Miata - Track Dog Racing Rotrex Supercharger Review 

@okterrific29 I’m about to order the TDR kit and I’m not sure which blower to go with.. the -84 or a -94 with larger pulley. What can you tell me about the power curve difference between the two units with roughly the same boost output?

Oh, that's awesome! Hope the install goes well. I'm SURE you'll love it! If you have any questions that come up while you're installing, feel free to shoot me a message and I might be able to help.

Aditya Maharaj Would be really interested to hear how it goes. I’m also in NZ and considering purchasing the same kit!

Would also be really interested how much it ended up costing you for the kit and shipping in NZD.

Do you have an Instagram or a forum build? Would love to see some updates

@@Hatvelocity Hey, the full kit ended up costing around $8000 + shipping taxes. Was a bit to purchase in one go - but it's got everything I needed.

Engine noise is pretty much the same as before, with the addition of the "hair dryer like" effect that I talked about in the video (note this wasn't as severe on the cars I drove with the smaller supercharger head). I run a full racing beat exhaust, which is perfect for a DD..louder than stock but not obnoxious or droney. You do get some induction noise when you're on it. As for the clutch, that's a great question and one I forgot to mention in the video. When my stock clutch died around 110k miles I put in a Flyin Miata "Happy Meal" in prep for some kind of forced induction. It's had no problems with the power /tq numbers I'm making.

@@gsxr5922 I wouldn't trust skunk2's power gain claims. I wouldn't trust them at all honestly, I've seen and heard some horrible things

Thank you! The head unit is a Sony XAV-AX1000 and I bought it because it was the cheapest Android Auto head unit on the market (that still had a volume knob and buttons to change track). The good news is that means it was super easy to install, as it just fits as a double din standard unit (if you have an NB). It gives me Waze, Spotify, bluetooth calling, etc. The downside is that since it's not a full Android tablet, you can't run tunerstudio lite for gauges etc. I just use a cell phone mount for that, but mostly just rely on my actual gauges for monitoring. I know others have done tablet swaps, but I always found that it never quite looks as flush of an install. You also then have to have an LTE plan for your tablet (monthly expense that I didn't want). My hope is that TunerStudio will put out an Android auto app, but I suspect the market would be way too niche.

Thanks! Glad to hear it was helpful! Unfortunately, I sold my NB earlier this year and gave the buyer all of the materials, but I'm sure Gary or Will at Track Dog would be willing to get you a copy if you reach out to them with your concerns. As far as the install goes, I wouldn't say that it's easy, but not because it's hard but just because of the number of things you have to do. If you're comfortable say, changing an alternator, belts, or pulley, then you can install this. I think the hardest part was just getting the rivets and mounting brackets for the intercooler in place (you remove the radiator and pull the AC condensor out of the way, but there's just not that much space since the condenser runs out hard lines that are easy to break). Anyway, best of luck to you as you do this! I loved the kit, miss the car dearly, and still hear from the new owner that it's running strong!

Thanks for the note! Looking back, I wouldn’t have done anything differently. I did the clutch first (years ago when my old clutch finally wore out) and chose to swap to a FM Happy Meal kit then. Beyond that, I also chose to go with the TDR Radiator at the same time as I live in a very hot climate (Houston, TX). Everything else is included with the kit. You could consider doing something like forged rods so that you can make more power, but at the kit’s standard levels, I’ve been making reliable power without any problems. There’s always a “next thing” you could do to get more power, but it’s always going to be pushing the limit. This kit does a GREAT job of getting the car to a very stable and enjoyable place without many restrictions.

Great question, and I'm honestly not sure. I'm pretty confident it's a weekend's worth of work for me had I not been doing rust repairs, etc. I'd imagine the professionals could cut quite a bit of time off of that with access to lifts, power tools, etc. I'm sure if you give the guys at Track Dog a call / email they'd be able to give you a better estimate. They also run a fully specialized Miata repair shop and have installed more than a few of these.

Matheoz El Matador an NB with a 1.6 swap? Why did the owner do that?

Javier Cervantes non-US car maybe?

You're welcome! Thanks for the comment! I saw some of that in my research, but it was mostly just stories, of which I could find equal amounts for other particular turbo setups. I couldn't find anything objective about failure rates, and given my personal experiences with turbo unreliability, just figured "what the heck...it's worth a shot." It's all still been super reliable at the time of this comment.

Thanks! It was just zip-tied over behind the drivers side headlight right next to the air intake. Probably not perfect, but I think it got close.

