Need Direction on EOIT Injector Timing for Big Cam Gen 3 ECU

[cobaltssoverbooster]

so the idea is to push the END of injection back further towards the intake so there isnt a pile of fuel sitting behind the intake valve waiting to get sucked straight through the open exhaust valve upon opening into the overlap event.
where this happens.....the motor will tell you its efficient spot based on peak mid range torque output and when the wideband shows proof of limited gain. if you record stock values and then push the event back and increase burn efficiency then the motor will need less fuel to run the new event. naturally your wideband would show a rich state that you would then need to correct by leaning out the mixture. if you keep testing this and see limited gains then you found the beginning off the efficiency window. the dyno is your real tell all as to where the sweet spot is. for most the smell factor and the wideband will get you close enough.

So to combat this, we are trying to move the injector timing just about to the point where the exhaust valve is just about closed and intake valve is coming off the seat. In the case .
So if I move my injector timing right at about where the EVC occurs (6.3) then I'll have about 18 degrees of IVO already.
I guess it's just somthing that needs to be tested.
I could start with 6.3 and work my way back

the math is fairly simple here. The computer measures incoming density and uses the tables to come up with a desired injector on time in ms we can call IMS. The boundary tells the computer you have this much time to get it done, and the normal says within the boundary window i want you to quite spraying at here...END.
Boundary and Normal define -END
END+IMS= start of injection. If the window isnt big enough you dont get full spray. anything else falls withing the limit. the EOI is a coded known (that user defines) based on revolution. the injector ms is added to this to determine a start of injection (SOI). By shifting EOIT you effectively move SOIT because SOIT is calc'd from EOIT.
RPM / 60,000 = Rev per ms. from here you can define the amount of angular rotation in one ms and thus convert IMS (R/ms) to angular rotation in deg/ms to determine required spray time.

some aftermarket computers can let the user decide if they want to reference spray off of EOI or SOI. most tuners i ran into used EOI because the users started off with some sort of GM knowledge and were comfortable with EOI already. either way the job still gets done.

[anniversaryss]

Just noticed my cam card is based off .050. Dans is .006.
I can use the cam worksheet i have and get the .006 numbers.
From what i hear using the .006 numbers is better off. This would dramatically change the values i was originally saying i was gonna use.

How close to the Boundary can you get while setting EOIT before actually needing to move the boundary.

If i go by what Dan said to set EOIT about 10degrees before EVC then i would get a number around 6.45.

Is it also doable if i was to as cobalt recommended and use 6.3 but increase the boundary I could get the same EOIT number by manipulating it that way?

Obviously testing it is the best way, which I dont have access at the moment but i guess we can talk theoretically.

[anniversaryss]

Can you explain your lean tip in?

[cobaltssoverbooster]

if you need to run a normal that close to boundary then change the boundary and adjust the normal to get the same result.
so a boundary of 6.5 and a normal of 6.45 = 381.5
bump the boundary up to 7 and drop the normal down to 5.95 and you get the same result = 381.5

[anniversaryss]

if you need to run a normal that close to boundary then change the boundary and adjust the normal to get the same result.
so a boundary of 6.5 and a normal of 6.45 = 381.5
bump the boundary up to 7 and drop the normal down to 5.95 and you get the same result = 381.5

Thats exactly what I was asking . Thanks for the clarification.

Now can you explain makeup and when to adjust that?

[cobaltssoverbooster]

makeup is only an EOIT for the makeup extra pulse per cycle.
Definition:
Makeup pulses are extra pulses that can be injected to inject more fuel during an injection cycle rather than having to wait for the next cycle. There can be more than one makeup pulse but the makeup EOIT specifies the EOIT of the first makeup pulse.

With that being said, i have left these alone and had good results. If i wanted to see where it was of benefit i would try adjusting it to increase mid range torque. If this had no effect i would use an eddy brake to verify cell by cell gains in efficiency by moving the makeup limit around.

[anniversaryss]

Thanks guys this thread has been super helpful. Believe it or not i have had this subject explained to me a few times already but I could never catch on till now. They were very smart guys and I guess I wasn't catching on to their terminologies.

Anyways my other interest is PPV
They said if your injectors are big enough and you can supply the amount of fuel necessary to get the injector timing close to peak piston velocity.

Any input on this subject?

[cobaltssoverbooster]

Not from me sorry. Never targeted ppv

[FC3S Murray]

I have a 228R cam, 114 lsa, zero advance. The EOIT calculator states that my NEW normal for EVC is 5.67 and IVO is 5.29. TRUE normal is 6.17 for both (since IVO amd EVC at 356)

Tried 6.17, 5.87, 5.67 EOIT today and did some datalogs. Results were surprising.

The 6.17 seemed to have the best low end response and made the car seem to accelerate quicker on light throttle. I ended up turning LTFT on and running in closed loop while cruising since my OL tune was already lean because of cold air temperature.

Here are the results of a 4 mile cruise (same route everytime. Took about 30 mins to do all EOIT tests).
Also should note these LTFTs are all 2k rpm and below.

EOIT of 5.55 had 3.0 to 1.5 LTFTs
-----> 5.67 had 0.7 to 1.5 LTFTs
-----> 5.87 had -0.5 to 0 LTFTs
-----> 6.17 had -0.9 to -0.2 LTFTs

now it was 45 degree F air temp today so obviously my tune that was dialed in at 70 F is running a little lean today but interestingly enough the 6.17 seems best (idles worse though) however I cant see how that can be given my 228R cam has ZERO overlap and the EVC and IVO happen simultaneously.

Any ideas or thoughts?

I may try 5.29 and see what that does

[FC3S Murray]

I input an EOIT of 5.29 tonight (calculator NEW NORMAL for IVO) and that was the #! Exhaust smell gone and idle up to 1800 rpm was richer on the wide band.

I uploaded my OL SD tune and dialed in the VE. Once that was finished I pasted that VE map into my normal OL SD/MAF tune. It drives very nice at low rpm.

Nothing crazy dramatic but the little surging I did have at 1500 rpm is gone and throttle response is very crisp.

Very happy I came across this thread. Nothing like refining an already dialed in tune even more.

Thanks all who contributed!

[anniversaryss]

On this subject anyone ever had issues with delaying injection timing to much causing fouling issues?20191022_001440.jpg

[FC3S Murray]

I will keep this thread posted on that matter. I usually pull my plugs after hard WOT tuning and every 300 miles city driving.