Date: Mon, 01 Feb 1999 00:04:37 -0800
From: Paul <rotaryeng@earthlink.net>
To: z <rotaryeng@earthlink.net>
Subject: rx7 knock sensor group buy proposed from rx7 list......care to
join in?
MAR34807@aol.com wrote:
I have informed the following that it will be posted in this forum!
Please
respond directly to him, not me!
From: "Wade Lanham" <aea@wvinter.net>
Subject: (rx7) [3] J&S group buy - Update #2
Okay, we have over 40 interested buyers. I think we can get a
pretty good deal on these things (which we should, with so many people
interested).
I'll be getting some prices soon... then I'll ask again for
those
who are *serious* buyers, given a discount price quote.
From: "Wade Lanham" <aea@wvinter.net>
Subject: (rx7) [3] J&S knock sensor PRICES
Okay, here's the situation. Please read this carefully.
I'll be the official keeper of the number of buyers (which
affects
the price). If you want to buy, but only if we hit the X price range,
say
so *specifically*. These replies will essentially be the list given
to the
provider of the units. Please put BUYER in the header of your message
to me
to make it easier for me to sort.
To guarantee we get the price we want, and the seller gets the
required number of purchasers, we plan to use Credit Cards to secure
the
orders. The seller will wait until he has the Credit Card # of our
target
number of buyers BEFORE charging anyone.
This will allow us the ability to cancel all orders if we
don't get
enough to make the purchase worthwhile.
I will send a confirmation to EACH person who mails me as a
buyer
before the group purchase is official.
Also, John (J&S) can make about 10 a week. So, if we have
more than
20 buyers, it *might* take about 2 weeks to get your unit. I'm
keeping all
the messages, so those who send me a confirmation sooner will get
their
units sooner. No one should have to wait more than 2-3 weeks.
Here are the prices:
J&S Knock retard system
Newest model, with adjustable sensitivity and adjustable max
retard
Billet aluminum case
Dual (A/F and timing) monitor
I'm counting on Shiv to post more details on the features of
the new
units. Hopefully, he'll also post fairly detailed information on why
and
how they should be used. Most of us wanting to purchase have heard
enough
about the units to be sold already, but extra information couldn't
hurt.
10+ $575 for unit and display
20+ $550 for unit and display (or $420 and $130)
30+ $525 for unit and display (or $400 and $125)
At 30+ buyers, we will save $125 ( 20% ) from the usual price
of
these (Rotary Performance in TX, or Mostly Mazda in CA).
We hope someone will provide a web page with a "howto." I've
been
told the instructions are pretty good, though.
I plan to post the BUYERs to the list occasionally (assuming
no one
minds - let me know if you do). This will allow all the buyers to
know how
close we are to closing the deal.
Also, we will probably put a limit on the purchase date - I'm
guessing we'll draw the line in about a week.
As we work out more details, I'll keep everyone informed.
If you've decided you need a knock sensor, *NOW* is the time
to buy.
The price keeps going up on these things, and there will never be a
better
deal than this.
Date: Thu, 28 Jan 1999 19:26:47 -0500
From: "Wade Lanham" <aea@wvinter.net>
Subject: Re: (rx7) [3] J&S knock sensor PRICES ADDENDUM
Let me clarify - DO NOT SEND ME YOUR CREDIT CARD NUMBER. You
will
call the seller with your CC#, address, etc, once we have confirmed a
set
number of buyers.
BACKGROUND INFO DISCUSSION FOLLOWS:
As far as I know, I am the first person to use the "new style"
Safegaurd on my
FD. It works flawlessly. A must for a modified engine, in my
opinion.
FWIW, years ago, I used the "old style" Safegaurd on my turbo Miata.
If I
remember correctly, the old style unit cost me $450. The display was
an extra
$150. The new version is far better in terms of build quality (pretty
blue
anodized alum. construction vs. cheap grey plastic). It also has the
option
for
extra fine resolution (10 degrees max retard vs. 20 degrees max
retard).
Certainly not a big deal, but all in all, I think the extra $50 is
worth it.
