m2k Build! From supercharged 1.6l to F20c
 

Another season has ended which means its time to tear into the Miata again. Last winter I built up the m45 supercharger setup with a custom wiring harness, new pulleys (~11psi), custom belt setup, air to water intercooler, ID1000's, and lots of engine bay clean up. I was making ~170whp on e85 which is good power for a light Miata, but I was still wanting more. After looking into a K swap I didn't want to use a miata trans with the potential to go turbo and grenade the trans. I happened upon a full F20c dropout (motor, trans, diff, driveshaft, axles, header, accesories, mounts, and the harness) for cheap while I was looking for an s2000 trans. Once I realized how good of a deal it was I made the spontaneous decision to pick it up and swap it.

I've already pulled most everything in the engine bay out and listed it for sale in the classified section.

Currently the motor is at the machine shop getting sleeved and cleaned up after finding out the motor I picked up had a spun bearing (still worth it for the price though). I picked up a new block and thats what will end up in the car. The plan is to complete the swap NA for next season and then turbo to ~350whp the season after that. I'm going to attempt to use my custom harness for the f20c and MS3x. This will be used for daily driving in the summer, track days and autocrosses. Probably no more rallycross once this swap is done.

How the car used to look:
https://cimg2.ibsrv.net/gimg/www.mia...5dd9ae9d8d.jpg

https://cimg3.ibsrv.net/gimg/www.mia...b1971cda9c.jpg

https://cimg4.ibsrv.net/gimg/www.mia...878b292327.jpg

https://cimg0.ibsrv.net/gimg/www.mia...0e94f26d47.jpg


And how it sits now:https://cimg6.ibsrv.net/gimg/www.mia...e69a8dc4bf.jpg

Turbo f20c sounds fun. 2.0 or 2.2?

I want the silver one

F20c is the 2.0l but yeah reliable turbo power (chuckles) would be stupid fun in this car. You can talk to acedeuce802 about the ls swapped 99. We've got a pretty crazy garage going on haha.

Sell it to me

Yeah good luck with that. Diff mount should be complete tonight. I've cut the PPF and added a turn buckle and tabs to the rear subframe to support the OS Giken diff in the torsen LSD housing.

:nono:

Not the prettiest picture, but it's in and works. Ignore the over spray, it's under the car and my level of fucks when I got to painting was pretty low.
https://cimg0.ibsrv.net/gimg/www.mia...69d95075e3.jpg

All of the motor bits are back from the machine shop. Just waiting on the pistons to come back from being coated till I can assemble the block. The head still needs some work unfortunately. https://cimg6.ibsrv.net/gimg/www.mia...285997f6d5.jpg

https://cimg3.ibsrv.net/gimg/www.mia...3280fa3671.jpg

Tonight I got the fuel lines in. Braided stainless supply line with inline filter and a rubber return with the flex fuel sensor. Also got the trans mount bushing sorted out, turns out a Chevy Camaro bushing has the same bolt spacing as the s2000 mount. Ignore the kinked rubber hose, its a place holder at the moment. Also you can see the mounting for the filter and flex fuel sensor are on the opposite side as the OEM mounting because the exhaust will be on that side now.
https://cimg6.ibsrv.net/gimg/www.mia...bd5e73d0b8.jpg

https://cimg8.ibsrv.net/gimg/www.mia...776d31d999.jpg

https://cimg1.ibsrv.net/gimg/www.mia...8c9f7b0579.jpg

Got the vacuum pump on the s2k manifold welded up. Currently waiting on oem engine parts to show up to put the motor back together. https://cimg8.ibsrv.net/gimg/www.mia...dfd49d715b.jpg

I managed to get most of the motor back together this weekend. Just waiting to get the head back now and it'll be ready to mock up in the engine bay.https://cimg6.ibsrv.net/gimg/www.mia...fca176daca.jpg

Details on the F20 build plans, low comp/stock compression? For <400whp I'd just use a supercharger, especially if you're going to do some track driving.

I'm rebuilding it to stock specs even though I had to sleeve the block. Tuned on e85 on a stock rebuild should be somewhere above 210whp. A supercharger is definitely under consideration given my experience on 1.6l. I think a turbo would be a more interesting challenge, especially when trying to make it reliable on track.

Good to hear! I think most people would tell you about peakyness of the F20 + turbo makes for a less enjoyable drive than a supercharger. If I tracked my AP1 more I definitely look at switching from a turbo setup to a supercharger

Yeah more low end torque would definitely be beneficial. Thanks for the first hand insight! That definitely helps make the decision.

Got the cylinder head back from the 3 angle valve job and installed the valves and springs last night. I'm going to attempt to have the motor completely back together tonight https://cimg6.ibsrv.net/gimg/www.mia...a19486e979.jpg
https://cimg9.ibsrv.net/gimg/www.mia...a1d58f1f81.jpg

Looks like it will be a lot of fun.

