[Diy_efi] forum and calculating sequential injection time

Mike niche
Tue May 17 21:19:58 UTC 2011

mmm, I wonder if the earlier injection time takes advantage of build up against the hot inlet valve
for some vapourisation... sounds interesting and yes big difference in CO - what about NOx though
and was that idle fully warmed up or was there a cold enrichment - even then CO is nicely low :-)

Whats the engine coolant temp, re thermostat or check on a datalogger.temp sensor ?

Have I missed something, what are you using to control the injectors and ignition timing, is it
one of those GM modules that can be hacked /reprogrammed or some Megasquirt type thingie, or other
custom, just curious and sorry if I missed something late night 5am here and too much red whine,
so I sleep well without being anxious about my heart rate's PWM or equivalent biochem control system <sigh>


off to sleep, all the best, more info - any pics, a picture paints a 1000 words... so more pics more wurds, thanks


At 04:39 AM 5/18/2011, Jay Rabe wrote:
>Thanks for the forum link and the its out there replies.
>Im running 5 82lb/hr injectors on a 2.3L engine (its a 5 cylinder turbo.)  I had guessed at injector timing and couldnt get it to idle smooth at 14.7.  It needed a displayed (new LC-1) 12.8 to not bobble at idle, i was getting about 7% CO.  Making the injector event happen 50 degrees earlier than my guess, lowering ign timing 1 degree, and lowering injector pulse i got CO down to about .2%. Thats a pretty huge difference.  It now idles smooth at 14.7 like this.
>  I failed emissions with it running closed loop at 14.7:1.  It was occasionally lean misfiring while they were testing it, im guessing from incorrect injector timing not allowing it to run smooth at 14.7:1.
>I tuned it at idle with a gunson CO meter.  Not exactly a drive it and log or watch whats going on type of tool.  Its basically only useful parked.  I ordered a used May something something CO meter i'm going to break apart and use as a reference for injector timing.  
>I'd like to still make a sequential timing calculator for when i tune other cars, at least to get the inj. timing in the ballpark.  Bruce Bowling sent me a paper on seq. inj. timing i still need to read and try to get my head around.  Thats my best lead so far.
>On Tue, May 17, 2011 at 2:55 PM, Mike <<mailto:niche at iinet.net.au>niche at iinet.net.au> wrote:
>from what i recall of the issue vs batch and sequential is the difference is not that much,
>batch can use smaller injectors, sequential needs injectors with more flow,
>batch seems to work fine on many production cars as half the time the spray
>is against the (hot) closed inlet valve, so some vapourisation takes place,
>timing the sequential might not allow as much time for evaporisation (comparitively),
>so the first (and quite important) question arises:-
>Why introduce complexities in respect of sequential when batch seems to work fine ?
>At 02:20 AM 5/18/2011, Jay Rabe wrote:
>>I have heard people refer to the forum quite a bit but never found anything but archives of this email list.  Is that what people are referring to as the forums? 
>>I know theres issues with the mailing list but figured its worth a shot to ask about sequential timing.  If anyone cant get through the diy list my email is <mailto:jayrabe at gmail.com>jayrabe at gmail.com
>>I am trying to figure out how to calculate sequential injector end time.  I have searched for hours and havent found much helpful besides <http://www.oocities.org/fwarner_au/mc_things/efiithoughts.html>http://www.oocities.org/fwarner_au/mc_things/efiithoughts.html which i believe was/is someone on here.  I started <http://efi101.com/forum/viewtopic.php?p=45567#45567>a topic on this at efi101 but i havent really gotten anywhere there.  I know on the dyno with a 5 gas analyzer is the correct way to do it but i dont have the $ for dyno time.  I need to get through emissions (adding a cat too for the tailpipe tests)
>>My standalone <http://i240.photobucket.com/albums/ff267/rabemotorsports/sequential7A.jpg>has a visualizer/gui which is kinda cool but doesnt help calculate injector timing.  I tuned the -60 row with a gunson CO meter in the tailpipe (no cat currently) and got the sequential timing close from idle up to 3krpm.
>>Im thinking of making an excel based calculator to help figure out sequential timing (at least ballpark) but i cant find the calculations needed.  the above oocities link is missing intake pressure/vacuum as well as injector distance from the valve.  Can anyone on here point me to calculations, a book on this, or anything else helpful to figure out sequential injection timing?
>>Thanks in advance.
>>Diy_efi mailing list
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