Why it's the answer to everything....

It's all perfectly clear now...

IMG_4470 by Leadfoot Lesley, on Flickr

I see some good bracing, some bilstens and red calipers.

I must be particularly dense this morning, I can't figure it out.

YX approximately equals ginormous muffler?

ND?

That's a stock ND exhaust. I wonder how much weight an aftermarket system would save?

Some, from what I hear. It could also do with a slightly louder (no a lot, just a tad) exhaust.

That muffler is huge!

One or two cats?

Yah, it's a brand new press car GS with the Sport Package. Really nice smooth power train. There is some piped in engine noise. Love the x brace plate and the longitudinal aluminum beam.

Looks like that tailpipe is connected to the gas tank.

I have been looking for an XVII, or something...

stuart in mn wrote: Looks like that tailpipe is connected to the gas tank.

I thought the same thing! Lol

Interesting - stamped mufflers are so much cheaper to manufacture...

The gas tank is tucked way up. Two cats, yah.

Is it just me or does that X brace look like it would do next to nothing? I mean it's nice that it's there, but it looks like it was stamped out of the same grade sheet metal they make washing machines & computer cases out of, and is just fastened onto the floor with four bolts. I suppose it would hold the exhaust off the ground if that were to fall off for some reason.

Miatas have had those aluminum beams (called Power Plant Frames) since the first car rolled off the line in 1989. The central X brace only showed up in 2001, although it was painted black for the first five years

Mazda trots out the "gram strategy" claim every time there's a new Miata. But this one's for real. There's pretty spectacular weight saving tricks all over the place. The weights of individual components are pretty impressive, although it comes at a price. The engine is so optimized (280 lbs with all accessories, clutch/flywheel and a sump full of oil) that there isn't enough meat in the head to allow porting, and you cannot overbore the block at all. The diff holds a mere 600 ml of fluid, the trans not much more than that.

Sure, the X brace is a piece of stamped steel. But it's three dimensional so it's stiffer than you think, and it's in a place where it can do a lot of good. We're examining that area pretty closely as part of our V8 conversion, and we're having trouble coming up with one that will do the job any better. The one ahead of it is really cool. Remember, all of this is in a low volume car that starts at $25k US.

Lesley, see if you can get behind the wheel of a non-Bilstein car. It's a much more composed ride.

Thanks for all that info Keith. This is actually the first look I've ever had under one of these little fellows. Only the base model here is available without the Bilsteins - haven't driven it but now I'm curious :-)

In reply to Keith Tanner:

Are you saying the head is too thin to even do a basic casting flash cleanup/gasket match/short side/bowl smoothing? This normally removes very little material in most heads.

first thought: who photoshopped the exhaust being piped into the gas tank. then i realized it is a ginormous muffler

WildScotsRacing wrote: In reply to Keith Tanner: Are you saying the head is too thin to even do a basic casting flash cleanup/gasket match/short side/bowl smoothing? This normally removes very little material in most heads.

Fire up the grinder at your own risk. That's what I'm saying. This is a highly optimized design with close tolerance casting.

The muffler isn't that big, it's simply attached to a small car. And you don't want to hear one of these for the first 30 seconds of running with a too-open exhaust. Nasty.

It does all sorts of interesting things to keep the cats to temp. You have to think of the throttle pedal as a torque request device. The car will juggle the throttle butterfly opening with the ignition and cam timing to get you what you're asking for, but it'll change strategies depending on the temperature of the cat. On initial startup, it generates almost no vacuum at all and makes a very distinctive noise - then, after a few seconds, it drops back down into a more typical mode. It'll do this at cruise as well but you can't hear it. Modern cars - and this is the first Miata that could be considered as such - are fascinating.

Oh, and don't think you can get much headroom out of those injectors.

In reply to Keith Tanner:

So basically power mods are going to be similar to the Renesis in the 8 in the fact you will spend a lot of money on stuff to get not too much more power (aside from a swap)

This is one car that I wouldn't even think about power increase. Handles like a gymnast, driving it makes me happy.

Keith Tanner wrote: And you don't want to hear one of these for the first 30 seconds of running with a too-open exhaust. Nasty. Oh, and don't think you can get much headroom out of those injectors.

Modern cars for years have done the "extra fuel/retard timing" as a way to get EGTs up and fire off the cats.

I think Moto-East has already stated he believes there is enough headroom in the stock fuel system for bolt-ons and E85.

stuart in mn wrote: Looks like that tailpipe is connected to the gas tank.

They're preheating the fuel so it combusts easier. I hear it's for emissions.

Bobzilla wrote: They're preheating the fuel so it combusts easier. I hear it's for emissions.

Nah, they pressurize the tank with the exhaust gasses, so there's no need for a fuel pump. Between the pump itself, the wiring, relay, and reduced need for capacity in the alternator and battery they managed to shave a pound and a half off the car! :)

Hey Keith, the x brace and plate just aft of it is stamped aluminum instead of steel (they passed the magnet test). Some weight savings to be gained there too. I'm now curious to drive the base, since I've driven this and the GT. Wonder how much I'd miss the LSD. Not to mention the heated seats