Engine Pressure Ration or MAP

When tuning a turbo engine would it be better to use Engine Pressure Ratio or Manifold Absolute Pressure for the load axis in the Fuel and Ignition tables? I have always used MAP for my load axis. Any advice would be greatly appreciated.

Tom

Hello engine pressure ratio is used in jet engines i have never heard of it before in aftermarket tuning software I always use map mgp or tps for tuning depending on the application

Regards Ross

Hi Ross,

Thank you very much for the information. I was taking a class on advanced turbo concepts and the instructor referenced using engine pressure ratio as the load axis. It didn't sit with me so I figured I would get a second opinion on that information before even thinking about using it. You have confirmed my initial thought. Thank you again.

Best,

Tom

Is this also known as Intake MAP / Exhaust MAP? I've seen turbo charged engines that run at altitude tuned that way. MoTeC hundred series allowed that as a load axis.

David,

That is exactly what it is. Standard MAP setup at the TB and a metal tube plumbed into the exhaust before the turbo and bring that into a MAP sensor mounted away from the heat. This will allow you to see the Pressure Gradient. Is that a valid way of tuning a turbo engine vs standard MAP and IAT at the TB?

I would say yes. The engine I knew was tuned by ShaneT, and ripped the clutch out making 1200+ HP at Bonneville.