Injector Timing? Reference Periods? refereencing what?

[S2H]

Yeah, the longer it sits the more it can evaporate I am sure. Problem is the stock cam really has no overlap.

Anyone else look at the LS7 stuff? There is quite a bit of difference there.

thats exactly why they did it where they did it...
they can get exactly the amount of evaporation time they want without having to worry about valve overlap sucking out the fuel.

[Wnts2Go10O]

Yeah, the longer it sits the more it can evaporate I am sure. Problem is the stock cam really has no overlap.

Anyone else look at the LS7 stuff? There is quite a bit of difference there.

if they have a drastically different boundary, theres something to it. the stock LS7 tune says the boundary is 520* or 5.78 for us lowly ls1 people.

the normal is 110* after boundary for a warm engine or 1.22 to us

EVC is 362 for the LS7 cam and IVO is 378

[LSxpwrdZ]

It's really hard to compare the newer PCM's end of injection pulse data to the GenIII. For one going by the description's for the parameters on a 07 Z06 file that I have the normal injection angle isn't added to the boundary. If I understand it right the boundary is what it's name is... the max bounds for that cycle of injection. It is also very unclear on the newer PCM's what the angle is in reference to. Is it cam degrees, crank degrees and in reference to TDC compression stroke or exhaust stroke?

So with that said until we can clarify exactly what the number mean in the newer PCM's it's hard to compare.

My only question is where does the -784 come from and why is it the GenIII PCM is setup to add the Normal to the Boundary? I would think the Boundary is the latest crank angle the injector could fire for that particular cycle and that the normal table is there for a normal pulse and the makeup is there for a multiple fire or makeup but the boundary should still be the limit. I really wish an engineer of the OS would elaborate on exactly what and why for the entire EOIT parameters.

[Wnts2Go10O]

It's really hard to compare the newer PCM's end of injection pulse data to the GenIII. For one going by the description's for the parameters on a 07 Z06 file that I have the normal injection angle isn't added to the boundary. If I understand it right the boundary is what it's name is... the max bounds for that cycle of injection. It is also very unclear on the newer PCM's what the angle is in reference to. Is it cam degrees, crank degrees and in reference to TDC compression stroke or exhaust stroke?

<snip>.

easy, crank. theres only 360* of rotation during one cycle of the engine for the camshaft. one can safely assume its in reference to TDC as well.

[WS6FirebirdTA00]

I think the LS1 stuff just was not as good, looks to me like the LS7 files all use subtraction from the boundary.

What are the LS7 intake valve events? If you add the values in the tables, it means ~350* injection angle at idle and around 370* just off idle. Gets earlier as RPM increases, to around 300* near 5000 RPM. Of course that is based off the assumption of other tables and degrees are additive and uses the start point of 0* and not a weird number.

We probably need to get Chris to give us a detailed explanation of the LS7 tables and what they are doing.

I just wonder if the motor benefits from that second shot in the cylinder right before the intake valve closes.

[LSxpwrdZ]

easy, crank. theres only 360* of rotation during one cycle of the engine for the camshaft. one can safely assume its in reference to TDC as well.

I understand that much of it... My point was the boundary and normal aren't added together and subtracted by 784 like ours is. It makes more sense that the normal table is subtracted from the boundary. Either way it'd be nice for chris or a GM engineer to elaborate on the subject.

[99 Camaro SS]

Been reading this Thread since it was started. I have learned a ton from it.

I finally made some changes using the spreedsheet that was attached.

Before the car had extremely strong gas odor during start up and idle. Added .72 accross the board. Now I have little gas smeel at startup (warmup) and virtually no smell once its warm.

Thanks guys.

[SargeZ06]

Been reading this Thread since it was started. I have learned a ton from it.

I finally made some changes using the spreedsheet that was attached.

Before the car had extremely strong gas odor during start up and idle. Added .72 accross the board. Now I have little gas smeel at startup (warmup) and virtually no smell once its warm.

Thanks guys.

What are your CAM specs and what engine are you running?

[99 Camaro SS]

What are your CAM specs and what engine are you running?

