I just fired up the 730 swap...and that damn surging idle is gone!!!!
OK, now I'm deciding on the best inj. constant to use before I start in on the ve tables. I know a lot of folk here prefer to not fudge a lot on the inj. constant to try to get the ve tables close; but rather put in the actual flow rating and then adjust the ves as much as they may need it.
I'd like to use the "actual flow" method (advantages??/comments??).
I'm using accell 30lbers (rated at 43.5psi) and started with inj. constant of 30.8 but it was way fat....so went to 38lb constant and still had to lean the idle out by 15%! (oh yea-my press is 42 with vac and 46 without.)
So would it be better to go back to 30.8 and just have to really lean out the 40kpa ranges????
It just seems like a lot of leaning of the ve table to use the actual inj. rating.....
I'd really appreciate some input before I get too far......
Thanks!

 

Well, first off, to set the pressure right at 43.5, do it without vacuum on the regulator.

Second, a cam larger than stock will require less VE than stock at low RPMs, higher than stock at high RPMs. The bigger (lopeyer sounding at least) cams will require the least idle VE in general.

For best results (as long as you don't hit code limitations), just use the actual calculated flow of the injectors and engine displacement. This way you can change injectors in the future or pressure, and just use math to get it back to decent (though low PW's will haunt you when changing injectors).

 

OK, I'll go with the actual rated flow for inj. constant-it just was really taking me off guard as to how much I'm having to decrease the idle area ves!!!! And it's a pretty conservative cam...228/222 at 50 with 114lsa.
Thanks!

 

Use the injector flow rate, and set the fuel pressure to the recommended PSI.

The adjust the tables as necessary.

 

It sounds like if you input the inj flow rate, with a modded engine, then usually the lower ve table will need to be reduced and the upper ve table increased yes???

With actual inj. value I'm finding the whole ve table is wayyy rich;hmmm; possibly these inj were mislabeled as 30lbers and are actually 36lbs....using 36 inj constant seems to end up with ve tables as above.....

 

To know if you're close with the injector constant and the VE just log a wideband with your open loop AFRs. I also use the old "VE shouldn't be more than x%" rule and when it approaches 95% on a n/a <400hp sbc I go back and increase the injector size and do a shift on the ve tables. That tends to work out well when you don't know for sure what size the injectors are. I know with TBI you just adjust the bpc until you don't see any 95+ ve, that's how I've been doing it.

 

So basically you disable closed loop and then adjust the inj constant so that the wide band shows its close to 14.7:1, yes???

Which brings me to another related question-if you dial in the ve tables, and then find that open loop is too rich so then adjust open loop-will that then effect the closed loop ve tables and vice versa.....

Thanks for all the info, I'll keep absorbing....

 

One thing I can relate to this is using the correct fuel pressure and injector constant as a starting point.
If you fudge it and boost the fuel pressure, anytime you need limp mode you risk flooding. I don't know if the limp settings in the resistors will account for anything but "stock" sized injectors so with the 30's the risk may still be there.
I've fouled my plugs too many times because of this and am going to go back this year and start from scratch.
good luck!