Big engine, meet little car

Thanks Keith.

I just searched eBay, and the Camaro diffs are typically 3.27, about $500+.

The G8 diff are 2.92, and going for about half as much ...

I've always thought that paying FM for a conversion was worth it. Getting a peek behind the curtain on the ND conversion only makes me more sure of that. Keep the pictures coming. 

The reason we changed to the G8 was because the Camaro diff is NLA new. Things are obviously different when you're doing a home build, but we only use new parts. I don't think we're using a 2.92, but I can check on Tuesday.

I have to give GM credit here. They're very willing (through SEMA) to provide 3D models of things like engines and diffs, so we can virtually swap in the G8 unit to see how it will differ from the Camaro.

That helped a lot with the steering rack, especially when we were trying to find a RHD variant. Given that the 5th gen Camaro platform is also found under a bunch of Holdens, we thought it would be possible. But unfortunately not yet.

Thanks Seth. We were able to address a bunch of things in the ND conversion that were weak points in the earlier ones and we've worked really hard on the details. There's a lot of collaboration between the FM staff members on this, a mix of 3D CAD work (we scanned the Mazda engine bay and subframes when we started this project) and more traditional fabrication. Before something gets committed to metal, we'll stand around and discuss it and see if we can make it better - lighter, stronger, cleaner or easier to service. We've got a great staff with a good mix of skills that works really well together. Some of these parts are difficult to justify from a business standpoint - just wait until you see the exhaust system - but we just can't help ourselves.

In reply to Keith Tanner :

FM is head & shoulders above the rest.

Thanks Keith for sharing this inside look. Anyone thinks it's easy ... NOT!

More updates!

The engine and transmission is ready for installation.
Or more accurately, the engine and transmission are ready for the car to be dropped on top. This is a lot easier with a lift.
We have to shorten some of the wiring harness to fit our small car, and everything is secured to avoid chafing and vibration problems. Nobody enjoys chafing.
The driveshaft is also installed here, but that's because it's easier to mate the transmission to the engine if you can tweak the rotation of the splines a bit. The driveshaft gives you an easy handle to do that with.

Before the engine goes in, we need to do some modification to the body.
It's pretty minor, but we are fitting a whole lot of metal into a car that's shrink-wrapped around a small drivetrain. All we had to do was make a small cut and reform the metal around it. You can try to do this without the cut, but the fact that it's on a corner makes that more difficult than it has to be.

As I mentioned earlier on, this is just the FM webpage build diary posted to GRM. That's why it comes across a bit as "here's how it's done" and doesn't invite comments. I welcome questions and discussion from my GRM friends! If you want to see details on something in particular, just ask.

The rear subframe and the mufflers are installed.
These are the big steps that are really gratifying. There's still a lot to do, but bolting in that big complex piece of metal feels good.

As with all of our ND exhausts, the V8 version is active.
These two little butterflies allow the exhaust to bypass the mufflers when desired. That means minimum restriction and maximum noise.
The butterflies are controlled via the CAN components that allow us to mate the GM powertrain to the Mazda platform. The windshield wiper intermittent knob lets the driver select "stealth mode" (always quiet), "hoodlum mode" (always loud) or have the butterflies change at a certain throttle position. That's my favorite mode, you can almost play the exhaust note like a musical instrument.

So what are the odds on "stealth mode" meeting sound at Laguna? :)

I guess that depends on the day! It's actually pretty well behaved, at least at lower throttle levels. WOT up out of turn 4, well, that's a lot of explosions to shut up...

Keith Tanner said:

More updates!

The piece of 2x4 wedged underneath that makes me realize that we're all playing the same game. 

It's a 100% fiber powertrain leveling block, available in a collection of standardized sizes. Because we are environmentally responsible peoples, it is both produced from renewable materials and is biodegradable.

In reply to Keith Tanner :

Does that mean the wipers are no longer intermittent, or that their delay changes with engine note?

You know, I don't remember exactly what the code is. I think we have the exhaust default to stealth mode when the wipers are on. I've got a few different options available to me.

Having a programmable gateway in the CAN system gives you the ability to do terrible things. I could probably program the horn to honk with the right turn indicator but only on Tuesday mornings.

Bravo!  A classic case of elegant re-engineering.  Well done.

Interesting to see the differences in the NC build and the ND build. You guys did a lot more in house with the mountings and subframes compared to my girl. Are you still doing the snorkel for the air intake? I forgot. 

We did all the design work in house on this generation, which does set it apart from the earlier ones. In the case of the NA/NB/NC we used V8Roadster parts to mount the drivetrain and did the finish work ourselves - PS, cooling, AC, intake, etc. We're pretty happy with how the ND's turned out.

Your car is the first of our NC swaps, so there are a few more hand-built parts on it than we use for later builds. It's the equivalent of Indy, the first ND V8. We'll often update the initial builds if it makes sense - Elvis got pretty much completely rebuilt at one point - but not always. We're about to deliver an NC V8 right now and you'd see a number of detail differences in that build as well. People who aren't as intimately familiar with your car wouldn't notice.

