HPDE track car.. need some suggestions and info
 

Hey guys, new around here. I recently picked up a 99 w/ 130k miles, NB1 miata. I'm not new to the track or track cars but been trying to gather all the info I can to try and do things right the first go around. The goal is a 220-250whp fun track car.

For cooling, is there a goto radiator option? I see Supermiata makes a crossflow radiator as does FM. The car came with a Megan Racing radiator which I'm guessing won't cut it with boost..?

For hubs I ordered a set of BroFab hubs. They seem like a solid option and should hold up better than new OEM hubs.

For brakes, the car has the non sport brakes. For the front the Afco 11.75x1.25" supermiata BBK seems like the way to go. For the rear, is it best to upgrade to the rear sport calipers and rotors, or will just the rear sport rotors (with some brackets for the non-sport calipers) be good? Is it also worth upgrading the stock MC? I see people have mentioned going to a full 1". Is there a preferred option? I like a nice stiff pedal and apparently the 99 has a smaller MC so it seems like a no brainer to replace the oem ones as I'm sure it's tired. Should I also consider upgrading the brake booster? Finally.. brake ducts.. with a turbo are brake ducts a pain to run? I'm personally opting towards getting the car running, seeing how pad life goes, and adding ducts later if need be but appreciate any input.

I'm sure I'm leaving out some other questions but for now that's enough. Obviously I will be getting a rollbar, seats, harnesses, but that stuff seems fairly straightforward. The Kraken kit with the 2560 with good vents seems like the way to go. I will remove the AC to allow better airflow to the radiator.

Any suggestions I'm all ears. I appreciate any help/input.

Supermiata radiator with a reroute here. No issues on track in the heat of the summer, but im just N/A, not boosted. Hottest day on track I think track temps were between 120-130, ambient was like 110... brutal... but the car ran great.

If you go with the big Afco setup you may or may not need cooling. I've got an 11.75x1.25 afco setup(not the supermiata one) and I put Foxhole Fab ducted backing plates on when I put the car together, but not running any hoses to them currently. You can add ducting later if you need it pretty easily.

As far as the M/C goes, I know there are a few pretty in depth threads on it, but MOST are talking about factory brakes at all 4 corners. With the big Afco's up front and their braking ability, you may or may not want/need to change the master. NOW a manual rear prop valve is a must to balance things out. Im on full sport rears, not brackets. My prop valve is only turned in about 1 or 1.5 turns so it doesnt take much, but maybe you like slightly more rear bias than front, you can adjust it.

Manual steering conversion... these cars are known to boil power steering fluid on track. Do a good one where the sector shaft is welded and the internal piston is removed, dont just pull and cap all the lines. Local guy here to Dallas does a really nice one with everything welded up and painted.

Put good coilovers on it... Xida, MCS, Penske's, etc... and good bushings. Im running A1GC delrin, or whatever they call it. Supermiata 863 bushings are another option that, since they were re-designed, seem to be a pretty solid choice also.

Theres other stuff down the rabbit hole like aero.

Thanks, someone mentioned the wilwood prop valve and it's on the list for sure. With the larger Afco's the thinking is the larger pistons would require more pedal travel to move the larger pistons. A larger diameter MC would compensate by moving more fluid, reduce pedal travel, and result in a firmer pedal..? The MC has to be replaced, so I hate doing things twice, I figured I'd just get the correct one from the beginning. I get changing the MC and booster is a bit more subjective though.

Interesting that's not something I heard.. I was contemplating going to a depowered rack but with wider tires I figured the powered rack would be nice. Does anyone make an underdrive pulley for the ps pump to maybe reduce assist?

Plan is to replace all bushings with some stiffer rubber bushings and mounts. The car has some (likely crappy) BC coilovers on it but I might just run them for the time being..

Ya that's a rabbit hole I hope to delve into later on. Maybe I can just get by with hood vents, ducting and sealing airflow to the radiator, and a big wing..

IIRC the piston area on the AFCO's isnt really that crazy compared to stock, but their braking ability far surpasses what a stock setup can do so need to be able to balance it. As far as M/C size, im not help because I run Honed booster delete which recommends a 7/8 M/C so I went the opposite direction of most people.

Ive never heard of anybody messing the power steering pump except to delete it all.

There is a massive bushing thread here to get lost in.

And as far as aero if you do a big wing you need a front air dam and splitter to balance it out... Your front grip will suffer and the car will be difficult to drive. Buddy of mine found that out as he was buying his aero in stages and did a track weekend with just the 9 live big wang and said the car was actually slower because of the understeer he was constantly fighting due to front grip.