Thanks! Depends on your state and how the emissions inspection works. To be clear, the car WOULD pass if I was able to run on a roller with a sniffer, as I have all cats etc in place. Unfortunately, my state requires being able to plug into the OBD2 port, which is not present on the MegaSquirt ECU.

I totally forgot to mention this in the review, but I upgraded to the Flyin' Miata "Happy Meal" clutch at around 90k miles when I bought the car and the clutch started going out as I knew I'd likely boost the car within life of the next clutch. That's been perfect for this power level without any problems. In terms of 5 speed vs. 6 speed, it really depends on a bunch of things, including which rear-end gearing your particular car has. Miata.net has a great document on this here: www.miata.net/garage/KnowYourCar/S8_Gears.html Also, K-Miata (for k-swaps) has a great calculator to help you look at some of the basics (e.g. what revs will you be cruising at at 70 mph with various combinations). kmiata.com/pages/gearing-calculator What this will really come down to is how you'll be driving the car. On the street? On the track? Autocross? For me, the car mainly sees street and autocross with occasional track days, and my car has the 5-speed with the 4.30 gears. This is a pretty quick gear ratio that limits the top speed (to around 140mph) but that's not a problem for my use. 2nd gear for me tops out around 60 mph, which keeps me well within boost and not too far into the rev limiter at AutoX. I also don't have to bother with a 2->3->2 shift, which always seems to negatively impact my AutoX run times. If I were to put in a 6-speed and keep the 4.3's, it would be ridiculously tight, limiting my 2nd gear to 50mph and top speed to around 130. This wouldn't be great for AutoX or the local tracks, but the car would always be in boost (could be fun on the street but also could be annoying to have to shift that much). If folks do a 6-speed swap, it's also very common to see them swap in a 3.636 or a 3.330 diff to get more reasonable ranges for everything. Also, the 6-speeds are known to be more stout under boost, but I've still yet to have a problem with my 5-speed. Sorry for the rambling response - hopefully this is helpful!

Michael Adrian yes this was very helpful! I don’t want to destroy a stock clutch with boost. I’m also looking at a 3.9 torsen LSD for a diff.

To be blunt, it didn’t make sense for me. If you buy all new parts, you’re looking at similar pricing (a new c30-94 supercharger head not a part of a kit is already $2,300, Megasquirt is ~$1000, etc), but with WAY more fab work (e.g. you’ll have to make your own brackets, etc.). If you really wanted to wait around and price it out, you could probably wait for a used supercharger head to come available, buy that, but if it were me, I’d still work with the guys on the rest of the kit. But, I’m also the kind of guy who’s too lazy to weld my own intake piping, etc.

Nope, they have fuel and timing cards that fully pass inspections that come as a part of the kit. I chose to go with MegaSquirt to eek out a bit more power/torque and for the experience of tuning. In all honesty, I wouldn't do it again...I'd just use the stuff that comes with the kit.

Great question! My car definitely had a bunch of the supporting mods, though it was mainly because it was a track car long before it got the supercharger. As for what's required, the track dog kit comes with everything you need, with the exception of the clutch. It comes with a Walborough fuel pump, new injectors, heat shielding for the exhaust, and every nut and bolt. I forgot to mention it in the video but I had upgraded my clutch when the factory one failed (a while before the supercharger). I chose a Flyin' Miata Happy Meal, though any slightly upgraded clutch would probably work great. I also ran a few extra things that are "nice to haves, but definitely not required". 1) the Track Dog Racing radiator, which is recommended by the TDR guys for track applications in high heat areas (110 degF ambient temps on a track can be pretty harsh). Supposedly they haven't seen cars overheat with a stock radiator in good condition, but I didn't want to risk it. 2) My car had a full Racing Beat exhaust (header back), which gives a slight performance increase. It is not required for the kit or the hp numbers that they list on the website, but given how rusty my exhaust was, I just decided to replace it at some point or another.

My car runs totally stock internals and am now at 2ish years with the kit on without any issues. Everything that I've read about boosted Miatas is that it all depends on how much power you're going for. Here's a great quote from Emilio (owner of 949Racing): "First a little background; The 90-93 Miata used a de-turboed version of the B6T turbo engine designed for the group a rally homologated 323GTX. The B6 in the 90-93 used the same forged crank, fairly stout rods with oil squirters and very stout block. The 94-05 use a 1.8 variant with the same basic configuration but different bore centers. The 99-00 have what most peiople think is the best starting point because the better flowing head design of those years. The 01+ has the same head but VVT variable valve timing which currently is a good an option as the 99-00. None of the Miata heads flow especialy well so the engines a natural candidate for a blower of some sort. Max whp/ part 400+ block 240 99-00 rods with perfect engine management 260 99-00 pistons 350+ crank 230 5 speed 300+ 6 speed 250 diff 180 motor mounts 200 the rest of the mounts 180 radiator 160 clutch A 200whp base 99 Miata has the same power to weight ratio as a 340hp Evo and will smoke a stock C5 Vette on a road course. A 300whp Miata is basically a street legal shifter kart." So, with that in mind, it's usually the trans that will go first (though, as I mention in the video, I've been lucky that my 5 speed has been fine). After that, it's the rods, and as long as you keep the power at 220ish who, you should be very reliable. Obviously, there's always risk, but I personally didn't feel it was significantly higher in the VVT cars for the power numbers I was targeting.

