Injector Timing? Reference Periods? refereencing what?

[LSxpwrdZ]

I think everyone is WAY overlooking at this!

On the next few middle size to large size cam car's I tune I will make sure to punch in some numbers and target the EOIT on the .050" exhaust valve closing point and a few other points to see if I can get any good results with similar strategy's

[S2H]

the computer uses an 9 reference point timing system (0-8). each full point is 90* per blue cat's info. the "0" is why 9 divided by 10 is in the equation. the ls1 is based on one full cycle or 720*. if the ls1 reference was based on 360* it would be a 45* reference or half an engine cycle and would mean the equation would use 45 not 90. this is why i see the "-784" as a random number that doesnt have much to do with anything and is used only to figure out the reference point based solely on the cam.

example: with your cams True New EVC EOIT of 6.29, your injection ends by 566.1 degrees through the engines cycle.

again, this is basing it all on cats idea that the 0-8 reference table is 90* increments starting at 0 meaning 0* (the tables allow for 0.0 to 8 values).

the stock boundary is 585*
the stock EOIT is 499.5*

it does not and cannot go over 720*

actually its a 8 reference point.. 0.0~8.0
the boundary and normal are added together.. netting you more than 720*
wrapping back around in the circle putting your end of injection on a closed Intake valve

I dont know why or how he came up with the 784 value...

if you change it to 720 it nets EOIT at 364.5.. which is still at the back of the closed intake valve stock...which puts it also after the closed exhaust valve as well..


let me try some math with the value set at 720 instead...and lest see what happens?

[Wnts2Go10O]

actually its a 8 reference point.. 0.0~8.0
the boundary and normal are added together.. netting you more than 720*
wrapping back around in the circle putting your end of injection on a closed Intake valve

I dont know why or how he came up with the 784 value...

if you change it to 720 it nets EOIT at 364.5.. which is still at the back of the closed intake valve stock...which puts it also after the closed exhaust valve as well..


let me try some math with the value set at 720 instead...and lest see what happens?

0 is still a usable value in the tables.

0: 0*
1: 90*
2: 180*
3: 270*
4: 360*
5: 450*
6: 540*
7: 630*
8: 720*

9 values.
the question becomes, if the entire thing is a 360* reference why is each reference point 90*? for there to be 8 reference points on a 360* cycle, it would have to be 45* each. or (Boundary+Normal)(45)-392

[S2H]

0~1
1~2
2~3
3~4
4~5
5~6
6~7
7~8


8 chunks

[S2H]

and it only makes sens that it would be 8 chunks no matter what you set it at...
360 or 720
360 would be chunks of 45*
720 would be chunks of 90*

I would bet on 720 because its a four stroke motor based on 720 per firing sequence
and IPW/IDC is based off of 720* as well...

[Wnts2Go10O]

and it only makes sens that it would be 8 chunks no matter what you set it at...
360 or 720
360 would be chunks of 45*
720 would be chunks of 90*

I would bet on 720 because its a four stroke motor based on 720 per firing sequence
and IPW/IDC is based off of 720* as well...

why do the tables allow for values less than 1? the 0 has to be taken into account otherwise its another "randomized" number. the information supports it being reference points on every 90* of rotation with values ranging from a possible 0-8 in the tables. anything less than one in the tables would reference under 90* on a 0-720* cycle. take away the 0 and all you have is a 90-720* reference cycle.

the actual range is: 0.0-8.0. thats 9 points with 0 being the ffirst at 0 degrees. if it was 8, it would only be usable values of 1.0-8.0

[S2H]

thats why weve been asking questions. because if the normal is supposed to be 499.5 degrees AFTER the 585* boundary, you subtract 135 from the normal (how many degrees from 720 the boundary is) and get 364.5*

I'll have 2 possible chances to play with the EOIT values next week hopefully..weather permitting...
I'm planning on playing with it as well to see what happens and where it makes the best power.... hopefully I can make some sense of the data

[S2H]

why do the tables allow for values less than 1? the 0 has to be taken into account otherwise its another "randomized" number. the information supports it being reference points on every 90* of rotation with values ranging from a possible 0-8 in the tables. anything less than one in the tables would reference under 90* on a 0-720* cycle. take away the 0 and all you have is a 90-720* reference cycle

you are over thinking the "zero" thing
0 is still a #....
0=0
1=90
2=180
3=270
4=360
5=450
6=540
7=630
8=720

you can put 0 in the table....it just means adding nothing to the event

[S2H]

why do the tables allow for values less than 1? the 0 has to be taken into account otherwise its another "randomized" number. the information supports it being reference points on every 90* of rotation with values ranging from a possible 0-8 in the tables. anything less than one in the tables would reference under 90* on a 0-720* cycle. take away the 0 and all you have is a 90-720* reference cycle.

the actual range is: 0.0-8.0. thats 9 points with 0 being the ffirst at 0 degrees. if it was 8, it would only be usable values of 1.0-8.0

and I dont even know wtf we are arguing about..
I think we are both saying the same thing..LOL

[Wnts2Go10O]

I think everyone is WAY overlooking at this!

i dont doubt it, theres just things that seem too random so we're trying to fill the gaps.

