Minimum IPW
Joined: Mar 2003
Posts: 394
Likes: 7
From: Used to be in Nor Cal, now working in Seoul
That is quite impressive.
If stock injector flow rate is 560cc/min exact, then 8 microsecond step is equivalent to ~7.5 e-5 cc = 75 nano liter!
Of course, as 03whitegsr stated, whether this little step can reliably be applied to the real system is another story.
I guess more resolution about the IPW step size from ECU side may not be needed.
If stock injector flow rate is 560cc/min exact, then 8 microsecond step is equivalent to ~7.5 e-5 cc = 75 nano liter!
Of course, as 03whitegsr stated, whether this little step can reliably be applied to the real system is another story.
I guess more resolution about the IPW step size from ECU side may not be needed.
Compare to this:
http://site.titanmotorsports.com/blo...ctor-graph.jpg
We tune around non linearities all the time. Many people non linearize the factory MAF when they take off the stock airbox and put a cone filter on. As long as the IPW is repeatable and reliable (precise) then we can work with it. We don't always have, nor do we need precision (linearity to 0ms). I hope that makes sense?
http://site.titanmotorsports.com/blo...ctor-graph.jpg
We tune around non linearities all the time. Many people non linearize the factory MAF when they take off the stock airbox and put a cone filter on. As long as the IPW is repeatable and reliable (precise) then we can work with it. We don't always have, nor do we need precision (linearity to 0ms). I hope that makes sense?
Sure, you can tune around it in a main fuel table or with latency changes...or you can compensate for it directly in the tables that were designed to do it. If this was a debate over adding an additional table that required code changes, I could see your point. The tables are already in the stock ECU to make it happen though and it is just a matter of calculating some values and putting them into the ECU.
Newbie
Joined: Jan 2010
Posts: 56
Likes: 0
From: Akron, Ohio
Ok, I'm trying to do this on my Evo8.
I'm trying to figure out how to set the min IPW to 1.1ms.
ctrl c ctrl v'd the xml, got the IPW 1,2, 3 and min IPW shll0 into ECU flash. the value was 0.040 in the last one.
incremented it up to ~1.1. car wouldn't start. I figured i had the philosphy wrong so i tried instead adjusting it down to 0.032. car started but idle was real erratic and lean.
My scaling and latencies seem to be OK, the car was driveable with the stock min IPW with this scaling and latency but idle was pig rich of course.
so wtf am i doing wrong?
again I"m on a 94170008 Evo8
I'm trying to figure out how to set the min IPW to 1.1ms.
ctrl c ctrl v'd the xml, got the IPW 1,2, 3 and min IPW shll0 into ECU flash. the value was 0.040 in the last one.
incremented it up to ~1.1. car wouldn't start. I figured i had the philosphy wrong so i tried instead adjusting it down to 0.032. car started but idle was real erratic and lean.
My scaling and latencies seem to be OK, the car was driveable with the stock min IPW with this scaling and latency but idle was pig rich of course.
so wtf am i doing wrong?
again I"m on a 94170008 Evo8
Newbie
Joined: Jan 2010
Posts: 56
Likes: 0
From: Akron, Ohio
yeah I changed them all down to 0009.
min IPW is sittin at 1.176ms right now. it oscillates between rich and lean. but it does run.
I'm, going to try lowering my fuel pressure to get a higher actual fuel flow resolution with min IPW increments.
My fuel pressure is not 43.5, its higher. I dont have any tools on me right now so I'll handle it tomorrow and update.
log
https://spreadsheets.google.com/ccc?...thkey=CJ2zh5sL
all stationary, idle, me blipping the throttle a couple times.
min IPW is sittin at 1.176ms right now. it oscillates between rich and lean. but it does run.
I'm, going to try lowering my fuel pressure to get a higher actual fuel flow resolution with min IPW increments.
My fuel pressure is not 43.5, its higher. I dont have any tools on me right now so I'll handle it tomorrow and update.
log
https://spreadsheets.google.com/ccc?...thkey=CJ2zh5sL
all stationary, idle, me blipping the throttle a couple times.
Last edited by Dirty25RS; Sep 8, 2010 at 06:11 PM.