MS3 build planning - 99 motor in 94 Miata (SC)
 

Hi there,

I'm hoping this thread can help me with my build planning, I've been researching a lot recently and am definitely deep down the rabbit hole of modding possibilties, but am slowly refining my approach. I hope people understand that if I say something stupid, I am open to being corrected in a friendly way, and am really not trying to sound like I know what I'm doing here. I'm an engineer by trade and education (soils and water, though I'm also pretty strong with mechanical stuff...electrical I have to think about longer and harder but I can usually manage eventually). I've only had the car for 9 months; before that, I spent 14 years learning about VW MkIV GTIs and working on them, so I feel like I still have a ton to learn about the ins and outs of the Miata platform. That said, let's get into it :)

I have a 1994 Miata Package A 5-speed that is supposedly on its second motor, with about 80k miles on it. It's burning metric butt-tons of oil and has only gotten worse in the few thousand miles I've owned it, so I pretty much don't drive it anymore. I acquired a used 1999 JDM(?) 1.8 motor with ~120kish miles that supposedly ran OK before being pulled, though needs a rear main seal and some ancillaries. I plan to give the head and bottom end to TrackSpeed Engineering in Santa Clara to do their "standard" rebuild (ACL race main bearings, manley H-beams, 9.5:1 supertech pistons and wiseco rings, billet oil pump), probably with upgraded valve springs too. To save on labor, and give me some work to do, I intend to mount the rebuilt head to the rebuilt bottom end and install the engine in the car as opposed to having TrackSpeed do all the work. Goal is a reliable, robust 7500 RPM motor that will either be supercharged as part of the build or can have a supercharger added on later. Intended use is weekend backroad use first, HPDE use second. Someday once the engine is all sorted, I do plan to convert this Miata to an Exocet.

I am planning on a Megasquirt MS3 because TrackSpeed works with Megasquirt, tunes them, and I was planning to use TrackSpeed to provide a pro-tune for the car once it's built. I'm looking at the FFS Supercharger Kits, either the MP62 or the TVS900, and I want to skip their "e-cool" TBI injection (I understand it probably works, but I find it very hokey, and TrackSpeed has already told me they won't touch it with a ten foot pole) and pair the physical supercharger, high flow fuel rail, larger throttle body, and intake manifold with four uprated injectors with a standalone MS3 and AEM widebands. I'm envisioning an 8 psi pulley most likely, and tuning for 91 octane pump gas. This all means ditching FFS's piggyback cards too, of course. I'm encouraged to go this route after speaking to a friend who did the same thing with his CARB-legal Whipple kit for his truck, he ditched the piggybacks and went standalone.

Sensor Details
I have to think hard about sensors because, as I mentioned above, electrical engineering is something I have to think through more slowly and carefully. I want to use the stock MAF instead of the MAP + IAT to avoid having the pressure line or other visual changes under the hood, even though I know that might leave a little power on the table. The engine came without the crank angle sensor, the cam angle sensor, the EGR valve, or headers, and I think I have to relocate the fuel pressure regulator (this is why I said the engine is JDM(?), the guy who sold it to me said it was JDM and pointed to the FPR location as the one difference between the JDM and USDM '99 motors, and suggested I go to Treasure Coast Miata to sort out a USDM mounting solution for the FPR. Not sure if that's something I have to do or just something I should do to make the engine look stock(er). I digress...

Reading this forum, it sounds like the cam/crank angle sensors for the engine and chassis years is important, so I'm happy I get to make that choice. What will be easier, to treat the motor as a '99-00 motor as far as the MS3 is concerned and just install it in a '94 car, or is it better to setup the motor so the MS3 treats it like the '94 motor?

I definitely plan on widebands, sounds like AEM is what everyone uses, and the AEM fail safe gauge looks like a smart add-on for that. I think the only sensor input left is the coolant temperature sensor, is that correct? MAF + 2x O2s + Crank Angle Sensor + Cam Angle Sensor + Coolant Temp is what I need to provide to the ECU? Some cars use crank trigger sensor instead of angle, are those actually different or synonymous?

