Thank you all!

Not ideal at all. It added a fair bit of pressure but took it in stride.

I was pushing!

Yeyeye. We do pretty well!

 

I've decided not to go to this weekend's track event, and instead spend time at home, organize the garage, organize my mind, and decide on next steps.

I received some unfortunate news this week and have decided to do a partout .... of the 6-speed transmission. My machinist friend said the hit on the tail was just enough to damage the bearing by 6 thou and I haven't had luck finding a replacement. That coupled with how the VVT feels at Autox and my local track makes me want to keep the 5-speed in there. So if any of you need 6-speed guts and a new MiataRoadster shifter, let me know!

As far as next steps with the car, I want to make it more competitive at autox without sacrificing track day capability. If the mods make the car more competitive at time-attack, then even better. These are the items I would like to address:

1. Inside wheel spin on power at lower speed corners (happened in Grand Junction and Autox)
2. Would like to negate aerodynamic lift without losing the little top end it has
3. Fix the oil leak
4. Improve IAT's
5. Reduce weight to 2330 with driver (~120 lbs off target)

Regarding point 1, I hear this is somewhat common on NA/NBs and the reason most run no rear sway bar in autox? My initial thought is to soften the sway bar and see how that works. If needed, remove it for autox and reinstall for track/street, but that sounds annoying already. If all else fails, I'm not opposed to grabbing an OS Giken with the SuperMiata tune (I want one of these anyways, but has been low priority). I'm also planning to install a larger and adjustable front sway bar per SuperMiata's recommendation. The current saw bar is not adjustable.

On point 2, it seems the 9lives racing medium downforce kit is very effective, but I don't like the look of the front air dam. I have seen pictures and posts about CSP Miatas running a small dam and splitter coupled with a spoiler. I do like what Nate has done with his NA, and also something similar to what Scott has done in his K swapped NB. I think something in between those two is what I would like for Scooter. So I'm leaning heavily towards a front GV style lip with 3" splitter+spats and an adjustable spoiler (e.g blackbird spoiler). Has someone tried this combination and has info to share? I'm also not against a **** (I like the 9Lives street ****), the only issue is that the car will not fit in my garage with one .


Nate's car. The Targa Miata has a similar setup with a splitter and canards


Scott's car. I like this, but maybe with a smaller splitter to work with a spoiler

Ripped these pictures off Nate's thread. Thank you Nate .

In all seriousness. I have no clue how to get started on building an air dam and splitter. Research required.

3. Yeah, the leak is still there, and seemingly getting worse. I'm gonna tear it down on Saturday and investigate.

4. IAT's were high (up to 70c) at autox until the car started to move. Even then it was around 57C by the end of the run. Would be nice to keep it under or closer to 50C if I can help it on a hot day. I have a header shield from TDR to install, and will attempt to wrap the ITB backplate in gold foil. I could also try to box in the intake piping near the headlight.

5. May not happen until winter time, but I've had a gutted dash sitting in a closet for a while. Between that and an antigravity battery I hope to lower 50lbs off the car. Those seem like the last two easy things I can do, and the lighter battery would make the car more front heavy. The rest is gutting the doors, gutting the trunk further, and start going after 1 lbs loses in 40 places. However, I don't really want to gut the doors until I have door bars installed since I still drive this on the road. Will have to think about this a lot more. Open to any ideas for further weight savings.

I only had a small chance to look through the datalogs of the weekend, but it all looked really good. The only issue I found was that launch control didn't activate correctly a couple of times, partially because the speed sensor spiked to 41mph when the clutch started to engage. The activation delay of 0.5s was also too long and caused a delayed activation once. Small stuff to play with another time.

 

Brother, do not be joking about partouts right now

Looks/sounds like a good to do list for the car's next iteration!

Sorry I can't remember if you mentioned it earlier in the thread, but what sways are you currently running? Sounds like you may have a beefed up one in the rear or is it stock? I don't know anyone who runs a beefed up rear bar even for track duty.

I've thought the consensus was that an airdam with no splitter and blackbird spoiler is the call for a low-mid power car, producing both drag reduction and a downforce bump. If you want to avoid the airdam, this article using an NA might provide some insight into how the splitter-only option would factor in.
https://www.verus-engineering.com/bl...closer-look-12

 

Aero... I ran front "Supermiata" aero with a BBFW lexan spoiler briefly. It was an in-between setup while the wing was on backorder, and IIRC I only did one track day in that configuration. The next time out it had a full cage and race top so lots of variables; I don't have any objective data to share, but that configuration should reduce drag and front lift. The 9LR wing was a significant improvement in high speed corners over the lexan spoiler.




This site has a pretty good CFD comparison of the the 'usual suspects' for front end mods: https://occamsracers.com/2019/05/23/...ront-end-aero/ The same info was posted here at some point, but I can't find the thread at the moment.

