Who thinks an EcoBoost Miata is a good idea?

californiamilleghia said:

Tick , thanks for the info , 

What kind of MPG does a stock ST Fusion get on the Highway at 75MPH, 

and is there Turbo lag ? Hopefully not like the "Widow Maker" 930 turbos !

and how much smaller is the 3 cylinder ?  That might be interesting for my Fiat 600  :)

This isn't exactly apples to apples, but my duratec 2.0L non turbo Focus does about 35 at 75 and 40 at 60, at about 2600lb. If you can stay out of boost there's no reason 30+ isn't possble in a small light car. 

TheTick58 said:

Conquest swap right?  In MInnesota right?  Me too, where abouts in MN?

Yep! Rochester. I like your FRE ethos, and I have a joke among some of my car friends that I think fits with it. When you have to choose two from fast, cheap, and reliable, choose cheap twice! I try not to make it a way of life, but have definitely been accused of choosing cheap twice on a few occasions.

I looked at Focus ST and Mustang Ecoboosts when I was still in the planning stages of my Conquest swap, and the $1,500-$2k starting point scared me right off. I had no idea there were 99% equivalent Fusion engines out there for <$400. My knowledge of Ford/Mazda platforms is not too deep. Although one of my goals for my project was to learn a new engine family, I ended up going Ecotec because GM stuff is still somewhat familiar to me. I'll be following this and the handful of other Ecoboost build threads so I can decide whether that was a mistake! Any chance you could get some more pictures posted? The linked ones don't work without a mnautox account.

I see you used a Ranger pan, which looks like a pretty traditional rear sump design. Is there a good front-sump option? Based on a quick Google search, NC Miata looks like about the closest thing to front-sump out there.

obsolete said:

TheTick58 said:

Conquest swap right?  In MInnesota right?  Me too, where abouts in MN?

Yep! Rochester. I like your FRE ethos, and I have a joke among some of my car friends that I think fits with it. When you have to choose two from fast, cheap, and reliable, choose cheap twice! I try not to make it a way of life, but have definitely been accused of choosing cheap twice on a few occasions.

I looked at Focus ST and Mustang Ecoboosts when I was still in the planning stages of my Conquest swap, and the $1,500-$2k starting point scared me right off. I had no idea there were 99% equivalent Fusion engines out there for <$400. My knowledge of Ford/Mazda platforms is not too deep. Although one of my goals for my project was to learn a new engine family, I ended up going Ecotec because GM stuff is still somewhat familiar to me. I'll be following this and the handful of other Ecoboost build threads so I can decide whether that was a mistake! Any chance you could get some more pictures posted? The linked ones don't work without a mnautox account.

I see you used a Ranger pan, which looks like a pretty traditional rear sump design. Is there a good front-sump option? Based on a quick Google search, NC Miata looks like about the closest thing to front-sump out there.

Sorry about the pictures, as I was copy/pasting I didn't realize they weren't following along.  I'll get the correct pics up loaded a little later.  "Choose cheap twice", I like it, I'll try to work that in too.

I havebn't had the car on a dyno yet, but the Fusion motor sems to respond well to the FPP kit, and it sure is a screaming giggle machine!

OK, I think I corrected all the images that were just links.  Let me know if anything isn't working.

Next on the list is to see if I can get the instruments to work.

The Speedometer on the NB Miata has a sending unit on the trans tail shaft.  The NC Miata (where my trans came from) uses the ABS signal, so there is no provision on the trans to connect the sensor to...  Santa brought me on of these for Christmas https://intellitronixgauges.com/gps-speedometer-sending-unit-s9020/  This uses GPS signals to determine the vehicle speed, there converts it to a pulsed signal that the speedo can read.  I need to wire it into the power/ground, find a location for the GPS antenna, and then figure out which wire feeds the speedo it's signal (yeah, electrical things...). 

The tach is a little more tricky.  I still have the entire Miata wire harness in the car, and the FPP harness that runs the motor is almost independent of the OEM system, so no ignition signal makes it's way to the tach.  Again Santa came to the rescue with this "tach adapter" https://www.autosportlabs.com/product/tach-adapter/  It isolates the signals coming from the coil packs so it's gentle enough for the instruments.  Similar to the speedo adapter, it's mostly a question of figuring out where to connect it.

