Timing (?)
PM west AM east
the factory 10 BTDC? In this months issue of Miata Magazine, they said
that it's a cheap way to get some extra horsepower.
Robert Wolov
(Frank Potter) wrote:
> In article <4li055$r...@carbon.cudenver.edu>, pmw...@ouray.cudenver.edu (PM
> It is, and it will work. Some people have even jumped theirs up to 18
> degrees BTDC. But you will have to buy high-test fuel - as high as you can
> get, short of racing fuel.
>
> Frank
I agree with Frank on all points save the last. I've bumped my timing up
to 18 degrees BTDC this winter and have switched to 92 octane with very
nice results on my 1.8L (especially in the midrange) with no pinging.
Still too early in this warmer weather to say absolutely, but I still do
not detect any pinging indicating having to go to still higher octane
ratings.
You should raise your octane to at least 92 or 93 depending on local
availabilty. Sunoco (my local does have a 94 blend, though I haven't tried
it)
Gee, Frank "short of racing fuel"? I hope that was just a figure of speech!
I didn't consider this (92-93) *that* high (though I'll differ to my
fellow MSCCW member Frank Potter whos been modifying Miata engines far
longer than I).
Robb W
Frank Potter
Story Leavesley
going to 14 degrees BTDC at altitude? I live in Boulder (5,400 ft.)
but frequently drive at 6,000-11,000 ft.
Can someone describe the procedure and necessary tools to change the
timing. This seems like a perfect addition to the FAQ.
Thanks for the help.
Story
===================================================================
Story Leavesley 95 R1100GS
Xilinx 86 K100RT
2585 Central Ave. 94 XR 600
Boulder, Co. 80301 92 RMX 250
(303) 413-3278 89 KDX 200
story.l...@xilinx.com
===================================================================
Robert Wolov (wo...@his.com) wrote:
: In article <fpotter-2304...@fpotter.his.com>, fpo...@his.com
: (Frank Potter) wrote:
: > In article <4li055$r...@carbon.cudenver.edu>, pmw...@ouray.cudenver.edu (PM
: I agree with Frank on all points save the last. I've bumped my timing up
Joseph F Guerrero
I am currently running 18 degrees BTDC on Super Unleaded (93 Oct)
and I noticed a significant difference. More power at lower rpm.
(No pinging. I never tried it at 89 octane)
Here's some instructions taken from the garage section
at http://www.miata.net
Ignition Wires
The Miata ignition wires are, arguably, the weakest point in the car. As
early as 20,000 miles, (but generally closer to 40,000 miles) the
insulation begins to break down and develop small pinholes which result in
the spark going through the pinhole to the block instead of across the
electrodes of the spark plug. This problem surfaces as hesitation at low
RPM.
The ignition wires in the Miata should be replaced every 50,000 miles or
sooner if you begin to develop a low RPM hesitation or misfiring.
Factory wires vs. NGK
The blue NGK wires are clearly superior in longevity to the original black
wires on the early Miata models. Newer models may come with the blue NGK
wires. (Can someone confirm or deny this?) Even with the higher quality
wires, eventually they will break down.
Ignition Timing
* Checking timing
Tools required
o Inductive Timing Light
o Jumper or paper clip
o External Tachometer
Begin by locating the diagnostics connector (close-up view) on the
driver's side of the engine compartment near the air intake. Connect
the jumper (or paper clip) from pin TEN to GND. (This puts the
on-board computer into the proper mode for setting the timing.)
Connect the timing light power cable to a source of 12volt power.
Since the battery is not in the engine compartment, you should use
the auxiliary power connector provided for this purpose. There is a
blue connector which is not connected to anything located on the
driver's side of the engine compartment close to the side of the car
about halfway between the diagnostics connector and the headlight
motor. Remove the dummy connector to expose the conductor. This is
where the timing light can be powered from. Connect the timing light
ground connection to a suitable grounding point. Put the inductive
pickup around the number 1 spark plug wire.
With the idle set to factory spec, check the timing by observing the
timing marks on the crankshaft pulley in relation to the fixed marks
on the timing belt cover. Each mark represents 2 degrees of timing
advance. If the timing is outside of the factory specification, 10°
before top dead center (10° BTDC) ±1°you need to set the timing.
