Turbo Miata

Crossroads

2008-04-21T20:04:55Z

I'm still trying to decide what to do. I haven't even cranked the car up since late January. In retrospect, I'm pretty sure it has spun a bearing due to the lack of oil.

Options:

Install a used 1.6L engine from junkyard/parts supplier
Install a used 1.8L engine

Junkyard
Part out my 1.8L car, use that engine, which has 80k/miles on it (slight problem, in that I need something to drive while doing this, as the 1.8L is the DD)

Rebuild an engine

The spun-bearing 1.6L (130k/miles)
The missing piece of pistons 1.8L (112k/miles)

Part everything out / sell it

I've got a quote for about $1000 in parts/labor to rebuild the spare 1.8L block I have in my garage, which is now mostly disassembled. A little more to get upgraded pistons ($350), rods (???) and ARP hardware. The quote includes new stock pistons, full gasket kit, bore/hone/etc and the machine shop will fully recondition the head. That is parts and labor. I figure I'm intelligent enough, I can bolt the head to the block and torque head bolts and install pistons/rings/con-rods to the crank and save on the labor for that part of the process and learn something.

Used engines are running almost $1000 for ones with a little less than 100k from what I've seen when I was looking. That's not a very enticing option. I can probably get a 1.6L motor for $400 used with close to 130k miles on it but all that work to put a motor in that probably won't have very much life in it? I paid $650 for a 60k/mile engine nearly 3 years ago. I guess we can thank the Spec Miata racers for drying up the parts market.

The whole thing running through my head is this is $1000 being spent on a car I bought in its entirety for not a whole lot more than that. In addition, I'm not sure how long I'll be able to keep the car given changing life circumstances, so I'm also trying to weigh that aspect into the process as well. Too many projects.

If I go with the 1.8L motor, I have to build a new turbo manifold. Not so bad doing it the second time and I have the turbo placement already worked out. I can probably knock that out in a day, especially if I use prefabricated head and turbo flanges.

Still need to think some more. Meanwhile, I guess I'll work on the other project car. :)

Two dirty words I was hoping not to utter...

2008-01-26T16:13:10Z

Rod knock and at least two quarts of oil burned in ~1500 miles. Great. :(

More commentary to come after I've progressed further through the Kübler-Ross stages.

Bigger brake musings

2008-01-22T16:11:11Z

In yet another in a series of diversions (feature creep), I've started to think about what I want to do about the brake situation. The 1.6L comes with smaller rotors than the 1.8L cars. If this is to be a trackable car, IMHO, I think it needs bigger brakes. :)

I came across some links (this one too) about fitting FD3S/T-II calipers to a Miata. The first one looks like a lot of work to me. The advantage is, though, I have a set of FD brake calipers in my stockpile, so those parts would be free and I have some race and street pads. If I were to, ahem, upgrade the FD, then I would also have spares for this car. ;)

Several concerns with this:

Cost of pads - I would like to have a wide selection and inexpensive pads. FD pads aren't made by as many companies as a Wilwood/AP/Outlaw caliper, so I'm limiting myself in this aspect. I should research the FD pad size and see what comparable "generic" pad for a racing caliper costs, if it is significantly cheaper, then this is a vote in favor of the racing calipers instead of trying to retrofit FD calipers.
Cost of rebuild - Mazda kits aren't too bad
Time/effort to fit - given the FM/Goodwin kits are $1600 for all 4 corners (different brackets for rear to increase swept area/rotor diameter), this needs to be cheap and easy. If there's a way to just bolt them on with an adapter, I'd be all for it but having to cut off the mounts and grind them down isn't very appealing and then I don't have interchangeable spares (until the FD goes bigger brakes).

Bob Bundy has played around with this quite a bit. I have some archived Miatapower posts on the matter for reference. I'm inclined to follow in his footsteps since his car is used for the same thing I intend mine for.

I have a spare set of 1.8L rear calipers/brackets I can use. Add pads/rotors/rebuild kit and I have a bolt-in solution for the rears for more swept area. The issue becomes bias with the fronts. From what I recall reading about the FM kit, they select the front calipers in such a way that a different MC isn't needed and the bias is not affected (with different brackets for the rear). Same thing goes for what I've last heard about the FD from RacingBrake.

