Thread: isuzu induction system

Originally Posted by c.h.i.e.f

Thanks fellas ill probably just go stainless now after that info! Why I ask is I have been using 2" stainless tubing from turbo to intercooler intercooler to motor but I'm thinking of upping it to 2.5" I believe 2" over the length may have been a tad to small...

2" is most certainly too small. Especially between intercoolera and engine.

What size are the pipes on the intercooler?

Originally Posted by isuzurover

2" is most certainly too small. Especially between intercoolera and engine.

What size are the pipes on the intercooler?

isuzurover,

Why do you comment on the intercooler to engine segment? With the increased density after the intercooler I expected that it is in this section that the pipe size would be less significant than pre intercooler where the density would be lower (greater volume for same mass). I'd also expect the greater surface area of pipe closer to the compressor would result in greater heat loss.

Your thoughts?

The 4BD1T intake manifold can fit nicely with a 2.5" tube. That is a pretty good reason in itself.

From a density point of view, it's true that a large pipe to the intercooler and a smaller pipe from the intercooler will give close pipe velocities. But I would rather pay attention to smooth transitions, particularly in pipe size.

Originally Posted by Dougal

The 4BD1T intake manifold can fit nicely with a 2.5" tube. That is a pretty good reason in itself.

From a density point of view, it's true that a large pipe to the intercooler and a smaller pipe from the intercooler will give close pipe velocities. But I would rather pay attention to smooth transitions, particularly in pipe size.

What about profile/cross-section? Is round better than oval or rectangular?

Wouldn't the smaller diameter pipe between IC and head cause a restriction and SLOW the flow through the IC?

Sorry, I'm gormless when it comes to turbo tech, so please bear with the questions, dumb or not......

Originally Posted by jakeslouw

What about profile/cross-section? Is round better than oval or rectangular?

Wouldn't the smaller diameter pipe between IC and head cause a restriction and SLOW the flow through the IC?

Sorry, I'm gormless when it comes to turbo tech, so please bear with the questions, dumb or not......

Round is best, it's maximum area for minimum wall contact. Everything in the system is a restriction, just do your best to minimise restriction within the space and money available.

Originally Posted by slug_burner

isuzurover,

Why do you comment on the intercooler to engine segment? With the increased density after the intercooler I expected that it is in this section that the pipe size would be less significant than pre intercooler where the density would be lower (greater volume for same mass). I'd also expect the greater surface area of pipe closer to the compressor would result in greater heat loss.

Your thoughts?

Mainly because the compressor outlet will be ~2" and a smooth transition is better than immediately going to a large pipe.

Thanks guys! Isuzurover just said about the segment between the compressor and intercooler is important I find this interesting as the length of that section can also be considerably longer than the other sections in the system which is probably related to Douglas statements to... I was concerned that 2" was way to small and after Douglas recent intake he just made and the gains he got I thought my system is twice as long and using such a small diameter tube it will be a thing that needs upgrading!

Sorry forgot to say my intercooler has 2.5" inlet and outlet.