* Setting timing
Tools required
o 12mm socket
o Socket wrench with articulated head (if possible)
For 1.6 liter engines locate the crank angle sensor (close-up view)
at the rear of the passenger side valve cover. It is a circular metal
unit that sits right on the rear of the valve cover. Locate the
locking bolt for the sensor. This is on the lower side of the sensor
bracket nearest to the passenger side. Loosen this bolt only enough
to allow you to rotate the crank angle sensor. As the crank angle
sensor is rotated (only a small amount at a time), you will see the
timing change with the timing light. When you get the timing back in
spec, tighten the lock bolt.
You can find the cam sensor on your 1.8 liter Miata by following the
driver's side hump in the valve cover to the back of the head. On the
rear face of the head you will find a round unit with a multiplug on
it. This is the sensor. There is one bolt with a twelve mm head on it
that is the hold-down. If you were sitting in the driver's seat
looking at the back of the head, the bolt is at about five o'clock.
Don't forget to jump the TEN and GND pins in the diagnostic connector
(close-up view) before setting. Use the yellow painted dot on the
crank pulley.
Jared Stack points out: It's best to set the timing when the car has
warmed up to the point where the idle has settled and the engine is
up to operating temp, but is still relatively cold. The motivation
for doing this is to make sure that when you check your timing that
the radiator fan is not running. If it activates, the timing will be
retarded by 1-2 degrees. The consequence of setting it at this point
is when you are on the open road at speed the fan usually won't be
running as much and the timing will be higher than what you thought
it was set to. There should be a fuse for the radiator fan... just
make sure you put it back when finished. :-)
If you tweak the idle this will affect the baseline value of the
timing. Tweak idle with jumper in place and correct the timing. After
adjusting the idle (improperly, without the jumper) to compensate for
the current draw of the Hella H4's, my timing was retarded by about 3
degrees!
Rick Fischer (rick...@ozemail.com.au) helps clarify Jared's
statement:
Timing must be set with the motor in a no load condition at
the specified idle speed. Electrical loading of the
alternator sucks horsepower, drag on the motor - slows it
down. Therefore the revs aren't right. The timing mark may
move when the motor drops revs but that is a function of
the rev drop not the electrical load.
The Hellas did not affect his timing by 3 degrees the
current draw and motor slowing did. Advancing the timing to
compensate will have just advanced his timing - period.
This may cause problems if the person doing the retiming is
not across the general principles of ignition timing, and
accepts Mr. Stack's comments on their face value. Someone
advancing their timing to the 16 or 18 degree marks and
then compensating for what they think is another factor may
well over advance the timing to the point where detonation
may occur; i.e. 16-18 plus 2 for the fans and 3 for lights
= 21 to 23. The Pinging may well be a very expensive noise,
breaking rings and cracking pistons in extreme occurences.
Very simply, time any motor - no load. No A/C, no lights,
no fans.
Extra power by advancing
Many enthusiasts have found that they gain a few extra horsepower by
advancing the timing to 14° BTDC. If you do this, you may experience
some pinging when running on regular gas. If so, try switching to
premium. If you still get pinging and it isn't caused by one of the
other problems described above, then back the timing down to the
point where the pinging is no longer an issue. (Pinging is usually
experienced under hard load driving - not idling in your driveway. So
you'll have to set the timing and drive it for awhile before you
really know the effects.)
Timing for Modified Intake Tract
If you've modified your air intake with the installation of a
turbocharger, supercharger, Cold Air Intake, or other type of
upgraded high flow intake system, the timing rules may change. You
should follow the advice given by the manufacturer of your unit.
David Heronemus
> In article <4li055$r...@carbon.cudenver.edu>, pmw...@ouray.cudenver.edu (PM
> west AM east) wrote:
>
> > Anyone have some comments about setting the timing to 14 BTDC, instead of
> > the factory 10 BTDC? In this months issue of Miata Magazine, they said
> > that it's a cheap way to get some extra horsepower.
>
> It is, and it will work. Some people have even jumped theirs up to 18
> degrees BTDC. But you will have to buy high-test fuel - as high as you can
> get, short of racing fuel.
