<Big Snip>
That brings me to the next question, what are the injector
specifications
that I should use if I don't purchase replacement mazda injectors? I
know
they should be of the high resistance > 13 ohm to work with Tracy's
system
but I'm not sure about nozzle flow rates. Also, are the primary and
secondary injectors different? Related to the injector diffuser
question,
if you replace the injectors with a different make should they work
with and
fit into the mazda diffuser?
Del Johnson - Another Glastar builder
Tracy says the engine needs up to 18 gallons an hour at full power.
BTW least you think that is high you would be wrong. 200 HP aircraft
engines also need that kind of fuel flow at full power.
I would say 20 gallons per hour to be on the safe side. Since there
are four injectors that is 5 gallons per hour or 30 pounds per hour
per injector. I'll be using the stock Mazda 88-91 turbo injectors. At
least initially.
Paul Lamar
List,
Summit Racing carries Ford 30lb injectors (set of 8, of course) for
$210. Maybe it would be worth just buying new injectors instead of fooling
around with the old ones.
Ken Powell
I agree with Paul about min of 20 gph. Keep in mind that injector flow is
at wide open and I think the standard is to assume you get a maximum of
approx 85% of the state flow rate due to the opening and closing transists
(period of time the injector is not full open/closed). I have seen over
20 gph on my 91 turbo II on cold mornings (OAT<32F) and 17-18gph is
frequently seen. Also if you ever decide to turbocharge/supercharge then you
would need the increased flow capacity.
Regarding old Mazda injectors. I have had several which turned out to be
bad or failed (after all they are getting rather old and work much harder in
aircraft application). Also new ones are rather expensive to say the least.
Also making certain you are getting the right impediance (low/high) can be a
bit confusing as thing seemed to vary from year model to year model.
Selecting the impedance (by the way Tracy's EC2 will work with low
impediance injectors, but you have to add resistors) then dictates the
injectors wiring connectors. The Mazda connectors have plastic keys,
generally if the key on the injector connector is off center then it is an
high impedance injector/connector. However, there is a least one year where
the key is in the center ( ususally meaning a low impedance injector) for
both the low and high impedance injectors) - so the old ohm meter is the
best method to check.
I first flew with some MDS 38 lb/hr injectors for the first 80 hours and
they worked just fine and only cost $50 apiece (at the time) brand new. The
draw back is that you can not use them in the stock Mazda Injector bossess
like in the block (they are too big in diameter at the nozzel).
So before you bore the injector bosses for size, carefully consider which
injectors you will be using as they require different diameter seats and in
some cases different injector connectors..
FWIW
Ed Anderson
Good points Ed. I am getting ready to bore those injector holders
and I was going to bore them for the stock Mazda injectors
I have. My injectors have the key in the center.
the part numbers are very small and are on the plastic part
alongside where the connection is made.
Number 195500-1350 630 on the other side is K 09. There also
appears to be a tiny ND logo which I assume is Nippon Denso.
DC ohms is 2.3.
The bore is about 16.5 mm or about .66" in dia. and .66" long.
Everybody that can... please measure your injectors and tell me what
you have so we can bore the injector holders to the right size.
Ignore the inserts for the moment as they are designed for
air injection. I just need the dimensions on the actual injectors.
Paul Lamar
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