Its in a 408 with a EPP blower CAM 232, 240, 115, 0 advance

[SargeZ06]

Its in a 408 with a EPP blower CAM 232, 240, 115, 0 advance

Did you use the "new normal" or the "true normal" values from the spreadsheet?

[99 Camaro SS]

Did you use the "new normal" or the "true normal" values from the spreadsheet?

I used the True Normal values.

Was that the right option?

Regards

[S2H]

I used the True Normal values.

Was that the right option?

Regards

unfortunately nobody knows what the exact right answer is yet...
I was going to test some things on the dyno, but the car I was going to test on had some mechanical issues to be resolved before we started doing pulls...
then I was supposed to try again monday, but we got hit with several inches of snow....so I got weather blocked....
hopefully when I get back in town next week I can test this stuff out on a car or two

[99 Camaro SS]

unfortunately nobody knows what the exact right answer is yet...
I was going to test some things on the dyno, but the car I was going to test on had some mechanical issues to be resolved before we started doing pulls...
then I was supposed to try again monday, but we got hit with several inches of snow....so I got weather blocked....
hopefully when I get back in town next week I can test this stuff out on a car or two

All i know that my buddy is happy with the reduction of gas smell.

I look forward in reading further research. I will post any changes that i see on this end.

[WS6FirebirdTA00]

Cold start response today for me was OK, but got really good after 32C when my table went up to ~5.9. Might try that cold and see how it does.

[Wnts2Go10O]

I understand that much of it... My point was the boundary and normal aren't added together and subtracted by 784 like ours is. It makes more sense that the normal table is subtracted from the boundary. Either way it'd be nice for chris or a GM engineer to elaborate on the subject.

i think 784 was nothing but a way to get the correct numbers as it relates to cam specifications.

[LSxpwrdZ]

I've not looked at the spreadsheet yet but will when I get off work. On the boundary and normal it doesn't matter what you put in each field to get the final number. Example: 6.5 boundary; 6.0 normal = 12.5 total. A 5.0 boundary; 7.5 normal also = 12.5 total. So the sum of the boundary and normal table will determine the EOIT.

Now I'm sure his spreadsheet is talking about changing the desired number based on the camshaft events so I'll take a gander at it when I can.

[Wnts2Go10O]

I've not looked at the spreadsheet yet but will when I get off work. On the boundary and normal it doesn't matter what you put in each field to get the final number. Example: 6.5 boundary; 6.0 normal = 12.5 total. A 5.0 boundary; 7.5 normal also = 12.5 total. So the sum of the boundary and normal table will determine the EOIT.

thats why im confused about it. if it really doesnt matter, why specify the point from which the normal is to be? or even have it as a value at all?


Now I'm sure his spreadsheet is talking about changing the desired number based on the camshaft events so I'll take a gander at it when I can.

its well put together. would be nice to have the back calculated starting point in there too though. (for us lazy ones)

[LSxpwrdZ]

Well all it takes is a little math to calculate the starting point however your starting point is going to vary greatly with different airflow, RPM, and injector sizes. So a defineate starting point doesn't really matter because it's alway's changing.

If you look at the data that Bluecat did in his post you will see he has a couple difference scenario's that equate to the same EOIT but different values adding up to the same sum on Boundary and the Normal table.

[Wnts2Go10O]

Well all it takes is a little math to calculate the starting point however your starting point is going to vary greatly with different airflow, RPM, and injector sizes. So a defineate starting point doesn't really matter because it's alway's changing.

If you look at the data that Bluecat did in his post you will see he has a couple difference scenario's that equate to the same EOIT but different values adding up to the same sum on Boundary and the Normal table.

yes i know, i posted the question of "if you can get the same values a x boundary with y normal, why is the boundary x?" gm didnt really do seemingly random things when it comes to these ecm's.


i also realize the starting point changes and as greg said, at higher rpm, its more a matter of when ISNT the injector firing? at idle however, you can calculate the starting point reliably and fairly easily, i was just wanting to be spoiled by a worksheet where i dont actually have to do that math. if i knew xls stuff, id do it myself

[SargeZ06]

I'm I the only one who's head is numb? lol