The process of putting together a turbo manifold was a lot more stressful to me than any other part of the car to date- besides the header before it.
The need to visualize and start to piece together weld elbows and straight piping isn’t something that I would consider a strength of mine. More of the opposite. I approached it the same way as I do many things in life. Identify the starting point, then the destination and finally connect the dots.
I started by bolting on the head flange which was easy because it was a quality piece and didn’t require me to crush the pipe into an oval. Then I mounted the merge collector on the turbo and slid in a piece of metal bar stock between them so I could mount it to the chassis with clamps. With the start and end identified it was simply about filling in the gaps
I started with the hardest runner first and tacked pieces together. It actually went along easier than I expected as I would tack and slice elbows until it went where I wanted. Occasionally an elbow was sacrificed but at $5 a piece it was a small cost of less than $15 to have a well fitting manifold.
At the end of the day it took far more money to build the manifold than I expected. Here is a quick run down of why mine was expensive:
Merge collector with flange-$80.
12 weld els-$70 (only used 9).
Straight stainless tube 12” long- $8.
Filler metal in 308L and 309L-$30.
Dual port argon regulator $130.
Argon $60 for 120 cu ft (used a good bit because of back purging
The parts were not that expensive but the 3 hours of fabrication to mock it up and 16 hours for welding it was more than I expected. This is probably a startup and learning cost of I had to state a reason. If I had the tools it would have been cheaper (I had the TIG welder..but this was largely it’s first use). A friend that is a solid fabricator (professional) said he would do it for $800. That’s a pretty good deal in my eyes.
Up next is to evaluate if polishing will work or if I should coat it followed by the down pipe and wastegate output into the exhaust. While I hate the fact the turbo is outside the chassis- there just were no other choices.
While summer appears to be winding down as do the number of days that I’m willing to drive the car. It’s a double edged sword because the garage is still hot as hell but a fan helps.
So what has been going on? A lot of wiring,a lot of waiting for parts and time bending body panels. I decided to remake the firewall as the old one had a large hole from the factory miata fuse box. The new one is plain with minimal holes and several bc opponents mounted from the back side.
The wiring harnesses are all net new (minus the engine harness) and we’re made using txl wire and concentric twisting. My initial expectation was that it was hype but the results were true my magic! It is far more flexible than I ever expected. For connectors I went with deutch connectors besides for the fuel pump and fan (their connectors for 10GA was $$$)
The PDM install was next and I was able to get it mounted with space for the Hondata ecu. Wiring is a bit hectic but it should be fine and contained under the scuttle. One project that remains is an aluminum plate for the front of the dashboard to mount the wide and sensor and gauge cluster. With 2 rails for wiring management I am hopeful it will be easy to remove and install the scuttle without much fuss. As seems to be typical I have a whole host of ring terminals but none that are the right wire size or loop size..
It took a while but I snuck a half day into working on the car with my dad. While I thought it was 3 hours of work it actually took 6.
First thing was to pull the k20a3 and remove the transmission and adapter plate.
Up next was moving those parts to the K20z3 and bolting them all back together.
From there we worked out what needed to be changed and we we removed and replaced a tube in the chassis. We also removed the old motor mounting plate and cut a new piece. After 5-10 minutes of welding we started to position the engine.
After measuring and cutting several tubes we had the left side mounted. Next we leveled the engine to 0.6 degrees and started on the driver side. They came out quite well
The final step was to check hood clearance. I didn’t expect it to fit but was nicely surprised. 3 mm to spare!
There week be some challenges with the steering and alternator but those are for a different day!
In an interesting twist it looks like we may be considering a Honda engine. After looking for small footprint and low heat options the Honda K series engines came to the top. After reading about using it with an S2000 transmission it appeared to have legs.
Hours of research highlighted that the S2000 transmission wasn’t a great choice for big power I somehow landed on a website- kmiata.com. These guys make adapter plates that allow the Honda motor to bolt to a Miata transmission. If I had not sold mine previously I might have had the swap up and running a while ago.
Given the option of a BMW Getrag 260 gearbox I decided to try find one. That was no way task! Luckily eBay helped and I found one about 20 miles away. After a good cleaning it looks pretty good! It will be a while before we understand its condition but it appears to have 5 forward gears and 1 reverse.
After that I managed to get a K20a3 motor to use as a mock up and potentially to use until I find a k20a2. The motor fits quite well and I’m optimistic it will work. Here is a picture of it just dropped into place and held by a 2×4
After having the engine and the transmission I needed to buy the adapter plate to marry them together. After the Ecotec problem I decided to stay as basic as possible until its weld ready. I bought just the plate and bolts and 3 days later they arrived.
I pulled the motor out and gave it a good degreasing and the blew it off with compressed air. Then out came the adapter plate.
The quality is impeccable and my hopes of being able to “spend my way” to completion is still alive!
One small hiccup is that the a3 engine has a different head (the inferior one..) and so it had a fitment problem. Nothing a grinder couldn’t fix.
Time was running out and I had to go shower but that wouldn’t happen before bolting the two together with a minimal amount of bolts. Until next time this is my view when going to work:
Hoping to have the next update and some good news in about a week’s time!