Miatapower List Archive

This read-only message was archived from a public mail list.
Mail From: Kevin Stone <(email redacted)>


Ok so the ECU cannot be replaced on the 99 and a Pigyback unit is
installed instead. What functions does the pigyback unit control.

Also as far as fuel delivery goes,does the 99 system use bigger
injectors or does it use fuel pressure modulation on the stock
injectors.

Would love to talk to anyone who has this kit installed.

Thanks

This read-only message was archived from a public mail list.
Mail From: (email redacted)


Anybody know the mass of the piston/wrist pin assembly?

Also, the center-to-center distance of a connecting rod?

Stats for the 1.8 preferred, but either engine OK.

Thanks, and happy holidays!

George, who is waiting for Santa's brown sleigh to deliver a HDHC DD.

"Ho Ho Ho and a bottle of octane booster..."

This read-only message was archived from a public mail list.
Mail From: "Malcolm Gray-Stephens" <(email redacted)>


.. and when you know ... I would like to know too .. if not I will pull my
bust 1.8 bits..

Malcolm G-S
----- Original Message -----
From: <(email redacted)>
To: Miata Power <(email redacted)>
Sent: 24 December 1999 18:33
Subject: Piston weight?


>
> Anybody know the mass of the piston/wrist pin assembly?
>
> Also, the center-to-center distance of a connecting rod?
>
> Stats for the 1.8 preferred, but either engine OK.
>
> Thanks, and happy holidays!
>
> George, who is waiting for Santa's brown sleigh to deliver a HDHC DD.
>
> "Ho Ho Ho and a bottle of octane booster..."
>
>

This read-only message was archived from a public mail list.
Mail From: (email redacted)


Somebody has some parts available, and he will weigh them next week. One of
us will post the results to the list.

George

Malcolm Gray-Stephens wrote:

> .. and when you know ... I would like to know too .. if not I will pull my
> bust 1.8 bits..
>
> Malcolm G-S
> ----- Original Message -----
> From: <(email redacted)>
> To: Miata Power <(email redacted)>
> Sent: 24 December 1999 18:33
> Subject: Piston weight?
>
> >
> > Anybody know the mass of the piston/wrist pin assembly?
> >
> > Also, the center-to-center distance of a connecting rod?
> >
> > Stats for the 1.8 preferred, but either engine OK.
> >
> > Thanks, and happy holidays!
> >
> > George, who is waiting for Santa's brown sleigh to deliver a HDHC DD.
> >
> > "Ho Ho Ho and a bottle of octane booster..."
> >
> >

This read-only message was archived from a public mail list.
Mail From: Doug Augustine <(email redacted)>

Kevin,

I put the BEGI system IV with the big intercooler on my '99 in July and
then added the Link piggyback from DlrAlt in September. The '99 kit
includes two additional fuel injectors on a seperate fuel rail mounted on
the final intercooler tube going into the throttle body. In my case
Corky supplied 55 lb/hr injectors. These injectors were controlled by a
fairly simple controller which came with the BEGI kit. When I installed
Bills' piggyback I gained the same type of control available in the M1
ECU for the additional injectors only (a matrix of boost and RPM zones).
The original injectors are still controlled only by the stock ECU and
provide all fuel until approaching boost. Fuel pressure is stock. The
piggyback can also retard timing in degrees from the stock timing values
in another boost/RPM matrix. I do not have absolute value control over
zone timing, only the ability to retard (no knock). I also have the Link
boost controller and the piggyback controls the boost level and control
characteristics. It would be nice to have the ability to adjust my rev
limiter and the other stuff but I probably have the best of both worlds.
Stock smootness when not under boost and the ability to squirt in more
fuel and kill detonation when under FI. The fuel and spark mapping is
totally manual as you can't have lambda on the piggyback. Lots of trial
and error (mostly error).

I am out of town until the end of next week but could talk when I get
back if you want. Email me.

Doug Augustine

Kevin Stone wrote:

> Ok so the ECU cannot be replaced on the 99 and a Pigyback unit is
> installed instead. What functions does the pigyback unit control.
>
> Also as far as fuel delivery goes,does the 99 system use bigger
> injectors or does it use fuel pressure modulation on the stock
> injectors.
>
> Would love to talk to anyone who has this kit installed.
>
> Thanks

This read-only message was archived from a public mail list.
Mail From: "Espen Tandberg" <(email redacted)>


> Anybody know the mass of the piston/wrist pin assembly?

Stock size 1.6 piston with all rings, wrist pin and clips: 386 grams

Espen

This read-only message was archived from a public mail list.
Mail From: Eric Vaillancourt <(email redacted)>



> > (email redacted) wrote:
> > >
> > > Anybody know the mass of the piston/wrist pin assembly?
> > >
> > > Also, the center-to-center distance of a connecting rod?
> > >
> > > Stats for the 1.8 preferred, but either engine OK.

