[random84]

I copied this from my post on HPTuners:

2013 CTSV - the original cam was a 198/216 .480 / .480 122.5LSA. Since I don't have 0.006" values for either the stock or current cam, I was thinking about using the relative delta change in valve events (similar to what Higgs Boson has suggested in a few of the bigger threads on this). Although I've been reading quite a bit, my ECM values don't seem to match very well with the spreadsheet(s) that have been so graciously shared here on the forum.

2013 OEM cam events estimated at:
EVO - 44* BBDC
EVC - 8* BTDC

IVO - 9* ATDC
IVC - 27* ABDC

-17* overlap

Now for the highly modified 2013 with a 400" motor (3.75 stroke, 4.130 bore, 6.25" rods) and a 2650 blower. Cam specs are 234.3 / 252.4, .640 / .648 119LSA

Aftermarket cam events estimated at:
EVO - 69* BBDC
EVC - 3* ATDC

IVO - 2* BTDC
IVC - 52* ABDC

+5* overlap.

So that means my exhaust valve closes ~15* later than the OEM cam, give or take. And my intake vale opens ~13* earlier

I am also running ID1300v2 injectors to account for E85, so my injector PW on 93 pump is relatively short, 0.8 ms at idle. Even at 7k RPM, my IDJ is 50%, so the injector PW duration is around 11ms at 18psi.

-----------------------------------------------------------------------------

Based on my reading, for low RPM / idle ranges, I could simply change the Injection timing boundary layer by increasing it 20*, to delay EOIT (and thus SOIT) by that amount for a cleaner idle.

My confusion stems from the "Normal EOI Target Adder vs ECT" tables not being constant, of course for cold start - the fuel will presumably take longer to get to a cold cylinder and thus we shorten the EOIT significantly, so the fuel is injected earlier in the cycle?

Current boundary is 520* across the board, but the Normal ECT table ranges from 240* cold to 105* hot, and a 12* Normal RPM adjustment put in there by the previous tuner.

That means, at idle, 520-105-12 = 403* idle SOI at operating temps. That seems right on for a boosted motor?

Cold starts (my biggest issue), is 520 - 240 - 12 = 268* idle SOI on cold start. Does this pass the "sniff test" for you guys or is it really advanced?

I am just thinking that with the larger injectors, since I primarily run 93 pump, I should advance the EOIT target for cold starts, say closer to 370*, ergo I should reduce the Normal EOIT adder vs ECT in the colder temps significantly?

 

[random84]

Okay, thanks for nothing you Cunts.


End of injection target (EOIT) adjustments worked.

I cleared up the gas smell at idle on cold starts. Because there was less blow by of gas, it richnened up like 15%.

I then reduced the MAF sensor calibration a bit and retuned VVE in idle ranges while hot.

Then I kept adding in idle airflow vs ECT adjustments to remove some airflow dip when touching the pedal but not moving (ie getting out of idle adaptives).

I will play with it further, potentially adjusting fuel delivery at idle for peak torque (not sure how to determine that beyond trial and error), but the real question is: when do I want to start injecting fuel at higher RPMs?

Based on my injector PWidth measurements, fuel delivery should take approximately 150 degrees of crank rotation near 7k RPM (ie 12-13ms)?

Do I want to split that duration over peak piston velocity or slightly advanced, taking in to account the airflow through the runners?

@Rubber Duck

Sent from my SM-G991U1 using Tapatalk

 

[Jim]

Glad we could help! 😁

 

[nsaness]

Sometimes it is better for me to look stupid; than to open my mouth and prove it.

 

[SofaKingSlow]

Random,
You remind me of an uncle of mine. He's the kind of guy who would throw me in the deep end of the pool and be shocked that I nearly drowned. He's also the kind of guy who would accidentally let it slip where in the garage his Playboys were stashed. Love that guy...

 

[theheder]

Okay, thanks for nothing you Cunts.


End of injection target (EOIT) adjustments worked.

I cleared up the gas smell at idle on cold starts. Because there was less blow by of gas, it richnened up like 15%.

I then reduced the MAF sensor calibration a bit and retuned VVE in idle ranges while hot.

Then I kept adding in idle airflow vs ECT adjustments to remove some airflow dip when touching the pedal but not moving (ie getting out of idle adaptives).

I will play with it further, potentially adjusting fuel delivery at idle for peak torque (not sure how to determine that beyond trial and error), but the real question is: when do I want to start injecting fuel at higher RPMs?

Based on my injector PWidth measurements, fuel delivery should take approximately 150 degrees of crank rotation near 7k RPM (ie 12-13ms)?

Do I want to split that duration over peak piston velocity or slightly advanced, taking in to account the airflow through the runners?

@Rubber Duck

Sent from my SM-G991U1 using Tapatalk

Yeah....my slide rule and abacus agree..... What he said


BTW - I am often referred to as the crazy uncle David

 

[random84]

Random,
You remind me of an uncle of mine. He's the kind of guy who would throw me in the deep end of the pool and be shocked that I nearly drowned. He's also the kind of guy who would accidentally let it slip where in the garage his Playboys were stashed. Love that guy...

Hey - I don't fuck around with pools or lakes. Saw a few too many "almosts" to take chances there!

But the playboys are definitely not in the big craftsman in the back, behind the box of used motor oil.

Sent from my SM-G991U1 using Tapatalk

 

[Rubber Duck]

Okay, thanks for nothing you Cunts.


End of injection target (EOIT) adjustments worked.

I cleared up the gas smell at idle on cold starts. Because there was less blow by of gas, it richnened up like 15%.

I then reduced the MAF sensor calibration a bit and retuned VVE in idle ranges while hot.

