here's my own corner weights for reference (stock battery):

LF 682 639 RF
LR 584 551 RR

Read up on some posts here, I only found one F20 swapped car with a heavier RR corner: https://www.miataturbo.net/race-prep...s-64687/page2/

My point is you may need to level your scales better, or you've got something heavy in the RR corner that's not the battery. I usually see these light RR corners with stock batteries.

Nothing jumps to mind that would make the RR heavier than any of the other corners. I've got the APR wing on the trunk and a regular/heavy battery back there, but nothing crazy.

To be fair, I only checked how level the front to back was. If I run out of other projects I might try to get it setup more correctly. This was mostly a sanity check.

What's the reason for that? Anything aside from the fact that the driver is sitting on the left side? Apologies in advance for the potentially stupid question haha.

That’s just how Miata’s corner weight, couldn’t tell you why. Yes, it most likely has to do with drive weight. I’d be curious to corner weight a RHD Miata, but I’ve only worked on one or two and neither were in my shop for a corner weight.

Tecnas can be adjusted lower than 4.75" / 121mm but they won't ride well. It's what we recommend to ride/handle as well as you are expecting and we intended. To go lower requires a bunch more spring rate and the damping of Xidas.
Even 120mm might bottom too frequently on some heavier builds like a turbo NB2 with A/C, hard top, roll bar, full interior and big driver.

Thanks for the info Emilio. That's what I figured based on the instructions but the confirmation is great to have. I think after driving around a bit they've settled in around 4.5-4.75" ride height now, and I'm not having any issues with bottoming out. My old setup made me pucker on any roads with a sharp dip. Overall really enjoying them and can't wait to see how they do at Autocross in a couple weekends.

Cool.
If you have Sport springs and your car is really light, you can push that lower ride height limit. Heavier and GT springs, ride heights need to be taller generally.

I'm on the sport springs. I actually just weighed the car last week and it was sitting at 2350 with 1/3 tank of gas an no driver. Not sure if that's "heavy", but if anything the car will be getting lighter it progresses.

There's no hard number or spreadsheet for this. Just depends on how bumpy the roads are and how fast you're driving. If it feels like it's bottoming and becoming unsettled then raise it up. Your car is about average weight for an NA/NB. We see a range from 2000 to 2600 lbs.

SimBa, do you find your rear visibility to be better or worse with the 2.5" risers under the wing?

https://cimg7.ibsrv.net/gimg/www.mia...6e831cfe86.jpg

I actually got the wing from my roommate who already had it on the risers, so I can't compare the two. I can say that side mirror functionality is unaffected :idea:

In actuality, the wing usually blocks the majority of cars behind me when cruising. They're easy to see if their close up, but if they're further away they can get mostly blocked by the wing. A positive side effect, is that the wing often is right in the beam of their headlights and helps block them at night. I'm pretty confident that if it was lower you would be able to see cars behind you easier but it probably wouldn't block headlights as well, which is the main reason to get a wing anyway.

Overall, rear visibility is adequate, but not excellent.

Do you know where the wing height is currently with the risers? On my NA, I had an 11" tall wing and rear visibility was completely unaffected. My second wing was 8" off the trunk and perfectly obscured any vehicle driving behind me lol. I had it on my list to make/buy a set of risers to get it higher but never got around to it. I'm 6'0 and had my seat mounted 1/2" off the ground for reference.

I've actually never measured it. It's the APR GTC-200 as far as I know, with their riser kit. Pretty close to being in line with the roof, but below it by a few inches

Ahh, going back through other photos, I see it now. So 12.5" height. I would've guessed that to not interfere with visibility, depending on driver height. Interesting..

Part of the reason I want to put a BIG WANG on the NC is so I don't have to deal with a blind spot in my rearview mirror again haha.

Thanks. I’m leaning towards the 2.5” risers. I’ve seen some 5” ones from another company. But at that height, I might as well use a wing with a 2D element

3D wings should not be used with risers. That puts it up into the more laminar flow so you are intrinsically going to stall part of the foil. The whole point of a 3D is to use the ground effect off downward flow over the trunk in the center and catch the upwards flow coming off the side of the car on the ends.
The amount and location of that twist should be optimized for the actual airflow paths over the back of the car. The GTC200 and other 3D's are generic shapes and not necessarily optimized for any one car.

