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

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Originally Posted by anniversaryss

Sorry dont want to seem so naive.
So your saying as JakeFusion said changing the values at temp your meaning just the 5.55 values which is anything over 154 degrees?

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So I believe what he means is to calculate the percent of change and then multiply it by the whole table. For example:

My new normal value is 6.41
So I take 6.41 / 5.55 = 1.154 (That's a 15.4% increase across the entire table)

So the new values become:

Attachment 85846

However he made reference that at lower temperature values that the air is more dense and those the change doesn't have to be as drastic, so I am assuming you could actually multiply by the percent you get above for temp ranges of 154*F and up, and maybe by 8% for the lower boundaries.

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Originally Posted by Danspeed1

So I believe what he means is to calculate the percent of change and then multiply it by the whole table. For example:

My new normal value is 6.41
So I take 6.41 / 5.55 = 1.154 (That's a 15.4% increase across the entire table)

So the new values become:

Attachment 85846

However he made reference that at lower temperature values that the air is more dense and those the change doesn't have to be as drastic, so I am assuming you could actually multiply by the percent you get above for temp ranges of 154*F and up, and maybe by 8% for the lower boundaries.

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Ah I get it. If he can chime in and confirm and I'll go from there.
I get the idea and I get graphing it but again I'm somewhat confused like the OP bc most the stuff I have is gen IV and it slightly different.
It's also easier for me to have it presented right on front of me so I'm not guessing that what I am doing is correct.

Also your using the true normal number not the new normal?
When you test this can you confirm that there is a change in wideband readings . Being 19? overlap my readings are obviously not 100% accurate and it should richen the mixture up due to better fuel burn and less exiting the exhaust.

I'm going to make this change next week. I will absolutely post results. What I am expecting to see based on the information is my fuel trims to move negative (VE to richen) at which point I will remap the VE and get my trims back to where they were.

I was referencing 85k5jake. I would apply my desired normal changes at full temp and verify the performance. Then I would figure that percent increase and apply it to the other colder temperatures.

The other Jake came in after my and confused my reference to which Jake.

Well, I couldn't wait so I broke out my laptop and cord and made all the changes today. I definitely was on the right track with this. I can confirm this is something that ABSOLUTELY needs to be adjusted if you are running a bigger cam. I don't necessarily see a reason to go crazy trying 2 degrees at a time. I doubt on a non DI motor this is really going to equate to any real additional power, even less so on an older style BBC or SBC, however it did resolve a few of my key drivability issues.

Here are the very noticeable improvements
1. The car is un catted but the eye burning richness moved to a light scent of fuel
2. The idle quality improved immediately. I have been chasing an aggressive idle with Overspeed/Underspeed and Integral Controls and it was meh... Now its nice and crisp
3. My VE was pretty close to start even with the erratic idle, but upon making the change my LTFTs moved from between 1-2% to 0.X in most areas of the table
4. Throttle feels crisper
5. My tip in issue seems to have improved, but I think I need more time in the drivers seat before I can confirm this for sure.

Overall I am pretty happy with the change. I am going to makes sure my VE table is 100% perfect and dial in my MAF and I think the results are going to be pretty stellar.

Attachment 85849

https://www.youtube.com/watch?v=hNiE0FmEjtQ

Enjoy the chop...

You will have to lean out the VE map... on all the cars I've done I end up in the high 20s low 30s in the idle regions when EOIT is adjusted correctly. And it's because you're spraying fuel more efficiently and need less overall.

So it looks like you went 8% on the lower regions and about 16%I'm the area of operating temps?


Also we are leaving out boundary and make up tables alone?

Glad you got it to a good starting point Danspeed1. That chevelle sound mean!!!

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Originally Posted by anniversaryss

So it looks like you went 8% on the lower regions and about 16%I'm the area of operating temps?


Also we are leaving out boundary and make up tables alone?

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Yes. Here's the carveout, the car was already at operating temperature when I made the change. However, if the car starts, runs, and warms up, even if it is a little rich only at warm up... I can live with it. Where we stand right now it is doing what I want it to do while at operating temp. I am not sure if there are any adjustments or improvements to be made to the makeup table however, cobaltssoverbooster recommended leaving the boundry set to stock unless the Normal table far exceeded it, that's why I left it like that.

So you see it idles great, and before you could see the exhaust, now it looks clean. Is there any other improvements? I don't know. I'm happy. Is it worth going further?