Then I kept adding in idle airflow vs ECT adjustments to remove some airflow dip when touching the pedal but not moving (ie getting out of idle adaptives).

I will play with it further, potentially adjusting fuel delivery at idle for peak torque (not sure how to determine that beyond trial and error), but the real question is: when do I want to start injecting fuel at higher RPMs?

Based on my injector PWidth measurements, fuel delivery should take approximately 150 degrees of crank rotation near 7k RPM (ie 12-13ms)?

Do I want to split that duration over peak piston velocity or slightly advanced, taking in to account the airflow through the runners?

@Rubber Duck

Sent from my SM-G991U1 using Tapatalk

Sorry Jesse. All of my cars, which I raced, used Holley Carburetors.
But I think there are a few on this forum, who can help you with your questions. . .

Cheers

 

[Blown376]

I can honestly say I'm not that guy. 👍

 

[07GTS]

dont worry too much about where u start to inject at higher rpm u want to just not have it finish too late, usually boosted with say no later then 550-560 boundary, with ect 85 deg, so total EOIT is 475 deg so ur a little past BDC but not too far u want to have time for the fuel to get in and mix around, also not come back out the intake valve, try bout BDC total end to inject see what its like and go little further up to the 475 deg

 

[random84]

dont worry too much about where u start to inject at higher rpm u want to just not have it finish too late, usually boosted with say no later then 550-560 boundary, with ect 85 deg, so total EOIT is 475 deg so ur a little past BDC but not too far u want to have time for the fuel to get in and mix around, also not come back out the intake valve, try bout BDC total end to inject see what its like and go little further up to the 475 deg

Yep - my logging computer is finally starting to shit itself after 7 years, so I didn't get any pulls in today.

But just driving to work, the injector timing adjustments I made resulted in markedly improved driveability at low RPM and less fuel smell.

I'll have to graph out what I want at higher RPM (or really, just to make sure I'm not messing something up); but the OEM tactic seems to be encouraging some pooling of fuel on the closed intake valve to aid in mixture and reduce IV heat. I suspect with ethanol I'll want to be relatively more advanced to help further increase mixture time and reduce heat (ergo one of the comments on HPTuners).

I should have started with this 2 years ago - it would have saved me a LOT of frustration.

 

[PGA2B]

Yep - my logging computer is finally starting to shit itself after 7 years, so I didn't get any pulls in today.

Careful if you get a computer with Windows 11 you will need to upgrade to a MPVI2 or 2+ if you haven't already done so.

I just had to.

 

[random84]

Careful if you get a computer with Windows 11 you will need to upgrade to a MPVI2 or 2+ if you haven't already done so.

I just had to.

Fuck that noise. HPtuners is also removing options with emissions related functionality with the 2+, aren't they?

Sent from my SM-G991U1 using Tapatalk

 

[PGA2B]

You can still adjust DTC's.

 

[07GTS]

Yep - my logging computer is finally starting to shit itself after 7 years, so I didn't get any pulls in today.

But just driving to work, the injector timing adjustments I made resulted in markedly improved driveability at low RPM and less fuel smell.

I'll have to graph out what I want at higher RPM (or really, just to make sure I'm not messing something up); but the OEM tactic seems to be encouraging some pooling of fuel on the closed intake valve to aid in mixture and reduce IV heat. I suspect with ethanol I'll want to be relatively more advanced to help further increase mixture time and reduce heat (ergo one of the comments on HPTuners).

I should have started with this 2 years ago - it would have saved me a LOT of frustration.

yep factory is aiming at the closed intake valve to help start atomization and help emissions, that in turn as u add more overlap sends it straight out the exhaust, its amazing how much it helps with the low to mid response just getting fuel properly into the chamber, i save about the 13-15% at idle and it also helps in the hwy cruise as well

 

[Rubber Duck]

Fuck that noise.

Sent from my SM-G991U1 using Tapatalk

 

[Rubber Duck]

yep factory is aiming at the closed intake valve to help start atomization and help emissions, that in turn as u add more overlap sends it straight out the exhaust, its amazing how much it helps with the low to mid response just getting fuel properly into the chamber, i save about the 13-15% at idle and it also helps in the hwy cruise as well

Just a few other considerations:
Quality combustion chambers generate good turbulence, as well as proper squish velocity. Along with those important engine variables, you typically find the spark plug facing the exhaust valve, making it easier for the kernel to ignite.

A bit of overlap with these engines would be, I am sure, very desirable, as it could be used to not only vacate the cylinders when using gasoline as the fuel, but to also allow for a more ideal lobe placement, or LSA / LCA (not more than 117°). However, these engines are normally equipped with 'Too Small' of a TB. So this requires that the lobe center-lines (LSA/ LCA) be widened. In many cases, in my opinion, they are widened to far, and then the camshaft grinder stipulates that we must advance the cam too far, particularly when the engine is being run on gasoline (JMHO).

So here, as shown just below, we do not desire to waste fuel being
blown out of the exhaust side of the engine during the overlap period.

Overlap and and VE%:
Trapped Volumetric Efficiency % PerCent from 65% to 135% {Scroll Down}
Theoretical CFM @ 100 % Ve = CID * RPM * .000289352. . . or, divide by 3456

Trapped Ve% is the Measured CFM minus the Ring BlowBy CFM , minus the CFM
lost during the OverLap Period, then divided by the theoretical CFM

TrappedVe = ( MeasuredCFM - ( BlowbyCFM + OverLapCFM )) / TheoreticalCFM

 

[07GTS]

@random84 also your cranking spark at 14 deg, try something smaller like the same as in my file i sent u it should help too, too much advance cold with ethanol can be worse so closer to TDC allows for more compression which can help the ignition of ethanol when cold, i usually start of low and as the rpm increases ramp up to idle spark advance