The truth about the 2019 Miata rev limiter

In reply to Keith Tanner :

We don't only name scandals, we name everything.  (Y2K. Brangelina. Mopar) But I see your point, "gate" implies a scandal. How about Mazda Absolute Revolution Vehicle Evaluation Limit, or MARVEL?

pinchvalve said:

In reply to Keith Tanner :

We don't only name scandals, we name everything.  (Y2K. Brangelina. Mopar) But I see your point, "gate" implies a scandal. How about Mazda Absolute Revolution Vehicle Evaluation Limit, or MARVEL?

That's some Gundam SEED-style acronym action there.

Are people looking at the tach instead of th cones ?

Keith Tanner said:

It took us a while and some connections, but we finally have a hard tech answer to the rev limiter question from a legit technical (aka, not marketing) source inside Mazda and backed up by testing.

As yes, Mazda marketing.  The people who perpetrated the idea of "front mid engine", a term about as valid as "road hugging weight".  (Moving the front axle centerline a couple inches forward does not make your car a completely different drive type!)

Note:  I currently own three Mazdas, and Mazdas comprise perhaps half of the total vehicles I have ever owned.  I am, however, a realist, and I call it like I see it.

The tach is offset by 300 rpm - at 7200 rpm actual, it reads 7500 on the dash. This is unrelated.

It is also SOP for Mazda.

My '80 RX-7 had a fairly accurate tach.  The speedometer read 10% high by doing time/speed/distance calculations, but if you took that into effect, the tach was accurate.  (So that 85mph speedometer was actually pegging at only 77mph or so)

My '85, and my '84, however, were HILARIOUSLY inaccurate.  MPH/engine speed never jibed with the '85 if you did the math, and an aftermarket tach confirmed this.  The '84 has both an aftermarket tach AND a standalone EFI setup, and both show that the stock tach is ridiculously high.

The spec for the tach is either .5% low (point five percent) or 10% high (ten percent).  The '84 meets this spec, barely.  At 7000rpm actual the tach is reading 7700.  At 800rpm actual the tach is reading 1100, so this is not a linear discrepancy either.

Keith Tanner said:

I have requested that whoever is driving the 2019 tonight do the "sustained redline in 2nd" test, maybe we'll find out then. I'm stuck driving the V8 ND to test some CAN programming, darn the luck.

Life sounds harsh over at Flyin' Miata.

Says the guy whose first job of the day was "Drive this last bastion of musclecar (Buick GN, aka the last performance car built on the midsize chassis GM designed in 1963, which was arguably the chassis that STARTED musclecars) to verify a certain issue at WOT"

aircooled said:

Nigel Tufnel: [pause] These go to eleven.

What going to 11 may look like.

(Just kidding.  It was way past 11, according to the wrecked engine internals)

When I built my DSP S13 240sx with the KA24DE truck motor and a JWT ecu with a 7200 rpm rev limiter, the first thing I did after I got it running was to drive it 23 miles to the dyno and bounce it off the rev limiter to make sure it would stay together.  The dyno used an inductance sensor attached to the #1 spark plug to measure RPM and guess what, the tachometer on the Nissan was optimistic by 300 rpm!  It's not just Mazda.

Mustangs are also famous for having optimistic tachs, as well.