Intercooler piping size

[egos_86]

Right folks, Im upgrading to an FMIC in the next few days and need to start orderin parts but I have no idea what the outlet turbo size is.

Im gonna use the standard pipng from filter to turbo but what size do i need from turbo to FMIC. Is it correct that the VF20 (GTX turbo) has a 2.25" outlet??

Please dont tell me to measure it as I know I can measure it but I work full time, need the car everyday and it isnt feasible at all to remove all that **** just to measure something. Hopefully, someone with a GTX will remebr what piping they used/bought.

Many thanks peeps

[BigMal]

The better answer is how far do you want to take the car. What size outlets does
you FMIC have. Most people are running 2.5" piping as it suits when adding
a bigger turbo. You get a flange made from the VJ20 gasket to then take it from
a 2" outlet to the 2.5" piping. I wouldn't recommend using the standard size
piping as after you have paid the money and when you want more power
you will have to redo the piping all over again.

[egos_86]

Oh right so its 2" ..thats sooo small. Right well Im gunna go for 2.25 cos thats what my FMIC is.

Many thanks Bigmal Ordering parts now!!!

[twilightprotege]

for optimal size, you really need to know the boost pressure you plan on running at because the size *should* be determined by the air speed within the pipes. you dont want it too fast or too slow. 90% of the time, you will also have a bigger pipe between the turbo and intercooler as you do between the intercooler and the intake manifold because the IC causes loss in air speed

[Dogo]

2" ..thats sooo small. Right well Im gunna go for 2.25

The difference is about - 6mm ?

[egos_86]

Originally Posted by twilightprotege

for optimal size, you really need to know the boost pressure you plan on running at because the size *should* be determined by the air speed within the pipes. you dont want it too fast or too slow. 90% of the time, you will also have a bigger pipe between the turbo and intercooler as you do between the intercooler and the intake manifold because the IC causes loss in air speed

Thats weird cos Ive heard from others that you should do it the other way round eg 2.5 from turbo ti FMIC then 3" from FMIC to intake. TBH, Im with you mate cos as u said ICs cause loss in air speed AND a pressure drop AND cooler air is denser thus needs smaller pipe. ( Id like to hear their reasoning though)

I am well and truly baffled, Im just gonna go for 2.5 now all way round cos cant find no 2.25 piping for cheap. Do ya think 2.5" will be overkill. Im only planning on running stock and full boost on a standrd vj20

[egos_86]

Originally Posted by Dogo

The difference is about - 6mm ?

yeah about, it will still make a big difference though, think of blowing down a milk straw and then a Mcdonalds straw!! BIG difference!

[twilightprotege]

i would think ideally you'd want to go with 2.5" turbo to IC, then 2.25" IC to IM. but that's just a guess, i cant tell without the full details of the setup

[pisana]

2.5" the whole way through will be sufficient.

+- 0.5" in piping will make NO difference in performance. The cooler itself is what will restrict flow.

[egos_86]

Cheers everyone for advise!!