Boosting an LS1 - protecting spaghetti rods.

Hi all,

Researching tuning a stock bottom end LS1, I have heard people comment about reducing timing through the rev range around peak torque, or trying to make a certain peak power by increasing boost instead of timing (where not knock limited).

My question is: Providing there is no knock, why would reducing timing and increasing boost help against bending a rod if the engine were to produce the same torque? Or is the idea that, as revs increase, ignition timing advance can be increased just to make the peak power higher in the rev range without smashing things to bits?

For example, assume a peak of 800nm 400rwkw is the goal (give or take, exact same engine, turbo and cam spec), which would you be happier with giving back to a customer?

Car 1: 8* timing at peak torque, 15* towards 6500 rpm. ~12 psi boost throughout 3000-7000 rpm rev range.

Car 2: 12* timing at peak torque, 18* towards 6500 rpm. ~9 psi boost throughout 3000-7000 rpm rev range.

Assume we had a third car running a Procharger with the same goals and specs, boost would increase with revs, the timing curve would be flatter?

Haven't tuned either combination, yet. Looking for some experiences before I start my own as I think out loud.

Happy and expecting to bend something in the name of learning!

Thanks in advance.

Ben, did you end up finding any answers? I am also curious.

My guess, and it's only a guess, is that the theory is that it reduces the peak cylinder pressure but continues the burn later.

That way the average cylinder pressure may be higher and/or the crank angle more advantageous.

If either of you have hard data, please feel free to update on this - or anyone else, for that matter.