Especially on a unique device that can safe your engine. As far as I
know,
there are no other systems available that do the same thing. That is,
unless
you don't mind rewiring your entire car, installing a $2000 TEC-II or
a $6000
MOTEC ecu, and use its somewhat inferior knock sensor capabilities.
Lots of
R&D
went into the J&S system... seriously.
Subject: Re: (rx7) [3] J&S group buy - Update #2
Greg said:
From my understanding of the J&S Knock Sensor, it does not start
working until your engine starts to pre detonate. Since the RX7
is so vulnerable to pre detonation it would seem bad to even let it
get to this stage. Wouldn't an ignition timing system be the safer
route? The ignition timing system I am thinking of is one that
would retard the timing based on predetermined maps.
Greg,
That is a different function--one that (as you say) should be built
into the engine management system. Also, your timing system would
have to either change in proportion to boost, or you would be running
more retard than necessary (lost power) at lower boost levels.
The J&S unit serves to safeguard your engine:
If you "upgrade" the car and boost control gets edgy.
If you decide to push the boost a bit to get by that pesky Mustang.
If you don't get your adjustment right when you are installing your
"ignition
timing
system."
If you forget to turn the boost down after using racing
gas.
If you find that something you have done (or another mechanic
has done) is not working as it should.
If something in the boost control system breaks.
If the weather turns cold, and you find your car running a little
lean.
If you are experimenting with the tuning of a PMC.
Ideally, the J&S system is more of an emergency over-ride which
activates before you hear detonation and alerts you that something is
too close to the edge. It is the difference between seeing a yellow
light or two, and waiting until you hear pinging--which is already
damaging your engine.
Further, it is highly sophisticated--able to determine which face of
which rotor is detonating, and only retarding spark to that face. If
two or more faces are detonating at different levels, it will retard
the
spark to each face in proportion to the severity of the situation.
True, if everything is perfect with your car (all the time) you
wouldn't need one. However, many of us have heard that dreaded
popcorn sound when we thought we were conservatively tuning the
system. Frankly, I would rather see a light flicker. I have had
one of these gizmos for over a year. I NEVER expect it to go
off--but when it does, I thank the rotary gods it is there. How
often can you say: "Oops! My mistake. But no harm done."
I have the readout that does not have the A/F meter. It is a series
of ten yellow looking LEDs, but they are red when they light up.
The meter was obviously designed to house both rows of LEDS
(knock/retard and A/F meter). If you don't order the A/F meter, that
space on the housing is simply blank. It makes practical and
aesthetic sense to have the two meters on one housing. And if I
know John Pizzuto, (the "J" in J&S) the A/F meter is a good one.
Both meters dim when it gets dark.
So, if you are currently using an inexpensive Cyberdyne A/F meter,
and you would like to de-clutter the cockpit a little, this is a good
opportunity. On the other hand, if you have invested $130.00+ in a
Halmeter, and are addicted to the larger number of LEDs, you
might prefer to keep it and get the J&S knock/retard readout
without the A/F meter.
I consider the display essential for dialing in the sensitivity of the
J&S. It's hard to feel when the unit is over or under retarding
(unless
you hear a knock, of course-- but then its probably too late). Seeing
the LED display makes the whole job a simple matter of tuning a knob
until you see the unit *just* begin to retard. Over-retard sucks away
power and heats the exhaust side up-- not good either.
Of course, you can borrow the monitor (from someone who already owns
one) just for the brief tuning process and then return it. That
should
work in the long run, but it's always nice to be able to see what's
going on under the hood. Compared to other upgrades, $150 isn't much
for the dual meter option, esp. if you don't already have a a/f
ratiometer in the car. When people see that red LED scan back and
forth, they say "Ohhh... like Knight Rider." I'm no superstar David
Hasslehoff, but I do like to keep tabs on my Trans Am... er.. FD.
Subject: re: (rx7) (3) J&S knock sensor install question
Steve Asked:
Hey everyone, im thinking about getting in on the knock sensor buy
but, odes anyone have a How -To uploaded anywhere? Can someone how
hard it is to install this unit?
Steve,
>From memory, so don't take this as anything but a rough indication
:
The knock sensor control unit mounts away from heat--usually under
the dash somewhere or in the glove box.