Anyone have any dealings with either iof these products?

No direct experience but looking forward to your findings. I actually have a set of Intellitronix LED gauges I was thinking about putting in my car. They make nice stuff.

Oh, I updated the list of cars "involved" in the build.

DO I get to count "home made" parts as another car model?

Hey Tick are you using the oem flywheel with the Fx350 clutch? 

damarble said:

Hey Tick are you using the oem flywheel with the Fx350 clutch? 

I ordered a stock replacement from Rockauto.

https://www.rockauto.com/?carcode=2002645&parttype=5348

what will you be doing for A/C?

In reply to RCP1990 :

I'm planning to leave all the parts in my shed.

On a more serious note, it might be possible to adapt the Ford compressor to the Mazda system; however, in Minnesota there's only a few days where I would use it.  I've had a Miata for 15+ years and often dint use it all year, so I never looked into it.

Looky what I have for you:

PS: I looked at connectors and sensors.  I have a bunch of new questions for you...

Ah man- I wish I'd known you were machining those- I spent $140 at demon tweeks for their plate.

TVR Scott (Forum Supporter) said:

Looky what I have for you:

PS: I looked at connectors and sensors.  I have a bunch of new questions for you...

I haven't followed up here in a while...

Thanks Scott, it showed up yesterday, looks great!

Glad I was able to help, and let me know if anything else comes up.

Update on my project, the weather here in Minnesota is improving for a couple days, so I'm taking the opportunity to get that clutch swapped.  After that I'm hoping to get the electric power steering fabbed up and mounted, and then...well, you get the idea.

Oh, I did pick up some new tires, 245-15 Falken RT660's, and a set of 15 x 10 wheels for them.  Fun stuff!

15 x 10!  Dang, that's a big tire!

You putting those on all four corners?

TVR Scott (Forum Supporter) said:

15 x 10!  Dang, that's a big tire!

You putting those on all four corners?

Yep, spreading the love far and wide!

One of the issues with having a Form motor in a Mazda was trying to make sense of the power steering.  Sure a lot of folks just ran a manual rack, and just "depower" to the powered rack and call it a day.  I've autocrossed Miata's with both of these setups, and I'm just not convinced this allows for the more subtle steering inputs that are often called for.  That and maybe I'm just not as tough as those guys...  So I went with the option of an electronically assisted steering column.

This weekend I made a mashup of the Saturn Vue and the Miata steering columns. All the mechanical work is done, and it's bolted in place. Just need to wire it in and mount the control box.

Epowersteering.com sells a control box that feeds the power column what it needs to see to be able to get it to work.  The kit comes with a 1 turn 10k potentiometer.  I've heard that most Miata folks have this set at "near zero assist" to get a good steering feel, and that it doesn't take much adjustment to have too much help.  To make this a little easier I picked up a 10 turn 10k pot to have a bit better resolution on the adjustment.

Amazingly the Saturn Vue and the Miata have the same steering wheel spline, so I didn't need to adapt the input side shaft. I did splice in the Miata outer tube (input side) so the mounting hardware and all the switch gear would still mount up correctly.  I made a copy of the 3 bolt flange, and the Miata outer tube was only JUST too small to fit over the EPowerSteering unit, so I have to add 1 1/4" of 1 5/8" exhaust tubing to be able to get it all to fit. 

Final step was a shaft coupler from epowersteering.com.  This coupler fits the output side of the GM unit, and a stub of the Miata steering shaft is welded to the non-splined end. 

What's not shown in the pictures is the firewall mount.  That was cut off the sacrificial Miata column and mounted tot he firewall "stand alone".  The shaft coupler is supported by the bearing in that mount, and aligns the GM column.  Now just need to finish up the wiring.

Awesome build, keep it up!

Looks like I haven't added any updates in a while...

