e8 secondary injector split map
 

the problem i have been having is when the engine is running positive manifold pressure the engine fell on its face.i had the split map at 20 degrees split across the rpm range.. i have mapped the secondary injector split map to 80 degrees split across the rpm range at 17 pounds of boost.that made a big improvement.is there a formula (primary and secondary injector over lap) in tuning this map?

Not that i am aware of, the split timing for injection is based on the difference in injector location, so you can get the secondaries to put the fuel in at the right moment, if they're too far off you get pooling, if their close enough everything goes through at the appropriate time and you get a better mixture/combustion.

Are you running Common mode or Primary Hold mode, on the staging setup?

You may also want to play with your main end of injection map, this also helps get a better mixture going, especially under vacuum, you can get away with leaner mixtures for part throttle, cruising, idle situations. And the rule of thumb on the end of injection angle map is, after you've gotten a decent running engine, move the map values until the mixtures richen up as much as they're going to without changing the main map, when that happens, then go to your main fuel map and start leaning them out and see what happens. Again, like somethings, its trial and error.

I really doubt the main reason for your problem lies in the injection angle. If it "falls on its face" then it's more likely a fuel map issue. As Claudio pointed out, injection angle is going to make the most difference at low revs and high vacuum when air speed in the intake is low. Once you've built revs to the point you're making positive manifold pressure you have enough air speed to mostly counteract the effects of fuel falling out of atomization due to an improperly timed injection pulse. Think of the difference between a piston engine running sequential versus batch fire. The improvements are mostly in idle and low speed running. Once under high load and higher revs the differences are largely mitigated.

Yeah, thats right, after 4000+ rpms all is happening so fast that its almost like a multipoint deal.

thanks alot for the replies.i will give you a little run down of what is in the car.it has a ford c4 transmission (i know automatics suck).it has a third gen stock port rew.stock third gen throttle body.an aftermarket lower intake with the four injectors in the manifold.850 primaries 1600 secondaries.aeromotive a1000 fuel pump.fuel pressure set at 40psi.fuel is set to semi sequential.staged injection is set to common mode.the stage bar is set on stage bar 11 (transition from vacuum to boost)it has a flat trailing spark plug map of 10 degrees at all rpm and loads.Saturday night i tuned the car on the freeway here in riverside until 3:30 am.when i had started tuning on my freeway dyno the secondary injector split map was at 20 degrees through the rpm range of this map.i spilt it to 80 degrees and this thing came alive.so i figured more is better.last night i tuned it from 60 degrees at 0 rpm to 100 degrees at 8000 rpm.i runs even better.my end of sequential injection fuel map is set from 230 degrees at 0 rpm and 330 at 8000 rpm.like you had mentioned in your reply i will tune this end of sequential map to see what happens .my egt is 1550 under full load.1200 freeway load.my temp probe is a couple of inches past the turbo.it is probably 100 degrees hotter at the exhaust port.i am running E85 this is good stuff.i am going to ramble for a second about my interpretation of this secondary injection split map.at 6000 rpm it takes 10ms for one complete e-shaft revolution.i was injecting 4ms of fuel primary and secondary.with the 20 degree split i had from the start. i was actually injecting all my fuel in 144 degrees of e-shaft rotation.now that i have thought about it Claudio, it makes sense that i was pooling fuel in the intake manifold. with the 100 degree split at 6000 rpm i have now, it made the injection time longer.now the injection time is about 244 degrees of e-shaft rotation.for this reason it runs 100 times better?thank you all for the replies.if you see any thing wrong with my post i take constructive criticism well.any more suggestions are welcome:scratch: