So apparently the ND MX-5 is severely limited by its exhaust?

That would actually be kinda cool. I like being able to mod my cars and actually see gains.

cmcgregor wrote: In reply to z31maniac: This is a $1900 header/midpipe combo and specific tune - so pump gas, but it's not exactly cheap

I'm well aware. We've been talking about this on the Miata forums for a few weeks now.

However, on the BRZ the rest of the exhaust adds another $1200 minimum, and another $700 for a top spec Flex Fuel kit.

So $2k more and having to use E85. Which should be worth another 10-15whp on the Miata.

It's downright insane what an exhaust and tune are doing for the Miata.

I would want to see independent corroboration of these numbers based on my own experience with the ND drivetrain. Claimed tuning numbers have not stood up to scrutiny.

If this is the Long Road Racing header, we have one of those. It did not perform to that level, and even the Global Cup cars did not see that level of increase running a programmable ECU.

Just thinking out loud, these SKYACTIV engines were tuned for fuel economy, not necessarily outright performance. But to do this they employed methods that usually equal bigger horsepower gains, things like really high compression, direct injection, dual variable valve timing, equal length headers, etc are all used to improve economy, when they are normally used for power gains.

It makes sense that tuners could use these already existing features of the engine, and turn them to improving power.

Still, that is a huge gain from such simple mods. Very impressive.

Keith Tanner wrote: I would want to see independent corroboration of these numbers based on my own experience with the ND drivetrain. Claimed tuning numbers have not stood up to scrutiny. If this is the Long Road Racing header, we have one of those. It did not perform to that level, and even the Global Cup cars did not see that level of increase running a programmable ECU.

Ditto. Many an aftermarket shill has used a dyno correction factor in their favor and compared to the OEM baseline, which is very conservative.

In reply to CyberEric:

Maybe, but probably not.

Wide open performance and fuel economy are so very far apart that the calibration for each have no bearing on the other. So, to me, it's unlikely that Mazda would leave anything on the table.

tuna55 wrote:

Keith Tanner wrote: I would want to see independent corroboration of these numbers based on my own experience with the ND drivetrain. Claimed tuning numbers have not stood up to scrutiny. If this is the Long Road Racing header, we have one of those. It did not perform to that level, and even the Global Cup cars did not see that level of increase running a programmable ECU.

Ditto. Many an aftermarket shill has used a dyno correction factor in their favor and compared to the OEM baseline, which is very conservative.

From what I've read, the claim is that the Goodwin tests were done before/after on the same dyno, although it was a dyno dynamics rather than the dynojet most people look at as the common standard.

alfadriver wrote: Wide open performance and fuel economy are so very far apart that the calibration for each have no bearing on the other. So, to me, it's unlikely that Mazda would leave anything on the table.

The tinfoil hat theory is that they are protecting the transmission. :)

Keith Tanner wrote: I would want to see independent corroboration of these numbers based on my own experience with the ND drivetrain. Claimed tuning numbers have not stood up to scrutiny. If this is the Long Road Racing header, we have one of those. It did not perform to that level, and even the Global Cup cars did not see that level of increase running a programmable ECU.

Got to do the +1 on this, there would have to be a serious defect in the tune and exhaust to get that out of a motor that small. Freaking Vipers only pickup 40-50rwhp with longtube headers and cat deletes and they have seriously restrictive headers.

Maybe the gains are from the tiny turbos hidden in the exhaust runners. Don't forget that you saw that here first

WildScotsRacing wrote:

thatsnowinnebago wrote: I saw that header in an email from Good-Win racing. Meant to make a thread asking Keith what he thought about it and then promptly forgot. Hopefully he'll chime in here. 40hp is a LOT to leave on the table from Mazda's engineers.

I do wonder if Mazda did it on purpose, to appeal to the true enthusiast/motorsports crowd... The ones who actually enjoy modding their cars for more power and better handling, while leaving a fairly docile Miata for the unwashed masses?

If that were the case, wouldn't they already have a MazdaSpeed exhaust and tune kit in the catalog? If they actually left that much on the table surely they know it's there.

thatsnowinnebago wrote: Maybe the gains are from the tiny turbos hidden in the exhaust runners. Don't forget that you saw that here first

Speaking of turbos have they made a turbo kit for ND's yet

thatsnowinnebago wrote: I saw that header in an email from Good-Win racing. Meant to make a thread asking Keith what he thought about it and then promptly forgot. Hopefully he'll chime in here. 40hp is a LOT to leave on the table from Mazda's engineers.

I thought the ND was rated at 150-155hp. 193whp is probably a minimum of 210 crank HP, probably more, assuming that their dyno isn't wildly optimistic.

fireball123 wrote:

thatsnowinnebago wrote: Maybe the gains are from the tiny turbos hidden in the exhaust runners. Don't forget that you saw that here first

Speaking of turbos have they made a turbo kit for ND's yet

There's an Australian one built for the 1.5L that was shown at SEMA. I'm not sure if any examples have made it into the US or how the 2.0 will respond. I suspect the existence of the 124 will hurt the forced induction aftermarket for the ND for a few years.

I agree with Keith, I'd want to see some independent verification of those gains plus as alfadriver pointed out, those parts are most likely not road legal.

That said, there does seem to be some power that's been left on the table, IIRC the MX-5 Cup car also gained about 15hp with a header, exhaust and presumably a tune.

Of course it sounds like Tom is about to try and convince us to all buy Fiats instead right about now.

codrus wrote:

alfadriver wrote: Wide open performance and fuel economy are so very far apart that the calibration for each have no bearing on the other. So, to me, it's unlikely that Mazda would leave anything on the table.

The tinfoil hat theory is that they are protecting the transmission. :)

Possible.

And if true, there's a big group of engine guys (designers and calibrators) who are REALLY angry. BTDT.

alfadriver wrote:

codrus wrote:

alfadriver wrote: Wide open performance and fuel economy are so very far apart that the calibration for each have no bearing on the other. So, to me, it's unlikely that Mazda would leave anything on the table.

The tinfoil hat theory is that they are protecting the transmission. :)

Possible. And if true, there's a big group of engine guys (designers and calibrators) who are REALLY angry. BTDT.

Anything is possible, and for full disclosure I don't work in Automotive anymore...

...but if I made a design of a part which required leaving a 25% power gain on the table, I would be fired immediately and there would be a team working like mad to fix it.

BoxheadTim wrote: I agree with Keith, I'd want to see some independent verification of those gains plus as alfadriver pointed out, those parts are most likely not road legal. That said, there does seem to be some power that's been left on the table, IIRC the MX-5 Cup car also gained about 15hp with a header, exhaust and presumably a tune. Of course it sounds like Tom is about to try and convince us to all buy Fiats instead right about now.

Of course it's not road legal, it removes the primary cat.

All aftermarket headers for modern vehicles make power by removing the high density, primary cat.

tuna55 wrote:

alfadriver wrote:

codrus wrote:

alfadriver wrote: Wide open performance and fuel economy are so very far apart that the calibration for each have no bearing on the other. So, to me, it's unlikely that Mazda would leave anything on the table.

The tinfoil hat theory is that they are protecting the transmission. :)

Possible. And if true, there's a big group of engine guys (designers and calibrators) who are REALLY angry. BTDT.

Anything is possible, and for full disclosure I don't work in Automotive anymore... ...but if I made a design of a part which required leaving a 25% power gain on the table, I would be fired immediately and there would be a team working like mad to fix it.

It's likely a parts defect contained to a small initial run, but Mazda is already replacing transmissions that are blowing up in the ND at stock power levels.

codrus wrote:

tuna55 wrote:

Keith Tanner wrote: I would want to see independent corroboration of these numbers based on my own experience with the ND drivetrain. Claimed tuning numbers have not stood up to scrutiny. If this is the Long Road Racing header, we have one of those. It did not perform to that level, and even the Global Cup cars did not see that level of increase running a programmable ECU.

Ditto. Many an aftermarket shill has used a dyno correction factor in their favor and compared to the OEM baseline, which is very conservative.

From what I've read, the claim is that the Goodwin tests were done before/after on the same dyno, although it was a dyno dynamics rather than the dynojet most people look at as the common standard.

You can vary the hp readout wildly on those dynos by changing the ramp rate.

Goodwin, like Flyin Miata are well known and respected in the Miata world. I doubt that they would play with dyno settings and risk losing their well earned reputation on something that is so easily verified.

z31maniac wrote:

tuna55 wrote:

alfadriver wrote:

codrus wrote:

alfadriver wrote: Wide open performance and fuel economy are so very far apart that the calibration for each have no bearing on the other. So, to me, it's unlikely that Mazda would leave anything on the table.

The tinfoil hat theory is that they are protecting the transmission. :)

Possible. And if true, there's a big group of engine guys (designers and calibrators) who are REALLY angry. BTDT.

Anything is possible, and for full disclosure I don't work in Automotive anymore... ...but if I made a design of a part which required leaving a 25% power gain on the table, I would be fired immediately and there would be a team working like mad to fix it.

It's likely a parts defect contained to a small initial run, but Mazda is already replacing transmissions that are blowing up in the ND at stock power levels.

Well then it further reinforces the point that an intentional power deficit is unlikely.

Especially because if Mazda did seek to reduce the power intentionally, they would almost certainly do it with software. Redesigning parts is very expensive.

No, nothing about this being intentional makes any sense at all.

I'm not as skeptical since the BRZ pickups around 25whp on a pump gas tune and proper long tube header......but also has much more internal drag in the engine (4 cams instead of 2, etc).

The Mazda engine also has the same interesting torque dip in the same RPM range as the BRZ, which I suspect is something to do with the exhaust/tune for emissions purposes.

Earlier in their development cycle I was amazed at the gains they were getting. Now I'm starting to wonder if there isn't a dyno-related issue.

The Ferrari 458 Special is the production record holder for naturally aspirated torque/liter and makes 88ftlbs/liter. Apparently the last naturally aspirated F1 2.4L V8s made ~89lbs/liter. Goodwin's Miata is making 95ftlbs/liter at the WHEELS. Yes it's a bit of of a stroker engine, compared to over bore engines in the first cars, but it's also making peak torque thousands of RPMs lower. I can't help but wonder if it is just too good to be true.

Thoughts?

Interesting that the Fiat version uses the old transmission. I imagine that they will pick up a few units sold just on that basis.