2019 Miata engine investigations.

Ah, there's nothing like taking apart your brand new car. I love this stuff.

We started with the intake manifold. This will tell us if the Edelbrock SC will fit and also gives us a first look at the throttle body changes. So, here are some pretty pictures to start off.

ND1
Edit

ND2

We can see the big difference in the ports. The divider is gone and they're now taller but narrower. That step in the ND1 gasket is interesting. The runners are larger diameter and the plenum size is larger. Interestingly, it looks like Mazda did their best to keep the new throttle body in the same place. There's also a divot on the #1 runner on the ND2 for clearance. There are some small bracket changes as well.

Here's an overlay of the ports. The one with the kink is the ND1 part. This doesn't bode well for the Edelbrock supercharger, as the edge of that gasket is just skirting the edge of the ND2 port. It may seal, it may not.

The ND2 also adds some (very light) insulation inside the manifold, probably to cut down on the DI chatter.

It looks like you will have to match the manifold to the head, no interchange.

Throttle body!

The ND2 throttle body is 5mm larger according to our measurements. Mazda, however, maintained the location (as best as we can tell), the pattern and the outer diameter. This means any piping before the throttle body is unchanged, and that bodes well for turbo kits (so far).

The electrical connection is different. Three long bolts have been made short bolts. The retaining lip for the intake only goes 3/4 of the way around, which would make for easier installation - nice touch there. The new TB weighs about 1/3 lb LESS than the old one.

The takeaway: if you do an ND2 engine swap on your ND1, you will want to transfer the throttle body over to maintain electrical compatibility. Or you may rewire, we don't know about that yet.

Here's how committed Mazda was to keeping that bolt pattern. Check out the way the bolt holes intrude on the opening.

Here's a shot of the side of the ND2 engine. You can see how far the intake ports continue before they split - on the ND1, the split is in the intake manifold. One thing you can't really see in the picture is that the alternator is also now clutched, so the drag can be removed when the alternator isn't needed.

Questions? More to come!

In an era of electrification, it's cool to see a manufacturer still sinking real engineering talent into refining their combustion engines--particularly for a low volume car like this one.  Someone on the executive team at Mazda must really love the Roadster.  Few other automakers would let their engineering teams dig this deep into any car at this price point.

Agreed. It's the only longitudinal engine in their whole fleet, it makes no sense to do this for a car that starts at $25k. Heck, the platform makes no sense at all. My theory is that the Miata is their halo car, so it defines the whole company.

Clutched alternator is cool. What are the chances that an enterprising young man could use this in other applications? Something simple like disengage the clutch at 90% throttle? 

Easy enough. I even have a magic relay that would read throttle position through the CAN stream and do the deed upon request.

Neat stuff! I can't wait to see what else you find.

Do you think Mazda knew they left some on the table (as far as the engine concerned) and were planning a mid-cycle update from the start? I know we were all a little surprised at the "low" numbers out of the gate. 

I expect that any engine that goes to production is outdated as soon as the drawings are signed off. Given more time and the opportunity, the engineers can always do more. Ferrari and Lamborghini keep eking more power out of the same engines every year or every time they introduce a special edition too.

I suspect there is a 5 year plan for the car. You can't get Mazda engineers to commit, but I've been led to believe that the lifespan of the ND platform will be typical for a Miata platform and they've always had a bit of a refresh every 3-4 years with the exception of the mid-90's economic problems.

The reason people were surprised by the "low" numbers is because it wasn't 400 hp. Anything less than a base Corvette is viewed as underpowered these days, and almost all the benchmarks being used for comparison were obsolete engines that couldn't meet modern emissions standards. Naturally aspirated 2.0s are actually really thin on the ground these days, with the BRZ/86/FRS being only notable exception. What nobody realized (realizes) is that the engine is not a dyno queen, but has a big fat torque curve. All the complaints about specific output died down as soon as performance figures started to roll in. I have a lot of respect for Mazda sticking to their guns on the engine's characteristics in 2015 instead of compromising that bottom end to get a big sparkling top end power figure. I'm also really glad they didn't do that in 2018.

It's fascinating digging into an engine and seeing how the OEs handle this kind of thing. They don't have to pay as much attention to how many parts are modified as the aftermarket does, as the incremental cost of a new X is far less when you have to make one anyhow as opposed to throwing a good one away.

In reply to Keith Tanner :

That alternator sounds expensive to replace. Is the pulley/clutch pressed on like a normal alternator pulley? I’ll be interesting to see in 10+ years which part fails first. 

A NA 2.0l isnt' dead, yet.    Thanks to Toyota, everyone is really questioning their turbo choices that have been made.  Then add in the increase in power that everyone is finding, 2.0l NA engines will go up to a small SUV and move it very smartly.