@@heymigo Thanks for the informative reply! My target would be around 200whp for my 2004 NB, which fortunately had the 6speed. Rods would be next in line on the chopping block at that point, right? I don't want to have to build this motor as it's only got ~70,000KM on it, so a conservative supercharger setup seems to be the way to go.

@@Christ_Enjoyer Yep, that sounds right and like it would be pretty safe. The stock rotrex kit tends to make ~220whp; however, I'm sure you could tweak that down a bit by changing pulley sizes (or if you run a MegaSquirt just by pulling some timing out of it).

Also only looking for maybe 175-200whp, nothing crazy. Like I said, I want to retain that stock feel and have it be reliable.

Hey Stefan! Two major changes need to be made around the radiator support. First, you'll bolt in new bottom radiator supports (this allows for the radiator to sit lower and creates more room up top). That being said, you also have to make two small cuts to the radiator support bar, and fold in around 3cm of metal to shift everything forward.

The radiator gets spaced forward (the new upper and lower mounts come with the kit but you could fab something yourself). You also have to cut and bend about a 1/2" of the Radiator support bar.

Just used the stock one and zip tied it up behind the headlight (you can see the blue zip tie in a couple of places). Didn't need anything special!

I actually sold the car a couple of years back as we had a kid and I needed something a bit more practical, but as far as I know, it's still running strong. Injectors were Deatschwerks 700cc injectors. Again, over sized a bit due to the megasquirt's ability to eek out a bit more power.

You'd have to check with the guys at track dog as I'm sure they'll have a better idea of CA emissions laws, but I believe that's true. I know for a fact it passes both VA and TX emissions (the two states I've lived in with the car) with the TDR Fuel and Timing cards.

You will never know untill you try it

It made 242hp at the wheels on a DynoJet in Houston last summer. I was running a slightly less aggressive timing map then, so probably would make more now (especially with less heat/humidity). A MegaSquirt is a fully custom engine computer that you tune yourself (with lots of help from the community), so each tune is just a file on your laptop.

Hello! I use a MegaSquirt 3 PNP from DIYAutoTune. It came with a base tune and I tweaked most of it myself, but then found a local Dyno tuner who was familiar with Tuner Studio to work the small details.

@@heymigo Sounds amazing :D

@@heymigo Thnx btw :D !!!

Yep, my engine is not currently built. If you did modify some internals, you could safely run a different pulley and make more boost, but it's not required. Tons of flexibility for the future!

I did, though I haven't installed the reroute yet. It hasn't overheated, and I honestly have been waiting until the engines out for something (I've been kicking around building it a bit for more boost), as I hate fiddling with stuff on the rear of the engine.

My car is my daily driver and sees around 25000 km per year, so my purpose was mainly for the street. It feels a lot like an inline 6 but with the benefits of it just being a bolt on. In the end, it depends on what you're looking for out of the car, but for me it was worth it and I don't regret the decision.

Depends on which one you drive the most. I'd probably keep the e30 pure and more stock, as they're way more rare than an NB1, but both would be a hoot!

It's a Sony XAV-AX100

Not a weird question. I came for the Rotrex. I left with Sony and Sparco :)

Thanks for the kind words! I was using an 80mm pulley; however, I believe TDR now offers a 75mm pulley for some applications as an upgrade.

@@heymigo thank you!

@@heymigo, I got an email from TDR saying not to go smaller than 85mm as it will overspin the Rotrex based on following calc: 130 mm crank pulley / 85 mm SC pulley = 1.53 x 9.5 (Rotrex internal multiplier) x 7000 RPM = 101,705 RPM. Are you limiting engine rpm to stay below or around 100k RPM mark for Rotrex? This is for the C30-94.

