Ordered a different cam

[L31MaxExpress]

Well the cam and lifters arrived on the 2nd to my mothers house 100 miles away. I sent them there to keep porch pirates from taking them here. Finally have my hands on them.

Spec sheet from Erson.

You must be registered for see images attach

 

[Pinger]

closes the intake valve later and opens the exhaust valve later than my current cam. Should help with the off-idle performance, cut the fuel consumption some from decreased overlap as well as bleed off some cylinder pressure to make the engine more timing friendly when it runs on pump gas.

Re the later closing inlet valve. Is that what will ''bleed of some cylinder pressure''? In the manner of Miller/Atkinson cycle late inlet closing?

 

[L31MaxExpress]

Re the later closing inlet valve. Is that what will ''bleed of some cylinder pressure''? In the manner of Miller/Atkinson cycle late inlet closing?

The intake valve close is sometime after bottom dead center with the piston already well on its travel to TDC. The earlier the valve closes the lower the piston on the upward travel and the more pressure it builds. Assuming the same intake centerline, the longer duration will have a later intake valve closing point.

You must be registered for see images attach

 

[Pinger]

The intake valve close is sometime after bottom dead center with the piston already well on its travel to TDC. The earlier the valve closes the lower the piston on the upward travel and the more pressure it builds. Assuming the same intake centerline, the longer duration will have a later intake valve closing point.

At low rpm the reversal of flow lowers the VE and eases ignition timing - your aim.
But, at the top end of the rev range the inertia of the fast moving incoming charge will resist the attempt of the piston to force it back out through the port and the engine will make good power.
Can you take a guess at the rpm of the transition? The rpm at which reverse flow ceases and ramming begins to dominate.