Only got a little time to mess around before my lunch break is over so I don't have time to put my two cents in for every question.

I ran the 11.75x1.1 Supermiata BBK all last season at 210whp. My setup included sport rear brackets, rotors, and calipers w/ steel braided lines, G-Loc R12 front and R10 rear pads, stock 7/8" master cylinder, an adjustable prop valve, and master cylinder brace. I didn't add the SuperMiata brake ducts until my last event. My car is dual duty so I run the R12/10 combo on track only and run G-Loc GS1 pads front and rear on the street. I got 7 and a half track days out of the R12 front pads and still have about 40-50% life left on my rear R10s. My brake pedal feels almost exactly like a fully stock setup with steel braided lines, maybe a touch firmer. I was honestly surprised I didn't notice a bigger difference as I installed the big brakes and MC brace at the same time.

Also running BC coilovers here. Xidas are on my upgrade list but I have no complaints about these right now.

Gotcha.. I read some threads with people complaining about mushy pedals but it's definitely subjective.

Did your friend add any front aero at all? I am planning hood vents. Some people don't think of them as aero but I installed hood vents in my s2k and a big wing at the same time.. I was surprised how the car didn't understeer and was fairly neutral. It tamed the rear end down at speed with just a touch of understeer. I'm hoping the miata will be the same, we'll see.

Appreciate the response. Thanks for your real world experience w/ the brakes. I am always left scratching my head because you have people say completely different things. Some people say the 11.75 kit will be way too big but clearly that's not the case for everyone. A lot of it comes down to driver. If you're slow, you're not going to be taxing the brakes, or you're just easy on the brakes. 7.5 days isn't a lot but it's also not horrible especially if the pads are affordable. That's good to hear on the brake feel. I prefer a stiff pedal with a shorter throw.

Ya I'm hoping the BC's will do alright. I haven't given them a fair shake. Old bushings I'm sure made my initial impressions worse.

He MAY have had hood vents at the time, but I dont know to be honest. He now has the full 9 lives front aero setup on his car so its all balanced.

On the topic of bushings, can you comment on your delrin bushings? Are these Sadfab or some other mfr? I was originally planning on just doing a stiffer rubber bushing for ease of maintenance and disdain for poly bushings but maybe delrin or other kits are better than the old ES kits. Any issues with your bushing kit?

as I already posted they are A1 Ground Control sold through Miata Roadsters... As far as I know Sadfab is out of the bushing market.

I love them, but again, my car see's zero street miles. They have basically zero compliance. Once step below a spherical.

Supermiata bushing kit is "similar" except instead of using delrin they use poly, but both kits have a steel sleeve in the middle that the bolt rotates around. The delrin or poly is just basically to hold the steel sleeve in place and provide "some" cushion.

I would recommend the A1GC kit 1000%, but again, its not much of any compliance and for a car that might see the street it might be to harsh... im running 1200/650 springs on my car also so its kinda hard to judge, but no complaints from me on the A1GC bushing kit.

My apologies, I punched in A1GC into google with delrin bushings and it didn't come back with anything. I didn't know what the acronym stood for. It looks like they are currently out of stock.

The car will primarily be a track car with occasional street miles. It looks like the A1GC bushings are out of stock. I will likely just get the stiffer than oem rubber bushings and call it a day. I know some very good drivers who run the same rubber bushings so if/when I get to a point where I'm pushing the limits of the car and notice some issues I'll cross that bridge then. Thanks appreciate your input.

Not sure why anyone would build a delrin-based 'poly-bronze' bushing. Delrin is stiffer than (most?) poly, a plus for racers, but delrin lacks the 'stiction' effect that the bronze bushing is meant to overcome. This requires no lubricant, presumably a steel/steel bushing would wear without the lube. Having used rubber (factory), poly, poly-bronze, and delrin, and currently running sadfab poly-bronze in my road-biased dual duty car, I vote poly-bronze for all but the most hardened track weapons, for which delrin-no-bushes would be my choice.

There has to be a reason that nobody runs straight delrin with no sleeve. I am pretty sure even Sad-Fab's delrin kit had the steel sleeves.

From memory (quite a few years ago), my delrin went into the outer bushing housing, there was what I called a hollow 'pin' (about which the delrin rotated), and the suspension bolt went through the pin and held the pin tight (ie not allowing the pin to rotate). That replicates the poly bushing arrangement, and doesn't need a sleeve as the delrin rotates freely (without 'stiction') about the pin. The poly-bronze arrangement inserts a bronze tube (sleeve) between the pin and the poly, it is held by the poly and rotates with the poly about the pin. Again from memory, all this is set out in the bushing megathread.

