intercooler pipe diameter

[CNHSS1]

ive decided to change my intercooler from a strapped volvo I/C to a bar and plate ally one, but im unsure of what diameter pipes to go for. Again response is my main concern rather than massive power.
Im currently using 60mm external tube but was thinking of 63mm tubing with matching I/C inlet/outlet ports.
Questions are:-
what sizes do people use on 250-300bhp setups?
has anyone found advantages/disadvantages from going bigger or smaller?
any thoughts?
any issues with I/C port sizes?
should i buy an I/c with the same size inlet/ outlets, or go larger and use silicone reducers to attach to the pipework.

thanks for your help as always chaps

[30psi]

I think 2.5 inch will be fine.

What are the sizes of the inlet/outlets?

If you have short i/c pipes then 3" will be fine, also I assume you have a 70mm external sized s13 throttle body, which will be better with 3".

Horses for courses, but if your i/c only has 2.5" inlet/outlet it wont make much odds.

If you have long 3" pipes then you would notice the extra lag associated with having to compress a higher volume of air

[CNHSS1]

pipe run length can be seen here, i dont think its long to be honest, probably shorter than most. The turbo to IC inlet run will be 6" longer i guess due to top mount now rather than the picured stock position.
I havent bought the cooler, but theres a few i have my eye on and theres a choise of 2.5 or 3"
2.5" suits me as itll be lighter and easier to package as there aint a lot of room under the bonnet anyway (when its on the car ) but dont want to use 2.5 if theres a possible restriction
EDIT running KA24 TB but cant remember the outer diameter

[Magnum]

2 inch hot pipe and 2.5 inch cold pipe.

[CNHSS1]

Hi Magnum
2" from the turbo housing to IC and 2.5" from the IC to TB?
why the different diameters?

[Wocketfast]

Im curious too as I would have thought it would be the other way round.

i.e. cooler air is denser therefore you get a pressure drop across and intercooler anyway, increasing the pipe diameter would only make that worse surely?

[Magnum]

Originally Posted by CNHSS1

Hi Magnum
2" from the turbo housing to IC and 2.5" from the IC to TB?
why the different diameters?

2" from the compressor to the IC to keep velocity. Then 2.5" to closesly match your TB size on the cold side.