MG MGB GT

I am not a suspension engineer so bear with me, since your car has a "live" axle in the rear, what is 

the advantage of the bell crank suspension? (It definitely looks great!!)

It seems to me you are moving weight higher up on the car for what gain?

Number of adjustments and ease of adjustments is probably only real benefit I'm after.

I wanted to ditch the leaf springs and didn't want to buy any of the off the shelf rear coilovers options. Since I was was starting more or less from scratch, I figured it would be a fun exercise and look cool.

Maybe nocones or others would have a different answer based on actually having driven stuff with bell crank suspension.

Thanks and it certainly looks cool!

SORRY- i'm back! Hey, looking at the rear suspension solution in situ, I'm concerned with your bellcrank orientation. Your bellcrank pivot point will see a high amount of stress as well as a series of concurrent rising/falling rates the way you currently have it set up. The picture below shows the differences in rocker orientation compared to yours. I'm not an engineer-just worked several years in Michelins' Motorsports group as a regional manager and raced in Formula Continental, so I'm coming from a position of being taught, so I could easily be missing something. In that case, take it all with a grain of salt! Just don't want to see great work get damaged!

In reply to 2GRX7 :

No need to apologize! Happy to have some feedback.

Can you clarify what differences you are referring to? I think I'm missing it.

Do Gifs work here?

Nukem- I think I see what's going on now, looking at the GIF (non-working),  actual static ride height is presented (went back to page 5).  Really enjoying this!

In reply to 2GRX7 :

Cool, glad that helped!

I might still do some FEA for fun at some point, but I'm feeling pretty good about getting this fully welded and burned into the car.

Seat brackets fit!

Someone needs this. Looks like an Ex Red Bull Mini Cooler promo car thing.

MGB front and Ford Explorer brakes powder coated in Ford Dark Blue and rebuilt:

And freshened up the steering rack (regreased, new boots and tie rod ends). Angle grinder had to come out to get the old tie rod ends off.

How about another tangent?

Last year I finally plopped a turbo in my 91 Miata and ripped it around all summer and Fall before parking it over the winter. The entire time the battery was on it's way out.

It is finally warm enough in New England to bring it back out, but the old battery wouldn't take a jump and needed replaced.

Unfortunately, a couple of fuses and the ECU apparently popped while trying to get the old battery working. All the ICs seem fine but there are some suspect components and some charred PCB around the 5V and inputs circuitry. I'm going to see if I can save it...

Plan A: Repair this DIYPNP board. I think I even have spare passive components enough to replace the suspect stuff. Does anyone have a good board layout? Ideally I'm looking for something showing all the PCB traces.

Plan B: I recently ordered a new Speeduino based ECU for the MG, which I could divert to Miata duty. This would require some re-work, but not a huge amount. I should be able to deal with the IO and plop my old tune on the new board.

Concerns: I don't really have a solid cause of the ECU popping. Any ideas / things I should double check before putting any ECU back in?

Current list of failed Items:

Room fuse

40A BTN fuse

Wideband controller (same room fuse circuit)

ECU (DIYPNP 1.5B)

a closer look at the carnage 

This crater is where one of the 12V inputs used to run. I can fix this part.

All of the resistors (near the burned up board at least) test out fine.

Pin 1B on the Miata N76 connector (White/Red on the Miata harness side, IIRC) is where I the ECU is currently trying to get +12V, but I believe Pin 1A (Blue/Red wire on the Miata harness side) also has 12V.
 

Any reason I wouldn't just use 1A instead? Currently it goes to nothing.

If I'm reading my wiring diagram right, I think using 1A would make more sense, as it is on a 10A fuse (room fuse), vs White/Red which I believe is straight off the Main Relay / 40A fuse.

What's going on with the melty looking bit on IG2? Any relation between those circuits? 

In reply to Shavarsh :

That's melty from the soldering iron from me soldering these stupid jumper wires when setting up the I/O last year. I'll check that it is safe from shorting out on the case.

It appears the 12V input trace to the 5V voltage reg is toast, and the reg itself is also toast. (The voltage regulator is on the backside of the PCB in the area marked 5V power)

I powered up the board on the bench, jumpered 12V to the input on the reg and only got ~0.9V on the output side, and it got really hot.

Time to fire up the speeduino? or is it replaceable?

In reply to Shavarsh :

There is a chance I can repair the Megasquirt, but Speeduino is my Plan B.

I've not built up the courage to cut off the factory Miata ECU connection yet, which I will want to do if I am to run the Speeduino. I think Speeduino will probably be the right long term solution anyway...

Plan B is go.

The ECU that was previously destined for the MG is this one: https://www.everythingfuelinjection.com/store/STM-Pro-ECU-p149186223

Supports full sequential fuel and spark up to 8 cylinders, so it's proper overkill for the Miata 1.6. I already have it on hand though, so it's perfect.

I'll try to get the Miata back up and running on wasted spark / fuel but I'll add full sequential to the backlog. I also ordered a crank trigger wheel from Flyin Miata. Adding that to the backlog too.

If I say Keith's name 3 times does he appear?

I'd love for some Miata guru to pat me on the back and reassure me that I'm not just going to fry the next ECU I throw in here due to some lingering electrical issue...

I am selfishly stoked that you'll be figuring out the stm pro before I start my project.

Edit: There should be some tests you can run on the wiring in the car without the ecu right? Just to make sure there isn't a short to ground on the main circuits etc.