The delrin in the A1GC setup is pressed into the control arm and doesnt rotate.

The delrin then needs to be reemed so the steel sleeve can rotate freely with very little slop.

The steel sleeve is what contacts the sub frame when everything is torqued down. So the steel sleeve rotates inside of the delrin. The bolt just basically aligns everything at that point and holds everything in place.

I think we are in agreement: The delrin moves with the suspension arm - that is, the arm/delrin rotates about the fixed pin(sleeve) which is held immobile by the suspension bolt. I look at it as the suspension arm moving relative to the car, you can look at it the other way around I guess.

IIRC in my instructions there was a suggestion that if the delrin was a looser fit in the arm and might/did rotate inside its housing, to pin it with a grub screw or similar. I never had to ream mine, but again that was mentioned as a possibility that may be required.

Question for you guys.. so is the OEM NB TB ok as long as you put some epoxy over the shaft/screws? It seems like the skunk2 has its own set of problems..

as long as you leave the intake manifold to block brace on you shouldnt have any issues.

It seems to be when people remove that brace that they have issues.

None of the S2 problems involve the ingesting of a screw.

None of the remedies to stop stock TB breakages are guaranteed, including epoxy, including the brace.

Don't be frightened, read the S2 threads, the fixes are kid's stuff and work, so you never again have to worry about whether the epoxy is going to work or the brace is working, maybe the screw won't do any damage on the way through ....

Any links to specific threads? I've been doing so much reading/digging over the last few weeks and I'm sure I'm still forgetting stuff. I'm all for changing things to avoid failure points, especially in a 25yr old car. It's clear the OEM design is pretty weak and adding stiffer mounts, power, etc. only adds more harmonics/vibrations to the engine which contributes to different failures. I appreciate the input from everyone and ultimately I might just err on the side of caution and get the skunk2 TB. I haven't started tearing into the car but will soon.

One question for you guys. It seems like Megasquirt is the goto standalone for Miatas. Is there a multi gauge setup/output that reads the CAN bus from the MS? My thinking was to run the standard oil press/temp into the MS and have an output (maybe via the CAN bus) to a gauge setup. Either a simple 2" gauge like gaugeART or some kind of tablet? If someone could point me in the right direction it would be much appreciated. I've been digging through build threads to gather more info but I could probably spend a year or two just digging in my spare time before I go through most info on here.
Edit: Man, there is a lot to digest with regard to displaying data including digital dashes.. Very cool.

Can confirm. I epoxied the screws on OE NB throttle and the shaft broke instead and sent a screw through my fresh 11:1 built motor.

There is no "standard" oil temp/pressure in an NB. There is a dummy switch for pressure. If you run an MS you can remove that sensor from the motor completely and put an actual pressure sensor in its place(its a 1/8 BSPT on the block so you need a converter to 1/8 NPT, they are only like 10 bucks).

To run an MS3 you need a wide band O2. I am running a Spartan 3 WB O2 via CAN. Lots of people run AEM X series. The AEM CAN signal is a bit different and a little harder to work with with the MS3 if you have other CAN devices on the network. I dont have a wideband o2 gauge of any kind, mostly because I would never actually look at it on track.

I have an AEM X gauge oil pressure gauge. This COULD output via CAN, but I dont care enough to go through the setup on the MS3 to get it on CAN at the same time as my Spartan 3. I run the 0-5v which is good enough for my purpose. I have an actual gauge I can look at(which I rarely do on track LOL), but my MS3 is setup for oil pressure fail safe to shut off if my pressure drops below 10psi(I have hot pressures of 18-20psi). If I was doing my setup again I might not even run a gauge and just use a 0-5v sensor wired direct to the MS3 and use it as a failsafe...or send the data to an AIM dash. Ballenger sells a nice honeywell 0-150psi sensor and the associated wiring plugs for like 95 bucks(and if you search I am sure you can piece together even cheaper). My AEM X gauge was ~$250... You could put that $150 towards an AIM dash.

I have no oil temp gauge as a buddy of mine has basically the same setup as me and he has never had oil temp issues. I run Amsoil 0W50 which is good to 300+ degrees. I think highest my buddy has ever seen is like 250-260.

