Last edited by Wnts2Go10O; 01-10-2011 at 10:29 PM.
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.
James Short - [email protected]
Located in Central Kentucky
ShorTuning
2020 Camaro 2SS | BTR 230 | GPI CNC Heads | MSD Intake | Rotofab | 2" LT's | Flex Fuel | 638rwhp / 540rwtq
2002 Camaro | LSX 427 | CID LS7's | Twin GT5088's | Haltech Nexus R5 | RPM TH400
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.
Sulski Performance Tuning
2000 WS6 M6 - LS6 (long block, refreshed top end), 10.8:1 CR, 90 mm ported FAST, Exo-Skel, 227/232 cam, QTP HVMC, EWP, GMMG, 9" w/4.11s
2018 Sierra SLT 5.3L A8 - Airaid intake tube, GM Borla catback, L86 Intake/Ported TB
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.
James Short - [email protected]
Located in Central Kentucky
ShorTuning
2020 Camaro 2SS | BTR 230 | GPI CNC Heads | MSD Intake | Rotofab | 2" LT's | Flex Fuel | 638rwhp / 540rwtq
2002 Camaro | LSX 427 | CID LS7's | Twin GT5088's | Haltech Nexus R5 | RPM TH400
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.
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
-Scott -
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.
Sulski Performance Tuning
2000 WS6 M6 - LS6 (long block, refreshed top end), 10.8:1 CR, 90 mm ported FAST, Exo-Skel, 227/232 cam, QTP HVMC, EWP, GMMG, 9" w/4.11s
2018 Sierra SLT 5.3L A8 - Airaid intake tube, GM Borla catback, L86 Intake/Ported TB
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.
James Short - [email protected]
Located in Central Kentucky
ShorTuning
2020 Camaro 2SS | BTR 230 | GPI CNC Heads | MSD Intake | Rotofab | 2" LT's | Flex Fuel | 638rwhp / 540rwtq
2002 Camaro | LSX 427 | CID LS7's | Twin GT5088's | Haltech Nexus R5 | RPM TH400
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.
James Short - [email protected]
Located in Central Kentucky
ShorTuning
2020 Camaro 2SS | BTR 230 | GPI CNC Heads | MSD Intake | Rotofab | 2" LT's | Flex Fuel | 638rwhp / 540rwtq
2002 Camaro | LSX 427 | CID LS7's | Twin GT5088's | Haltech Nexus R5 | RPM TH400
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
Last edited by Wnts2Go10O; 01-11-2011 at 07:08 PM.
I'm I the only one who's head is numb? lol