Fuel Injectors
What are good fuel injector choices for a ~200 rwhp supercharger application, keeping in mind that the car will be running 91 octane pump gas without water/meth injection or throttle body injection? The smallest aftermarket injector I've seen is 440; Trackspeed's smallest is 640 which seems too much; I've also seen RX-8 injectors used, and I don't know what their flow rate is.

Ignition
I like the idea of going to a coil on plug setup, either the Toyota version of with LS1 coils. Is that a good idea, or am I just spending money I don't need to spend? If I do it, or want to do it in the future, do I need to be particularly careful about which ECU I choose or anything like that? I just replaced my stock ignition coil recently...

Cooling and Air Flow
I have a new OEM automatic transmission radiator sitting downstairs so I was planning to use that, probably with the stock fans since they seem fine. I was planning to do a 10 or 16 row oil cooler and an intercooler as well. The car has no heater core in its heater loop right now; if I fix that, it will include a coolant reroute, though more likely I'll end up never fixing it, going to an Exocet, and then having no heat at all. I am thinking of doing a stock 01-05 exhaust manifold.

ECU Choice
TrackSpeed sells the v3.57 board, but I've also seen the MS3Pro ECU from other vendors. Does anything about my application indicate I should go to the Pro or is the 3.57 going to be good? I guess the 3.57 architecture still shares some quirks from the MS1 which the Pro has eliminated; I could not understand fully if that would actually impact my build.

Appreciate thoughts and feedback while I work on wrapping my head around this job, thank you all!

You could use an external map sensor to eliminate the long vacuum line and use the stock IAT sensor. Would be stealthy and let you use speed density.

You really want to use map + iat sensors instead of the maf. Leave the maf in place if you want stock looks. Install the iat in a not too visible spot. The vacuum line can't really be a problem.
You could transfer the CAS to the 99 motor, but you want to use the 99 sensors for better accuracy, they are not cheap though.
EGR is not needed, just block it off.
The 94 exhaust manifold will fit. The intake will not. Get one from a 99, including its vics valve.
I'd rewire everything through the 94 connectors and treat it as a 99. This will require some rewiring of course. Nothing major though.

The Basic MS3 sold by Trackspeed does NOT use the V3.57 board but a custom motherboard, with all the cool features: switching power supply, onboard realtime baro, upgraded crank/cam decoders, multiple free analog inputs, separated grounds for PCM logic, sensors, I/O and injectors. So yeah, completely nothing like a 3.57 board.

Thanks for the replies!

I should say for clarity, I know I'm not going to meet every letter of the law, but I do aim to pass smog in CA. With an OBD1 car my understanding is that they won't read codes off of it, so as long as I show no CEL, pass a sniffer test (proper tune), and pass the visual inspection (keep things looking as stock as possible), I should be good. That means I will be using an EGR because I can't get away with removing it and pass visual inspection, even a smog tech on their first day will catch that. That's also why I want the MAF, but I appreciate that the stock housing and running MAP + IAT in a discrete fashion may also be workable, but I've already had the experience of a sharp smog tech catching a small change on my last car and marking it "tampered" in the state system so I'm hesitant to push my luck. Reading the MegaSquirt setup guide, it sounds like MAF and MAP + IAT are their two recommended routes, can anybody here REALLY make it clear why the MAF is the inferior choice? The only thing I've read about it is that it loses 3-5 HP due to the blockage in the intake. My attitude is that, whatever power this thing has with a supercharger will be enough and I'm not chasing every last ounce of power. A robust, reliable solution that has a good chance of passing smog is the goal here.

I'm happy to buy new sensors for the 99 motor, I think that would be my preferred route, and I like the sound of setting it up as a '99 motor. I could re-use my exhaust manifold (I'll check it closely for cracks, though I don't know of any at the moment) but understood the 01-05 is a superior exhaust manifold in terms of flow? At the very least, I've heard the 99-00 stock exhaust manifold sucks. Also, since I bought the entire 99 motor, I have its intake and throttle body and VICS already. I do want to use the stock 94 wiring harness and wire routing as much as possible for sure!

Thank you Reverant for clarifying TrackSpeed's board. You're making it sound like it's superior to the v3.57; how does it compare to the MS3 Pro? Do I have any use for the analog inputs?

Sorry if I'm asking questions that are answered elsewhere, I am in the thick of reading the MegaSquirt manuals as this thread evolves.