>
> Frank
How does the horsepower increase compare going from 14 to 18 deg BTDC??
I am currently at 14, with a Walker super turbo muffler, K&N Air Filter
(factory box??) Thanks!!
Frank Potter
DJH...@cris.com (David Heronemus) wrote:
> How does the horsepower increase compare going from 14 to 18 deg BTDC??
> I am currently at 14, with a Walker super turbo muffler, K&N Air Filter
> (factory box??) Thanks!!
I have no idea what the numbers are, and I wouldn't believe them anyway
unless they came from a dyno test. All I can report is what I have heard
from other Miata owners who have done this. Most of them liked the
improvement.
I personally would be nervous about doing something like this without an
MSD box or a J&S knock sensor. On the other hand, I hear that Miata
engines don't cost all that much to replace...
Frank
PM west AM east
: How does the horsepower increase compare going from 14 to 18 deg BTDC??
: I am currently at 14, with a Walker super turbo muffler, K&N Air Filter
: (factory box??) Thanks!!
_Miata Magazine_ states that 18 BTDC improves horsepower/torque over 14
BTDC mostly in the range of 1000-3000 RPM, but has *less* power than 14
BTDC starting at 4500+ RPM by 5 horsepower. So, it's matter of how you
drive your miata as to which would be best for you. Don't forget you'll
need to be running 92+ octane with the 18 BTDC.
Timothy G Reynolds
>
>Anyone have some comments about setting the timing to 14 BTDC, instead of
>the factory 10 BTDC? In this months issue of Miata Magazine, they said
>that it's a cheap way to get some extra horsepower.
The fall issue of the Miata magazine (the official publication of the Miata
Club of America. If you own a Miata and haven't joined the MCA yet, I think you
should.) had an article regarding dyno tests done on the 1.6l engine that
suggested significant improvement in torque (especially low-end) with a timing
setting of 18 degrees BTDC. I had this change made last time I had Sam in the
shop.
At first I didn't really notice any change. My habit was to upshift around 4250
RPM because I got my best MPG that way. When I got it out on the highway and
started really winding it out I started feeling the change. The power comes on
quietly but steadily around 3750RPM. With the stock 10deg setting I used to
experience a sudden burst of power around 4500RPM. That blip is gone and the
car powers smoothly all the way to the rev limiter. I'm not convinced, based on
my seat of the pants driving, that the acceleration is that much better, but
it's REALLY nice to have a smooth power curve.
The biggest difference is that the car now feels uncomfortable to upshift at
4kRPM. The car really wants to be driven above 5kRPM and doesn't feel right if
I shift below 6kRPM. This puts more of my driving in the higher performance
area of the power band. It also has had a negative impact on my MPG, and since
I need higher octane fuel to prevent detonation, an even greater impact on my
MP$.
-timmi
Timothy G Reynolds
In article <fpotter-2304...@fpotter.his.com>, fpo...@his.com says...
>It is, and it will work. Some people have even jumped theirs up to 18
>degrees BTDC. But you will have to buy high-test fuel - as high as you can
>get, short of racing fuel.
Not entirely true. With the timing on my '91 set to 18deg I can safely run
89 octane here in Mass without noticable detonation. That's with the ambient
temp staying below 60farenheit. I run 92 when I can get it to be sure there's
no detonation that I can't hear.
timmi
--
Mariner Blue '91
MCA# 49723
SCCA# R240580
Tehdoi
>I am currently running 18 degrees BTDC on Super Unleaded (93 Oct)
>and I noticed a significant difference. More power at lower rpm.
I run 14 degrees BTDC using 87 octane most of the time. When it gets
hot, I run the mid-grade fuel. I've read that the 18 degrees is OK, as
long
as you don't mind paying a little bit more.
For those of you concerned about emissions, I just had my '94 tested
(in Illinois). We only use a low rpm tailpipe sniff. Results:
Hydrocarbons (HC): 1 ppm, test limit is 220 ppm.
Carbon Monoxide (CO): 0.00 %. test limit is 1.20 %
So, no measureable impact on emissions. More low end torque.
And it's free.