So, It's been 3 years now since I started this! The season is mostly over in this part of the country, and I see I haven't been keeping up on recording my FREcoBoost adventures. I'll try to catch up on a few things, but I'm sure I'll miss a bunch, I'll try to get them added in.

So, looking back you see I added a bigger radiator. This was a "dual core" Miata radiator. More coolant, more radiator area, all good right? Well, while it was certainly better than the OEM radiator, once I got the car on track at a track day event, it just wasn't enough. I hit 240 degrees in about 5 laps... So I "bit the bullet" and ordered up a "SuperMiata crossflow radiator". Word on the street was this was bees knees as far as high power Miata radiators! I ducted everything in so all the air coming in through the front opening went to the intercooler and the rad. I also added vents in the hood to let the hot air out. 

Dropped that in, redid the coolant lines, took it out on track and.....240 in about 5 laps. 

The next Miata option after this were $700 custom radiators. Didn't really fit the whole FRE theme, so... I bought a dual core (twice as thick), dual pass (water enters on the drivers side, travels across to the pass side in the top half, than back to the drivers side on the bottom half) big block Mustang radiator! I had to make new mounts for it (big surprise), but it fit, held a full gallon more coolant than one of the other radiators, and best of all was a bit taller, so it stuck out the bottom past the intercooler letting the rad see fresh/cool air rather than everything being preheated by the IC! With THAT radiator and a splitter, I can now run full honk for a full session, and only saw 199 degrees! For reference I drove a stock Focus ST to work, and on the highway and 60 mph it runs about 210.

So what else happened this Summer...

Well, one of the things detailed earlier was that the steering rack needed to be remounted slightly lower than original due to the motor. This causes a little more of bump steer. This isn't uncommon in lowered Miata's, and the usually cure is to raise the steering rack. Since I couldn't raise the rack (see comment above) I instead added some longer "outer tie rod ends". This amounts to using some parts designed for circle track cars that use Ford Pinto uprights (yet, 90's Miata's have the same taper as a 70's Pinto), and some big rod ends. The rod ends will need to be looked after, maybe replaced every couple years, but at least they aren't too expensive.


About half way through the Summer I had a "fueling problem" at one of the Track Night in America events. This was the same time I was having overheating troubles (see post #186 above), but as I was a couple corners past the concrete at DCTC the motor just quit. I looked things over, even checked the fuel pump fuse in my added fuse box and couple find anything obvious, but it wouldn't restart. I suspected a dead fuel pump since it was still the original pump, or something related to the OEM pump wiring since I have "tapped into" the diagnostics port under the hood to run the pump. Once I had it home and looked over a few more things I found it was the Mazda fuel pump fuse (not the fuel pump fuse I added). Go figure. Car seemed fine, and looked at all the obvious places and found nothing, so I hoped for the best (or said differently, "ran out of time"). Went to the TNiA event at BIR excited about my first "Big Track" trackday. Got to turn 3 on the first lap, car died again. After coasting to the fence I knew where to look. Replaced the fuse again, car started right up. Figured I'd call it a day rather than risk being stranded. Made it to Pit In before I blew another fuse (good thing the HVAC uses the same fuse)! That one got me onto the trailer.

After getting home (which included a flat tire on my trailer) I looked closer.

If you remember back a few pages when I was working on the exhaust system, the EcoBoost motor (when mounted longitudinally) has the exhaust on the passenger side (Miata motor the exhaust is on the drivers side). Since there is no exhaust on the passenger side, Miata's have some wiring run down that side of the transmission tunnel. A couple of these wires run the fuel pump...... I THOUGHT I had secured the wiring up out of the way, but the adhesive anchors I used weren't up to the task and had come loose. When I would turn left hard enough, the wire bundle would swing over and contact the exhaust. It must have taken some time, but eventually it melted through the insulation. THEN when I turned left hard enough it would short out the fuel pump, blow the fuse etc. I spliced on the burned part, wrapped it up in some heat shield, and bolted the anchors up pout of the way this time.... Live and learn (and buy fuses I guess...).

So, after fixing the overheating (4th radiator), fixing the bump steer, fixing the fuel wiring, I have a car that seems to run reliable.

