Flow Matched Injectors?
It's a fundamental assumption, in multiport injected,
single feedback EFI, that all the holes are running the
same. Bankwise, on these cars, you control 4 with one
sensor and 8 with a single open loop air mass value.
I've dealt with a couple of cars that had developed
injector imbalance from silt. That's going to be a problem
on all these cars with stock type fuel fails, silt accumulates
at the dead-end positions. If the motor is torn down for
something, that's a good point for injector service with
a flow test at the end, verifying that it was done right.
I've been told, or read, that natural injector tolerance
is something like 5%. The leanest hole sets your fuel
and timing, and all the fatties are not pulling their
weight.
It's kind of like "balanced and blueprinted". Grocery
getter with 9:1 compression and way detuned, why
bother? But if you're going for everything you can
get, you probably want to get the injector imbalance
downsides off the table.
Some setups seem to have rear cylinders consistently
lean (manifold airflow distribution?) and if you know
this is the case, you can use the flow match data to
pick out the highest-delivery ones for the trouble spots.
single feedback EFI, that all the holes are running the
same. Bankwise, on these cars, you control 4 with one
sensor and 8 with a single open loop air mass value.
I've dealt with a couple of cars that had developed
injector imbalance from silt. That's going to be a problem
on all these cars with stock type fuel fails, silt accumulates
at the dead-end positions. If the motor is torn down for
something, that's a good point for injector service with
a flow test at the end, verifying that it was done right.
I've been told, or read, that natural injector tolerance
is something like 5%. The leanest hole sets your fuel
and timing, and all the fatties are not pulling their
weight.
It's kind of like "balanced and blueprinted". Grocery
getter with 9:1 compression and way detuned, why
bother? But if you're going for everything you can
get, you probably want to get the injector imbalance
downsides off the table.
Some setups seem to have rear cylinders consistently
lean (manifold airflow distribution?) and if you know
this is the case, you can use the flow match data to
pick out the highest-delivery ones for the trouble spots.
It is very important in an aftermarket high power engine!
Unfortunately most FI companies:
1) don't know how to measure dead time (offset) and don't know how it effects flow,
2) just match their injectors based on static flow (which will never happen in an engine)
It's sad how far behind the curve aftermarket fuel injection is from OEM. It mostly comes down to budget i suppose.
Unfortunately most FI companies:
1) don't know how to measure dead time (offset) and don't know how it effects flow,
2) just match their injectors based on static flow (which will never happen in an engine)
It's sad how far behind the curve aftermarket fuel injection is from OEM. It mostly comes down to budget i suppose.
9 Second Club
Joined: Nov 2003
Posts: 13,616
Likes: 185
From: Norn Iron
It is very important in an aftermarket high power engine!
Unfortunately most FI companies:
1) don't know how to measure dead time (offset) and don't know how it effects flow,
2) just match their injectors based on static flow (which will never happen in an engine)
It's sad how far behind the curve aftermarket fuel injection is from OEM. It mostly comes down to budget i suppose.
Unfortunately most FI companies:
1) don't know how to measure dead time (offset) and don't know how it effects flow,
2) just match their injectors based on static flow (which will never happen in an engine)
It's sad how far behind the curve aftermarket fuel injection is from OEM. It mostly comes down to budget i suppose.
AFAIK, the OEM ecu doesnt allow this ?
But it does seem odd how so many places, RC included who fow matched based on static flow. After having my own properly tested, flow when static was nothing like flow at 30% and 50% DC
Each injector did behave differently, and more than I'd like.
It is very important in an aftermarket high power engine!
Unfortunately most FI companies:
1) don't know how to measure dead time (offset) and don't know how it effects flow,
2) just match their injectors based on static flow (which will never happen in an engine)
It's sad how far behind the curve aftermarket fuel injection is from OEM. It mostly comes down to budget i suppose.
Unfortunately most FI companies:
1) don't know how to measure dead time (offset) and don't know how it effects flow,
2) just match their injectors based on static flow (which will never happen in an engine)
It's sad how far behind the curve aftermarket fuel injection is from OEM. It mostly comes down to budget i suppose.
I know for a fact that Racetronix flows its injectors dynamically, not sure about other vendors I have not dealt with!
Dead times are more complicated than saying it is x or y. It's very application specific, and prohibitively expensive. Most people simply do not car about injector dead times. It's a lot of labour to accurately tell what the dead time of an injector would be on the bench. Then it wouldn't be the same on any cars.
At what the price of flow matched injectors are do you think people will pay the extra money it would take for that kind of research?
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Staging Lane
Joined: Jun 2010
Posts: 69
Likes: 0
From: Kingfisher Oklahoma
flowmatched I think its a big scam . if they make an injector there should be enough quality control involved that they would all be the about same.. But since quality control isnt up to what it should be by the manufacturers you can pay them to check their own product lol! give me 8 that are equally sloppy....
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