Toiyabe

iTrader: (2)

By making this post I am committing myself to sharing my hack rebuild and limping along of a BFMR, as well as some Miata projects. It's a reasonable place to store some information that might be useful for all 25 people still into these cars as well.

Here it is as of today:

Toiyabe

iTrader: (2)

I bought the car in November of 2016, some 13 years after my previous GTXs. I had done much of the more modern turbo AWD cars, but really missed the little things. As Keith Tanner said at one point (iirc): "You can absolutely feel that this was the company that made the Miata soon afterwards."

This car was an interesting one. It had been modified by the person I bought the car from, parts well, parts badly, parts kind of wtf. Here's some of the copy from the original builder:

I don't even know where to begin on that statement.

And this:Some issues with this: The VR4 brakes aren't VR4 brakes. It's an Escort GT front caliper with Galant SOHC AWD front rotors (266mm). The rear calipers were 1993 Miata, but the rear rotor is from a DOHC FWD Galant. Etc, etc...

The person I bought it from had installed new KYB GR2 shocks front and rear (rear from a 626 with the spacers) and a JDM intake manifold, which has a massively different design than the US market one. he also claimed the engine had a relatively fresh ring and bearing job, and ARP head studs.

Toiyabe

iTrader: (2)

So I carted it all to my new shop, and began doing some detail reworking.

The first thing was my best friend (a Miata nut, had an NA6 with a BP swap I now own, now owns an ND) sent me a set of Racing Hart Spec D wheels. OMGWTFBBQ win. So I mounted up a set of ZII* 205/50-15 tires, threw some brake pads on it and started driving it.

For suspension I removed the 626 parts and sold them on the Yahoo group. I had purchased a set of freshly rebuilt DMS 40mm Grp. N struts for a GD Subaru. I had been doing some measuring and was fairly confident I could make them work.

I was very right. With Cusco top hats and redialed mounting holes they fit perfectly, and give me tons of travel and excellent spring and damping rates. They are a fantastic tarmac setup for this car, obviating the need for a big rear bar. The only negative is that there is so much droop in the front that the inner CVs can bind, which means I had to install limiting straps.

I also replaced the front control arm bushings with Whiteline pieces, and did a good alignment.

Then I went after the idling and boost issues.

The major boost issue was that the EBC solenoid was hooked up backwards, so it was just running off the waste gate spring. I also removed the VTA crankcase ventilation which was tucked in a fender well and had been puking oil out the breather to a proper system with one line before the turbo and one from valve cover to manifold with a GTX PCV valve. This turned out to be a mistake, but one I tried very hard to make work.

I extended the short intake into the now unused fender well using 3" tubing and a big cone filter, properly attached. Much colder air?

The idle issue was much more interesting. The JDM manifold has a dual feed fuel rail and an IAC which is supposed to sit between runners 2 and 3 on the flange. The coolant passages for the throttle body are integrated into the upper plenum. The US TB, on the other hand, has coolant passages on it, and an IAC that is attached to the front of the manifold (which is one piece). The shop which had installed the manifold had routed the coolant through the TB and then through the upper plenum, but not to the IAC which was zip tied to the manifold. When the entire system would heat soak, the IAC would have the warm-up regulator actuate, and it wouldn't idle, something that wouldn't occur without long heat soak.

So I removed the coolant lines to both the TB and plenum, routed them to the IAC, bolted it on a bracket I fabricated for the manifold, and retuned. This made it much better. Although closed-loop idle on MS is a pain.

I replaced the master cylinder and booster with a 929S master cylinder and a Protege booster I grabbed at the junkyard, and got some Hawk black front pads on closeout for $12 a set (I bought 4-all they had). This, coupled with the ATE Typ200 fluid made an fantastic brake pedal for a GTX.

My wife got Adam at Revlimiter to make me some super awesome MRT logo key fobs and steering wheel boss.

Alignment of new suspension:


Racing Hart goodness:


Engine bay after initial rationalization:


Biplane!


Great exhaust; sounds good, fits well, nicely built, 2-1/2" everywhere.