Water temp on the NB is a 3 wire sensor which basically has 2 sensor loops inside of it. One goes to the dash and one to the ECU. While the dash gets the same "signal" as the ECU it can only interpret it 3 ways(cold, ok, hot). Cold is less than 165, normal is 165-227, and hot is above 227... When I am on track mine will flicker between "normal" and "hot" and back and forth... I datalog everything on my MS3 so after a session I will look at it... 225-230 when running is normal here in HOT HOT HOT Texas... no concern. Again MS3 can be setup with temp fail safes. One thing that IMPORTANT and cheap is a coolant PRESSURE light. Just get you a cheap 12v LED and a cheap pressure sensor(I have an AC Delco C8020). Pressure sensor grounds when pressure is lost so feed 12v to your light and ground the light through the sensor. If you lose coolant pressure, light lights up. I think mine lights up at 4psi. Temp sensors dont sense temp of air real well so you can have zero coolant and your water temp gauge will show normal...for a while... but a low pressure light will alert you to coolant loss way faster AND as long as you put it in your line of sight you will actually see it while on track.

There are a few gauges out that can grab all the CAN data and display it... They are small... you will never be able to look at actually decipher them on track IMO.

A few people run small tablets that run TunerStudio on them and run gauges via that interface and a USB cable.

The best setup is probably an AIM dash running on the CAN bus. Takes more work to get it all setup, but probably the best overall setup.

Sorry I was lazy typing. When I said "standard" I meant standard for a track car to have oil temp, oil pressure and water temp.

What size oil cooler do you run a 19 or 25 row setrab? It seems like oil cooling is definitely not a problem for most people with a 25row Setrab. A 25row is probably a little oversized for a ~250whp car so that makes sense.

Why do you recommend a coolant pressure sensor? Interesting I've never seen that recommended but I guess it certainly can't hurt if the water pump stops or you suddenly lose your coolant (although you'd probably notice the latter).

Thanks for all the info. Gauge/sensor setups are definitely tricky and tedious. I guess no way around it. A full digital dash definitely seems to be the "best" way to output the data you want without having a million gauges everywhere. I've also seen some tablets I guess running Tunerstudio.. I will say a couple multigauges are pretty effective though. Here's one I installed in the passenger visor of my s2k and I love it. The interface/setup is clucky like many but it works well and is easily visible on track and the street for the sensors I just check periodically (water/oil temp, oil press). That's a really old picture. I changed the font to white and the output but it's very visible.
https://cimg0.ibsrv.net/gimg/www.mia...43234a8654.jpg

I dont run an oil cooler on this car... If I was turbo I would run one. Setrab has a pretty good chart of cooler size needed for various HP levels. I think for 250whp(probably slightly under 300chp) I think a 19 row is likely enough as long as you have good flow through it.

And the thing is you might NOT notice you lost coolant since most people run straight water so it has no smell. Buddy of mine had that happen and he had a real water temp gauge, but by the time his water temp gauge registered it was hot, it was way way to late and his motor was fucked. Again pressure sensor will tell you almost instantly(again 4 psi) if you lose coolant.

And as far as that little gauge with 6 things on it goes, no way you would EVER see that on track, at least I wouldnt. I BARELY can take the time to look at my oil pressure gauge and its fairly large. It has an alarm function on it, but I doubt I could hear it with my helmet on and my ear plugs in. Like I said, using the fail safe functions on the MS3 is the way to go vs. relying on yourself to see a gauge and react all while trying to push the car at 10/10's on the track while watching flag stations and managing traffic... I'm personally not that good. The only gauge I really care about on my car is the tach... everything else is superfluous and its all caught in the datalog to look at later... and the fail safes for low oil pressure, high coolant temp or excessively lean O2.

That makes sense and is a good point.

I have it configured to show 4 lines. Again, that picture isn't indicative of how it looks in real life but it's very visible. I can even read the numbers from my gopro footage that sits above the center console. I completely agree that failsafes are the way to go, but it's nice to be able to check values periodically so you know if things are hunky dorey. Also, I try to be methodical and it was interesting to see and log changes stock vs adding mods (oil pan, cooler, turbo, etc.) Things like water/oil temp/oil pressure shouldn't change very quickly and they are nice to check on a straight. It was interesting for me to see in real time the oil pressure change as oil temp climbed. Unfortunately hondata doesn't support datalogging for external inputs, which is one reason I'm switching to Infinity.