On to making it handle. I had been using the Megan shocks the chassis came with, upgraded to some of the shelf Koni's I had. I also picked up a couple sets of 15x9 wheels. I tried 15X10, but even though the fenders are rolled and even pulled a bit, the fronts (with 245's) still looked like there was bound to be an unhappy meeting of tire and fender. So until I cut the fenders (which I don't plan to do, remember street car...), I'll be sticking to 15x9 and 245's.

I did upgrade the aero package with a second hand wing, and splitter/air dam designed and build by a friend, the car looks the part. I can't speak to whether it helps or not (since I had overheating troubles and lousy shocks before), but when I could run a full session at the TNiA and DCTC is was pretty fun! I do also have a bigger splitter, so I have options there. I had to make some adapter parts to get the wing designed for an RX8 to fit the Miata, but they mount the same way the 9 lives wing does, so if I ever go that route it'll bolt right up. I do still have the original uncut hood, trunk lid and the unmodified front bumper cover, so in about 15 minutes I can make it into an unassuming, boring appearing Miata again.


Before the last MOWOG I attended a Dyno day at Moh's Performance. Something happened that I think caused the ECU to cut boost (it suddenly dropped about 70 HP at about 5800 rpm). The 2 repeat pulls didn't have the original peak, but lined up with the "cut" numbers after 5800. I think it was just some crumby gas I had at the time. Even so it still pulled 225 hp, and 33 lb/ft of torque (with the torque peak at 3400 rpm)!


With the Koni shocks and some second hand 225 Nankang CR1 tires I was able to set fast "fender car" time at the last local autocross. Still most of 2 seconds off the pace in PAX, but getting closer.

So, all told, the cars (finally) works as a track day toy (and it pretty exciting to drive on track), works as an autocross car (and it's pretty exciting to drive on course), and works just fine as a daily driver/commuter car (where, you guessed it, it's pretty exciting). Turns out heaps of torque CAN be synonymous with MIATA!

So next year I'm hoping to come to grips a bit more with it (it's a bit different than driving a 110HP FWD CRX I've been driving for years), and have some fresh 245 tires, and I do have a few more upgrades planned...

Looks great!

I'm totally going to copy you on the electric steering assist.  Really nice use there.

Also good to know the cooling info.  I'm planning a lot of ducting on my car.

TVR Scott said:

Looks great!

I'm totally going to copy you on the electric steering assist.  Really nice use there.

Also good to know the cooling info.  I'm planning a lot of ducting on my car.

The power steering is still stronger than needed in such a light car even when it's set at the lowest setting.  I've read that an early Toyota Prius controller will work (the 2 use the same sensor).  The advantage the Prius controller has is that it has a "fail safe" mode that it enters when it isn't receiving a CANBUS signal.  I picked up a controller from a local U pull R parts yards for $15, but haven't tried it yet.  Im hoping the "fail safe mode" will be less powered.

TheTick58 said:

TVR Scott said:

Looks great!

I'm totally going to copy you on the electric steering assist.  Really nice use there.

Also good to know the cooling info.  I'm planning a lot of ducting on my car.

The power steering is still stronger than needed in such a light car even when it's set at the lowest setting.  I've read that an early Toyota Prius controller will work (the 2 use the same sensor).  The advantage the Prius controller has is that it has a "fail safe" mode that it enters when it isn't receiving a CANBUS signal.  I picked up a controller from a local U pull R parts yards for $15, but haven't tried it yet.  Im hoping the "fail safe mode" will be less powered.

In reply to TheTick58 : Loved the whole thread!

I'm a lover of the ecoboost (have the 3.5 in the truck) and an ecoboost swap in my nb sounds like a great pastime. Your thread happened to pour gasoline all over my preexisting burning drive for an ecoboost swap. In your defense, it's your fault it looks so awesome. 
I was wondering if you had any tips to pass on (outside all the wonderful information in this thread) to make life easier for the next person to dive in. 
Roughly how sad did your frecoboost end up making your wallet, to the point of the first start? 
Are there any parts you put together yourself that you'd recommend we don't bother with fabricating and just go and buy online to save the pain?
After having done it, are there any alternative engines you wish you would have tried? 
If the above question doesn't apply, I'd love to just hear more about how absolutely awesome it is to drive and what the new power is like in comparison! 
And finally, when you're really goin fast, is the car now more terrifying to drive, or does it feel like the opposite? 
Awesome car and I look forward to trying to put one together myself! 

