Not another Miata build thread - BoxheadTim tries to build his '95 Miata for road and track use

I've had the car for a bit over a year, modded it a little and took part in a few SCCA HPDE sessions until it became clear that for once, the car was holding me back and not the other way around. That's a new feeling for me, usually it's the other way around.

So, here it is in all its glory with a mismatched hardtop and dented nose. It's rust free (a new experience for me), but unfortunately the PO has had a bit of an off-road excursion and a lot of the work I've done to it was to alleviate the damage from that. I also have the impression that it was running some thumpin' sound system at some point as there are a few holes for wiring etc that are Sawzall rather than stock. But it's driving nice-ish, has only about 138k on it and a new-ish top to boot:

So far, the mild mods on it are:

• Stock MSM shocks and springs
• GarageSTAR front and rear tow hooks and offset license plate bracket
• Braided brake hoses and Hawk HP+ pads all around
• Retrofitted a "real" oil pressure gauge instead of the fake one
• "Mail-order Bride" seats on original Bride lowmax rails
• Rear suspension and steering rack fitted with polyurethane bushes.

The suspension is still fine on the road, but it has trouble coping with track use. Between that and the all-seasons on the car, something had to be done. Due to some other issues I had to cut short the 2012 track season, but after our house move, I finally decided to start the project proper. Current target date for getting everything back together is April 6th as that's the annual tech day for the local SCCA chapter. What could possibly go wrong?

During the downtime - the car's and mine - I've started collecting parts for the project. This is only a small part of the stash, there is a lot more, some parts are still in transit and several other major parts (suspension, wheels, tires, exhaust) haven't even been ordered yet.

There's also a roll bar, an undimpled nose in much nicer condition with an unbroken air guide, a replica R-package from lip and a couple of complete ARC intakes that have just become unnecessary.

The first job was to get cracking on the roll bar because that had known fitment issues and I wanted to find how unhappy I would be with the fit so if I decided I was too unhappy, I could talk to a local-ish place (as in, in the same time zone) that fabricates very nice rollbars that aren't cheap but supposedly very high quality (Blackbird Fabworx). I'm saying supposedly because I have only seen photos of the work.

First the job started by adding lightness by removing the majority of the interior and plonking the bar in to get a feel for the fit and see where the parcel shelf would need tweaking:

The trial fitment showed the need for cuts in the expected places, but I also ran into an unwelcome and somewhat unexpected snag. The foot plate on the passenger side is noticeably too wide to fit in between the ECU and the B-post:

The plate looks like it's at least 5-6mm (sorry, I'm metric, call it 1/4 inch) too wide to even fit in the available space. Issues like this tend to upset me, especially because I had to wait for a fair amount of time to get the bar in the first place as the fabricators in Sacramento had fitment issues with them and the whole production run got delayed. This bar supposedly has the fitment issues fixed...

Maybe I'm just a little too Germanic about these things but this is a powder coated (not painted) rollbar that might need - well, the foot plate will need - cutting and potentially holes enlarging in order to get it to fit. Because it's powder coated, fixing up the cuts will be problematic (paint would be much easier) and it's not going to do anything nice for the finish, either. Mrmpf.

Now, this wasn't an unexpected problem, but given that I'm striving for a pretty high quality build it's time to call Blackbird Fabworx to see if they can fit me in or not. If not, I guess it's time to "adjust" the rollbar.

Why not just move the ecu over?

Partially because there's also an ABS ECU lurking next to the main ECU so I'd have to reengineer both mounts. Either way my unhappiness stems more from the fact that these ECUs tend to be in the same place on most Miatas so the fact that the plate is too wide is probably not a sign of great quality control.

Actually the longer term plan is to go MSPNP so if that ECU turns out to be smaller, that would neatly solve this problem, too.

Either way I'm thinking that tweaking the mounting plate would be a more appropriate solution.

If that's a hard dog rollbar (it doesn't appear to be), the instructions specifically call for you to ditch the upper left ECU bracket, and file down the post it was attached to.

If it makes you feel any better I bought a REALLY cheap hard dog bar, only to find out that new (read: wildly different) upper feet had been welded on. Had to fab some new backing plates, but still irritating.

Not a hard dog bar. But I'd move the ECU myself.

Any chance you can spread the rollbar a bit?

It's an EGR rollbar from the clubroadster group buy. I appear to be just another buyer in a long list of buyers who has a few issues with the fitment.

