Hi all,
After a year of lurking and taking the plunge to turbo my Miata, I am ready to jump into this forum and start the process to de-noob myself. This is a long post so hopefully in the lanes for introductions but also includes some build story and requests for advice.

My name is Rich. I am 50 years old and live in the Twin Cities suburbs. I’ve some experience wrenching on cars when young and then more recently have done some mods on a Jeep and a boat but that’s mostly bolt on stuff which is pretty tame. With a teen son that loves cars it was time to get a car project going. So, I bought a stock 1990 with 48k miles in Fall 2017 as a father/son project. He loves Japanese cars so my big HP muscle car project will have to wait for another day. In the meantime I’ve really taken a liking to this car…super fun to drive and cheap/easy to mod. It’s kind of like the VW bug of my high school days, affordable with plenty of parts available and you can change out major components with a couple of buddies in an evening. We live in the countryside so lots of curvy roads play on and this car is perfect for that.

What we have done so far:

Phase 1 over first winter:

· FM 2.5 suspension kit with yellow Konis.
· Sport brakes with blingy slotted / drilled rotors and red calipers (yes mainly for looks as I read that NA brakes are fine and of course lighter)
· 15 x 8 6UL wheels with Yokohama S rubber.
· Interior bling including Sony double DIN stereo with CarPlay (surprisingly, Siri can actually hear me with the top down). Retrofitted in seat speakers, replaced door speakers, used JDM tombstone for nice fit. New center console, etc.
· Replaced all lights with bright LEDs and put in an air horn in hopes to increase my odds not to be run over by a large SUV.
· Performed basic maintenance, etc.

Drove it all summer last year and taught the kid to drive a stick (very humbling for him as an “expert” Xbox driver). Lots of fun, wife loves it too. But somehow not totally satisfying from a performance standpoint as well as a project car standpoint. I knew adding power was not going to be incremental, it was going to require doubling down on the cost to turbo or supercharge it. In the end I decided it is a keeper and we are all in. After doing my research I ordered the MK complete kit and all that the extras that was going to require.

Phase 2 over this past winter:

· MK Turbo complete kit with MTX-L (added boost gauge as well, A pillar mounted)
· EBC (MAC valve from DIY), dual port wastegate actuator from ebay
· New plugs and wires
· FM stage 1 clutch / flywheel kit
· Torsen diff and axles sourced off a guy in NC (via ebay)
· New drive shaft
· Supermiata coolant reroute
· AC delete
· Blingy new steering wheel

As a winter project it all had to be done at once without the option to drive it between mods, which I know is against the conventional wisdom of starting with MS, learning to tune, then adding injectors and finally a turbo. Thankfully we got everything installed, but not without some drama. The old axles were not coming out under all conceivable force we could apply, so that drove us into new knuckles and even one lower control arm which was prisoner of a bent long bolt. We got it all together and running a couple of weeks ago, comfortable that the mechanicals and electrical installation in good shape. However, the tuning vexes me to no end. I’ve read the Cramer/Hoffman book and the MS3 manual but it is like a foreign language and I feel like I know enough to order a meal and find the bathroom but not to actually carry on a conversation. With help from Eddie at DIYautotune and Nigel at Flow Force, I’ve got the base tune modified to run and I’ve got a slot with a tuner and dyno in mid June (they are backed up with everyone else’s winter projects).

So far my tuning has been mainly initial required changes from the baseline tune received with the MS3PNP and then reactionary to problems. First I set the timing and injector settings. On the base tune the car ran well once warm but idle was not great, so found some advice on YouTube for tweaks to ASE, RPM curve, and tested and set my IAC duty cycles. I had some hot starting issues so bumped up the cranking pulse and can fire up now at any temp.