Steering wheel boss:


Intake and PCV:



Interior:


The fun original stickers. I have had some people comment on the "fake stickers" I must have applied.



Next time I buy a complete other car and start putting together more things.

Fireindc

iTrader: (13)

I love the build please keep it going! I too have one of these gems and I love it. Any more pictures or details about the subaru suspension swap? Sounds interesting, and mines in need of suspension soon.

Scaxx

Ugh, I love the gtx, such a sweet car. Looking forward to the updates!

Toiyabe

iTrader: (2)

I have an absurd love of these little things. The two I have now are my fifth and sixth respectively. I've owned every color!

The suspension is easy, and I'll make sure to take some photos for you. That is unless you want a set of Tokico Dirtra I have on the parts car...

The GD sedan parts are a really close match for the GTX stuff. The upright is the same thickness, the length of the struts are very close, and the perches are even close. The main difference is that the two mounting bolts are bigger in diameter (12mm vs. 10mm) and the bolts themselves are farther apart (like 58mm vs 45mm, iirc). The top stud diameter is also bigger (12mm vs. 10mm).

So take the shock and blast the paint off the ears, and then bolt the upper bolt with the upper hole on the front, and the lower bolt with the lower bolt in the rear. Mark where to cut new holes, and using your favorite cutting tool make new holes. I make them a bit larger. Assemble the struts, use the GTX top hats with the holes drilled out to 12mm (or a set of camber plates with GD top nuts). Install the suspension, set ride height, and align. After it is align put the car on a lift (or jack it up), and unbolt one bolt from a strut. Put a structural washer under the head and nut, and tack it into place on each side. Repeat for the other bolts.

You now have a very good, inexpensive, suspension that works on a GTX. The rear struts are angled a little inwards unless you move the mounting holes towards the strut body a bit, but there is no rubbing, no contact, and excellent articulation.

Toiyabe

iTrader: (2)

First, this is how much travel I now get at full droop with the GD WRX suspension:


Clearance to adjusters on the rear:



So the car was driving OK, but I had some odd woes with BOV/intercooler to throttle body plumbing. So I made a new piece, and welded a Turbosmart BOV in place. I also painted the valve cover and verified the car had ARP headstuds. The car seemed to use oil, and it seemed to have poor oil control anyway, so I resealed the baffles in the valve cover at the same time, and then did a VTA catch can setup eliminating any boost connection to the crankcase.





Well, the car had an issue. This is after 25 minutes of spirited driving, all out of the now full 1.5qt catch can:


So I decided to buy another car, either as a fun driver while putting this one back together, or as an eventual replacement or source of parts. I found one locally and bought it. It was far rougher than advertised, but had a bunch of spare parts (two transmissions and an engine), a bunch of good parts (perfect interior, US side skirts, Tokyo Dirtra, etc...) and was fundamentally a solid car. It had sat in a hangar for years though, and most mechanical things were destroyed.

The ad for buying it ( I paid far less):


Mechanical parts after sitting, including a supposedly newly rebuilt (and very seized) turbo:




The two cars together at the shop:





Next time, rebuilding some engines and finding a decent crank!

viperormiata

iTrader: (24)

Very cool.

andyfloyd

Cool build man, 323 GTX is a cool car. Sucks the engine on the 2560 car is spewing oil like that. But Im sure youll build it better! Do people ever swap in BP engines into those?

Toiyabe

iTrader: (2)

I am very happy with the new engine, which will be covered here in a few posts.

People do swap BPT engines in, but there are some issues. I've been part of two: one a rally car with a full BPT/GT-Ae drivetrain swap and one just an engine. The extra length and different mounting point really does some weird things to the cars, but if ultimate power is your goal (and you realize you're wasting your time on a BF/BG) it's the way to go. I like the B6T, and I like the way the cars drive, and I have a metric ton of spares, so I kept the B6 drivetrain.

Toiyabe

iTrader: (2)

Oh, and I did a few other things before I started not driving it regularly while building the engine.

