Intercooler pipes

[Dell'Orto]

Okay, Im currently making my engine bay look pretty
However the intercooler to throttle body pipe looks like arse, and I doubt even polishing or chroming could improve the look of the damn thing.
Basically, I want to replace it with something more smooth looking, but the factory pipe starts at 2", then flares rather suddenly to 2.5 at the throttle body.
What Im wondering, is can I replace the whole thing with a 2.5" pipe, or will I have to somehow get a pipe that replicates the standy one?
Still have the stock intercooler there, running a CT20b anywhere between 10 and 18psi

[RS13]

I'd just get another 2.5" pipe made up. Samco I think can make silicon joiners to any size, (including adaptors to go from 2" to 2.5") for any application, I believe, and silicon is pretty enough..

[Dell'Orto]

Yeah, I got lots of Samco joiners already I'm more concerned that the 2.5" will create lag

[RS13]

Well, I'd imagine with such a minor increase in diameter, loss in response would be minimal, hardly noticable if anything. I'd imagine, as smaller piping means increased airspeed/increased turbulence/heat, larger piping, with slower airspeed/less heat/less turbulence, would mean a denser charge, more power?

[Erelyes]

Well, I'd imagine with such a minor increase in diameter, loss in response would be minimal, hardly noticable if anything. I'd imagine, as smaller piping means increased airspeed/increased turbulence/heat, larger piping, with slower airspeed/less heat/less turbulence, would mean a denser charge, more power?

My guess would be that the 2" to 2.5" change would induce turbulence. If theres a bend in the pipe, the press bend would also increase turbulence, as it goes large>small>large.

That's my take on things, I am of course talking out my ass but thats what I've heard here'n'there.

So: 2.5in mandrel pipe would be fine

Edit: And reducing turbulence is good.. more airspeed = less lag.

[Lloyd]

Well, I'd imagine with such a minor increase in diameter, loss in response would be minimal, hardly noticable if anything.

2 inch up to 2.5 inch is an increase in area/volume of around 56%

[Malcolm]

I think that with such short piping the 2.5" won't make any significant (or even noticable) increase in lag, however since the exit from your turbo, and entrance to the intercooler are both 2", you will be increasing then decreasing cross sectional area, then increasing again coming out of the intercooler, and you may (just a maybe) find that a standard 2.5" mandrel bend isn't tight enough to fit in nicely up to your throttle body, so you might need a rather tight donut type, so infact the 2" might flow better (ie less turbulence and hence restriction) than the 2.5". 2" should still be plenty big enough too, provided you don't intend to further upgrade your turbo