M2cupcar's 1990 Mazda Mx-5 Miata FE3 Turbo (35th)

[m2cupcar]

From Tallahassee I was headed to Tampa for a big Miata event. It was an awesome drive on two Florida highways with nary a car. At least up until I started hitting pockets of traffic lights north of Tampa. With each light synchros were failing. I was putting the car in first while rolling up to the light to get around that. But then the groaning and moaning was increasing too. About an hour north of Tampa the transmission gave up- couldn't shift to any gear and horrendous grinding in neutral. Steve (GRM FreeEMS challenge Miata owner) picked up a trailer and dragged me back to his shop in Tampa. On the way there we stopped by Miata salvage shop and picked up another Miata 5spd for $80. We'd planned on working with challenge car's tune on Friday, but my transmission called for a change in the plans. Unfortunately the transmission swap is more than a swap. The little Mazda transmissions are multiple sections and in my case have to be combined with the truck transmission front section to fit the FE3 engine. Time consuming because there's four sections, so six machined faces have to be cleaned and sealed on reassembly. That took most of the day, but in the end the car was back to running/driving.

Grassroots Motorsports Challenge car Tetanus keeping broken Miata company.


Had to make a case splitter/puller/pusher to get the old trans apart.


Old trans broken apart for disassembly.

[m2cupcar]

Car made the trip back to Atlanta from Tampa trouble free. That was over 900 miles round trip on FreeEMS running on an A3 and no issues aside for the transmission. I need to work on my mechanical empathy for weak transmissions.


While the transmission was fresh on my mind, I ran by our local Mazda salvage yard, Mazmart and picked up an FD transmission and R trans drive shaft.


Overall size is very similar between Mazdas big/strong R transmission (left) and the small piece.


I have a bell housing from a full size Mazda van that will allow me to bolt up the R transmission to the FE3. I'll need to get a driveshaft made and create an adapter for the power plant frame to connect to the tail shaft of the FD transmission similar to this below.

[m2cupcar]

Got my idle sorted and adjusted. Turned out my Ford idle valve solenoid was completely seized up. Managed to salvage a valve off a spare Ford throttle body, get it swapped in and tuned. Idle control is nice.
Seized solenoid:


Different valve had different connector, so I set it up with a pig tail for connecting.




Installed



Also did some tip-in tuning.

[Fred]

Re mazda gearbox relative size being similar, there is an extra 5kg in the big box, or maybe more. I can't quite remember. But 40kg rings a bell for the big box?

Also, I *love* this photo:

[Fred]

Went out logging and riding in the passenger seat of this tonight. Rob did a few boosted pulls in various gears, feels good, mostly.

Diagnosed one miss and a couple of rattles. Looking forward to having a drive of it myself tomorrow or in a few days. Can't wait.

Also proved that internet based dwell settings are bullshit and probably from poorly designed/manufacturd low-price DIY ECUs of a certain kind. Cough. :-)

This car ran acceptably at 2ms in neutral and 3ms (or less, didn't try 2) in boost/gear. Was setup for 5ms at cruising voltage. Not sure what ideal is, a rich cold start is needed for that, but less than 5, probably.

Awesome :-) Makes me want to fix my truck... hmmm.

[Fred]

Late this morning Rob cut a resonator out of the exhaust and redid it with a section of pipe. Pretty major works before a 7 hour drive, I thought.

But it reduced the vibrations and noises quite a lot and didn't majorly impact the sound level from the tip. Good. While it was on the hoist I wedged some silicone vac hose behind a factory heat shield to guarantee it couldn't resonate/rattle/buzz. Win, too.

Then we left and at some point I took over driving and got the pleasure and honour of putting about 3 hours and 200 miles on this thing down in Florida. Back driving into Tampa Florida on FreeEMS power just like the very first car in 2009, 8 years later. Destination address the same, but coming from the north, not south, and arriving about 3 hours earlier in the evening without having chased a drunk woman in a mini-van/people mover.

The 2 litre turbo setup in the MX5 is a good combination and turns a fairly limp-wristed car into a torquey and powerful cruiser that barks on command. Nice.

Maybe Rob will drop in here at some point add his 2c to the story. He's busy now, so I doubt he'll even notice this for a few days, at least ;-)

[m2cupcar]

Can't resist- my 2c:

Feels good to wrap up another 900 mile road trip in the car.

Wonderful things:
1) working AC
2) 3.63 r/p that gives me 3500rpm at 80mph (and so on)
3) fixed exhaust without rubbing/rattles.
4) boost in 5th for passing all things

Things to fix:
1) BOV tension is too tight
2) injector dead time is wrong
3) cam cover gasket leaks everywhere because ancient
4) Front spoiler - victim of launched road debris
5) Vband exhaust leak in down pipe after WG dump

Enjoyed having a co-driver (and photographer) to swap sides/duties. This car seems to have grown smaller, or maybe I have become accustomed to driving my portly 190e?

[Fred]

Don't forget these:

1) Overrun rattle around 2500 RPM
2) ECU-caused miss at certain specific RPMs
3) Aircon leaking into footwell/out of floor pan
4) Could do with an alignment, it was *slightly* wandery at higher speeds in a dead straight line
5) Fan wiring wrong, needs change to prevent sticking on at key-off

And possibly others.

Thank you so much for letting me be your co-pilot, it was an absolute pleasure in multiple ways :-)

I have a video on my phone that I'll probably try to get published soon.

[m2cupcar]

I've gotten a bunch of items knocked off the to-do list:

✓ Fan rewired so it shuts off (if running) when the key is turned off
✓ Idle air valve tube added to valve and cold side IC tube, connected with hose. This should ensure the there's no boost leaking from the system via the idle valve
✓ New vband flange installed on downpipe second section- no more exhaust leak
✓ New ecu connection for map hose
✓ BOV - sticking/leaking fixed
✓ Aircon condensation leaking into footwell/out of floor pan- fixed
✓ cam cover gasket leaks everywhere because ancient - replaced
✓ fixed center console gauge light wiring (weak crimp)
✓ coolant fan gasket installed to protect radiator (replaced hack weather strip)
✓ Installed a new head unit with SD card and usb slot to replace the ancient CD player. Car is now 5lbs lighter.

[m2cupcar]

First v-band I ever welded. Lesson learned- be kind, weld in small steps, take breaks in between.