I swapped my NA6 to an NA8 torsen and put the VLSD in the rear differential of the GTX, I sourced and modified the original steel belly pan to work on the car, and I took the intercooler and cut off the inlet and outlet and welded new ones on.

The engine at the point that the oil was puking was given a leak down test:

#1- 9%, #2-27%, #3-25%, #4-5%. So nothing cataclysmic, but not a healthy engine. All past the rings. I assumed a broken ring land, scored cylinder, or something of the sort. When the engine was autopsied, it was very interesting...

Fireindc

iTrader: (13)

YES. Please sell those to me. I'll shoot you a PM.

I have a 1.6 VLSD from my miata sitting in my garage and want to do this as well. Any special knowledge required? Not sure if there is any measuring/shimming required or if it's drop in.

Toiyabe

iTrader: (2)

It's pretty close to a drop in. You should check the pattern on the ring and opinion, and adjust as necessary, but these don't make enough power and traction to break the rear r&p, so just get it close. I did the paint like and other diff swap and it was very very close.

I responded to your PM, btw. Let's see what I can do to make your car happy again.

Toiyabe

iTrader: (2)

So I started tearing down some spare engines that came with the cars, and that I picked up from various places. Did I mention I have 5 transmissions and 7 engines?

So car number one came with a "tired" spare engine. Here it is:



Huh. Well, no worries. The other car included an engine that was GUARANTEED to be ok.







Well then.
So I tore apart another engine, which had a great crank, and disassembled everything for a trip to the machine shop. I took this opportunity to build an engine for an NA6 for a good friend, actually his son's first car. Eventually, after the son gets some more money and skill, plus much autox, it will get boost. Yes, a BP would be better, that's what I have in my NA6, but that's what they wanted.

Tear down:


I had the block bored 1mm over, and bought Supertech 8.8 pistons and Manley rods. Given the stock 7.8 CR it was hoped it would make a big difference to spool. It did. I opted to keep the oil squirters because rally. ARP head studs, Cometic gasket, NPR rings at a fairly generous ring gap (moderate boost? I remember the number if not the name of the recommended spec). Lots of Redline and Torco assembly lube, matched rod and piston weights. Went for a piston to wall spec just a hair tighter than the middle of the recommended range. It's very quiet on cold start. ACL bearings. I rebuilt the lifters a way I read about on here; basically you pop the hydraulic lash part out of the bucket and clean clean clean. Worked a charm. No HLA noise after initial start. Rebuilt the stock oil pump which looks very good. When I did this the Boundary pump wasn't in stock anywhere for the B6, but given the low redline (6800 now, stock is either 6300 or 6500) and modest power I just shimmed the relief valve and cleaned and checked everything. Stock GTX cams, all NSK rollers, Conti belt, mixture of SKF, Felpro, Stone and Mazda gaskets. I had initially gotten the Supertech valve stems seals and then read the horror stories here, so I changed them for factory Mazda. Thanks guys! New intake and exhaust valves and guides.

Random assembly pics:

Toiyabe

iTrader: (2)

More assembly work.







Some out of order pics exist. Please forgive me. A few more:





Here is the block for the NA6:



Put the owner to work, I did.


I decided to add some gauges to my NA around this time.




Next time is engine removal and reinstallation in the GTX.

Neilv

iTrader: (1)

I almost bought one of these way back when but realized there were no rallies local to me. They are still awesome as hell. Please rebuild all of them and keep them cool.

Roda

I test drove one of these when they were new (and scared the hell out of the salesman!) but couldn't buy because I was a broke *** college student. Still want one badly, and it's one of the few cars on my 'list' that hasn't appreciated beyond reasonable 'fun car' money. They're very scarce here in the southwest, but I try to keep an eye out.

Great project, I'm enjoying watching!

iantboyd

iTrader: (11)

keep the content coming. I love mine. Unfortunately the transmission took a dump to winters ago backing out of my drive way. totally out of the blue. So its been sitting while I finish some other projects.

Fireindc

iTrader: (13)

Beautiful car man. Gotta get it going! BPT swap time? I hear the BG has a slightly stronger trans with wider gears.

Toiyabe

iTrader: (2)