KAOS, AZ (Papa Smurf)

Ok, the plastic that we have now does not really trap heat in like metal does. It makes some sense since we are trying to keep the intake temps as low as possible. So wouldn't a piece of aluminum (I think that is what they use) absorb heat, and transfer it to the air that passes through it? Maybe it's past my bed time. What about the non smooth interior walls? I'll leave it open for debate.

EdP

But on the other hand, the RS4 is an all aluminum 3 piece instead of one, and the pipes are right behind the fans, no?

banance too the thnner wall of the plastic to offset the thermal insulating factor of plastic.

The other compromise is tbb tears vs potential higher temps. Where is JamesR, He'll test anything.

Gop-Dogg

First, the plastic bi-pipe would be more likely to "trap" heat, since plastic is a thermal insulator. Also, I don't think the inside walls of the plastic part are all that smooth to begin with. Given the speed at which the air moves through the pipe, the short length of the bi-pipe (resulting in a very short residence time) and the heat generated by the engine as it is, frictional heating caused by the rough aluminum inner surface will be a negligible contribution. Given the size, location and lack of adequate ventilation under the hood, heat dissipation is not really an issue the bi-pipe is meant to solve. After all, the bi-pipe is not a CAI. The Al version is a sturdier part, so it can handle the higher throughput seen with bigger turbos and ECU upgrades.

titanium

Yes it will.

Tostao

I SHOULD transfer more heat to the intake so, there you go, I would have made it out of something else OR heat shield it somehow.

It should have been very expensive to produce, so, even if APR 'discovered' this little 'problem' during testing, I doubt they would change it at all or admit it would give you higher intake temps.

Even with the piece sitting behind the fans, the air temps. that the fan blows is higher than the temps. of the intake after the ICs.

Best thing you could do if you get one is to heat shield it as best you can.

Gop-Dogg

if there is really all that much heat transfer related savings to be had (especially concidering how hot the S4 engine runs).
After a hard run on the track, an aluminum bi-pipe will be hotter to the touch than, say, a CF bi-pipe. However, how much hotter would the air that passed through the Al bi-pipe have been compared to a CF one? Not appreciably different, IMO.
As I said, the bi-pipe is not meant to solve heat-realted issues. Just pressure-related ones.

LMDA1

Well, wouldn't this also apply to aluminum BPVs ?