So that engine may have some special parts that are unique to the Miata, but it *should* be far from a small volume engine, overall.

The clutched alternator is pretty cool.

And I know there's another 2-3% more FE more available, which is free.  Just found it a few months ago, and I'm 99% sure nobody else is aware of it, which is kind of funny.  And this is FE you will notice.  As a matter of fact, most here (sporty car drivers) will appreciate the side effect of doing this more often.

In reply to alfadriver :

What is this “FE” you speak of?

OHSCrifle said:

In reply to alfadriver :

What is this “FE” you speak of?

Must be Fuel Enjection

Found Energy

parker said:

Found Energy

 

Or fuel economy. Same thing. 

alfadriver said:

And I know there's another 2-3% more FE more available, which is free.  Just found it a few months ago, and I'm 99% sure nobody else is aware of it, which is kind of funny.  And this is FE you will notice.  As a matter of fact, most here (sporty car drivers) will appreciate the side effect of doing this more often.

Tease.

The 2.0 Skyactiv does get used in other applications in the Mazda line, of course. But the Miata has a special one that's tuned more for sporty and less for minivany, and of course these intake manifolds will only fit the north-south engine. I wonder if the CX3 will get a 7500 rpm redline?

I drove our turbo ND1 to Denver last week. Last time I drove home from Denver was in the brand new ND2. I got better fuel economy in the ND2, which is interesting given that the turbos usually see a very slight increase in economy on a cruise. 35 vs 40, ish. I did have a bunch of rain in the turbo ND1 drive but not a lot of wind. In fact, I was going slower in the rain due to visibility and standing water. So the ND2 engine is more efficient as well as more powerful. Wins all around!

The only reason I could see one wanting a clutch on an alternator is if one were really concerned about rapid engine accelerations like WOT in 1st gear, or mid-shift throttle blippage.

On the other hand, this IS the Miata, so maybe.

 Then add in the increase in power that everyone is finding, 2.0l NA engines will go up to a small SUV and move it very smartly.

I remember when Kia's n/a 2.0 got a power bump years back and it came out that a 2.0/6spd manual Kia Soul would do 0-60 in 6.7 seconds. Nobody knows that because nobody bought it, but i found it pretty comical and memorable. I always love comparing modern 0-60s to the SN95 Mustang GT which is a reliable punchline among automobiles. I think it did it in 6.4.

Knurled. said:

The only reason I could see one wanting a clutch on an alternator is if one were really concerned about rapid engine accelerations like WOT in 1st gear, or mid-shift throttle blippage.

 

On the other hand, this IS the Miata, so maybe.

 

 

Or economy. I suspect it’s disengaged on the highway at times. And there’s nothing wrong with decreased drag on the engine for better performance! I think I need to log this.

Alternator would not need to run all the time, how much gas do you save cycling it?  Not much, but they take an every little bit helps approach on weight, why not for other things.

In reply to Keith Tanner :

Automakers have been cycling the field off under certain conditions for a long time.  With no field, the alternator is just a spinning mass, under cruise the power difference between an unpowered alternator and a declutched alternator would be so low as to make no difference.

This is why I think it may be acceleration-related.  After all, automakers have been putting one-way clutches on the alternator so that its spinning mass doesn't try to backdrive the belt as the crank pulley undergoes its normal torsional harmonics.  Longer belt life, less belt noise, less tension required...

In reply to Knurled. :

Which makes a lot of sense- when you measure fuel economy on an easy cycle, such as the FTP test we all have to run, over 60% of the energy used is to accelerate the car.  So removing that inertia does help.  Not sure how much- I'd have to measure it.  But it does address the worst fuel consumption area. 

My theory is that the current Miata is the "skunk works" project for Mazda engineers. Ford does the GT and FiatChrysler has the Demon cars and almost everyone has that one product that's kind of out there but let's the engineers flex their brains in a way that's a bit non-linear to profit. Mazda could go factory racing or build a properly dumb show car or......put all that extra thought into the Miata. It looks like it makes no sense, but it makes better engineers and they can then go out to the normal product lines without being stuck in the production car box of thinking. I'm glad they're doing it, the ND is a neat car. That's my theory anyway. 

In reply to mazdeuce - Seth :

I'll just say that the GT is not our skunks works.  They just turn up the volume of fuel, and let it rip.

And given the significance of the MX5, I honestly doubt the Miata is a skunk works car, too.  The 3 is far more important, so all the focus on making the best motor ever has to be focused on that platform vs. the Miata.  And by best- I mean total systems best, not best performance.  

Mazda could go factory racing or build a properly dumb show car or

Or maybe build a dumb show car and imply  you're going to race it but let it burn to the ground on a major TV show instead!  Plot twist! 

Very interesting, thanks for taking the time to share what you found Keith!