That's why we switched to high mounted 2D wings 12 years ago on Crusher, to reduce drag for a given foil surface area by eliminating the stalled sections. That seems to have started a trend and why high mount 2D wings are now basically standard for track Miatas.

Thanks for the education Emilio. Good to know.

As much as I don't consider my car to be "rice", the wing kinda is. I'm not regularly at speeds where I think it would make a measurable performance gain. I always thought big wings were cool when I was younger and this one was laying around in the garage, looking for a new home. It's also interesting to hear that about the risers. I assumed that the wing and risers were specific to a Miata (I assume that at least the wings width is tailored to the car), but I suppose APR sells the risers so people can adjust the height to suit their specific needs.

Small update today. Last week I pulled the valve cover to double check my timing. I started another thread trying to figure out why Virtual Dyno was saying my car made so little power. Still working on it, but TLDR my spark map was very retarded.
In my haste, I threw the valve cover back on and gave the RTV around the cam caps very little time to setup. Sure enough, my car starts dripping oil on the garage floor when parked. I already had noted some leaking oil from the rear of the head, so I ordered a new plug for the rear cam cap and a new valve cover gasket.

Do you ever do something, and look back completely confused about why you did it? When I built the engine I reused the cam cap plug because I forgot to order a new one and I wanted to get the engine together. I smeared some RTV on it and I think it held pretty well. However, I reused the valve cover gasket which had already been on the car for a while. Why? Couldn't tell you. I replaced every other gasket in the engine, but that was the place to cut corners.
https://cimg9.ibsrv.net/gimg/www.mia...5c6b75e978.jpg
OEM VC Gasket probably would have been smart, but this was what Amazon had available.
https://cimg0.ibsrv.net/gimg/www.mia...c30b436ab5.jpg
Note the oil that's accumulated around and below the cap.
https://cimg1.ibsrv.net/gimg/www.mia...7ae9fc8e3d.jpg
This was after I wiped up the oil that was dripping over the edge when I pulled the cap. I assume it's normal to have oil pool here, but this shows how easy it would be have a leak if the seal isn't good.

Looking at the photo above, it almost makes me want to create a channel to encourage the oil to drain back into the head instead of pooling up. Maybe if I ever build another engine I'll consider it.

I also ordered some connectors that will allow me to install the FlowForce LS Coil setup I picked up used a while back. Wanted to go with COPs but I got a good deal on these (assuming they work) and want to free up the space at the back of the head. Hopefully that job will be happening next week or the week after.

Autocross this weekend and then another PCA event the following weekend. Can't wait to see how the car handles with the Tecna's (Tecnas?) and rear ARB.

Haha, I did the same thing on my engine. Swapped every single seal during the rebuild except the crank seal. Couldn't tell you why either. Too many coals in the fire and not enough brain bandwidth left, probably. Sure enough the crank seal started leaking two months in lol.

Timing was set correctly, I assume? When I put my engine back together the second time, I over-advanced the intake cam by a tooth and it ended up costing me about 20 peak whp on the dyno. Doesn't sound like that was your lack of power issue, though.

Stoked to hear how the Tecnas and sway bar treat you this weekend! I expect nothing but greatness.

Mechanical timing was correct, base timing was off a tiny bit, but not much. Arguably within the margin of error for our timing light.

I got a good amount of feedback in the other thread (https://www.miataturbo.net/diy-turbo...epower-109760/). I also spent a lot more time listening to my knock sensor and figuring out what I was hearing. There were some noises that sounded exactly like knock examples I'd heard, but turns out that's not the case.

I was pretty confused because your NA build was pretty close to mine and IIRC you reported 250+ WHP on a spark map that you had shared with me. I ended up with similar numbers to your map when I "tuned" my spark table earlier, but VD was showing like 160-180 HP at 10-15 PSI.

Regardless, learned a lot about Virtual Dyno and engine sounds/knock in the past couple weeks. Not sure if I'll get to a dyno anytime soon, but am probably going to figure that out once/if I get some larger setup changes out of the way (Kraken + Link G4). I'm sure there's some power left on the table, but I think the latest VD estimate was ~220, which is the highest I've ever seen from this car.