LT4 Cam position Desired Angle 2017 vs 2019

[TriPinTaZ]

Any know why Z06 vs ZL1 tunes have different desired intake cam angles?


top 2017 ZO6
2017z06.PNG

bottom 2019 Zl1
2019zl1.PNG

[orange ss]

power output control? vehicle dynamic delta?

[IARLLC]

Yeah, that Z06 looks to be limiting cylinder pressure at lower RPM for some reason.

[TriPinTaZ]

That is actually increasing cylinder pressure. The lower the number the less degrees of cam retard. The point is, it seems like the OEM tunes for ZL1s vs Z06's are different in regards to desired cam angles at WOT.

[orange ss]

maybe trans related? ZL1 auto?

[IARLLC]

That is actually increasing cylinder pressure. The lower the number the less degrees of cam retard. The point is, it seems like the OEM tunes for ZL1s vs Z06's are different in regards to desired cam angles at WOT.

Yep. No doubt they are different.

I agree that the lower number/less cam retard. The way I have always understood it, advancing the cam at low RPM will get you more cylinder fill/pressure...and the opposite, retarding the cam at low RPM will lose you some low RPM cylinder fill/pressure...or retard it even further and get the EGR affect. The Z06 has 6-7 degrees of cam retard from off-idle up to 3600 RPM. That is why I wrote that the Z06 looks to be limiting cylinder pressure at low RPM. You are saying that retarding the cam at low RPM increases cylinder pressure?

[TriPinTaZ]

maybe trans related? ZL1 auto?

Both manuals

Yep. No doubt they are different.

I agree that the lower number/less cam retard. The way I have always understood it, advancing the cam at low RPM will get you more cylinder fill/pressure...and the opposite, retarding the cam at low RPM will lose you some low RPM cylinder fill/pressure...or retard it even further and get the EGR affect. The Z06 has 6-7 degrees of cam retard from off-idle up to 3600 RPM. That is why I wrote that the Z06 looks to be limiting cylinder pressure at low RPM. You are saying that retarding the cam at low RPM increases cylinder pressure?

No I am not, I'm talking about the area before peak torque and into peak torqueat WOT where the Z06 advances the cam more than the ZL1 meaning the Z06 is bleeding off less cylinder pressure compared the to ZL1. I wondered if anyone knew why the tunes were different in this area if the engines are the same. The Camaro does have a different exhaust manifold and intake. Maybe they needed to reduce cylinder pressures?

[HeavyChevy305]

Both manuals




No I am not, I'm talking about the area before peak torque and into peak torqueat WOT where the Z06 advances the cam more than the ZL1 meaning the Z06 is bleeding off less cylinder pressure compared the to ZL1. I wondered if anyone knew why the tunes were different in this area if the engines are the same. The Camaro does have a different exhaust manifold and intake. Maybe they needed to reduce cylinder pressures?

That's the only thing I can think of as well. Maybe the Camaros build more boost because of the added restriction.

[IARLLC]

Both manuals




No I am not, I'm talking about the area before peak torque and into peak torqueat WOT where the Z06 advances the cam more than the ZL1 meaning the Z06 is bleeding off less cylinder pressure compared the to ZL1. I wondered if anyone knew why the tunes were different in this area if the engines are the same. The Camaro does have a different exhaust manifold and intake. Maybe they needed to reduce cylinder pressures?

I see what you are talking about now. I was looking at the way the Z06 retards several more degrees than the ZL1 right off idle.

As far as the massive dip after that...Yeah, I'd have to agree it is probably related to the exhaust restriction. Those ZL1 manifolds don't flow nearly as well as the Z06s.

[JaegerWrenching]

I see what you are talking about now. I was looking at the way the Z06 retards several more degrees than the ZL1 right off idle.

As far as the massive dip after that...Yeah, I'd have to agree it is probably related to the exhaust restriction. Those ZL1 manifolds don't flow nearly as well as the Z06s.

It could also be the heavier weight of the zl1 making more load sooner at the same cam timing. This also wouldn't be real apparent on a dyno as loading them both the same amount would yield the same result on the same engine.