94 1.8 rev limiter.

Read in a few places that the 94 1.8 is limited at 7000RPM. Mine seems to
spin a bit further than this, looks like 7200 on the tacho. Anyone confirm
what it really is?

In article >,
"Mal Osborne" > wrote:

> Read in a few places that the 94 1.8 is limited at 7000RPM. Mine seems to
> spin a bit further than this, looks like 7200 on the tacho. Anyone confirm
> what it really is?

The ECU cuts the injectors at 7200 rpm. It may appear to vary from one
Miata to the next, but that's because the tach isn't especially
accurate. 7000 is a good shift point.

--
Lanny Chambers
'94C, St. Louis
http://www.hummingbirds.net/alignment.html

Was that the same for the 1.6? What Mal describes is exactly the way my 92
1.6 was. My 99 1.8 cuts out almost exactly at an indicated 7000, just as it
is beginning to really 'SING'............Now even I am thinking about how to
bump the rev limiter up a bit ;-)

Chris
99BBB

"Lanny Chambers" > wrote in message
...
> In article >,
> "Mal Osborne" > wrote:
>
>> Read in a few places that the 94 1.8 is limited at 7000RPM. Mine seems to
>> spin a bit further than this, looks like 7200 on the tacho. Anyone
>> confirm
>> what it really is?
>
> The ECU cuts the injectors at 7200 rpm. It may appear to vary from one
> Miata to the next, but that's because the tach isn't especially
> accurate. 7000 is a good shift point.
>
> --
> Lanny Chambers
> '94C, St. Louis
> http://www.hummingbirds.net/alignment.html

In article >,
"Chris D'Agnolo" > wrote:

> Was that the same for the 1.6? What Mal describes is exactly the way my 92
> 1.6 was. My 99 1.8 cuts out almost exactly at an indicated 7000, just as it
> is beginning to really 'SING'............Now even I am thinking about how to
> bump the rev limiter up a bit ;-)

Before you do that, you might want to look at a power curve and see if
there's actually any point...

>
> Chris
> 99BBB
>
> "Lanny Chambers" > wrote in message
> ...
> > In article >,
> > "Mal Osborne" > wrote:
> >
> >> Read in a few places that the 94 1.8 is limited at 7000RPM. Mine seems to
> >> spin a bit further than this, looks like 7200 on the tacho. Anyone
> >> confirm
> >> what it really is?
> >
> > The ECU cuts the injectors at 7200 rpm. It may appear to vary from one
> > Miata to the next, but that's because the tach isn't especially
> > accurate. 7000 is a good shift point.
> >
> > --
> > Lanny Chambers
> > '94C, St. Louis
> > http://www.hummingbirds.net/alignment.html

I think 7000 is about the optimal point to change on my '94. A 7200 limiter
would allow a little slack, but 7000 would be a pain.

"Alan Baker" > wrote in message
...
> In article >,
> "Chris D'Agnolo" > wrote:
>
>> Was that the same for the 1.6? What Mal describes is exactly the way my
>> 92
>> 1.6 was. My 99 1.8 cuts out almost exactly at an indicated 7000, just as
>> it
>> is beginning to really 'SING'............Now even I am thinking about how
>> to
>> bump the rev limiter up a bit ;-)
>
> Before you do that, you might want to look at a power curve and see if
> there's actually any point...
>
>>
>> Chris
>> 99BBB
>>
>> "Lanny Chambers" > wrote in message
>> ...
>> > In article >,
>> > "Mal Osborne" > wrote:
>> >
>> >> Read in a few places that the 94 1.8 is limited at 7000RPM. Mine seems
>> >> to
>> >> spin a bit further than this, looks like 7200 on the tacho. Anyone
>> >> confirm
>> >> what it really is?
>> >
>> > The ECU cuts the injectors at 7200 rpm. It may appear to vary from one
>> > Miata to the next, but that's because the tach isn't especially
>> > accurate. 7000 is a good shift point.
>> >
>> > --
>> > Lanny Chambers
>> > '94C, St. Louis
>> > http://www.hummingbirds.net/alignment.html

In article >,
"Mal Osborne" > wrote:

> I think 7000 is about the optimal point to change on my '94. A 7200 limiter
> would allow a little slack, but 7000 would be a pain.

