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ITB's and injector staging
Posted: Sun Sep 02, 2007 9:46 pm
by RdSnake
I have a 90 1.6 miata with ms-II 3.0 edis with ITB's. I am using stock injectors and stock fuel pressure regulator.
What injector staging should I use for this setup? injector staging is currently set at 2 squirts alternating.
off idle tip in produces a bog and idle seems erratic.
I am looking for responsive accelaration from my setup.
TIA
Posted: Tue Sep 04, 2007 10:06 am
by 73Inka2002
A lot of people with ITBs (myself included) have had good success with 4 squirts alternating. Also, the latest beta code (with faster MAP sampling?) or the MSII Extra beta code (with faster MAP sampling and EAE) are supposed to help a lot with lean tip in. Oh, a vacuum accumulator thing may help too. The idea is to tie all the vacuum lines together into a single plenum device to smooth out the MAP signal so you get more accurate and consistent fueling.
I assume your VE table is already pretty dialed-in?
Regards,
Robert
Posted: Tue Sep 04, 2007 10:54 am
by RdSnake
Robert:
Im gonna give 4 squirts alternating a try.
Ive got an accumulator hooked up to the itbs and its a definite must have to smoothe out vacuum to MS and fuel pressure regulator.
I was so quick in blaming MS and its current tune for my bogging and hesitation. Apparently my #4 spark plug had started fouling and messed up my tune. Changed to a new set of plugs and car runs like a champ even without AE.
Lesson learned is, "Its not alsways the tune and MS."
Posted: Tue Sep 04, 2007 11:10 am
by 73Inka2002
Let us know how it works out.
When you switch to 4 squirts, you may need to retune your VE table a bit unless you have your injector opening time setup nearly perfectly. It's not a huge problem, but something to be aware of.
Posted: Tue Sep 11, 2007 1:00 am
by bcal
I have 2 alternating and have tried different combinations but found this to be the smoothest at idle. Though I must admit I've never tried 4 squirts.
I found the accumulator to have made things worse. It just added extra capacity, therefore lag, to the system.
I found the best setup for my engine was a .6mm mig tip in the line from each TB and 1 more for good luck in the line to the ms. That's 5 in all.
Sounds like overkill but dampening each TB individually made a big difference to the size of the pressure pulsations without loosing too much response.