I need to get the Miata in the garage with the wheel off and see how the FD caliper would fit and do some research on pads. Bigger rotors are going to be the same money wise and are essentially independent of the caliper decision (thickness aside). They will definitely cost more than a combo set of stock 1.8L rotors/pads from PlanetMiata.com.

More on this after I do some more research.

Back together, sort of...

2008-01-19T21:00:45Z

Put the radiator mounts back together and the automatic throttle body on. Decided to just front the $2.00 and use the paper gasket. It cranked it back up and idles okay (a little hunting though). Yay, back to two running cars.

Found a source for a new TPS sensor connector - a Bosch 4-wire connector but requires minor trimming of the alignment tabs.

Now, I just need to order the pins for the COP plugs and do the wiring to the 'Squirt and it should be ready for dyno tuning.

First track event of the year is coming up early February. I'm not sure if it is realistic to get the car sorted out and a rollbar in it in time...

Catching a falling star, err, falling vapor...

2008-01-07T07:02:49Z

After putting the car together for the first time and finding a nasty oil leak (which prompted me to pull the oil pan AGAIN), I realized that I capped off the outlet for the valve cover and was pressurizing the crank case. Oops! So, to make sure that wasn't causing the oil leak at the front of the motor, among other things, I added plumbing to the intake side of the compressor so that I didn't cap off crankcase.

Well, you see, you don't necessarily want a hose going directly from crankcase vent to the intake, because there is all sorts of nasty stuff in that vapor, so most folks install a catch-can in between. I built a catch-can out of scrap aluminum tubing, some stainless steel scrub pads and a radiator drain-cock. Remind me to NEVER make my own weld-bungs. Takes for-freaking-ever to tap NPT fittings in 3/8" thick aluminum. Well worth the $3 each to just buy them and weld them in but what can you do when you can't get them locally and you want your car back together ASAP?

Anyhow, I'm pleased to report that the DIY catch-can works like a charm. I've drained for the second time and I'm not getting any oil, only some "milky" liquid, probably mostly accumulated water vapor (but it smells of petroleum products). I guess the motor is okay (no blow-by from rings) and the oil feed/drain for the turbo isn't backing up and causing oil to blow past the seals and get into the intake there, either. It is good when you almost engineer something right the first time!

Down for some "light" maintenance/upgrades

2008-01-07T06:48:19Z

With the radiator mount "broken" (it is really a 5 minute fix, if that, but I want to get better hardware from Lowes/Home Depot instead of the Harbor Freight assortment I originally used), I decided it might not be a bad time to take the car down for a bit and do some maintenance and inspection.

One item I've been neglecting is installing the 1.6L automatic throttle body so that I can have a proper TPS sensor for the MegaSquirt. I still need to find a suitable way to connect to the electrical terminals on the sensor since the connectors are different between the two TPS sensors. Yuck.

I got the TB bolted on, only to find the gasket material not reusable, so I need a new gasket. I started to cut one out of copper but it isn't proving to be as easy as I thought it would. I should probably replace the small coolant lines for the throttle body and thermowax/idle valve while I am at it, since they are original and are a potential failure point.

Another thing I would like to get done is the COP wiring. I need to order the pins from Newark and wire up to the MegaSquirt, which reminds me, I need to mount it permanently, find the missing end-plate for it and while I'm in there, either re-ground the Innovate to the 'Squirt or recalibrate the Innovate output to compensate for the slight difference in AFR shown by the 'Squirt versus the Innovate LM-1 (it errs on the rich side, so I wasn't concerned). These mods would get me to the point where I would feel comfortable in spending money to tune the car (on a proper dyno, of course).

I should also probably reinstall the stock water temp and oil pressure gauges in the cluster so I'm not "blinded" by the lighting from it at night and speaking of night driving, move the Hella lamps from the '94 to this car since it is being driven more or start crafting a dual headlamp pop-up kit ala Moss with Xenon bulbs/ballasts. I'm resisting the urge to put a bar and plate intercooler because of how ugly some of those welds are, among other things.

Ahh, good old feature creep! Down boy, down! Just get it back up and running again!

Finally "broke" after 1100 miles

2008-01-07T06:43:25Z

I was taking pictures of the car today for the blog and noticed that something finally "broke" on the car. The whole time I've been driving it, I've been expecting "the other shoe to drop" and have mostly met with success.

The driver-side radiator mount lost the one and only bolt/nut/lockwasher holding it, so the radiator was only being held by the passenger-side mount.

