KMiata SCCA Solo XP swap

[aMaff]

Project "Bolt-on bumper bar" is underway
I figure the engine will likely be in and out a bunch with the upcoming project, so I might as well make it easier on myself and be able to pull the engine and trans straight out the front as a package.
I cut as much of the upper rad 'support' as I could get away with, without affecting the hood pins and bumper-cover supports (the dzus brackets), and will be making the crash bar a bolt-on piece.
There's so much room for activities!

[aMaff]

Engine's out:



And the new subframe in. I had to pat my head and rub my tummy and figure out which order the bolts wanted to go in so that all the holes lined up (thanks V8R!!! :diaf but once I figured out which hole was the furthest out and started there, it all bolted in.



Next I get to figure out if any of the control arms will bolt up...

[aMaff]

I got the ends of the frame rails where I cut out the bumper bar boxed back in, for both strength and safety working around that area.

MIG welding thin, old sheet metal with .030 wire is a pain in the ass but I made it work. I need to get a bigger piece of copper to use as a heat sink for stuff like this, but the little Harbor Freight copper spoon did the job.





And of course, a little "grinder and paint make me the welder I ain't" to complete the look.



I wanted to finish the bumper-bar part today as well (boxing in the ends, and welding the 'ears' to the bar), but I broke the bandsaw blade (it just never ends...) so I'll mess around with those tomorrow.

[aMaff]

Finished off the bumper bar side of things today. Welded the ends, then welded the 'paddles' to the bar.

I'm pretty proud of this one. Turns out, getting welding practice makes your welding better.




All welded up, with a couple coats of paint.



On to the next. Probably going to finish up the steering linkage next, then start working on the fuel system.

[aMaff]

Been chipping away at a bunch of small stuff, but pieces are starting to fall into place.

Apparently they now have a 'universal' upper coolant housing that doesn't need to use the Miata's stock temp sensor, but I didn't know that, and I've already got this one (and a Miata coolant sensor...) so why not use it. I plan on using the Honda cooling sensor, so I just needed something to plug the hole. I chucked the temp sensor into the late to knock the connector off, and learned that the whole thing is basically 2 pieces. The brass "housing", and then the connector / sensor assembly. As soon as the parting tool touched the join between the 2, the sensor broke free and could be pulled out. I cleaned the end up a little to make it a little more low-profile:




Next started work on putting together the intake manifold. The gasket is...whatever the opposite of port-matched is. There was a really significant (1/8" or so) step, all around the notch for the injectors. The rest of the port wasn't great either, but that bit around the injectors was awful. Kinda hard to see in the pictures, but I opened it all the way up and smoothed the transition between the gasket and port.




Still looks pretty rough in the "after" picture, but I took it apart and deburred and smoothed everything out off the head.




I've ordered the rest of the fuel system components today and some tubing for an intake.

I say that... there's absolutely going to be something I missed or some angle fitting I wasn't expecting to need, but it'll get me most of the way there.

[aMaff]

The engine's basically ready to come off the stand so I can notch the bellhousing for the starter. Other than that, it's ready to go.



Now to start with fueling.

So...that's gross. It's not a rats nest (despite looking like it). Other than the leaves there's no other sign of life in there. Kinda wonder if it's the result of some "there's a surprising amount of grip in the grass..." lines during the last couple hill climbs :lol:

[aMaff]

As is usual with non-standard builds using non-standard parts, it's a matter of working through 1 small problem after another. The KMiata swap is likely no problem if you use all stock Honda parts, but throwing oddball stuff into the mix tends to have knock on effects.

Case in point: Water pump and alternator belt tensioning. They do not use a tensioner pulley, but they add an idler pulley, and you shim the alternator with a washer or 2 on the bolts to tension the belt. Using a stock crank pulley, they send a belt that's the correct length for that to work fine.

An ATI SuperDamper, however, is a smaller diameter than stock, so that belt won't work.



I reached out to KMiata and it turns out they run that pulley on one of their race cars, and have a smaller belt recommendation (a 6PK1035. Apparently they don't make 7 rib belts short enough so you've got to run a 6-rib).
After getting that belt in, it was a lot better but the provided washers weren't enough to tension the belt.



So I went and got a few more M8 washers. I ended putting 3 washers under each bolt, then attaching the idler pulley. Even with that it was still a little looser than I like, so I cut a notch into another washer so it's a C-shape, and used a pry-bar to space the alternator out enough that I could put that 4th washer over the top bolt. MUCH better.




On to the fueling mods next.

[aMaff]

I finished up the mount for the RacePak. Added a gusset and welded it out. For whatever reason it looks crooked when sitting in the seat, but I checked it with an angle gauge and the cowl of the car, the dash bar of the roll cage and the top surface of the dash mount are all within a degree of each other. so maybe it's my dumb face that's crooked.







Hopefully the only other welding I'll need to do will be to add a mount for a central-ish (hell that might end up off center too...) rear view mirror, Prod-car style for track use once I get the 2nd element of the wing in next week. Something along these lines:

[aMaff]

This is a Walbro 450 that's going in. This The only thing I think I want to do different at this point is add another worm clamp to make sure it stays put, and extend the return tube with some rubber line.

I'm swapping to an NB sender because the ends above the tank are SAE quick connects and much MUCH easier to adapt to AN.
There was some question if the NB sender would fit in the NA tank. I have a feeling the issue is the extra width from the stock NB fuel pressure regulator that would sit on the opposite side of the pump, adding a lot of width to the 'column' that's fed in, because once all that's removed it slid right in.

I also needed to shorten the feed hard-line from the pump to fit the taller Walbro, and cut off the fitting for the return line to the pressure reg.

[aMaff]

The reason I wanted to swap to an NB fuel sender: https://www.summitracing.com/parts/RUS-644113






GM ethanol sensor:

[aMaff]

woohoo I've made my first AN line! ....god I hope they don't leak :lolsob:





2 more down. Gotta wait on the rest of the fittings to come in later this week.



Also waiting on some line separators to keep everything tidy and from rubbing anything it shouldn't.

I was trying to figure out how to mount the E85 sensor



But then the internet came to the rescue:

https://www.thingiverse.com/thing:2965407



Apparently I'm not the only one to have had this issue before. So, I've got a buddy with a really good 3D printer cooking one of these up for me.

[aMaff]

Fuel system progress.

I need to close the holes in the package tray up, and a couple spots need chafing protection. The reg and filter took up way more room than I was expecting, hence putting it all in the trunk.






This one'll also be getting a panel to keep rocks from the tires away from it (or I might try and find the stock one). I mean, the brake lines have been fine for years naked, but while brake failure isn't great, it's less likely to set you on fire...



I also made a standoff / hose stay out of a scrap bit of hose (and used another length to keep the zip tie from chafing it) to keep the fuel line from rubbing the brake hose.

[aMaff]

I'm normally not shy about getting out the cutting tools, but hacking into a nice, cast aluminum bell housing (even if it's to an empty case that I have for exactly this) gave me the heebs. That said, it's serving its purpose (mockup), and I'll know how to do the quaife box a good bit better.

[aMaff]

Eating the elephant 1 bite at a time.



I should have it mocked up in the engine bay tomorrow so I can bolt everything in and finish running fuel lines, start running coolant lines, and generally figuring out where everything wants to live.

[aMaff]

This happened today.



Of course after I finish up all the hose routing, it all comes back out again to fix a few issues and get nut-and-bolted (again), but it's a big step.