I finally finished my DIY (with help from welding friend) on my 1990 miata. The first time around early in January I detonated cylinder number 4 in my 1.6 because of small fuel rail. I then found a 1997 1.8 motor, and started a new build. I've had the car since 2002, and it was definitely time to make it go fast. Here's a picture of the car:


Now here's the turbo build details:
- HKS cast manifold
- Nissan 300ZX Garrett T25 turbo (91 twin turbo)
- Stainless divorced gas downpipe which merge into 2.5"
- One piece 2.5" aluminum charge pipes
- Yonaka air/air 26" intercooler
- 1992 Porsche 911 Turbo BOV
- AEM EMS, AEM 2.5 bar map sensor, AEM IAT
- Gizzmo Multiscramble Intelligent Boost Controller
- 460cc rx-7 injectors
- M-tuned dual feed fuel rail
- Prosport oil filter sandwich plate, -4an oil feed, -10 oil drain into welded bung on pan
- BEGi universal adjustable bent arm wastegate with universal mount
- Flyin Miata lower coolant hose
- AEM Dryflow air filter

I think that's the majority of it. I just finished it tonight, and quickly took a bunch of timing out of the boost MAP on the AEM, and kept it out of boost on my way home from the shop I work at. I should have it on the rollers tomorrow, and I'm hoping to run it up to 12lbs of boost. Now here's the important part, the pics!:
Pic 1, intercooler, and can just barely see the bottom of the hard pipes peeking through the bottom:

Pic 2, Hardpipes front view

Pic 3, Hardpipes underneath view

Pic 4, TIG welded downpipe:

Pic 5 & 6, downpipe installed


Pic 7, hardpipe from top

Pic 8, exit of downpipe, fits perfectly

Pic 9 & 10, everything installed. Car is dirty as hell from sitting for a month, but it's worth it:



Anyways, interested to hear some feedback. I'll post the dyno #'s and driving impressions once I get it tuned.

 

dope! cant wait to see the #'s

 

Dude Very nice!!

How is the intercooler mounted, though? To the bumper cover?

 

Nice work, i love the blue!

 

Looks good!

 

Awesome build. Very clean.

Did you make the DP yourself? If so where did you pick up your turbine flange?

 

Wow...that's nice.

I envy your flex joint location on downpipe.

 

Pretty sweet setup, I wish I knew someone who can weld aluminum!

Don't worry about those flames though, a hairdryer will help those come off pretty easily.

 

nice! but those blue flames

 

Anyone notice the boobies in the DP photo?

You know something is wrong when you have looked through this thread half a dozen times and just NOW see it.

 

beautiful craftsmanship on the whole setup. the downpipe, charge pipes, intake, etc all look great XD

 

lol, I didn't notice it last night until I showed the picture to my wife, and that's the first thing she saw

It's mounted underneath the rebar, basically welded a huge aluminum block to the intercooler and ran 2 bolts through a plate that already existed on the car.

Hey now, I still enjoy the flames, but I'll admit that if I could go back, I wouldn't have done it. I checked with one of the tips, and the paint has completely faded around the flames now, so when I take them off, I'm going to have to get it resprayed. So they stay on.

Thanks for all the feedback folks! I'm very happy with how it turned out. Now to just convince my boss to tune me tonight...

 

Yup, made from scracth, even ovalled the collector with 2.5" round and a dead blow. I got the flange from Specialty Z online. They are awesome guys, and the flange was a great quality. I had a previous divorced gas downpipe flange, but it was just a flat piece with two holes. This one actually blocked off each chamber, so if you just wanted to dump the wastegate gasses, it would work awesome for that.

 

I just got back from the dyno, and the power numbers are interesting. I have it running about 13 psi, and it made 178 WHP, however, it made 200.4lbs of torque, and the torque is full just after 3000 rpm, and it carries for quite a long time. Driving impressions is amazing. My friend has a 90 1.6 with an upgraded greddy kit, and he's 199 lb of torque, and 204HP, but our power curves are totally different. We'll have to take it to the local drag strip and see who gets the upper edge. It's a toss up for me from driving both of them.

I'll get the dyno sheets tomorrow, and will put them up.

 

Sorry, still haven't gotten the dyno sheets transferred onto my usb stick. I've been running into lots of tiny little problems. A stupid plug on the bottom of the hks manifold keeps falling out, so I'm working on fixing that. My charge pipes have also come out a couple of times (didn't have them tight enough), and the car was starting to overheat on me when I was going up medium grade hills with boost. I have a second fan hooked up to a switch, and that brought the temperature down, but I wanted the cooling system to be a little more effective. I then remembered that I took the undertray off of the car for this project, and that if my memory serves me, it helps a ton with cooling. I put that back on and so far so good, no need to use the second fan.

My driving impressions are still about the same - it's freaking insane. The power comes on so hard because of the torque, and yes, it uses a lot of gas. I find for just regular driving, setting my boost controller to 7lbs makes life a lot easier. It's nice to be able to hit a button and have it automatically go to 13lbs when I need it.

Anyways, here's the modifications that are coming next since the turbo started working:

- Mini Cooper hood scoop to be installed as per instructions on miataturbo (woots!, thanks folks)
- Koyo aluminum radiator (this'll have to wait a little bit)

Past that, there's not much else. The rear rubber isn't going to last long the way it comes out in 1st and 2nd.

 

I was originally planning to go with that turbo (I still have it sitting on a shelf). It looks like that turbo would be excellent for an autox/street car. 200lb-ft of torque at 3000rpms is awesome, congrats. I assume the torque curve falls down pretty rapidly after that, right, since it was originally sized for 1.5L of displacement on the 300zx TT?

 

Surprisingly it carries for quite a while. I'll try to have the dyno chart up tomorrow night.

 

Here's the dyno sheets:
HP & Torque

HP & PSI

Torque & PSI

 

need better boost control like whoa.

 

Quality Build! Congrats.