Not good because if that mount goes, the radiator is being supported by the two radiator hoses/plumbing which is not very sturdy.

I have some ideas on how to beef up the mounting brackets but I think I'll just put some better quality hardware on there for now until I get a chance to really spend some time on the nose of the car (the ducting), which may require me to change my mounting strategy.

The next VMIC setup I do, I will definitely use a "beefier" mounting strategy than the brackets I fabricated for this project.

Boost pattern observations

2008-01-05T07:39:11Z

Was observing spool-up patterns driving around in 5th gear around town today. I can floor it at 40mph in 5th gear and the car doesn't go all "weaksauce" begging for a mercy downshift as it would N/A.

2000rpms: seeing positive manifold pressure
2500rpms: ~4-5psi
3000rpms: solid 7psi

Tachometer tends to read high compared to the tach on the MegaTune, so the actual engine RPMS may be lower than indicated. Need to look at datalogs to corroborate.

I wonder what happens when I turn up the wick to 10-12 psi? I've got the fuel and intercooler for it. Are my pistons and con-rods up to the task, though?

The current "laundry list"

2008-01-05T07:00:00Z

Stuff left to do:

Add some ducting to the IC and radiator

...not that it really needs it with air intake temps 10 degrees of ambient
Reinstall undertray

Clean up the ECU wiring/install
Get car corner balanced and aligned (bushings/new camber adjustment bolts beforehand though)
Transmission whines in 4th, investigate possible fluid leak
Upgrade stock 6" VLSD differential. Uh, yeah. That's not going to last long. Time for something bigger and bulletproof. :)

Adapt N/A FC3S differential?
T-II differential?
Hybrid '94+ Miata?

Miscellaneous rattles and noises (front bumper cover needs some fasteners)
Install competition motor mounts, make sure steering shaft rub is resolved (drive a cloverleaf with some speed)
Permanently mount ECU and stereo amplifier
Rollbar, seats, harnesses

Cut out stock seat mounts from chassis to get me needed 1" of height

Replace POS unsprung race clutch with something more streetable, maybe 1.8L + light flywheel?
Relocate water temp sender for ECU since it shows false hot (210F+) when bubble or coolant evacuates to reservoir and immediately drops down to ~190 in seconds
Reinstall stock water temp gauge with linearization mods
Adapt Autometer pressure sender to stock gauge (break out PIC programming references/beg EE for simple l-pad solution)
Fix oil leak
Re-fit piping for Magnaflow catalytic converter
Move 'squirt fan output to different ECU pin, current pin will be needed
Wire in clutch-switch for flat-shift/LC (after differential and clutch replaced)

Future:

SuperPro urethane bushings and newer camber bolts
Bar-and-plate I/C
Oil cooler
Make a mold of gauge cluster hood, add "ears" for gauges, modify/fix so the mounting tabs don't break
Bigger brakes

Use FD3S fronts or acquire "racing" product

Investigate price/pad availability for each caliper
Brake bias with bigger brakes?

I have spare 1.8L rear calipers/brackets

DIY "built" 1.8L motor

Equal-length turbo manifold
Divorced wastegate downpipe or external wastegate

The first few weeks back on the road

2007-12-26T07:37:08Z

The good:

MegaSquirt fired up on the first cranking. Good for me for double-checking my wiring and double-checking that I had the coils reversed. After swapping the plug wires, it fired immediately and idled. Sweet.
No major leaks with "10 miles" of relatively untested coolant piping
Car didn't fall apart or strand me with around 25 miles of driving
Update: ~200 miles on the trip-meter, still running strong, running 6 psi of the WG spring
Update: ~1000 miles on the trip-meter, everything is fine, probably should take it apart a bit to check/torque everything

The bad:

Lots of noises/creaks. Some I can identify (hard top, glovebox), some I can't.
Still leaking a little oil. Darn. Oil pan has been installed twice since the car was taken offline, I'm not doing it a third time.
Stutters occasionally. Probably due to excess fuel. I think the spark plugs are begging for mercy and I'd need the COP system in place to light the fire.
Maps are pig rich everywhere. Need to be leaned out. AFR of 10's under boost (which FM considers "low" and to be tuned to 12.5). Ignition values are unknown but don't hear pinging. Again, tuning ($125/hour x 2-3 hours).
Losing coolant somewhere or coolant doesn't bleed well with the radiator as positioned as reservoir tends to be empty.