Once I had the idle and hot starting solved I did some VE analysis and autotuning with VEAL. I found my boost peaked at 6.5psi with the wastegate actuator supply coming off the compressor. I moved it to the charge pipe in front of the TB, expecting to pick up 1.5 -2 psi lost across the IC but nothing, still 6.5. I figured that was due to the WG actuator spring, which is not adjustable on my Churbo. I started looking for info on wastegate actuators and determined that a dual port actuator should be better at holding shut under boost. I got one off ebay for $40. With that installed I can only achieve 5psi (pre EBC), rats! More on boost to come.

Last weekend I am driving around with the wife and experiencing some occasional backfires when downshifting under no load conditions. She is not impressed. I know my tune is not right, so wanted to start from the top with the AFR table. I started to think perhaps my AFR table from the baseline tune may not be ideal for a boosted engine. I read up and found some threads on AFR tables here on Miataturbo.net. I copied a table supplied by Braineack and autotuned against that. No more backfiring but now I am too rich on idle, spitting soot from the tailpipe. Solving that is next weekend’s project.

Stuff left to do (not really in order):

1) Get the EBC working properly. So far my first few attempts to tune the EBC did not make any changes to the actual boost achieved. I’ve confirmed the valve is working and I am plumbed correctly, and that I have continuity in the grounding line back to the ECU connector. However, I don’t get any higher boost at 0 or 100% duty cycle in open loop mode. For reference, without the EBC valve I got about 6.5psi when using the original single port WG actuator and now I get about 5 on a dual port actuator when only using the top port. If I use both ports (with the MAC valve installed/open with EBC control turned off in the tune), I spike right up to 10psi at about 3000 rpm before ECU overboost protection shuts that down. I figured I would get it working on the single port first so tried multiple iterations of the boost control duty cycle table and none of them resulted in any increase over the boost as it was without the valve. I started thinking maybe the pin (R / high output 2) in the ECU is not making contact with the pin in the connector, but it only goes in one way and it is in correctly and the ECU pin is straight, so likely it is just my failed tune attempt. I will try that whole process again from scratch with the dual port set up, starting out with all zeroes on the boost control duty table and work my way up to see if that gives me a more controlled outcome. FYI with the wastegate wired open it peaks at 2.5psi…a bit higher than I’ve read that I want to be at but going with my existing port job for now.

2) Install Walbro 255 fuel pump as advised by the tuning shop (DB Performance Rogers, MN).

3) Maybe a new radiator. I was guided by Lars that the stock radiator will be good enough for my (it is not brown), so left that in. So far I am getting up to 210-220deg after running hard autotuning, which is in cool outside temperatures. This summer it will get up to 90+ and hopefully not become a problem. I have the stock fan on the driver’s side, deleted but kept the a/c fan and perhaps can put back on and tie in to provide more suction. I am also still trying to get my undertray to fit which will help cooling. I need to trim the IC charge tubes on the passenger side to pull them inboard a bit to clear the tray. The downside of that is the IAT sensor will then be inside the tray, hopefully that will not cause it to heat soak.

4) Confirm my BOV is not leaking at idle. I frankly have no idea how to do this. I can clearly hear that is opens and exhausts pressure and my turbo does not sound like any compressor stalling is happening. I did not make any changes to the spring rate so I am running blind on how to adjust it. There are no directions with it so any advice on that would be great.

Last: learn to tune. Yes, you don’t have to tell me that. I will continue to read about it, watch videos on it and tweak my tune up to my professional tune appointment (and beyond). Hopefully the light will turn on and I will get more self sufficient with the changes and in the meantime perhaps some forum members will take pitty on this noob and point out my failures as per Miataturbo.net tradition.

I know, pics or it didn't happen:

 

Hey, looks good! Sounds like you have done the research and are on the right track.

 

Hey Rich! Welcome to the forum. We all started in a similar place with the megasquirt but it gets easy quickly as you play with the settings and get some pointers.

You did well choosing the MK Turbo. Lars is great.

 

Welcome, from a fellow MN miata driver.

