my custom intercooler setup questions
 

Hello everyone,
I have a JDM 96 type RS rx7, current mods are 3" exhaust, apexi intakes, recently rebuilt motor with 3mm apex seals, HKS coilovers and thats pretty much it.

I have just bought a Vmount intercooler, the core measures 32 x 31 x 8cm so its not the biggest in the world but should be a nice upgrade from the stock one.

I and am going to have a go at building my own intercooler setup on a budget. ( i am planning on doing a thread on my build once i have acquired all the required parts)
I was planning on doing a vmount setup but really cannot be bothered moving the radiator etc so am currently leaning towards mounting my new vmount in the SMIC position.

so heres the real question...my new vmount intercooler has 70mm inlet / outlets but there is a distinct lack of 70mm aluminium tubing around here at reasonable pricing.
I am planning on buying a few generic bends of aluminium pipe (U bends) and fabbing up my own piping from it. The catch is 70mm tube will cost about twice the price of 76mm tube.
Due to the price i am leaning towards going with the 3" pipe (76mm) and getting a welder friend to change the size of the inlet/outlets on the intercooler to 3" ( 76mm).
I cant see this being too much of a problem but if i did go that route i would need to use silicone reducer join things that go from 3" to 2.75" (to connect the stock elbow to the new 3" intercooler piping and the Y-pipe to the new 3" pipe also)
I realise reducers can never be ideal but figure for the difference in price i might as well go with the 3" pipe and just use two silicone reducers to connect it to the stock elbow and y-pipe
What do you guys think, do you think this will be ok?
cheers

No stop being a cheap a$$.

I concur.

Just buy the correct size piping you'll need. If you don't think you have the money for it, hold off until you do.

If you are going to mount it in the stock position, I suggest looking for a good used IC with a proper duct. By the time you get through buying all the material and the time and materials for welding, it will have cost you more than a good used SMIC setup with a duct.

I've seen properly engineered SMICs with ducts going for $300-700 depending on brand.

what you COULD do, if you were so inclined, would be to buy the 76mm piping and just use silicon couplers with some hose clamps but that will only hold up depending on how much boost you run

considering you are running the stock turbos you shouldn't have a problem