ETA: Z_WAAAAAZ posted the old article while I was typing...

 

I only did it because you've been a trooper about it.

The car has an Eibach non-adjustable front bar, somewhere around 1.05" thickness off memory. I'm planning to go with a SuperMiata/Racingbeat tubular and adjustable 1.125" bar. The rear bar is 14mm and has three adjustment holes on each side and I have ran it in the middle all this time. I believe is either a Racingbeat or Eibach, but can't recall. Both bars were in the car when I bought it.

Interesting point about rear bars. All I know is that SuperMiata recommends a 14mm rear bar for dual duty on their site, so I figured I would keep that but run it at a softer setting? Sway bars are 3/4 to the bottom of this page: https://www.949racing.com/supermiata...lignment-info/. But you're not wrong, and maybe I should consider a smaller rear bar.

Thanks for that link! I hadn't seen the original article and data before, but those images are the ones I had seen in other posts/blogs. Based off those I'm thinking of doing option 3 or 4, the small dam options. Clearly the big dam is crazy effective, but I don't like how they look in an NB, and possibly being unbalanced with a spoiler?

Thank you sir! That's really good information. Do you recall how the balance was with that BBFW spoiler? I wouldn't mind a big **** kit but it won't fit in my undersized 1 car garage. So for now I'm restricted to the spoiler.

From occamsracers post regarding spoilers, he points out that about ~3" tall spoiler keeps drag the same, and increases downforce which would be great. I found this picture of his car that seems to be what I'm after:

Do you have any takes on whether this may be a relatively balanced aero solution?

 

Mine didn't feel unbalanced or overly tail happy with the BBFW lexan spoiler, but speed in high-speed (70+mph) corners definitely went up with the wing. That was with 3" of splitter (I'm now running 4").

For reference, I'm running the SPM 'big grip' sway bar setup: RB 54107 / SPM 14mm on softer setting.

 

Hmmm... regarding the sway bars, I ran the 1.125" sway you're speaking of the entire time I tracked my car, along with a stock rear sway. I never moved the RB front bar out of the softer position (I should've experimented more) but that combo was pretty well-balanced once I went with a more proper front to rear spring ratio (started at 10k/8k and moved to 14k/10k). Your spring rates will play a factor of course, and I'm spitballing a bit here, but to me it seems like you could easily soften your rear bar a bit or even move down to an OEM (want mine? Lol.) for lessened wheel hop in AutoX. Again, my conjecture is based on personal experience alone.

Regarding aero, I like what he's running. Haven't seen many (or any?) of those mini-airdam/splitters on our cars before. More data from my personal experience alone: My aero setup was pretty balanced when I was running an airdam w/o splitter and a generic 59" NRG wing, which was flexing my trunk skin a bit and probably wasn't the most efficient wing. Still assuming the wing was making more downforce than a BBFX spoiler, it seems to me like the aero setup on that red NA would balance out pretty well.

Edit: Roda and I replying in near-perfect tandem all afternoon is pretty rad lol.

 

Fun fact: Running a torsen lsd requires both rear wheels to remain in contact with the track I presume from above you have torsen (sorry, been following but can't remember)?. On my atmo racecar I was surprised to see from trackside photos just how much droop the inside rear was exhibiting, and that was a caged car with an NA (11mm?) rear bar, big front bar, race valving and 12/10(?) springs.

Clutch pack lsds FTW! That takes one factor out of consideration when selecting springs/bars/shock valving.

 

Noted! Thank you for all the info. I'll up the front bar and soften the rear and then start ordering aero parts. I had heard BBFW hadn't been responding to orders/emails recently so I reached out to them before posting an order. I also wanted to know what the difference was between the CSP legal spoiler and the regular one. Since my car is in XB, I could get away with a larger spoiler but they don't post dimensions on the site. We'll see what they say.

Sweet. Thank you too for all the info. And certainly seems like I've been running my rear bar too stiff so I will go to the softest setting. I was always afraid of having too much understeer but should have experimented earlier. Oh well. It's at least an easy thing to play with.

Yes I like his setup too. Since my main goal is to reduce lift and not necessarily having huge downforce (for now at least) I think something similar might work for me.

You guys are awesome

Yep, this one has an OEM torsen. I have a feeling that droop is not impressive in my car haha. And good to know you're a fan of clutch pack LSDs. I know a lot of people love the OS Giken, and I've also read about bad experiences related to their tune. Given SuperMiata's reputation I'm confident their tune would revolutionize the feel in Scooter, but it appears I should play with the sway bar first and leave the LSD for another time.

 

Just pop an endlink off, takes less than 5 minutes and you don't need to jack up the car. Super easy to put back on at the end of the day.