OK, for those interested, the following weights were measured with an
electronic shipping scale that is calibrated on a three month schedule,
(last done 11/99), and is capable of measuring in the 0-9000 gram range.

'96 1.8L stock Piston with rings, wrist pin & (2) retainers = 401.8
grams

Wrist pin alone = 78.7 grams retainers = 1.9 grams

Bare piston = 289.7 grams Rings = 31.5 grams

Stock Connecting Rod w/cap & nuts, (After shot peen, balance & resize) =
540.7 grams

Rod was weighed with the wrist pin bearing in place.

Center to center length measurement of the rod from the same motor =
132.74 mm (or 5.226" for those metric challenged).

Measurements were done with a Brown & Sharpe Coordinate Measuring
Machine, (CMM). The cap was not torqued down, so it had a standard
deviation, (amount out of round), of about .06 mm, (.0025"). Because of
this I interpolated the center based on the rod end bearing radius,
which had zero deviation from a perfectly round bore.

I hope this helps those who were interested.

Eric

This read-only message was archived from a public mail list.
Mail From: (email redacted)


Thanks to all for the responses. My request was prompted by a question that
Malcolm Gray-Stephans posted recently, about the differences between the
stress levels at various rpms, and how they compare to the compressive
combustion stresses. I plan to do a bit of analysis to satisfy my own
curiosity. If people are interested, I'll post the results. No guarantee
on the accuracy, though, as I don't do this stuff for a living any more. :)

George

Eric Vaillancourt wrote:

> > > (email redacted) wrote:
> > > >
> > > > Anybody know the mass of the piston/wrist pin assembly?
> > > >
> > > > Also, the center-to-center distance of a connecting rod?
> > > >
> > > > Stats for the 1.8 preferred, but either engine OK.
>
> OK, for those interested, the following weights were measured with an
> electronic shipping scale that is calibrated on a three month schedule,
> (last done 11/99), and is capable of measuring in the 0-9000 gram range.
>
> '96 1.8L stock Piston with rings, wrist pin & (2) retainers = 401.8
> grams
>
> Wrist pin alone = 78.7 grams retainers = 1.9 grams
>
> Bare piston = 289.7 grams Rings = 31.5 grams
>
> Stock Connecting Rod w/cap & nuts, (After shot peen, balance & resize) =
> 540.7 grams
>
> Rod was weighed with the wrist pin bearing in place.
>
> Center to center length measurement of the rod from the same motor =
> 132.74 mm (or 5.226" for those metric challenged).
>
> Measurements were done with a Brown & Sharpe Coordinate Measuring
> Machine, (CMM). The cap was not torqued down, so it had a standard
> deviation, (amount out of round), of about .06 mm, (.0025"). Because of
> this I interpolated the center based on the rod end bearing radius,
> which had zero deviation from a perfectly round bore.
>
> I hope this helps those who were interested.
>
> Eric

This read-only message was archived from a public mail list.
Mail From: The Dealer Alternative <(email redacted)>


FWIW, same rod on both engines. Keep us posted. The carrillos weigh 442 grams

(email redacted) wrote:

> Thanks to all for the responses. My request was prompted by a question that
> Malcolm Gray-Stephans posted recently, about the differences between the
> stress levels at various rpms, and how they compare to the compressive
> combustion stresses. I plan to do a bit of analysis to satisfy my own
> curiosity. If people are interested, I'll post the results. No guarantee
> on the accuracy, though, as I don't do this stuff for a living any more. :)
>
> George
>
> Eric Vaillancourt wrote:
>
> > > > (email redacted) wrote:
> > > > >
> > > > > Anybody know the mass of the piston/wrist pin assembly?
> > > > >
> > > > > Also, the center-to-center distance of a connecting rod?
> > > > >
> > > > > Stats for the 1.8 preferred, but either engine OK.
> >
> > OK, for those interested, the following weights were measured with an
> > electronic shipping scale that is calibrated on a three month schedule,
> > (last done 11/99), and is capable of measuring in the 0-9000 gram range.
> >
> > '96 1.8L stock Piston with rings, wrist pin & (2) retainers = 401.8
> > grams
> >
> > Wrist pin alone = 78.7 grams retainers = 1.9 grams
> >
> > Bare piston = 289.7 grams Rings = 31.5 grams
> >
> > Stock Connecting Rod w/cap & nuts, (After shot peen, balance & resize) =
> > 540.7 grams
> >
> > Rod was weighed with the wrist pin bearing in place.
> >
> > Center to center length measurement of the rod from the same motor =
> > 132.74 mm (or 5.226" for those metric challenged).
> >
> > Measurements were done with a Brown & Sharpe Coordinate Measuring
> > Machine, (CMM). The cap was not torqued down, so it had a standard
> > deviation, (amount out of round), of about .06 mm, (.0025"). Because of
> > this I interpolated the center based on the rod end bearing radius,
> > which had zero deviation from a perfectly round bore.
> >
> > I hope this helps those who were interested.
> >
> > Eric