Mount the microphone on your rotor housing. One of your housings
already has the mic from the stock knock sensor. Use the analigous
space on the other housing. The mic cable terminates in a plug
which fits into the control unit.
There are four wires to run: Two are used to interrupt (and route
through the control unit) the low tension signal that fires the
leading plugs--between the coil and igniter on my 1st gen. In other
words remove the igniter wire from the coil. Attach it to one J&S
wire. Attach the other J&S wire to the coil. The wires are color
coded.
The third wire is hot (switched). The 4th wire is ground. (Note:
If your ground wire comes loose from the body, you will lose ALL
SPARK to the leading plugs. Secure the ground wire well.) These
four wires terminate in a multi plug that goes into the control
unit. The unit comes with a shorting jack that fits into the end of
the multi-plug. Use this if you are diagnosing a problem and want
to take the J&S unit out of the picture. It simply turns the
ignition signal around and sends it back without going through the
box. Pretty nifty. I used it when my ground wire came loose one day
when I was on the road. You should see what happens to exhaust temps
when you are only firing the trailing plugs.
There is an optional 5th (yellow) wire used if you notice the knock
sensor activating during over-run conditions. This can happen if
there is unburned fuel left in the combustion chamber. The knock
sensor is sensitive enough to detect this stuff burning off in an
uncontrolled way. Even though it won't harm the engine, some people
don't like seeing the indication that the knock sensor has activated,
so the yellow wire is provided to hook up to a voltage source like
the TPS. This prevents the knock sensor from operating when your
foot is off the throttle. Note that the knock sensor already knows
not to operate below a certain RPM threshold. I don't remember what
it is--probably somewhere between1200 and 2000 rpm.
The knock/retard readout gauge simply plugs into the control unit.
The A/F meter portion of the gauge has (I think) one wire to T into
the O-2 sensor, and another wire. I don't have this feature so I
don't recall where it goes.
The following controls are on the front of the old model control unit.
The
new one may differ:
There is a set of dip switches with which you can select options like
retarding total timing according to the worst knocking rotor face, or
retarding each rotor face independently. There is a sensitivity
control which will probably end up open about a quarter turn from
full counter-clockwise, with the screw slot somewhere around 11 and 5
o'clock.
There is another adjustment for the rev limiter. No one mentions
this because our cars under boost will over-rev on the trailing
plugs alone (not controlled by the knock sensor). Nevertheless,
there is a sophisticated rev limiter included. If I remember
correctly, you tune it with a VOM and a screwdriver so that the VOM
reading corresponds to the red line. The unit cuts spark
intermittantly from that amount of RPM to 10% over, and totally cuts
spark
after that. If someone figures out how to make this work for both
leading and trailing plugs on our cars (without buying a second
knock sensor) it would be VERY handy.
Once again, this is from memory after installing my J&S unit well
over a year ago. The new model must have a switch to select the
"10% max retard" mode Shiv mentioned. Take the above as a general
indication of what is involved to install it, and not as specific
instructions.
Those of you taking the plunge and ordering J&S units are in for a
real treat.
For what it's worth, my J&S is tuned so I see 1-2 LEDs flicker (1-2
degrees of
ignition
retard) whenever I run through the gears at full boost. Although the
car will
not knock
with the Safegaurd removed/diactivated (i.e. with no active retard),
it's nice
to know
that it's poised and ready to pull out more timing if the motor runs
even just
a *tiny*
bit less smooth than it does normally. On the track, I see 2-4
degrees of
retard once
things start to get hot. Same thing happens when the car is doing
repeated
dyno runs.
It's nice to see it always work and then work a tad harder in more
harsh
conditions.
In case your wondering, there was no measureable difference (either in
hp or
EGT) on the
dyno with the Safegaurd on or off. In other words, the 2-4 degrees of
"excessive" retard
is unlikely to hurt performance in any way.
Also, it should be made clear that the Safegaurd is not intended to
take the
place of a
remapped ecu in a modified engine. As some have noted, it's there as
a
safegaurd in case
you need it. To keep things running well, use it in conjunction WITH
reasonable and safe
boost/fuel/timing maps, NOT as a subsitute for 'em.
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