But it's not one of those things that *requires* thought. Simply find a
power curve for the Miata and *see* if that is the correct shift point.

>
> "Alan Baker" > wrote in message
> ...
> > In article >,
> > "Chris D'Agnolo" > wrote:
> >
> >> Was that the same for the 1.6? What Mal describes is exactly the way my
> >> 92
> >> 1.6 was. My 99 1.8 cuts out almost exactly at an indicated 7000, just as
> >> it
> >> is beginning to really 'SING'............Now even I am thinking about how
> >> to
> >> bump the rev limiter up a bit ;-)
> >
> > Before you do that, you might want to look at a power curve and see if
> > there's actually any point...
> >
> >>
> >> Chris
> >> 99BBB
> >>
> >> "Lanny Chambers" > wrote in message
> >> ...
> >> > In article >,
> >> > "Mal Osborne" > wrote:
> >> >
> >> >> Read in a few places that the 94 1.8 is limited at 7000RPM. Mine seems
> >> >> to
> >> >> spin a bit further than this, looks like 7200 on the tacho. Anyone
> >> >> confirm
> >> >> what it really is?
> >> >
> >> > The ECU cuts the injectors at 7200 rpm. It may appear to vary from one
> >> > Miata to the next, but that's because the tach isn't especially
> >> > accurate. 7000 is a good shift point.
> >> >
> >> > --
> >> > Lanny Chambers
> >> > '94C, St. Louis
> >> > http://www.hummingbirds.net/alignment.html

In article >,
"Chris D'Agnolo" > wrote:

> Alan, I think there's a bit more to it than that but my butt dyno tells me
> the engine is still pulling strong and the sound is really coming into it's
> own right about there. In my old 92 I'd almost never hit the rev limiter
> (indicated 7200) because the engine felt like it had given all she had by an
> indicated 7000 but, in the 99, I hit it fairly often as it feels like it
> wants to keep winding out.

Actually, there is almost nothing more to it.

Maximizing acceleration consists almost entirely of maximizing the area
under the horsepower curve.

And I'm not saying that the rev limit *itself* constitutes a measure of
where that happens; your feelings may very well be correct. But looking
at a horsepower curve will tell you that, too.

>
> Chris
> 99BBB
>
> "Alan Baker" > wrote in message
> ...
> > In article >,
> > "Mal Osborne" > wrote:
> >
> >> I think 7000 is about the optimal point to change on my '94. A 7200
> >> limiter
> >> would allow a little slack, but 7000 would be a pain.
> >
> > But it's not one of those things that *requires* thought. Simply find a
> > power curve for the Miata and *see* if that is the correct shift point.
> >
> >>
> >> "Alan Baker" > wrote in message
> >> ...
> >> > In article >,
> >> > "Chris D'Agnolo" > wrote:
> >> >
> >> >> Was that the same for the 1.6? What Mal describes is exactly the way
> >> >> my
> >> >> 92
> >> >> 1.6 was. My 99 1.8 cuts out almost exactly at an indicated 7000, just
> >> >> as
> >> >> it
> >> >> is beginning to really 'SING'............Now even I am thinking about
> >> >> how
> >> >> to
> >> >> bump the rev limiter up a bit ;-)
> >> >
> >> > Before you do that, you might want to look at a power curve and see if
> >> > there's actually any point...
> >> >
> >> >>
> >> >> Chris
> >> >> 99BBB
> >> >>
> >> >> "Lanny Chambers" > wrote in message
> >> >> ...
> >> >> > In article >,
> >> >> > "Mal Osborne" > wrote:
> >> >> >
> >> >> >> Read in a few places that the 94 1.8 is limited at 7000RPM. Mine
> >> >> >> seems
> >> >> >> to
> >> >> >> spin a bit further than this, looks like 7200 on the tacho. Anyone
> >> >> >> confirm
> >> >> >> what it really is?
> >> >> >
> >> >> > The ECU cuts the injectors at 7200 rpm. It may appear to vary from
> >> >> > one
> >> >> > Miata to the next, but that's because the tach isn't especially
> >> >> > accurate. 7000 is a good shift point.
> >> >> >
> >> >> > --
> >> >> > Lanny Chambers
> >> >> > '94C, St. Louis
> >> >> > http://www.hummingbirds.net/alignment.html