@@johncherian3942 I'd follow their advice. I actually sold my car (new kid in the family) so was going off of pictures and notes I had. It could be a fair case to lower the rpm but make more boost lower depending on your use case

I actually ran the TDR radiator out of convenience and knowing that setup worked well for the guys with the supercharger and Texas heat. trackdogracing.com/rad_tdr.aspx

Seems relatively normal, I'd guess, though I've never seen the stock ecu jumper setup. The ECU will be getting a reading from the o2 sensor, then adjusting, so a bit of cycle seems normal. You'll also see AFRs increase a bit as the car heat soaks. Mine idles around 14.2, but can span to upper 15s. Most important thing is more what they're doing when you have load on the engine, as that's when your big risk for detonation is. I have mine set to cruise in the low 15's, idle in the mid 14's, and be in the mid 11s at redline / full boost

@ Michael Adrian I'm going for a 50-100 mile break-in this Tuesday. I'm going to try to watch the numbers at all speeds/gears.

Sure thing. You can reach out to me on Reddit at u/eymigomigo or miata.net at irex or somehow send me your contact info and i'd be happy to help. I'm still fiddling with the tuning on the A/C idle-up but would be happy to send mine as a starting point. Note 1: Be careful, as I chose the DW 700cc injectors, so my fuel tables are likely off of yours. They'd also be slightly different if you don't have the C30-94 Rotrex head. Note 2: I'm not a professional engine tuner so you should be sure you're comfortable with the timing maps, etc. I just recently got a copy of the FM timing maps and am curious to compare if I'm being too aggressive or too mild.

Thanks just left you a private message on Miata.net

Good tip! Never thought of it!

Not in its current state with the MegaSquirt, thought it is emissions legal in the base kit from TDR. Since the MegaSquirt doesn't have an OBD2 port, it automatically can't pass emissions (though it would pass if I was allowed to just use a sniffer test). Passing means swapping back in the old ECU, which means changing injectors, re-installing the MAF, and plugging in the factory ECU. From there, it just takes about 1h to get the ECU to show readiness, and then you're good to go.

You're right that's what in the Rotrex manual, but not what I meant. I've been changing it every 5k but that could just be a total misread on the TDR manual. I'll check it when I get home. *facepalm*

@@heymigo It happens lol. Hopefully it's the 50k cause that's what I have been doing.

@@candycornpeeps Hey, at least that makes the $100 for a bottle of Rotrex oil a little better!

came here to say this lol! sheesh

I'll have to see if I can post the Dyno charts at some point later. Below 3500 rpm, it's basically just a slightly punchier Miata, but gains aren't significant. The car really wakes up as boost builds (around 2psi every 1000 rpm).

Michael Adrian so you feel a significant change in power under 3500rpm? I actually bought a 1993 MR2 in Dallas in January because I love the small go kart feel. It's a 2.2l non turbo. I figure next I will get an NB miata so i can supercharge it. I dont like turbo lag so that's why i'm looking at superchargers

@@cmhidalgo it's noticable under 3500 RPM but not hugely significant since you're only making a couple of psi of boost. It really does drive like an inline 6. It doesn't feel like turbo lag from a "nothing nothing nothing EVERYTHING" standpoint, it just builds like a wave. A roots style blower will make more power / torque down low, but at autoX / track I'm typically always above 3000 rpm so it works very well.

Michael Adrian yeah I just talked to my mechanic he mentioned a roots or twin screw is what I want. Is yours centrifugal?

XenoMorph811 Mine’s a rotrex

Sony XAV-AX1000. I liked it because it kept the volume knob and some of the basic manual controls. Worked great for Android Auto!

$4900-$5000 for the full kit

@@heymigo ???????YIKES 0.0

It all depends on where in the rev range you want to make power. A centrifugal (like the TDR Rotrex kit) puts out air at the square of the RPM, the engine takes in air at RPM, so boost and power/torque goes up pretty much linearly with RPM. If you want instant power, starting at low RPM, go with a roots. If you want it at high RPM, useful at the track and autoX where the revs will be high, a Rotrex tends to be a better fit.

@@heymigo I'm just unwilling to hack up my Miata to fit the TDR intercooler. Otherwise it's a nice kit!

@@MendicantBias1 Fair enough!y car was not clean enough to care. Half of my work in doing the install if not more was rust repair, so the two cuts for the intercooler were the least of my worries 🤣

I've only had it to MSR Houston so far, and it wasn't in August, but it did great! I do have the higher flow radiator and heat shielding. I also have a coolant reroute that I can't bring myself to install but will go for it if I ever have issues.

No heating issues at all. We do recommend a coolant reroute and our aluminum race radiator and we have improved air ducting that comer with the intercooler. We also offer a mirror-image engine oil cooler on the opposite side of the Rotrex oil cooler. We have plenty of customers that track the Rotrex kit with zero issues.

