Finished up one of the changes that I had intended to make for some time. I could never understand why the outlet of the intercooler was routed the way it was, seemed like a lot of unnecessary tubing length and bends. I also saw a dyno test of an enlarged intake inlet on a Dodge Cummins turbo that netted 75 lb/ft torque between 1500 and 2000 RPM. The cost and design of the enlarged inlet wasn't to my liking so I designed and built my own system. I will be going out later this month and will have some results to report then.

Here is the link to the write up:
revised intake system

Inlet:

Original intake layout:

Final layout:

As usual, "Great Work Ed!" Anxiously awaiting your report on the increase in power.

Do you still need to replace the pipe coming out of the turbo too? From the picture it appears to be stepped down.



A little known factoid, each 90 degree fitting is the equivalent of 6+ addition feet of hose in an airbrake setup. I wonder if that's true on the turbo boost side too?

This now makes 11 tech pieces that are in a PDF Format from Ed.

quote:

Do you still need to replace the pipe coming out of the turbo too? From the picture it appears to be stepped down.

Actually it is stepping up. The air from the turbo is hot so it can be a smaller pipe and as it goes from the turbo into the intercooler, it goes from something like 2 1/4-2 1/2 inches turbo outlet, that sweeping bend where it goes to 3 inches and then to 3 1/2 inches as it enters the intercooler.

Nice work!

"A little known factoid, each 90 degree fitting is the equivalent of 6+ addition feet of hose in an airbrake setup. I wonder if that's true on the turbo boost side too?"
It is now about 5 lineal feet shorter; two 90deg elbows removed which equals 12'; and a long-radius inlet replacing a more-restrictive short-radius 90, so the net reduction in intake length will be about 18' to 20'?? Will this significantly reduce the resistance and thus increase the pressure? Orr... was the original design a "Ramcharge" type where velocity is effectively increased by lengthening the intake pipe??
(Responders must post their equations!!)

Sorry, no calculations but, in general longer tubing in the intake path of a turbo system doesn't really make any difference because the ram effect isn't or doesn't work when the long runner(s) is under a boasted condition. Pressure will not increase but the response to change of throttle and the losses due to sidewall friction is greatly reduced, which will make the turbo more efficient in its work.

As a further note, many years ago we messed around with different exhaust manifolds and found very little differences between a log style and equal length runners. Changing the exhaust manifold material from cast iron to stainless made a huge difference as stainless absorbed far less heat then cast iron.

quote:

Originally posted by MWrench:
Pressure will not increase but the response to change of throttle and the losses due to sidewall friction is greatly reduced, which will make the turbo more efficient in its work.

Just like an airbrake setup, the response times should improve. Who wants slower response times in a brake system?