The ugly:

The rust. Need to do something about it before it gets worse.
Paint/fiberglass chip on the hardtop. Annoying.
Car needs washing. Bloody Durham county water restriction. Can't wash car in my own driveway with water that I pay for. Mental note: take pressure washer (which only uses a couple of gallons of water) borrowed from parents to wash house, wash car at parent's house in Forsyth county at next visit instead of extortionist car washes.

A long time ago...

2007-12-25T08:01:42Z

...on an eBay auction far, far away (New Jersey)...there was a turbo Miata...which seemed to be a heck of a deal.

Having ridden in and owned a stock Miata, I knew that a turbo Miata was in my future. However, I didn't know what a rocky road it would be to get one "right".

Having spent so much time working on this project, I have lost count of all the things I have found that were wrong, both serious or benign. I started to keep track of them but the list just got so darned long, I gave up. I'll attempt to recount all the things wrong with the "deal of the year".

Intercooler:
Routing of pipes "doubled back" just to use the stock configuration of piping of the NPR/Conquest I/C
Pipes hung low and were once knocked loose by exiting my driveway wrong. This results in the AFM-based stock ECU not knowing what to do and the car was marooned half-way exiting my driveway.
Pipes so low they scraped.
Undertray doesn't fit with said pipes, undertray omitted/removed, cooling issues ensue (watch stock water temp gauge climb as you got on boost in warmer weather, well, there are other issues at hand as well)
Steel pipes, ghetto stick welds, JB weld need I say more?

Motor:
OIl pan tap for oil drain - leaky
Oil drain hose - ghettofabulous copper fittings from Home Depot plumbing that leak
Wrong type of hose for oil
Rediculous number of AN fitting for oil feed hose
Home-built banjo bolt for oil feed
AN-6 oil feed, no restrictor in feed
No water lines for turbo
Wrong turbo. Too freaking big, spools up at 5000rpms (many contributing causes possible for this)
Fuel management = set static fuel pressure to 90psi (not even an RRFPR)
No timing retard device
Boost @ 10 psi with above (granted, it made 150 rwhp peak as configured on a DynoJet)

Wiring:
Wire-nuts used copiously
Solder used where it shouldn't be
Crimps done wrong
Wire insulate occasionally "slitted" and new wire inserted to "tap"
Wires wrapped together and throw electrical tape on them
PWM dimmer circuit tapped and all sorts of rediculousness to dim the gauges
Vampire taps (evil buggers)
Two fans wired to the RELAY power source
...this was done the HARDEST way possible, by cutting/splicing wires in the fusebox and not just grounding the coolant thermoswitch to turn both radiator fans on at once (or by tapping in the diagnostic terminal box)
No horn button, bare wire for horn, if that
Airbag light taped over with electrical tape instead of putting resistor or disconnecting airbag computer OR removing lamp from dash cluster
Clock-spring missing

Safety:
No stock seatbelt latches
4-pt race latch and link harness to a poorly implemented "harness bar"
Seats installed with sheet metal screws
Seat install "ghetto"
Brakes: mushy, probably never bled (as evidenced by stripping 1 bleeder screw in caliper and the other 3 equally "rusted" in place)

Aesthetics:
Huge chip/defect in hardtop NOT pictured in auction photos of all the other "paint defects"
Typical Miata rust behind the doors
One side cut out to make "muffler" hole
Soft-top removed, not mentioned in auction but was pictured if you looked for it
A/C removed (acquired from a local 1991 SM buildup)
Front bumper support removed

Handling:
Crappy KYB GR-2 shocks way past worn out
All-season "kraptonium" 185/60/14 tires on a TURBO car = can go sideways when you least expect it = dangerous

Exhaust:
Horrible welding and fabrication
Huge cracks in downpipe, exhaust manifold (thank you eBay manifold)
Seller claims he prototyped the original eBay manifold and received the crappy thin-walled SS as compensation
No muffler in exhaust (no NC inspection without a muffler)
Lousy gaskets used in critical exhaust joints (turbo to mani, mani to head)
Exhaust flex joint "pre-tensioned" and permanently "bent" due to not supporting weight of exhaust aft of downpipe
Cut off exhaust hanger welded to body to fit muffler pipe exiting in side-sill