LocostUSA.com

Finally got the Miata frame out of the garage and scrapped, this seems a good time to take a pause, retrench, and post some pictures of the progress to-date! Things really started Sept first when "the book" arrived and I started to construct a table.

Taking an idea from Dave, I'll reserve this space for an overall update picture and post the first set of pictures in a reply. I've been studying his build left and right as I'm planning on a similar build. I like how he and Riviera have been able to integrate the subframe. I'm crossing my fingers hoping I won't regret going for the "book" width rather than a +4/442/442e. Unlike Dave, I'll try to keep my photos PG rated.

Welcome to the forum. Yeah, Dave's a great resouce. Be sure to study his great check list procedure that he followed before his first test drive .

There's a great group of guys on this forum and you'll always have someone that'll have the answer you're looking for.

OK, let's see the photos.

Ron

Ha, I was being polite by not bringing that up again. I'm planning on fully welding all the parts before testing things at speed. I'm sure I'll find my own unique mistakes to make along the way.

<flattered modesty="false">Everyone needs a "don't do this" manual</flattered>



The clearance between the tires and the cockpit is a bit tight for a Miata subframe wrapped around a 442. Rivera got around it by notching the cockpit, if memory serves. My saving grace was pushing the rear axle back farther than most. (that wasn't planned, and I still am not sure how it turned out that way, comparatively speaking.)

With a book frame, you'll have gobs of clearance there. Perhaps more than you want. Set up your subframe with wheels and tires and mock up the cockpit with cardboard or whatever and see if it suits you. Depending on what size tires you're using and what kind of look you're going for, you might decide the Miata track on a book frame looks a bit leggy.

But frankly, I wouldn't sweat it too much. Better to start building and worry about it later.

I suppose if you later decide that book was a bad I idea (I don't think you will), you can convert it to a 442e. Not that I'd plan on getting there that way...I'm just saying that you could.



Whaaa?!? You mean you can't stand the site of a little blood? Wimp.

-dave "bloody right" hempy

I was actually referring to the 'other' picture. That or I'll just make sure not to polish any of the shiny bits of the car.

Feedback is always welcome. Here are the first batch of pictures.

Build started on Sep 1. The first step was to clear enough space in the garage. Pretty much everything that was on the floor is now screwed to the wall or the ceiling.

Once I got this far I put the frame on hold to work on dismantling the Miata. To make good progress going forward I really need some measurements and parts to test fit from the donor.

You don't need to keep the M1/M2 tubes vertical. They're only there to mount the trailing links to a live axle, which is irrelevant to you. Better to move those tubes to be structurally useful, connecting the two nearest vertices.

That's also why the K3/K4 tubes are pushed in an inch. I'd rearrange them now if you're just tacked in place. I didn't realize it until later, so ended up doubling the K3/K4 tubes instead of just pushing them out.

Discussed here: http://locostusa.com/forums/viewtopic.php?t=2858

IIRC, there are two or four edges on the bottom rails you won't be able to weld once the H tubes are in place. Think about it, and you'll probably want to finish weld those edges before tacking the G tubes. Be sure to solidly tack the opposite side of those joints to reduce bowing. I didn't, which may be why my bottom is a bit convex.

-dave

Step 2: Order model! It wasn't 5 minutes before I had a screwdriver out and was modifying it. I'm just not a fan of the wing style fenders.

I'm also baffled by the models claim to having a "functional door". Odd especially since the box is custom printed with "Caterham" across the bottom. I'll also note there is the distinct lack of a pull back mechanism. Still an excellent model, highly recommended for the 7 nut.

Love the roll bar. Reminds me of my first racing one. Basically just one large diameter bend. If you rolled sitting upright, which was likely because the harness held you in that position, there was no bar at all directly behind you. I convinced myself that if I thought I was going to roll I'd force my head and shoulders sideways. Glad I never had to test that theory.

I hope all the inevitable mods to come go as easy as your first one on the model.

Ron

I see you are starting a Miata IRS space frame... I seem to be a few steps a head and thought you may want to see my build log to help? viewtopic.php?f=35&t=7793&p=80392#p80392 I mention this because I see the rear section (I think) in your build, that I had to cut-off to mount the IRS from the Miata. After much debating, and waight compairison, the stock Miata IRS subframe is perfect! I have the fortune of several race car builders at Sears Point (Infinion) who all (but one) agree this was the best part of the Miata chassis! The hold-out wanted me to keep the Watts link solid rear, but it's my build, so I am doing it my way!

I like you table!! Today I cut mine to make gussets for the subframe!

I'm definitely going with the IRS sub frame. If you look really closely in those pictures you'll see a pair of tubes tacked on there for the book's solid rear. I've since removed those and pushed the K3 tubes flush to the sides. The M1/M2 tubes will probably also get moved to connect that corner node but I'll hold off on that tube for the time being. It seems wise to see how the seat fits in there first to see what issues I have with clearance on the seat back adjuster. The frame is book width, so fitment issues I know I'm due for some head scratching and shoehorning to get the seats in.

Do you remember how close you were able to get the sub frame to the back of the frame and how far off the ground you mounted it? Looks like you were able to get a tube underneath the LCA bolts.

Your build looks great! More comments there.

Added: The current plan is to use two pieces of 1"x2" so I can pick up the 3 staggered mounting points on each side of the sub frame so that the entire piece can be unbolted if need be. Then run 1x1 back up to the O tube then put side plates on the outer sides to catch the spring mounting points. Still unsure where that mount point will actually be, maybe I need to spec out springs first.

Plasma cutter?! Hey! That's cheating!!

Yes, green with envy.

And there I was all excited to install the motor mounts I cut on the water jet and I find clearance issues with the engine!

It looks like I will have to drop the oil pan 1.5" below the frame rather than the 1" that I was planning on and at the same time also lift the nose cone up 1". Since that exposes the front lower frame rail, I could cut the nose and stretch it vertically 1" but that would make the already narrow looking nose narrower. I'm also seeing about .5 to 1" of clearance problems with the throttle body where the accelerator cable attaches so I think it'll be wise to sleep on this.

Has anyone successfully sardined a Miata engine into a book sized frame?!

It can be done without tall bodywork, e.g., Keith Tanner's car. Tanner chopped his sump. If you browse at http://www.cheapsportscar.net/ (or buy the book) you can probably find details.

Just paint the chin tube flat black. No one will ever see it.

You could fab your own intake manifold. Pity to waste all that Japanese engineering, but you could make it fit easy enough, and save a few pounds to boot.

-dave