I sure hope so! I got really motivated and got the motor fully assembled (minus small hoses and what not) tonight. LS coils are just chilling there but that's where I'm considering placing them assuming they clear the hood in the car.https://cimg8.ibsrv.net/gimg/www.mia...daa218fd46.jpg
https://cimg9.ibsrv.net/gimg/www.mia...7697a16e8e.jpg

https://cimg7.ibsrv.net/gimg/www.mia...eae9ad3ffb.jpg
https://cimg2.ibsrv.net/gimg/www.mia...c5ba591c49.jpg
Got the subframe chopped up and motor very close to its final position. I had to create a lot of clearance for the exhaust on the passenger side so that half of the subframe is gonna require more playing to finish up. The motor sits extremely low so a skid plate will definitely be in the works.

God this is going to be cool

Got the motor mounts tacked together. should have the motor side of them fully welded up tonight. https://cimg5.ibsrv.net/gimg/www.mia...f2911bccbc.jpg
https://cimg7.ibsrv.net/gimg/www.mia...da348892ff.jpg
https://cimg9.ibsrv.net/gimg/www.mia...2548e278d9.jpg

Where does the steering rack go....

Awesome build.

Yeah, that's a good question.... I was considering dropping that rack under the oil pan and proportionally moving the outboard points, but then the steering rack will hit everything I bottom out on. I'm coming to terms with moving it forward of the motor just under the crank pulley. I may end up doing something custom outboard to compensate for that.

Do you have an estimation on how much it'll actually move? Obviously you're balancing between having a well mounted rack versus keeping geometry happy. You could make a bracket that offsets the inner tie rod pick-up point closer to the stock location. Just do a quick analysis to make sure it wouldn't have deflection issues with being that cantilevered. But something similar to this: https://store.partsshopmax.com/shop/...ing/RSPCR.html

It's probably a legitimate 4in forward of the original point. I think if I did brackets that long, I'd need some sort of bearing support to react the moment from the tie rod so I don't grenade the steering rack gears.

Got the engine mounts cleaned up and fully welded. Planning to install them tonight and start work on the trans cross member. Pro tip: welding over flux core mig tacks blows. https://cimg9.ibsrv.net/gimg/www.mia...834518d59d.jpg
https://cimg3.ibsrv.net/gimg/www.mia...599ef0da7c.jpg
https://cimg9.ibsrv.net/gimg/www.mia...828b9a4eb7.jpg

awesome job, but I suspect you're going to need to support those tabs with some gussets.

I definitely considered it when welding them up but they're 3/16 and have quite a bit of clamp area so I'll keep an eye on them are and add strength if necessary. I got those in place today and finished my fuel lines as well as mounted the coils off of the fuel rail.
https://cimg1.ibsrv.net/gimg/www.mia...c397d4e1b6.jpg
https://cimg6.ibsrv.net/gimg/www.mia...a790e5536d.jpg

Are the coils just cantilevered like that?

They are, which you would think is an awful idea, but I tested this if you look at my original engine bay shot. That coil mount was cantilevered as well and once robust enough, never had an issue. If I run into an issue with these I'll make a bracket from the top mounts to the valve cover bolts. Maybe I'll just do that anyway....

Just noticed how thick and burly those mounting tabs are on the coil. It's all metal there unlike the d514a, right?

Yeah, they're all metal around the mounting holes. If anything fails it'll be the mounting holes on the fuel rail.

Pretty much finished the trans mount today. I used a modified stock s2k mount with a GM bushing and mounted that to a custom cross member. All I need to add is some plate behind the bushing to keep the angle it's bent at to meet the floor and some sandwich plates inside the car. https://cimg7.ibsrv.net/gimg/www.mia...b3b084dbef.jpg
https://cimg6.ibsrv.net/gimg/www.mia...b60072f9fc.jpg
https://cimg4.ibsrv.net/gimg/www.mia...b566edb7d7.jpg

I got the steering rack completely depowered to help add clearance to the front of the motor. I got it back in the car and quickly mocked up to see where it might go for the first time. like other s2k swaps it looks like it'll have to move forward exactly 4in. https://cimg0.ibsrv.net/gimg/www.mia...9c067deb11.jpg
https://cimg4.ibsrv.net/gimg/www.mia...7dc883484e.jpg
https://cimg7.ibsrv.net/gimg/www.mia...374322067d.jpg
https://cimg0.ibsrv.net/gimg/www.mia...8076d48e70.jpg

So while I have been designing and working through the steering rack mount, I have also been trying to figure out my header situation. I had one that came with the motor that I cut up to see if I could get it to fit, but no luck. I tried a stock one from a friend and again, no luck. I didn't feel it was worth it to make my own header and then in a year make a turbo manifold so today I bought this.
https://cimg2.ibsrv.net/gimg/www.mia...24aaeebb2b.png

OGMOGMGOGMOGMOGMOG

You are doing everything I want to do for my next build. Except the v8 part.