We're using the snorkel on the NC, but the low nose of the ND prevents that. We tried to make it fit but it didn't want to.

Keith Tanner said:

I could probably program the horn to honk with the right turn indicator but only on Tuesday mornings.

I did this to one of my roommates in college with a trailer wiring pigtail and aligator clips...

Thanks for the pictures, this is really cool to read/watch along. One day I'd love to have y'all build me one of these!

Update time! Let's start the weekend off with the money shot.

I mean, I don't really need a caption for this. But here you go.

And boom, the engine is in.
This is one big, gratifying step that happens really quickly. We'll sometimes install and pull an engine several times, especially on earlier models where there's more sheetmetal work to fit it. In the ND, it's more of a one-and-done sort of deal.
There's obviously still a lot of work to do here. Lots of wiring, the AC system, intake...but you have to admit it makes you feel good to see it.

Now some more of the detail.

Those who know the ND engine bay will note that the battery isn't there.
Nope, it's back in the trunk where it belongs. Really, Miatas have been made with front mounted batteries for almost as long as it was ever in the trunk, but we like them back there. It's good for weight distribution and it opens up a lot of room underhood.
In this case, we've mounted an Odyssey PC925 in the right rear corner. These little guys pack a big punch without being fussy, and they'll sit happily for months and months if you disconnect them. There's a cutoff switch just above it that makes it easy to store the car or to work on the electrics.
We also put a jump point underhood in case you find yourself with a dead battery. While it's possible to release the trunklid without a functioning electric latch, you need to disassemble non-trivial parts of the car to do it.
We always make sure there's no way the trunk can close and lock before we have all this wired up.  That would be a pain in the...shop.

Remember the spider brace?
Here it is in place, snuggled around the exhaust and transmission. This is some tight packaging. The exhaust is mounted to the brace with a couple of silicone grommets to allow for movement and heat expansion.

Here's a view under the car with all the major components installed.
The white coating on the exhaust is Swain ceramic to control heat.
The oil pan is an exclusive part of ours that adds excellent oil control and a very low profile. This means we can drop the engine down low without a ground clearance problem. We have them in aluminum and steel, this customer chose steel.

Leaving this pic for last because I just love how it turned out.

The exhaust from the rear.
You can see the attention we paid to ground clearance here - we know that a lack of ground clearance makes a car far less useable in the real world. Almost everything is tucked up inside the body. The oil pan is well protected by the subframe. The cats are armored behind the spider brace. The exhaust is inside the tunnel. The one exception is where the exhaust ducks under the rear subframe. This is the low point on the stock setup as well, and it won't scrape on speed bumps because it's between the rear wheels.

Keith Tanner said:

The reason we changed to the G8 was because the Camaro diff is NLA new. Things are obviously different when you're doing a home build, but we only use new parts. I don't think we're using a 2.92, but I can check on Tuesday.

It's way past Tuesday, but I can report that this is a 3.70 rear end. I can pull the part number if you want to know what it is.

Lookin' good!

Is the owner going to get to pick it up at Summer Camp?

We're shipping this one back to Hawaii. No high-horsepower deliveries at Summer Camp this year.

So, the Summer Camp is over. It's a lot of fun but it sure is a distraction. Here's the current state of the beastie.

The engine bay is coming together.
You can see the custom intake hose and heat shield here. We use a very cool LS7 intake on the earlier chassis, but it just won't fit under the ND's low hood. The GM PCM is also housed in the shielded area to protect it from underhood heat.

A proper expansion tank. Fitting this puppy underhood wasn't easy.

The underhood jump point.

Fun story for GRM - I was driving the latest ND build home (an RF, so sexy and sweet with the 430 hp engine) a couple of days ago and I stopped to adjust the shocks. Right as I got out of the trunk after doing the rears, the car stopped and I slammed the trunk before I thought about it. Car was completely dead. I must have bumped the kill switch in the trunk - it's usually got a pretty solid detent, so maybe it was in the "almost but not quite" position. Anyhow, I had to phone a coworker and get a jump. Trunk popped right open, I flipped the kill switch over again and we're all good to go. I'm very happy we put that point in there...

Here's a piece of ND trivia most don't know: partway through the 2016 model year, the specification of the fuel pump changed fairly dramatically.
The later ones can feed a hungry V8 but the early ones can't. Humu is an early car, so we swapped in a new later pump.
This was a very convenient change for us, as the ND has an extremely compact fuel pump and there are not currently any aftermarket upgrades available.

GRM note: Indy, our in-house R&D V8, was on the first boat of NDs to arrive in the US so of course it had the weenie pump. It's running an in-tank setup that includes an aftermarket pump out of an NC along with the upper part of the NC surge tank, strapped to the bottom half of the ND surge tank with stainless safety wire applied via Clamptite. Not a production solution, but it's been solid! Well, except for the time the fuel output hose popped off inside the tank. We break cars so you don't have to. I also shattered a CF driveshaft on about the third day that car was mobile...