nopistons94

hey guys,



I was just bored and thinking about some stuff and had a question about intake temps. Since the exhaust and intake are on the same side, and say with a big T88 or something, the turbine housing is only a few inches from the bottom of the UIM right. Say in theory you could swap the intake ports to the other side of the motor ( i know its a stupid thought but bear with me), how much of a difference would the temps be?



Im just wondering about that cause straight 6 motors have a setup like that



thanks!

Lynn E. Hanover

One of the advantages of the crossflow head as in your 6 cylinder above, is lower intake charge temps. So the thinking is clear enough.



There are some very difficult problems to deal with on the rotary with the intake and exhaust ports so close together. A insulating jacket around the hot side of the turbo, reduces radiant energy polution and prevents energy loss from the exhaust flow. On NA installations it is manditory tht a shield of some sort, be fitted between the intake and exhaust. For years I ran with the carb and manifold potted in a foam jacket, and a two layer heat shield over the headers. On a cool morning I could get carbureter ice forming in the venturies. Now that is cool.



A simple shield of two layers of sheet stock with a bit of airflow between, upsets the radiant transfer, and does a fine job of blocking heating from the headers. You can wire some ceramic wool insulation between the turbo and the intake manifold for even more benefit.



Insulating the whole inlet tract is good for power. The underhood temps in summer time can be close to 300 degrees. Detonation is charge temperature dependant. Inlet air should come from the center of the grill opening, as high above the ground as is possible.



Also another vote for not removing the exhaust port liners.



Everything you do as far as going to a bigger radiator, bigger intercooler, bigger oil radiator, raises the under hood temps, and adds more heat to the inlet tract plumbing.



The obvious benefit of insulating the inlet plumbing is more power, and longer engine life.



Lynn E Hanover

j9fd3s

we've made some oem'y heat sheilds by saftey wiring some of that header wrap stuff to the underside of a peice of sheet metal, works pretty well

heretic

That's a fairly recent development. Back in ancient times when carburetors were on the majority of engines, almost all inline six engines were non crossflow. They needed the exhaust heat to keep the fuel from wetting out in the long, stretched out intake manifolds when using a single carburetor. Didn't always work too well even then but it was better than nothing. Corporate inertia kept things that way even after going to EFI. Nissan's L-series sixes were all non crossflow, even though they went to EFI in the mid-70's. Likewise, Ford's inline sixes in the domestic market maintained non-crossflowness right up until the end, even though they were all EFI after some point. (The Australians wisely made a crossflow head when they converted their 4.1l to fuel injection)



Point is kind of moot for us, since we are pretty much required to have a non crossflow design. If it's any consolation, any heat you'd get will more likely than not come from the manifolding and not the engine itself.

RONIN FC

RB has a heat shield for the Holley intake mani that prolly could bolt to the TII manifold. I have it for my SE, im thinking of making one for my TII.

nopistons94

Cool, thanks for the info guys