For the splitter, the easy mode is the RGR mounting kit, and just cut your own splitter with the template. Though you could make your own mounting much cheaper if you have a cable swaging tool some cable and some angle aluminium.

 

Is it really that easy? If so I'll give it a try!

Agreed that RGR kit is the easy button. A friend offered to help me build a splitter and maybe a spoiler too. I'm sure he'll be happy if I show up with prebuilt splitter mounts. I'm planning for this to be a winter project though. Right now I'm focused on the sway bars and doing a couple more trackdays this season.

Time has been tight the past 3 weeks and will be worse for the rest of the year. I've done 0 work on the car since the autocross, but the only thing it really needs is that oil leak fixed. I did get some magnetic numbers, and ordered a knockoff GV lip. Haven't heard back from BBFW about their spoiler, and after taking some measurements, I think I can squeeze the 9Lives street **** in the garage with some rearrangements . The street **** might be illegal for XB though (extends ~7" over back of bumper), but I'm just going to build this thing to my wants and it'll land where it lands.

 

Hell yeah man! **** gang is where it's at! I agree, for XB just build the car and run it.

I think most people in the class realize that it's pretty loose rules wise, and won't be worried about the legality of the wing. FWIW my car is illegal because I have a wing and a spoiler and you're only supposed to have one or the other. I'm missing other bits as well that technically make the car illegal for XB, but nobody really cares. If you start winning at nats then you will get protested, but until then you should be fine.

My car came with no rear swaybar and I've been running that way ever since. I'm actually debating grabbing a stock rear bar and throwing it on. Unbolting the end links is pretty common. I've seen people do it at lunch to see how more/less bar feels when they get a new setup.

 

I can confirm the VVT mechanism definitely impacts oil pressure. I have an NA6 oil pressure gauge in my 2001, and the oil pressure changes with throttle inputs. That includes including brief, almost instantaneous dips as you get on and off the gas. I did an experiment once and unplugged the VVT, and all of that behavior went away.

 

Numbers look good, man! I need to get some magnetic ones for my car. Rolling around on the street with stick on door numbers is cool but definitely draws some unwanted attention from the authorities haha.

I'm with both of you guys on classing. I definitely want to build my car to be competitive in certain classes but we're all amateurs at the end of the day and I'm not going to let classing rules keep me from installing a mod I really want lol.

 

Thanks for that! I guess that pretty much settles it for me. Street **** it shall be! It does seem the local club here is also very relaxed about the rules; glad to hear it is possibly more widespread too.

Thanks for the info on the swaybar. I want to keep the one I have in the rear but run it in the softest setting and will also experiment with removing one link and see how it behaves!

That's what I thought and have also seen in this new engine. Getting on throttle sometimes causes a brief drop in pressure, but nothing concerning. It helps to know it is normal behavior. Thank you!

Thanks Zak! The magnets are pretty neat and surprisingly reliable it seems. I imagine it is a bigger deal in California than it is around here. In my little town the officers are used to seeing weird stuff, but the wing will certainly attract attention. Been there done that with Nate's car....

Yep, that's where I stand too. Just gonna build the thing and have fun.

In recent news, the SM front sway bar arrived and the engine is starting to show rust in the coolant. I bought one of the sacrificial anodes from SM to see if it helps any and will also do a flush. I'll try to get both of these tasks done this week. I say try because my XJ has been in need of attention and just today I noticed the AC fan isn't working, so the Miata must wait a bit more. The next planned track event is at the end of September so I still have time to get this done.

 

Yea, look at how the offroad guys do it, they have quick release pins.

https://optoffroad.com/products/quic...43967551668482

I have some 8mm alumalite already cut if you're interested. I also have the RGR setup mounted to a big sheet of alumalite and my spare trunk with ebay clown wing mounted as a big spoiler, you're welcome to test while my car is down.

 

I literally do that with my Jeep when I off road. I use Velcro straps to hold the sway bar from smashing into the suspension and that’s what I was worried about in the Miata. Thanks for pointing that out haha!

dude, that would be super awesome to test! Although the NA trunk won’t work with my
NB, would it?

 

What are the rules for wing overhang in XB? Looks like no more than 4.25" to me.



I did mount my street wing further forward than the instructions said. Mine is as far forward as I could get it while still being able to open the trunk.

 

The regs I am familiar with here measure overhang from the rear-most part of the car (the rear bumper trim), in my case 300mm was the limit, and my wing was 298mm! In my case this included anything on the wing, like mounts, end plates, and nuts/bolt heads. I conceded fully aft airfoil location to allow the endplates to extend to the rear of the permitted envelope - in hindsight that might not have been the smartest move I ever made ...

 

Thank you for checking that, Nate!

It sounds like a similar method is applied here, but with smaller dimensions.

The rule in this case is this

As GeeEmm said, I think the endplates count for this one, but that's still maybe half an inch more? Seems like it'll work!