Finally got time to put my turbo in - spoolup is maybe a hair slower than stock but no biggie, SOP power meter tells me I gained hp & torque. Biggest difference in driveability is higher rpm pulling power, have 3kgsk and it would pull to 3k, but not like it does now! I checked drive pressure before/after and boost at 60 mph on flat ground. Boost @60mph was 7psi, now 0/below 4psi where gauge starts, drive pressure with stock turbo was 1-2 psi higher than boost up to about 36psi, above that or above about 2200 rpm the drive pressure would keep going up to a max of 60 psi, with max boost about 40-42 psi, and egts up to 1400 degrees With new turbo, max drive pressure is 44psi, with boost max 44-45psi and max egt 1200 degrees. Overall, I'm very happy with this turbo for my truck, for power, driveability, and egt control.

 

Dumb question here but what do you mean by Drive pressure?

 

The drive pressure (not driveline pressure) is the pressure between the exhaust manifold outlet and the inlet of the turbo---kind of right where the pyro would/should be. As I understand it, the ratio between intake manifold boost and exhaust manifold boost (the pressure measured between the manifold and turbo) is a good indicator of turbo efficiancy--ie, 60 psi at the exhaust (turbine drive pressure) and only 40 psi at the intake would be, I believe, a grossly inefficient turbo setup. Kind of like wee-ing into the wind If I'm confused on the whole thing, though, someone step in and slap me around a bit, please
greg

 

Greg - you got it right, no slapping necessary

 

Greg got it right.
Drive pressure...more commonly called "back pressure". Proper engineering term is T.I.P. - Turbine Inlet Pressure! It's important cause it builds pressure back into the cylinder exhaust valve and can, if pressure gets high enough, result is higher cylinder combustion temps and higher EGT's. The 5.9 Cummims is better than most at handling reasonable "back pressure".

Wild Bill - nice numbers on the new turbo...injectors will probably put you back where you were on TIP!

RJ

 

I gotcha now...Thanks