Good call on going to Shane at DB. He does good work for the vast majority of the feedback I've heard and did a great job tuning my RSX some years ago. Some locals have had a less than perfect experience with him but I wouldnt take that too close to heart.

If you ever end up needing OEM parts or anything really, check with MiataSource. He's a local guy that buys and stocks as many miata parts as he can manage. He's a younger guy but awesome to deal with and very fair with everything.

If you or your son are on FB you could join the MNMX5 group as well for info on meets, cruises local for sale items and asking general questions. The group is fairly split between loud mouthed idiots and nice/helpful folks. Per usual for FB car groups but I'd say this group is a little better than most. A pretty big and consistent age range as well among members.



Anyways, welcome, hope to see you and your son around this season

 

Thanks for the warm welcomes 1RMDave, sixshooter and KevinK121.

Kevin, I am glad to hear you had good experience with DB and well noted for MiataSource. I am not on FB, is there any other way the group communicates? I am interested to meet some local enthusiasts and especially folks who can speak the language of mods, turbos & tuning!

 

Unfortunately, not that I'm aware of.

There used to be a few neat local car forums but FB groups have since paved the roads right over the old forums.
I'm not that old but even I miss the forums. Much more effective and efficient.

We should get an email list going lol. I know theres a few other non fb users in the area who'd like to keep up these things. I'll bring it up to the page mods.

Alternatively, I have more than a handful of friends who created facebook accounts for/about/featuring their car for the sole purpose of tracking events, pages and for-sale items. They dont even use their own names or pictures. Just their car's name and pictures.

Just a thought.


Theres another local member whos fairly active on this forum under the handle der_idiot(or some such). Hes got a beaut of a turbo build going. Big ol borg efr and all.

If I werent replying from my phone I'd try and link his build thread.


Anyways, best of luck.

 

Kevin, I will PM you my email address in case you have any traction with an email list, thanks for that! I will have to noodle on the FB account for my car...interesting idea and might allow me to stay out of the slippery slope that I would otherwise like to avoid. In any event, nNow that I am up and running I will also be seeking out some cars and coffee type stuff to get connected to the local community. I believe there is a club sponsored by Morries in Minnetonka, could be a lead as well.

 

Welcome! Fellow Twin Cities member as well here so good to see you and your build on here.

a) That MNMX5 group is the same one that Morries hosts

b) MNAutox is a forum with a few Miata-philes - made for autocrossers but still a great community of helpful folks in the local area

c) Clubroadster forums has it's own MN space but I do not jump on there much if at all. Only reason is to browse for sale sub-forums to look for parts

 

Thanks Miataki, appreciate the tips/leads.

 

Very Clean Car.
How do you like your Cipher wheel, and what center console is that?

 

Many thanks Nordz. The center console is from IL Motorsports. It is comfortable for my arm but the cup holders are not very functional. They are shallow so a standard size water bottle will tip over. Also, when you push the passenger seat forward there is interference. My passenger seat is always all the way aft, so that's not a big deal expect for when I want to pull the seat out and need to get to the rear bolts.

 

Oh and I love the Cipher wheel! Massive upgrade in comfort and style. 10 minutes to install too.

 

We almost have the same setup. The only differences are things I would have chosen anyway. You are just a few months ahead of me. And vastly better looking car.
Its like looking at someone elses school project and realizing they made a better version of my project. haha.

 

After 6 weeks of patient waiting I finally got the tune done today at DB Performance in Rogers, MN. Shane really knows what he is doing! I was targeting 180hp and 165 ft-lb torque @ 10psi. He achieved 191.4hp and 172 ft-lb @ 10psi. My EBC problems were my own doing as I had the negative lead pin in the wrong slot in the MS option connector. I was "reading" the diagram in the manual mirror image thus what I thought was pin R was actually pin J. Once that was swapped over the the real pin R the EBC valve worked like a charm and we were able to get a steady 10psi from about 4000 rpm up to 6500. I am one happy camper!