--
Bill Cardell
The Dealer Alternative, Inc.
Grand Junction, CO
dlralt.com
200mphmiata.net
970-242-3800 tech inquiries
1-800-FLY-MX5S orders only

This read-only message was archived from a public mail list.
Mail From: (email redacted)


Somebody recently posed a question about the stresses in a con-rod in
boosted motor at 5000 rpm vs. those in a N/A motor at 7000 rpm. I decided
to take a crack at understanding these loads a little better, hence my
request a week ago or so for internal weights. My thanks to all who
responded with information.

I have done some basic calculations, and present my findings below. Before
I continue, though, I'll state the obvious. The numbers shown below are are
a result of a simplified analysis, and are intended to stimulate
conversation & thought only. Nobody in their right mind should use them for
any sort of design purposes.

I'll present my methods as well. For those of you who want to go straight
to the numbers, here is a summary:

Approximate tensile load at 7000 rpm: 15,000 N or 3350 lbf
Approximate tensile load at 5000 rpm: 7600 N or 1700 lbf

Compressive load @1200 psi (N/A motor): 45,000 N or 10,000 lbf
Compressive load @1500 psi: (15 psi motor): 56,000 N or 12,500 lbf

So, at 5000 rpm, the tensile loads are roughly half those at 7000 rpm (not
surprising - 5*5 = 25, 7*7=49), and the difference appears to be about 1600
pounds or so. The compressive loads, however, seem to increase in the
boosted motor by a greater margin, about 2500 pounds or so.

Does this matter? That's a much harder question to answer. Fatigue
analysis is a bit of a black art, and is usually highly specific to the
particular case in hand. Generic (i.e., non-automotive) engineering
textbooks can only offer so much insight. That said, my engineering
textbooks say that in many cases, the fatigue life of a member is related to
the maximum stress (tensile load), minimum stress (compressive), and the
range (tension + compression). If that's true, then the boosted case has
two strikes against it (greater stress range and greater compressive stress)
while the N/A case has one strike (greater tensile stress). Without more
information, there's no telling if either case is damaging from a fatigue
standpoint. In the end, I'm waaaay out on a limb here. There just isn't
sufficient information to make any meaningful observations, at least from a
fatigue analysis standpoint.

Now those continued high-speed runs and tire-smoking acceleration contests,
they will tell us allot, at least eventually. :) So far, I haven't heard
of any rods failing in a fatigue mode. Has anybody else?

Methods - Tensile loads

I used the following equation for computing the peak inertial loads, which
occur at TDC during the exhaust stroke:

accel = 0.5 * R * omega^2

where R equals half the stroke, and omega is the crank speed in radians/sec.

To get the force, simply multiple the above by the mass. Determining the
mass, however, is more subtle than first glance. Of course, one must
include the mass of the piston, retainers, rings, and wrist pin. This came
to 402 grams according to a recent weighing.

However, since the objective of this exercise is to understand peak
connecting rod stresses induced by inertial loads, a percentage of the
connecting rod mass must also be included. I assume that the peak tensile
stress in the connecting rod will occur at the point where the rod begins to
taper up to a larger cross section near the big end. Thus, all mass above
this point will contribute to the peak tensile stress, as it is all being
accelerated in the vertical direction at the same rate as the piston.

Taking a WAG for the con-rod contribution of 250 grams, this give a net mass
of about 650 grams, or .65 kg.

Methods - compressive loads

For the peak compressive loads, I used the graphs on page 5 in Corky's book
to get an estimate of combustion chamber pressures. The graph shows
combustion chamber pressures vs. crank angles for a 1-bar and 2-bar engine.

To get the compressive loads, I just multiplied the area of the piston by
the pressure.

I did not subtract the tensile loads from the compressive loads, as
suggested by Corky's book. Doing so would lower the compressive loads
substantially.

Those of you who have read this far, here is a little bonus. Inertial loads
of a certain Honda motor, running at 9000 rpms, with similar internal
weights - 24,600 N or 5500 lbf. To paraphrase Corky, that's a Ford
Expedition (or is it an Excursion?) hanging from your connecting rod!

George

p.s. If anybody want to take a crack at measuring the cross section of a rod
(in order to compute the area), it would be fun to compute the stresses.

This read-only message was archived from a public mail list.
Mail From: "Mel Hoagland" <(email redacted)>


George,

Nice job. I liked reading through your methods and the conclusions you drew.
You mentioned Corky near the end of your message, so I'm sure you've read
Maximum Boost. In it Corky gives an analysis of the stresses in a boosted
internal combustion engine. The conclusion he seemed to draw is that the
complex loads somewhat balance each other out, resulting in far less stress
on the internals than you might think. I was encouraged.

