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Injector Latency Algorithm change

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Old Aug 19, 2010, 12:03 AM
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Lightbulb Injector Latency Algorithm change

Originally Posted by Hunt for Red October
Captain, radio. We're receiving flash traffic on the V.L.F. emergency circuit.
Hi All,

So while tuning up some ID2000's I have made a startling discovery.

In previous Evo's (CT9A) the injector latency raw value was multiplied by 0x18 (or 24) to get it into "microseconds".

So in your scaling for "InjectorLatency" you will see x/0.024 (which is really 24/1000, we divide by 1000 to get microseconds into milliseconds)

HOWEVER, and this is the cool/ghey bit, for CZ4A the wizards at Mitsubishi decided to use 0xF (or 15) as the multiplier.

So here we are still using 0x18.. So all of our latencies are being DISPLAYED incorrectly.

Now as long as when you tune you use the tried+true method of "trim watching" then your fine.

But hasn't it always IRKED you that the manufacturer latencies didn't match what you were putting into the table?

So to fix this SNAFU simply open up your evo10base.xml and replace

Code:
<scaling name="InjectorLatency" units="ms" toexpr="x*0.024" frexpr="x/0.024" format="%.3f" min="0" max="4" inc="0.024" storagetype="uint8" endian="big"/>
with
Code:
<scaling name="InjectorLatency" units="ms" toexpr="x*0.015" frexpr="x/0.015" format="%.3f" min="0" max="4" inc="0.015" storagetype="uint8" endian="big"/>
You will notice that I have ALSO modified the "inc", so now you can use + and - to add or subtract latency WITHOUT the huge jumps!

BTW - The ID2000's that I am tuning now actually match the 14V latency as specified by the manufacturer - chance or co-incidence?

Cheers
D.

Last edited by tephra; Aug 19, 2010 at 12:11 AM.
Old Aug 19, 2010, 04:34 AM
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Cool!

That would explain the big jumps when trying to dial in the ID1000's
Old Aug 19, 2010, 04:38 AM
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yeah Matt's final ID1000 latency is actually fairly close to the ID specs.. I little bit of on lower voltages but that wont affect anything except startup..
Old Aug 19, 2010, 07:03 AM
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tephra, you are a g0dd@mn machine! It's not always the BIG stuff but the little stuff that really makes these cars better overall. Very nice work!

wait, why are you installing ID2000's.....
Old Aug 19, 2010, 07:07 AM
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Haven't tried it yet....but that is amazing David.
Old Aug 19, 2010, 07:14 AM
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Originally Posted by scheides
wait, why are you installing ID2000's.....
I'm not! I wish I had a build in progress that required them..

But they are for someone else... If the owner allows me I will post up progress on his tune You probably already know his build, its fairly well documented
Old Aug 19, 2010, 07:15 AM
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Sweet! I was wondering why the latencies were a bit off on the DW1000's compared to the spec sheet! Will implement these changes when I switch out to the big MAF housing! Thank you!!!
Old Aug 19, 2010, 07:17 AM
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I have another thread to post up (in the X forum) that details how to setup the ECU to allow LESS than 1.28ms IPW

Obviously this will only be required for 1500cc injector plus sizes... But it should allow for better AFR control at idle
Old Aug 19, 2010, 07:17 AM
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I converted my definitions. But now I will be off from Cobb AP stuff. I'll probably have to have them both (old and new).

Mine looks closer now too. Data sheet says 1.000 for 14v. I have .915 for 14.12 v. And the old way was 1.464 for the 14.12 v. A lot closer.

This also explains why 8/9's had such different scalers for the exact same injectors.
Old Aug 19, 2010, 07:20 AM
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Does Cobb use the 24/1000 scaling? Bummer

Oh well - in my next email to Trey I might give him a heads up - unless he's already seen this thread
Old Aug 19, 2010, 07:25 AM
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Yeah, just like the scaler changes for Airflow. I have an old set and a new set for copy and paste.

I really should make a Cobb Load Scaler so that I can just copy and paste over the target boost load tables. It would make it easier than having to subtract 32 from them. I still don't understand why they add 32 to all those tables and the Load Values.
Old Aug 19, 2010, 07:41 AM
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Tephra, I'm going to post this "over there" so others can see this.
Old Aug 19, 2010, 07:44 AM
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okey dokes!
Old Aug 19, 2010, 08:12 AM
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Originally Posted by tephra
I'm not! I wish I had a build in progress that required them.
It wasn't that long ago that there were no options between 1k and 2k. I have a set of the ID2000's waiting to go back in on the 31st (we couldn't get them to work well enough a few months ago). These findings are very timely. I didn't want to get stuck with $900 paper weights.
Old Aug 19, 2010, 08:19 AM
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If anyone wants to keep their original and just add this as a new item, you can add this XML to your _mods file for 52680015:

Code:
<scaling name="InjectorLatency_NEW" units="ms" toexpr="x*0.015" frexpr="x/0.015" format="%.3f" min="0" max="4" inc="0.015" storagetype="uint8" endian="big"/>
 	<table name="Injector Battery Voltage Latency Compensation NEW" category="Fuel" type="2D" scaling="InjectorLatency_NEW" address="556cc">
		<table name="Battery Voltage" type="Y Axis" elements="7" scaling="BatteryVoltage" address="6512e"/>
	</table>


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