Ill continue making changes and playing around with it as long as there continues to be interest in the thread. I think this area of the tune is normally overlooked and the 25 pages in the other thread is a lot about theory and little about results. I am happy to keep learning if you guys keep posting.

Dan

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Originally Posted by 85K5Jake

Glad you got it to a good starting point Danspeed1. That chevelle sound mean!!!

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Thanks Jake, took hours to get the idle there but it sounds pretty close to what I was looking for. And it drives really nicely as well.

Removed from a different thread:

Injection Timing Boundary: Fuel injection delivery boundary as number of reference periods after TDC. (Stock value = 6.5)

Normal Injection Target vs. ECT: The end of injection target measured in reference periods after the injection boundary that the normal injection pulse should finish. (Stock values range from 2.55 at low ECT to 5.55 at high ECT) [EFI Live: This table will offset the actual opening of the injector referenced to the reference pulses and engine coolant temperature. {B3702}]

Makeup Injection Target vs. ECT: The end of injection target measured in reference periods after the injection boundary that the makeup injection pulse should finish. (Stock values all at 5.55) [EFI Live: This table modifies the timing of the additional pulses that maybe required after the {B3702} Injection Timing offset limits are reached. These values should not exceed those in {B3702} Injection Timing. {B3703}]

Dan, really happy to see that you got this beast running and working well. It sounds mean as hell! Your build thread was on ls1tech right, have a link again?

Anniversaryss I think you're good where you're at. From everything I've read and tried it seems that just before the EVC event is the best point. I've tried .00x changes to .0x changes with no gain that I could tell for performance or on my wideband for AFR. I think the valve events happen so fast that is hard to dial in completely with the ECM trying to stay at stoich and being in the general ballpark is good enough for a little crisper throttle and cleaner idle. I'm sure there is a way to be 100% dialed in, I just can't get there for now.

Alright i think things are clicking for me a little lol. I had to actually graph it out.
But anyways using the Gen3 EOIT calculator i got my Event as is
EVC 367
IVO 348
Overlap is 19
New normal 5.79
True 6.29
So I graphed these and used -784+((Boundary + Normal) *90) for EOIT

I guess my question is, we are trying to move the EOIT closer to the EVC so the SOIT will occur later so and we arent losing as much fuel out the exhuast?

Using Cobalts suggestion of 6.0 to 6.3
If i use 6.3 that would put my EOIT around the same time the EVC is happening.

I had a bunch of other stuff to write but my brain is so jumbled researching this idk if im gonna even make sense at all typing it.

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Originally Posted by anniversaryss

I guess my question is, we are trying to move the EOIT closer to the EVC so the SOIT will occur later so and we arent losing as much fuel out the exhuast?

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Yes in an LSx based platform the factory cam timing doesn't allow for much if any valve overlap. So the factory uses retarted injector timing so the fuel sprays before the intake valve opens. The evaporation of the fuel from the valve serves two purposes. First it cools the valve, but more importantly the fuel evaporates from the head of the valve and when it opens the incoming charge is a better mix and leads to better efficiency. On a cam with overlap, particularly long overlap that theory goes out the window. The incoming charge escaping from the open exhaust valve is more detrimental than the benefits of evaporating the fuel mix. 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 of my originally carbureted big block, its really a moot point because I'm lucky air and fuel even makes its way into the combustion chamber. The engine isn't anywhere near as efficient as the new stuff, and the idea of puddling fuel is less important than just making sure the fuel doesn't go out the exhaust valve. I hope this explains it a little better.

What I took away from this thread more than anything (this is something that never seems to be posted) is that in most cases, if you have a cam with large over lap and the symptoms I mentioned in my first post, in theory you could guess your way to a close enough value to improve the condition. By INCREASING the NORMAL values by 5% at a time, you should be able to find improvements along the way. Or you could use one of the calculators that were posted and have a good place to start from. Likewise I would assume decreasing the values would move the needle in the opposite direction.

if the normal exceeds the boundary value then the system will default to the boundary value because that is the defined spray window size.
play with boundary and normal values in the calculators to see the relationship.

nice chevelle, it sounds great. glad to help find a decent starting spot.

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 .[/QUOTE]
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

Quote:

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Originally Posted by cobaltssoverbooster

if the normal exceeds the boundary value then the system will default to the boundary value because that is the defined spray window size.
play with boundary and normal values in the calculators to see the relationship.

nice chevelle, it sounds great. glad to help find a decent starting spot.

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YES! Thank you for the help. I am putting all this information to good use!

I think I am going to try matching my Normal Values to my Makup Values and see what happens next.