@CGLockRacer - spreading it won't help, the bar is in the correct position but the foot plate is too wide as it is hitting both the b-post and the ECU at the same time. So it's in the right place, just suffering from a lack of spatial awareness .

Can you move the ecu to the passenger footwell like early Miatas?

In reply to BoxheadTim: Ahh. I didn't see it hitting the B-post at first glance.

EvanB wrote: Can you move the ecu to the passenger footwell like early Miatas?

You can, but it's a bit of work unless you want a big snarl of wire in there. Basically, the ECU is on an extension harness that also carries about 3 other wires. I'm not as sure about the ABS.

It would be a lot easier to simply move it sideways. Get some rivnuts and it becomes an easier job than posting about it on a forum :

Keith Tanner wrote:

EvanB wrote: Can you move the ecu to the passenger footwell like early Miatas?

You can, but it's a bit of work unless you want a big snarl of wire in there. Basically, the ECU is on an extension harness that also carries about 3 other wires. I'm not as sure about the ABS.

Not sure if the ABS ECU has an extension harness or not. I think I'll have to find out. I'd rather keep the ECUs where they current are anyway as they're much more accessible there and I'm planning to MSPNP the car in the longer run.

Keith Tanner wrote: It would be a lot easier to simply move it sideways. Get some rivnuts and it becomes an easier job than posting about it on a forum :

Yes, but where's the fun in not complaining about it on a forum?

I'll have a look if there is enough give in the harnessess and also enough space in general to move the whole shebang towards the transmission tunnel.

Creepers I think you are over thinking things. Have a cold beer, then move the ECU and abs box's over. This is a race car now not a poser street car that has to look perfect!!!! LOL. 15 min job max. Oh-ya and it it matters you will be moving mass towards the center of the car so by moving the ECU you are actually improving the handling.. .. Ya I know I am reaching on that one. LOL

I made my own roll bar and still moved the ECU over.

dean1484 wrote: Creepers I think you are over thinking things.

I'm a German (software) engineer. Guess what sort of person does come up with all that "needless complexity" that you get from BMW and VW, hmm?

dean1484 wrote: Have a cold beer, then move the ECU and abs box's over. This is a race car now not a poser street car that has to look perfect!!!!

Well, it still is a street car so it has to look good. To me, at least.

dean1484 wrote: LOL. 15 min job max. Oh-ya and it it matters you will be moving mass towards the center of the car so by moving the ECU you are actually improving the handling.. .. Ya I know I am reaching on that one. LOL

Any justification will do .

it's behind the seat, you'll never ever see it unless you drive around with the passenger seat pushed forward all the way and folded forward.

You're not looking at a lot of movement, so you shouldn't have trouble with harness length. Moving them is SOP for Hard Dog bars as noted earlier.

German software engineer, thanks for the warning

Your are going to get rid of the soft top aren't you. since you have a hardtop. That probably sheds 100 lbs (guessing). Oh and my opinion, move the the ECU a half inch and be done with it.

Nope, soft top is staying - as mentioned this is not a race car, it sees more street miles than track time. For starters, I have to drive it to the track...

I have a nefarious plan how to overcome the additional weight I get from leaving the soft top on .

It's about 35 lbs for the soft top, by the way. I took mine out of my street car not because of the weight savings but because it opens up a lot of really useful space back there.

Keith Tanner wrote: It's about 35 lbs for the soft top, by the way. I took mine out of my street car not because of the weight savings but because it opens up a lot of really useful space back there.

Yep... Makes for a nice place to mount an ecu, if one were looking to undertake such a project.

Sneak preview of what Fedex dropped off today, aka horsies in a box:

If you're going to use the stock ECU and if there's no MSD ignition retard box under those peanuts, it's well worth the investment. They're about $150.

I'm initially planning to use the stock ECU (long term plan is to go MSPNP). I didn't dig too deeply into the peanuts yet - they and our cats don't mix well - but there is an MSD ignition retard box in there and supposedly also something called a "Voodoo Box"...

Voodoo Box good Voodoo plus MSD better.

My suggestion for those blowers is to do the easy stuff and then just drive. They're pretty close to the point of diminishing returns right out of the box, you can spend a lot of money to get an extra 20 hp out of them.

The MSPNP is more to satisfy my urge for tinkering and hacking. It's hard to overestimate the draw a mappable ECU with available source code has on someone like me .

I'm not planning to go turn this into a "must get 250whp from a blower that's too small for by spinning it at a zillion rpm" project like you see on certain forums but I'd just like to get the bit of extra oomph you get from bolting on one of these and leaving it more or less at stock rpm.