Unfortunately no, however KraftWerks makes a kit for it I believe

I didn't run an oil cooler for the engine oil and it was fine on track, so street will be fine. The oil cooler in the wheel well is for the Rotrex oil which is a self contained system and I'd imagine with any supercharger you'd need some way to keep it cool. That cooler comes with the TDR kit.

Any topics of interest? I have a sale pending on the car (we had a baby so moving to something a bit more practical) but I may be able to do one more video before it goes.

Michael Adrian hi, I really want to get this kit for my 1.8 NA. And I would like an update too. I don’t see many rotrex Miatas so it’s definitely something different. Topics: mainly supporting mods before supercharging and reliability update. Possibly?

@@theaznvideos I'll see what I can do! Quick TL;DR on reliability - still not a single problem with another 6-8k miles on the car (I started driving it less once we had the baby). I did a compression test for the guy buying the car and it came out perfect.

Mind if I ask what you sold it for?

In a straight line, it depends on the tire and weather. On a 245 mm BFG Rival S 1.5 in the summer, no way...but neither does our 550hp e63 😀. On all seasons in the winter, a redline shift out of first will have no problem breaking them loose. With some steering angle (autoX etc) it'll easily break loose. Because of how the power builds, it's less likely to just spontaneously break loose though.

I had two sets of wheels and tires for this car: Daily: 205/45/16 - BFGoodrich Sport Comp All Seasons Track / Autocross: 225/45/15 BFGoodrich Rival S 1.5 Friends ran 245's; however, that tends to require a light fender roll that I didn't want to deal with.

Any traction issues with your daily tires and the extra hp? I run the same tires on mine and they’re plenty grippy for backroad bombing, etc.

@@chrisrader8547 All depends on how you drive, really. In a straight line in warm weather, they're fine. If you're at 4000 rpm coming out of a corner and you stomp on it, it'll jump out.

Yep! No problems!

I drove a car with the power cards when I went up and visited the guys in Dallas, but not back to back with the MegaSquirted car. Generally, my car makes a bit more in the mid range that gives a bit more punch (bigger supercharger head and more specifically tuned). That being said, if I had it to do again, I'd probably just go with the power cards. You give up power but don't have to deal with a) passing emissions, b) megasquirt quirks (e.g. my car still won't run right in the summer with the A/C on, and still randomly just dies once or twice a week when I put the clutch in), c) tuning your car. As a daily, I think it's the easy answer.

The standard kit comes with fuel and timing cards that you wire into the factory ECU. They give you a very stock ECU experience (e.g. the car always starts, idles great etc) and the car will pass emissions; however, you give up some power under the curve. You also have to stick to the smaller injectors and supercharger head. If I had it to do over again, I would strongly consider it.

@@heymigo thank you sir for this information.

@@heymigo along with the Racing Beat header, what are the other items in your exhaust system?

@@ericvonhellens8822 I also have a racingbeat cat back. The midpipe is OEM.

Yep. The supercharger pushes more air into the engine, but you must have a way to tell the engine to put more fuel in to match the extra air. It's also necessary to adjust engine timing. You can do these things through the TDR Fuel and Timing cards or a standalone ECU like the MegaSquirt.

Wow, cool! I'll have to look that up. We're in Spring! I sold my NB but have been slowly but surely building an ND2 Club that we picked up early this year!

HR FB Pricing for the base kit is $4,900 and it is totally complete with everything you need to install on the car. I did the install myself so not sure on cost there, but I would assume it’s somewhere between 1-2 days of work, so that could be anywhere from $1000-$2000ish depending on your local shop rates?

It comes with pre-wired fuel and timing cards. If you want to go the megasquirt route, that’s on your own (though they will discount the price of their default option back off the top of the price)

Nope. I chose to use a full racing beat exhaust, but it is not required

Michael Adrian awesome thanks just picked up a stock Miata today. Once I’m done with maintenance, fixing my overheating problem and put supporting mods I’ll definitely want to supercharge it.

Houston, actually!

@@heymigo kewl! I miss Texas

If you keep your foot out of it, it's not far off from how it was stock. Highway is still 25mpg or so (at 80mph). My commute is mostly back neighborhood roads, stop and go, and zero highway. If I attempted to keep fuel economy good it's be in the very low 20s. If I'm honest , I averaged somewhere in the high teens.

It made 242hp at the wheels on a DynoJet in Houston last summer. I was running a slightly less aggressive timing map then but a bit more boost, so it could make more now (especially with less heat/humidity).

@@heymigo Holy crap!

@@heymigo how can you adjust boost on this supercharger?

@@henrylima6974 Different pulley sizes...

They have the different models for different years on their website