Haha so just the turbo part then?

nah, K swap is the new v8. I'm excited to see where this goes.

Ah, cool. Steering rack mount updates to come later tonight!

lol this thing is going to be a monster

Awesome project, should be a riot once complete!

I'm curious to hear your feedback on the steering setup once complete. We did our first K swap very similar and then re-did a lot of it to put the steering rack back in the factory position. I also think our engine was protruding further forward than yours is, so hopefully you'll have better luck.

Would a dry sump let you put the rack in the stock location?

I'll certainly report back with how the steering is. Unfortunately there will be a 6 month gap of driving so not exactly back to back. You would still have to lower the rack from the stock position with a dry sump because of the angle of the motor about the crankshaft. That would be simpler to compensate for because you could move the outer tie rod point down on the knuckle and the geometry would be identical.

I got the steering rack bracket welded up today. the tabs are offset so that the larger tube sits lower than the oil pan for protection and it adds a flat surface for a skid plate to mount too. I'll be adding oil cooler brackets tomorrow and starting to permanently place it in the car.
https://cimg2.ibsrv.net/gimg/www.mia...327ea50ac6.jpghttps://cimg8.ibsrv.net/gimg/www.mia...ca05482b70.jpg
https://cimg9.ibsrv.net/gimg/www.mia...f998ce3ffc.jpg
https://cimg6.ibsrv.net/gimg/www.mia...b108c89926.jpg
https://cimg7.ibsrv.net/gimg/www.mia...551330ddd1.jpg

keeps getting better

I had some time to kill at work so I welded up the tabs for the oil cooler on the steering rack mount. https://cimg7.ibsrv.net/gimg/www.mia...ac668de974.jpg

The steering rack is tacked in place and I just pulled the subframe so I can finish bracing the steering rack mount and playing the subframe.
https://cimg2.ibsrv.net/gimg/www.mia...6a4beca8dd.jpg
https://cimg5.ibsrv.net/gimg/www.mia...8d58c6a49b.jpg
https://cimg6.ibsrv.net/gimg/www.mia...fc4ca15efe.jpg
https://cimg9.ibsrv.net/gimg/www.mia...885a0aaf6e.jpg
https://cimg7.ibsrv.net/gimg/www.mia...d7272c1f0a.jpg

I managed to get the subframe out and start finishing that up. I still need to finish plating up the cut outs and then triangulate the steering rack mount.
https://cimg2.ibsrv.net/gimg/www.mia...018b35053e.jpg
https://cimg3.ibsrv.net/gimg/www.mia...850027897a.jpg

Sneak peak of turbo in relation to motor. should be finishing up the subframe this week after work.
https://cimg5.ibsrv.net/gimg/www.mia...430692e10f.jpg
https://cimg0.ibsrv.net/gimg/www.mia...4eee528a73.jpg

Sexy build, this thing is gonna be a beast

Thanks!

The subframe is complete besides paint. I'm going to try to get it fitted back in the car today.
https://cimg7.ibsrv.net/gimg/www.mia...87a11e0169.jpg
https://cimg5.ibsrv.net/gimg/www.mia...805e8ab65f.jpg

Lines made, turbo placed, starting manifold soon.
https://cimg1.ibsrv.net/gimg/www.mia...668b1dac9b.jpg
https://cimg5.ibsrv.net/gimg/www.mia...050f6eb9e4.jpg
https://cimg7.ibsrv.net/gimg/www.mia...fde654f0ac.jpg
https://cimg9.ibsrv.net/gimg/www.mia...1f4d93a5c3.jpg

I still don't see how you're going to package a downpipe without performing v8 treatment to the passenger side..

Without the brake line and wiring harness there a 3" 90° should fit. It may have to be more than 90° and then turn back towards the rear of the car, but at least a 3" tube fits between the bell housing and the subframe now. I'm also considering a side exhaust if that doesn't work...

Worked on placing the flanges for the turbo. I got them tacked together and I'm having the flanges scanned in CAD at work so I can model the manifold.
https://cimg4.ibsrv.net/gimg/www.mia...df0fa46441.jpg
https://cimg8.ibsrv.net/gimg/www.mia...4f67df529b.jpg

https://cimg5.ibsrv.net/gimg/www.mia...66fa37c707.jpg
https://cimg9.ibsrv.net/gimg/www.mia...5329fa50fd.jpg

Manifold scan, hopefully ill have the whole thing modeled early next week.
https://cimg0.ibsrv.net/gimg/www.mia...1e8a6c8a0d.png

Made some progress on the manifold design. I need to make sure the turbo wont physically interfere with any of these tubes but progress nonetheless!
https://cimg1.ibsrv.net/gimg/www.mia...1467a9b5d1.png

https://cimg2.ibsrv.net/gimg/www.mia...9e57778160.png