well... I think I might be "a little" qualified to help... EDITING for GTX not GT right now
1.
ECU: The stock ECU is pretty much done by 12psi. It can be remapped, you have to send it to those who can remap it. Turn around time couple-3 days... now you can go up to 16psi with proper fuel and timing maps.
2.
Turbo: the stock VJ14 is a nice lil, conservative turbo. the first up grade is to the Mazda 626 VJ11, which is a bolt on, slightly laggy down low, but much better up high. Also the 626GT can donate a significant stock IC upgrade over the tiny 323gt Ic. Lastly, Dallas Turbo does a really nice hybrid VJ with a combination of Vj11, VJ11, and Thunderbird Turbo coupe turbos into one nice flowing package. We harder-core 323 GT/GTX owners have tried and tried to get compressor maps for the VJ's and simply the maps arent out there. The 1.6 likes boost, was purpose built for boost with oil squirters for the piston skirts, gallaeries made for external oiling for the turbo. Beefy con-rods in the GT/GTX are a lil heavy but VERY hard to hurt.
3.
Manifolds:
*
intake: not much out there. some have tried Miata and Kia cars with the NA DOHC but nothing to be gained really. The stocker is surprisingly well matched for the 1.6 DOHC the EDM intake is often sought after, but requires alot of changes to work for a very small gain.
*
Cold Air intakes: The B6T 1.6 DOHC uses the VAF, Vane Airflow Meter. its not easily replaced or tuned. As long as your ECY is Mapped properly the flow through the VAF is actually not a restriction. an off the shelf Spectre adapter ($13) and then a 3" diam piece 90* steel exhaust elbow will get a good filter out of the engine compartment and into the inner fender for cold air but high enough and away from water.
*
Exhaust manifolds: the stocker is prone to cracking on the bridge reinforcement between cylinders 2 & 3. It can be welded or replaced, Mazda still stocks the Manifold for about $210. The stocker will hold all of the VF-platform turbos, including the hybrids. For bigger turbo conversions the Log style is the easy starting point. After that, there are a few places making 1.6 Mazda DOHC ram-horn styles, mainly for the Miata crowd. they can work on the FWD applications. but you really need the turbo up higher for oiling. I prefer the log-style.
http://jgsturbo.com/ is where I got mine.
4.
Exhaust: 2.5-3" down pipe is easily fabbed. the exhaust is a straight shot down the trans tunnel. then you have (2) 90* bends and a lil tight section going over the rear suspension. Mine in the 323GT is all Magnaflow. 2.5" down pipe, hiflow cat, 4" diam x 26" long resonator, then a 4"x9" turbo style muffler just before the rear suspension. sounds perfect. the Hatch GTX will have the DP a mid-resonator then a REAR mounted muffler at the rear bumper instead of a tail pipe like the GT.
5.
suspension: this is where things get tricky.
* struts: there are options like koni adjustable inserts into the stock Gt or GTX housings. Also the older Tokico Illumina adjustable inserts can be done.
*
Bushings: Pedders have the entire front end in urethane in their catalog since the BF chassis is so wildly popular in Australia. Cork Sport can get them for you. Rear ios a bigger challenge. Nothing is available. What I have done is a 3-prong attack.
A. take the stock "C" shaped trailing arms and lateral links and boxed them with 1/8" steel.
B. Ordered off the shelf bushings from Energy suspension. Then had to turn down the outside diameter on some of the bushing location, drill out the ID on some and finally cut off the shelf bushing sleeves down for length.
C. Lastly the body side trailing arm mounting bolt is one size smaller than the lateral link bolts. so I drilled out the body mount to the same size, converted the entire rear suspension to SAE (easier to find Grade 8) and upgraded all the bolts. The GT has non-adjustable lateral links the GTX (AWD Hatch) has adjustable links that can be used. however not really necessary and VERY hard to find unabused.
D. on the lateral and trailing arms there is also the option of making full tubular arms with sperical rod ends for the ultimate rear set up. I will try to find the link to the build up I used for the set I made.
* sway bars: nothing for the GTX but yes for the 323gt.
6.
Brakes: This is the area needing the most attention.
* the stock set up the disc is bolted to the REAR of the front hub, meaning you have to take it all down, press the hub out, then rebuild it all. The vented fronts are tiny and warp VERY easily in regular commuting-type driving, let alone spirited driving.
* solution is what is commonly called the " Galant brake upgrade" using non-turbo 91-94 galant front rotors, 91-95 Escort Calipers, and off the shelf s/s lines, its a billion times better than stock. To dial it in fully a Mazda 929 non-ABS brake booster and MC make it feel OE and stop like nothing your felt.
* the rear discs are fine. just use good pads.
7.
Wheels/Tires: this is tricky. stock are 14x6's with 185/65-14" wheels. tires choices in 14-16 are getting tough to get a GOOD performance tire. Most guys stick to 16". 17"s can be done but you get VERY close tot he strut's lower spring perch. so then you have to fight offset/backspacing versus moving the wheel too far out into the wheel opening of the body. Personally I think 16" looks best for the body size/style. 15" works very well and if you can find tires, they are usually dirt cheap.
8.
Transmission: ITS fragile. Period end of story. other than a full on Rally gear box. You're stuck. clutch actuation is hydraulic and definitely can use a s/s line to the slave cylinder. Cluthces are available in all stages. I personally prefer the Centerforce Dual Friction. Many love the ACT.
9.
Interior: the dash cluster is either digital and VERY temperamental or analog (much better ans surprisingly accurate). GTX's seats are great. Most all modified GT/GTX's you see have some sort of seat upgrade. I personally like the i90's Nissan Pulsar NX seats. This was that car Nissan did that had the inter-changable rear hatch to be a coupe, wagon, or fastback. they are all over the salvage yards.
10.
Body:
* aftermarket reproductions of the front fenders and hood are a click away on ebay for cheap.
* Front bumpers: the BG (91-94 323/protege') will fit with a lil tweaking and a lil moulding addition. I ahve the JDM 323GTX bumper on mine. Also the Isuzu I-mark bumper is a popular swap. the stock front bumper just looks like a stuck on afterthought. you will have to figure out how you want to handle the running lights in the OE bumper with any of these swaps. Most people convert the outside corner lights to both turn signals and running lights.
*
Rear bumpers: nothing. Occasionally a remanufactured one will pop up on Ebay.
*
Body Kits: Eubrini (sp) makes a full kit that supposedly fits the sedan (since they made a 4-door + hatch, 5-door version in the UK and Aust.) i ahve not looked into it.
*
Spoilers: Front lower: Chevy s-10 from the mid 90's fits with a lil tweak, also the 89-90-ish 626 lower air dam fits with trimming. Rear
That should cover most of the basics. stock had the bi-level spoiler set.
Ask me anything you like. I prob have either done it or had it happen... LOL.
Rob