Edit: Found a better shot of the gauge. Sits right next to the mirror. Very easy to see. The lower AEM AFR gauge is definitely useless on track.
https://cimg7.ibsrv.net/gimg/www.mia...81ee150d57.jpg

Lets just say I am into a minimal interior, gauges, etc... I have the factory gauge cluster installed, just not in this pic, but honestly just a tach would work for me. The factory water temp gauge is useless, the factory fuel gauge is to damn slow to be useful, and I could care less about my MPH.

​​​​​​https://photos.smugmug.com/Miata/i-Q...IMG_5611-M.jpg

Very nice! Yes I'm not a fan of gauges in my face at all, especially on a street car. A lot of people use lights but I'm a big fan of a shift beeper personally. You don't even have to look at the dash and keep your eyes up. https://modifry.com/index.php?route=...&product_id=66

Been searching the interwebs lately and this looks like a pretty compelling price point for a dash. $1k and looks decent.. Definitely would be nice to have no/minimal separate gauges.. Anyone run one? https://dd-efi.com/collections/pro-d...sh-90-05-miata

For front bumper bars.. does removing the stock bumper support help airflow significantly? It looks like a couple different people make a replacement/smaller bar. Someone on this forum and there's Charlie Moua making a Doryoku bar.

Another few random questions.. what is the lowest amount of boost that can be run on a Kraken top mount and 2560R garrett? Does it hold the wastegate spring pressure of ~8psi or does it creep at all? Also, what is the power level at ~8psi, 200ish whp?

At this point, I'm hoping to do a lot of maintenance stuff (timing belt, seals, hubs, BBK, clutch) and run the car NA for a few events before putting the turbo on. I'm sure it'll have way too much tire and brakes with 15x9.5 and 245 square but the current rpf1s I'm pretty sure won't clear the BBK.

If you are doing the Afco with 11.75x1.25 rotor you will almost 100% need to run a x10 wheel, not a x9, unless you plan to use spacers to clear the caliper.

Also a 245 on a x10, on a track car, supports the side wall much better than a 245 on a x9... Most people who track x9's use a 225.

I have had zero issues with my setup running NA with 245 x10's and AFCO's... would the car MAYBE be a tiny bit faster on a 225 due to less rolling resistance, maybe, but I have full aero which tends to limit my overall top speed anyway, so...meh.

Was out running this past weekend and came within 1 second of my buddies built NC which has 70+ whp on me. We were chasing down cars with double and triple the HP... And my car has probably 4-5 seconds in it on this track, but the nut behind the wheel isnt that good yet, also the nuts below the wheel arent big enough. I ran a 2:19, but a buddy with a similar car, who is a way better driver, has gone 2:15. He went 2:11 on hoosiers.

I'm sorry I should've said 15x9.5. I haven't ordered the Konig freeform 15x9.5's but that's what I'm planning on running. According to SM's website these wheels clear the BBK. I guess I could run a 15x10 but honestly I doubt I could ever notice the difference and saving a few bucks is nice.

Lol. Sounds like fun. I'm looking forward to getting back out on track more frequently.

What I was told when I was looking at 9.5 or 10 is that the 9.5 was really a wheel intended for NA's as they can run them slightly deeper in the wheel well to help clear the NA fenders and still not hit the suspension and what not on the inside, but on an NB with our much better fender setup, a x10 is really the preferred wheel. I also was looking at 9.5's because they were cheaper than x10's.

Again sidewall support on track.

Not so say with either you arent still going to have to roll and flare your fenders, but the X10's are the way to go.

Just a thought re: brakes - depending on your power plans you may consider the AFCO F88 11.75" x 0.81" setup, it's not listed on his website but BroFab made a run of adapters for that caliper - should be able to order them if you contact him directly.

Fits under some 8" wheels, most others with a small spacer, and uses the same massive 7420 pads. Calipers are <$50 a piece (while still available, I bought 4 spares since they're cheaper than the rebuild kits).
Gives up an amount of thermal capacity but, I suspect, is the sweet spot for factory transmission power levels (<250 lb-ft) and didn't render my collection of 8" & 9" wheels useless. Gutentight makes ducts if temps demand it.

Total cost to piece together a kit is ~$700 before pads, fluid, ducting.

Thanks for the suggestion. Yes I saw that option but the SM kit with the larger AFCO caliper which allows the larger 1.25" rotors I think is worth the extra money. I ordered a set. I'm hoping pads should last a good while and I'm going to run w/o ducts initially.

I did order a set of the BroFab hubs though as they seem like a solid upgrade over the OEM style hubs but a few bucks cheaper than the "Miatahubs."