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M2cupcar's 1990 Mazda Mx-5 Miata FE3 Turbo (35th) 
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LQFP112 - Up with the play
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Joined: Thu Feb 07, 2008 9:04 pm
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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.
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Had to make a case splitter/puller/pusher to get the old trans apart.
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Old trans broken apart for disassembly.
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90 Miata | 302rwhp @ 6450rpm | 281rwftlbs @ 4800rpm | FE-dohc 2.0L turbo


Wed Apr 26, 2017 6:34 pm
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LQFP112 - Up with the play
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Joined: Thu Feb 07, 2008 9:04 pm
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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.
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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.
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Overall size is very similar between Mazdas big/strong R transmission (left) and the small piece.
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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.
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90 Miata | 302rwhp @ 6450rpm | 281rwftlbs @ 4800rpm | FE-dohc 2.0L turbo


Wed Apr 26, 2017 6:39 pm
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LQFP112 - Up with the play
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Joined: Thu Feb 07, 2008 9:04 pm
Posts: 123
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:
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Different valve had different connector, so I set it up with a pig tail for connecting.
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Installed
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Also did some tip-in tuning.
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90 Miata | 302rwhp @ 6450rpm | 281rwftlbs @ 4800rpm | FE-dohc 2.0L turbo


Wed Apr 26, 2017 6:45 pm
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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:

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FreeEMS dev diary and its comments thread and my turbo truck!
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Thu Apr 27, 2017 12:29 pm
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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.

_________________
DIYEFI.org - where Open Source means Open Source, and Free means Freedom
FreeEMS.org - the open source engine management system
FreeEMS dev diary and its comments thread and my turbo truck!
n00bs, do NOT PM or email tech questions! Use the forum!
The ever growing list of FreeEMS success stories!


Wed Oct 18, 2017 6:04 am
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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 ;-)

_________________
DIYEFI.org - where Open Source means Open Source, and Free means Freedom
FreeEMS.org - the open source engine management system
FreeEMS dev diary and its comments thread and my turbo truck!
n00bs, do NOT PM or email tech questions! Use the forum!
The ever growing list of FreeEMS success stories!


Thu Oct 19, 2017 7:21 am
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