This is more of a general single turbo question than specifically rotary.

I recently saw two different Diesel engines with intercooler pipe and turbo inlet ducts running very close to the exhaust with less than 5mm gap to touching, and no heat shielding. My immediate reaction was shock that someone had actually approved having less than 5mm of gap between hot exhaust (though not as hot as rotary) and intake plumbing. But then I wondered if it was actually that big of a deal.

So this got me curious, and here's my question:

How close to the exhaust manifold would you be okay with running a charge air pipe or TID, and, how much of an effect on intake temps would you expect from having less than 5mm of clearance?

Thanks

 

Seriously, no replies in a full day?

 

I dont think it really matters as long as you have the proper size intercooler to get the intake air temps back down.

 

Certainly, for a spark ignition engine, there are major benefits to reducing Air Intake Temperature. And you should strive to prevent unwanted heat from entering the intake tract. That said, sometimes it is really not practical to route the intake and exhaust plumbing far enough away from one another to prevent heat exchange. In these instances it is advisable to make good use of modern heat barrier systems. These can be very effective even in close quarters (like exhaust turbine housing less than 1/2" from intake manifold, anyone?).

That said, on a diesel engine it may not be so critical except from a air density standpoint.