a 6.5 boundary point that can be mimicked with a seemingly infinite amount of combinations is way too random if the rest is so well thought out.

the 0.0 to 8.0 usable reference points fit really well into a 0-720* engine cycle with 0 equaling 0 and 8 equaling 720, it makes sense. it also makes sense to do the calculations based specifically on the camshaft specifications that doesnt spit out numbers on teh 720* cycle. you can easily take that number and get the overall end of injection with Normal or Makeup*90

[Wnts2Go10O]

and I dont even know wtf we are arguing about..
I think we are both saying the same thing..LOL

lol i think about how it all adds together. you did edit and post while i was typing

[Wnts2Go10O]

you can put 0 in the table....it just means adding nothing to the event

thats the catch. theoretically, you can have values of .1 and such which is under that 90* reference. thats why the zero means more in the case of calculating everything.

[S2H]

theres no x to the n'th power going on.. so zero is a rational number(even though zero is not a number in science..LOL)

so zero doesnt matter... in add and subtract world zero is ok... and we are in add and subtract simple math world

[Wnts2Go10O]

theres no x to the n'th power going on.. so zero is a rational number(even though zero is not a number in science..LOL)

so zero doesnt matter... in add and subtract world zero is ok... and we are in add and subtract simple math world

i agree with you about zero not mattering most times. if usable values were 1.0-8.0 this conversation wouldnt happen but because of the usable values under 1 (0 to .9) it has to be factored into it all and is how i arrived at the .1 equals 9*. thats it. simple math as you put it

[S2H]

Nevermind... the math just hit me...

Looking at the data Bluecat has in the other post....
he did an actual bench test to see when stuff fired and how long the injector was open... his test showed EOIT to be the 300.5 for stock and it followed when he changed the overall values as well....
its just the math it took to back calculate...
I'm pulling down my 720 EOIT reference sheets...
-784 is correct

I have no idea of why GM used that for math.. nor do I care.... but it does line up

[S2H]

Here is what I believe to be correct based on Data from Bluecat's test bench and some simple math


now all we need to do is get to testing to see if we can actually find a relationship between our cam and best power/torque at various rpm's

[Wnts2Go10O]

thinking in periods representing 45* instead of 90*
comes out a little odd to me...
boundary of 6.5 = 292.5*
normal of 5.55 = 249.75*
add together and you get total = 542.25
Which puts EOIT at 2.25* after BDC intake stroke....
stock cam closes at 573* @0.050
so it still fits technically...
and me having a cam that closes at 591*
I set my EOIT normal to 6.29 based on -784 bluecat value...
put me at 575.55* for EOIT...
still makes sense..sort of... but goes against the firing on the back of the closed intake valve phenomenon

but from what I see in Blucat data in his spreadsheet...he set it to 8 with no ill effects

it was a sim. while i think and know sims are awesome tools, a running engine will fill in the gaps and show us more specific things.

it could very well be that we are simply using many legitimate ways to get to the same end

[Wnts2Go10O]

Here is what I believe to be correct based on Data from Bluecat's test bench and some simple math


now all we need to do is get to testing to see if we can actually find a relationship between our cam and best power/torque at various rpm's

if Googles results are anything to go on... well... itll be interesting..

I have a 6.0 L92
@ .006 274 280 .610 .613
@ .050 int 5- btdc 49 abdc
exh 52 bbdc 2- atdc

I have right at 18% added to my makeup and normal tables for a even gain of 28.6 +or-.5 ftlbs from 1000rpm to 3400rpm.

[S2H]

if Googles results are anything to go on... well... itll be interesting..

based on original formula
as a guess.. puts him around normal or 6.55ish = 390*ish EOIT
which would be 30*ish after his exhaust valve closes roughly

based on 720/90* concept...
it puts him around 450ish, which is just shy of his Highest lift point.

based on 720/45* concept its around 590 ish which would basically be his intake closing point
to me this makes no sense because engine dynamics basically say that air should be pushing stuff back out the intake port at that point...piston is on its way back up already...not like huge amounts.. but its no longer going to have velocity helping it out to suck fuel in

[WS6FirebirdTA00]

Quote from Chris on LS7 injection tables.

Boundary is the latest point in time that fuel can make it into the cylinder for the current injection period. It is measured in degrees AFTER TDC compression. It is also the earliest the injector can fire again after the completion of the last injection event. ie. the boundary defines the start/end of a complete injection cycle.

Normal End of Injection Target (EOIT) is the angle before the boundary (in degrees) that the normal pulse (the main pulse) should finish. The hardware calulates the start of injection time from the EOIT and the desired PW.

Makeup End of Injection Target (EOIT) is the angle before the boundary (in degrees) that the first makeup pulse should finish. 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.

The makeup PW minimum is a minimum PW for the makeup pulses, they cannot be shorter than this (if they are they don't happen).

So you have the boundary that defines the injection cycle, a normal EOIT that specifies the EOIT for the main pulse, and finally a makeup EOIT that specifies the EIOT for any makeup pulses that might be needed if a fuel increase is commanded during an injection cycle but after the main pulse has occurred.

Hope that helps.

Chris...