Clutchburner said:

TheTick58 said:

TVR Scott said:

Looks great!

I'm totally going to copy you on the electric steering assist.  Really nice use there.

Also good to know the cooling info.  I'm planning a lot of ducting on my car.

The power steering is still stronger than needed in such a light car even when it's set at the lowest setting.  I've read that an early Toyota Prius controller will work (the 2 use the same sensor).  The advantage the Prius controller has is that it has a "fail safe" mode that it enters when it isn't receiving a CANBUS signal.  I picked up a controller from a local U pull R parts yards for $15, but haven't tried it yet.  Im hoping the "fail safe mode" will be less powered.

In reply to TheTick58 : Loved the whole thread!

I'm a lover of the ecoboost (have the 3.5 in the truck) and an ecoboost swap in my nb sounds like a great pastime. Your thread happened to pour gasoline all over my preexisting burning drive for an ecoboost swap. In your defense, it's your fault it looks so awesome. 
I was wondering if you had any tips to pass on (outside all the wonderful information in this thread) to make life easier for the next person to dive in. 
Roughly how sad did your frecoboost end up making your wallet, to the point of the first start? 
Are there any parts you put together yourself that you'd recommend we don't bother with fabricating and just go and buy online to save the pain?
After having done it, are there any alternative engines you wish you would have tried? 
If the above question doesn't apply, I'd love to just hear more about how absolutely awesome it is to drive and what the new power is like in comparison! 
And finally, when you're really goin fast, is the car now more terrifying to drive, or does it feel like the opposite? 
Awesome car and I look forward to trying to put one together myself! 

Clutchburner-Sorry I haven't responded sooner, been a busy Summer, and I haven't checked in here lately (lame excuse I know...).

No real "short cut tips" other than what's in the thread above.  Being the only EcoBoost(ed) NB as far as I know, there isn't much out there for parts/advise etc, so I mostly looked at how other swaps were handled (see KSwaps, V8 roadsters, EcoTECH swaps, etc), and targeted similar solutions.  The EcoTech swap motor mounts might even work, the motors look similar, but placement front to back is important to fit the oilpan behind the (modified) subframe, and to keep the HP fuel pump from being pushed too far into the wiper tray.  There are a lot of Miata's out there that people have modified in most any way you can imagine, so the solutions are out there.

The biggies are ditching the counter balancer, getting a rear sump oil pan (I used a Ranger pan, but it only holds 4.5 qts), and modifying the front subframe.  As far as engine management goes, there's a guy on ebay selling what looks like a fair bit like the FPP kit.  This is the same guy that makes the controller for the electric power steering I'm using.  If I were to do this again I'd buy from him and try that one (particularly since the FPP kit isn't available anymore...).  And buy a motor pout of a Fusion.  It has the same parts (turbo, head, valves, pistons) as the focus, but is WAY cheaper (I picked up my 73k mile motor for $324 complete with turbo and even the alternator).

All told, including the purchase of a non-running rust free NB (I bought it a year before c19, so prices were better then), I had a running/driving car for about $5000, and that's without having sold off anything.  I've upgraded a number of things since then (wheels, wing, painted the hood etc), but I think I could do it again for about that.

As far as driving, it both feels JUST like a Miata (great handling, easy to drive etc), and not at all like a Miata (can you say TORQUE?).  On the autocross course I get into 3rd quickly and never need to down shift (even in slow pin turns).  It pulls like a...direct injection turbo motor!

Here's a couple more "mostly" current pics.  Since these pics were taken I have designed new wing mounts that were made by an on line laser cut shop ("send cut send", love these guys, and they are very reasonably priced) that cleans that up a bit.

I'd say it totally worth it.