In article >,
Alan Baker > wrote:

> Maximizing acceleration consists almost entirely of maximizing the area
> under the horsepower curve.

Not quite; I think the torque curve is more relevant. Torque
multiplication via gearing is a factor as well, and the optimum shift
point may be different in each gear. The goal is to shift at the point
the next gear will provide better acceleration. If you plot rpm versus
acceleration in each gear, it's where the curve for one gear crosses
that of the next. Practically speaking, many cars' gear spacing and
redlines will not permit reaching the crossing point, and so shifting at
redline is the best one can do.

--
Lanny Chambers
'94C, St. Louis
http://www.hummingbirds.net/alignment.html

In article >,
Lanny Chambers > wrote:

> In article >,
> Alan Baker > wrote:
>
> > Maximizing acceleration consists almost entirely of maximizing the area
> > under the horsepower curve.
>
> Not quite; I think the torque curve is more relevant. Torque
> multiplication via gearing is a factor as well, and the optimum shift
> point may be different in each gear. The goal is to shift at the point
> the next gear will provide better acceleration. If you plot rpm versus
> acceleration in each gear, it's where the curve for one gear crosses
> that of the next. Practically speaking, many cars' gear spacing and
> redlines will not permit reaching the crossing point, and so shifting at
> redline is the best one can do.

<sigh>

No. Torque curve is *not* more relevant.

Horsepower is torque multiplied by rpm (multiplied by a constant, of
course) and hence torque at the rear wheels, is horsepower divided by
RPM at the rear wheels. Are you with me so far? So if you want maximum
torque at the rear wheels, at any given moment you must be in the gear
that delivers maximum horsepower, *not* maximum torque.

Alan Baker > wrote:

>In article >,
> "Chris D'Agnolo" > wrote:
>
>> Was that the same for the 1.6? What Mal describes is exactly the way my 92
>> 1.6 was. My 99 1.8 cuts out almost exactly at an indicated 7000, just as it
>> is beginning to really 'SING'............Now even I am thinking about how to
>> bump the rev limiter up a bit ;-)
>
>Before you do that, you might want to look at a power curve and see if
>there's actually any point...

Well, for the 2006, I see no indication that you would want to shift at
7,000 if there was no rev limiter.

http://flyinmiata.com/tech/dyno_runs/NC_vs_MSM.pdf

Leon

Actually, here is a better one
http://flyinmiata.com/tech/dyno_runs/NC_sweep_times.pdf

They think the difference between the curves is inertial, but I would
think it should be an effect of mixture tuning?

Anyway, clearly silly to shift at 7000.

Leon

>>
>> Chris
>> 99BBB
>>
>> "Lanny Chambers" > wrote in message
>> ...
>> > In article >,
>> > "Mal Osborne" > wrote:
>> >
>> >> Read in a few places that the 94 1.8 is limited at 7000RPM. Mine seems to
>> >> spin a bit further than this, looks like 7200 on the tacho. Anyone
>> >> confirm
>> >> what it really is?
>> >
>> > The ECU cuts the injectors at 7200 rpm. It may appear to vary from one
>> > Miata to the next, but that's because the tach isn't especially
>> > accurate. 7000 is a good shift point.
>> >
>> > --
>> > Lanny Chambers
>> > '94C, St. Louis
>> > http://www.hummingbirds.net/alignment.html
--
Leon van Dommelen Bess, the Miata Bozo, the Miata
http://www.dommelen.net/miata
The only thing better than a white Miata is two white Miatas