Thanks for the replies!

I should say for clarity, I know I'm not going to meet every letter of the law, but I do aim to pass smog in CA. With an OBD1 car my understanding is that they won't read codes off of it, so as long as I show no CEL, pass a sniffer test (proper tune), and pass the visual inspection (keep things looking as stock as possible), I should be good. That means I will be using an EGR because I can't get away with removing it and pass visual inspection, even a smog tech on their first day will catch that. That's also why I want the MAF, but I appreciate that the stock housing and running MAP + IAT in a discrete fashion may also be workable, but I've already had the experience of a sharp smog tech catching a small change on my last car and marking it "tampered" in the state system so I'm hesitant to push my luck. Reading the MegaSquirt setup guide, it sounds like MAF and MAP + IAT are their two recommended routes, can anybody here REALLY make it clear why the MAF is the inferior choice? The only thing I've read about it is that it loses 3-5 HP due to the blockage in the intake. My attitude is that, whatever power this thing has with a supercharger will be enough and I'm not chasing every last ounce of power. A robust, reliable solution that has a good chance of passing smog is the goal here.

I'm happy to buy new sensors for the 99 motor, I think that would be my preferred route, and I like the sound of setting it up as a '99 motor. I could re-use my exhaust manifold (I'll check it closely for cracks, though I don't know of any at the moment) but understood the 01-05 is a superior exhaust manifold in terms of flow? At the very least, I've heard the 99-00 stock exhaust manifold sucks. Also, since I bought the entire 99 motor, I have its intake and throttle body and VICS already. I do want to use the stock 94 wiring harness and wire routing as much as possible for sure!

Thank you Reverant for clarifying TrackSpeed's board. You're making it sound like it's superior to the v3.57; how does it compare to the MS3 Pro? Do I have any use for the analog inputs?

Sorry if I'm asking questions that are answered elsewhere, I am in the thick of reading the MegaSquirt manuals as this thread evolves

So I tried to post last night, messed up and like quadruple posted it before I noticed you guys do moderator reviews on posts (whoops). Ah, the joys of being a newb.

In any case, I was having more brainwaves.

Seems like there's an argument for breaking this job into smaller pieces, so at the very least I think it makes a lot of sense for me to get the engine built naturally aspirated, install it, get it to work with the ECU, and do the supercharger later. Probably do the supercharger at the same time as the COPS conversion? I'm also starting to think that, if I plan on running the 94 sensors on the 99 motor, I can actually get the ECU installed on the car as it sits and get it halfway dialled in before I do the engine swap. The engine I have does burn oil, but does otherwise run reasonably normally, moves the car around, gets it down the freeway if I need it to...it should be enough to get an ECU installed and working. I guess the downside of that is that it commits me to using the older sensors, which people mentioned are not as accurate as the 99 sensors?

So looking at it that way, if I wanted to run the car with the following sensor inputs for ease of wiring and stock appearance, what do I stand to lose over a more ideal setup?: Stock MAF with coolant temperature sensor, 1x wideband (mounted farther downstream?) and 1x narrowband, and the 1994 cam and crank sensors.

There is a huge thread in miata.net about a guy from CA who went ffs+hydra and Jeremy from FM tuned his car. Couldn't get past 180 whp without detonating.
Save your wallet and tears.

This might be worth a read: [NB] Can FFS work with megasquirt3? - MX-5 Miata Forum

You know why this site is called miataTURBO.net?
Because the supercharger forum self destructed from heat, knock, and gayness.

But if you do want to pursue this route, just pick up a used unit and buy the CARB sticker from me for $20 ;)

Yeah I remember opening that thread back when I still considered my options. You can clearly see what I ended up with.

You will have a harder timing tuning your car using MAF load. Also, fewer people will be able to help you in comparison to the enormous number of cars running speed-density.

You can literally reuse the existing wiring from the EGR function sensor and add a MAP sensor with a 2" long vacuum hose. Maximum stealth (you can leave the MAF in).

Do all Basic MS3 have this? Or just recent Basic MS3? Or just those sold by Trackspeed? I don't see it mentioned on TSE or on your site.