Mel
------------------------------------------------------------
Mel Hoagland ((email redacted))
"Wheezy" black 96 FMII vrrooommmm

----- Original Message -----
From: <(email redacted)>
To: "Miatapower" <(email redacted)>
Sent: Tuesday, January 04, 2000 9:08 PM
Subject: Tensile & Compressive loads in connecting rod (long)


>
> Somebody recently posed a question about the stresses in a con-rod in
> boosted motor at 5000 rpm vs. those in a N/A motor at 7000 rpm. I decided
> to take a crack at understanding these loads a little better, hence my
> request a week ago or so for internal weights. My thanks to all who
> responded with information.
>
> I have done some basic calculations, and present my findings below.
Before
> I continue, though, I'll state the obvious. The numbers shown below are
are
> a result of a simplified analysis, and are intended to stimulate
> conversation & thought only. Nobody in their right mind should use them
for
> any sort of design purposes.
>
> I'll present my methods as well. For those of you who want to go straight
> to the numbers, here is a summary:
>
> Approximate tensile load at 7000 rpm: 15,000 N or 3350 lbf
> Approximate tensile load at 5000 rpm: 7600 N or 1700 lbf
>
> Compressive load @1200 psi (N/A motor): 45,000 N or 10,000 lbf
> Compressive load @1500 psi: (15 psi motor): 56,000 N or 12,500 lbf
>
> So, at 5000 rpm, the tensile loads are roughly half those at 7000 rpm (not
> surprising - 5*5 = 25, 7*7=49), and the difference appears to be about
1600
> pounds or so. The compressive loads, however, seem to increase in the
> boosted motor by a greater margin, about 2500 pounds or so.
>
> Does this matter? That's a much harder question to answer. Fatigue
> analysis is a bit of a black art, and is usually highly specific to the
> particular case in hand. Generic (i.e., non-automotive) engineering
> textbooks can only offer so much insight. That said, my engineering
> textbooks say that in many cases, the fatigue life of a member is related
to
> the maximum stress (tensile load), minimum stress (compressive), and the
> range (tension + compression). If that's true, then the boosted case has
> two strikes against it (greater stress range and greater compressive
stress)
> while the N/A case has one strike (greater tensile stress). Without more
> information, there's no telling if either case is damaging from a fatigue
> standpoint. In the end, I'm waaaay out on a limb here. There just isn't
> sufficient information to make any meaningful observations, at least from
a
> fatigue analysis standpoint.
>
> Now those continued high-speed runs and tire-smoking acceleration
contests,
> they will tell us allot, at least eventually. :) So far, I haven't heard
> of any rods failing in a fatigue mode. Has anybody else?
>
> Methods - Tensile loads
>
> I used the following equation for computing the peak inertial loads, which
> occur at TDC during the exhaust stroke:
>
> accel = 0.5 * R * omega^2
>
> where R equals half the stroke, and omega is the crank speed in
radians/sec.
>
> To get the force, simply multiple the above by the mass. Determining the
> mass, however, is more subtle than first glance. Of course, one must
> include the mass of the piston, retainers, rings, and wrist pin. This
came
> to 402 grams according to a recent weighing.
>
> However, since the objective of this exercise is to understand peak
> connecting rod stresses induced by inertial loads, a percentage of the
> connecting rod mass must also be included. I assume that the peak tensile
> stress in the connecting rod will occur at the point where the rod begins
to
> taper up to a larger cross section near the big end. Thus, all mass above
> this point will contribute to the peak tensile stress, as it is all being
> accelerated in the vertical direction at the same rate as the piston.
>
> Taking a WAG for the con-rod contribution of 250 grams, this give a net
mass
> of about 650 grams, or .65 kg.
>
> Methods - compressive loads
>
> For the peak compressive loads, I used the graphs on page 5 in Corky's
book
> to get an estimate of combustion chamber pressures. The graph shows
> combustion chamber pressures vs. crank angles for a 1-bar and 2-bar
engine.
>
> To get the compressive loads, I just multiplied the area of the piston by
> the pressure.
>
> I did not subtract the tensile loads from the compressive loads, as
> suggested by Corky's book. Doing so would lower the compressive loads
> substantially.
>
> Those of you who have read this far, here is a little bonus. Inertial
loads
> of a certain Honda motor, running at 9000 rpms, with similar internal
> weights - 24,600 N or 5500 lbf. To paraphrase Corky, that's a Ford
> Expedition (or is it an Excursion?) hanging from your connecting rod!
>
> George
>
> p.s. If anybody want to take a crack at measuring the cross section of a
rod
> (in order to compute the area), it would be fun to compute the stresses.
>
>