I ask because I don't know if my Basic MS3 has this capability. My understanding is that it uses the internal MAP sensor to sample barometric pressure only once at key on prior to engine start and that if I change elevation I will have to cycle the ignition to capture a new barometric pressure reading.

All MS2 and MS3 can have onboard baro.

It can be added to any MS2/MS3. On some MS3 Basics it's done by adding a second MAP sensor wired through the DB37. ~18mos(?) ago, it was made standard on the MS3 Basic (dedicated sensor inside the box). Dimitris can tell you if your box has it based on the serial number.

Be aware that the difference in fueling between sea level and 6500ft is only a ~9% correction. Onboard baro is definitely desirable, but for most people driving on most roads, 10% EGO authority will keep things running smoothly.

My personal experience with Marcello's MSLabs MS3 could not be any further from this.
and we literally tested what you're talking about here, 0 vs 6-7k elevation
I'm really hoping it was just his 1 unit having issues/glitches and just being faulty.

Should be easy to determine from datalogs. There are channels for both the initial baro reading (KPA measured at key-on) and the fuel correction from that baro reading.

Thanks!

Thanks for all the replies guys, I'm definitely in the steep part of the learning curve. I'm leaning more and more toward doing the standalone on my existing motor, making it work, and then doing the swap soon after (probably straight to naturally aspirated, change the wiring to the 99 cam and crank sensors with the swap, run 94s in the meantime?), do the Exocet as the next big thing and THEN leave supercharging on the table if I want more power later on. Otherwise, a ~900 lb. weight loss oughta do the trick...that approach makes me stop trying to do everything at once, which I always try to do and then go crazy planning.

But that still means selecting a setup that will handle my future plans, though I guess any MS3 will technically do just about any way you cut it? I need to better understand the Pro's versus the PNPs versus the DIYs, versus why Trackspeed's is custom...there are a lot of variants and I admit I still don't understand what varies between them!

Thanks, that was pretty informative after you waded through the shouting match. I hate to say it but Tom's attitude in that kinda makes me not want to even give him business, and I do have a lot of issues with the engineering of the FFS kit that give me pause though there's meat to his arguments too, and I do love a supercharger...

Don't knock gayness, some people are into it! :D

But more seriously, I've had turbos for 14 years straight until recently and I've had it with lag, even a little bit. Full respect for the turbo guys, and I've been tempted by the performance and support available, but I'm pretty set on having a naturally aspirated or supercharged setup in a Miata or Exocet.

Definitely, I did more reading on MAF tuning and I can see how much it seems doable in concept, but is actually a major pain with minimal support. That MAP location and routing sounds like a good approach, would it preserve my EGR function?

The same turbos for 14 years, or modern ones? Lag is defined by the design of the system and the technology inside the turbo.

I said this in my email to you, but the truth of the matter is that you aren't getting away from the 5th injector setup. Because the FFS system does not use an intercooler, it relies on the cooling properties of the fuel being injected into the blower to reduce IATs to safe levels. You can control this 5th injector any way you like, either by using powercards or a standalone ECU or even a combination of the two, but you cannot delete it.

The only way around this would be to spray water into the ports instead. Every CC of water you spray is displacing a CC of air/fuel mixture, which means the engine makes less power. You are effectively reducing the flow capacity of the system by adding water, which cannot be combusted. You could use a 50/50 meth mixture to partially combat this, but you still won't make as much power.

Are 5th injector setups hokey? Hell yes. It is insane to me that you would spray fuel into the blower to reduce IATs.

The combination of these realities is why I declined to tune your car. You cannot safely install an FFS system without a 5th injector setup, and I don't want to touch anything with a 5th injector setup. Therefore, I don't want to touch an FFS system.

I would strongly urge you to re-evaluate the decision to use an FFS system. There are other good blower options. A Kraftwerks Rotrex kit with a little DIY improvement is a good option, or any MP62 or TVS900 hotside system with dual-throttles and a conventional FMIC will do the trick as well. Even an old Whipple "coldside" like the FM Ubercharger would be a great option. If none of those strike your fancy, and you must stay away from turbos, I would go to a K24A2 setup.

Alternatively, I would urge you to drive a modern EFR-equipped Miata, preferably something equipped with an EFR6258 on the proper 0.64a/r turbine housing. The powerband and throttle response may change your mind.