1g tb with what piping size?

[hypnoticpimp]

So i have recently been looking for my next mod on the gsx and I came across doing the 1g tb upgrade... I plan on buying the 1g tb from throttlebodys.com(63 mm as opposed to 60mm)... I am currently running the fp big t28 with the supra intercooler and greddy intercooler pipes (uip is 2 1/4, lip is 2")... My plans for the future are to max out the turbo using water injection, I love the sleeper look...

My question is since i will be using a 63mm tb (2.48 inches) would it benifit more that i get 2.5 intercooler pipes as opposed to 2.25 pipes?... I hate the idea of my piping system going from 2 inch(lower pipe) to 2.5 inch(supra in & outs) to 2.25(upper pipe) to 2.48 inches with the newly installed tb... Any input would be great.

 

[Supa Dexta]

Yes it would be better, how much who knows. The 1g nt Tb will need a 2.75" coupler, (reducer to whatever pipe size you use).. I've now got my short route fmic down to 2 pipes, one from turbo to fmic, and then from fmic to TB, certainly helps cutting down possible boost leak sources. And it makes for 2.5" right from turbo outlet, to the 2.75 at the TB.

 

[romeen]

Agreed, get a 2.5" UICP. Going from a 2.5" IC discharge to 2.25" UICP would not be ideal. The .02" decrease from UCIP to TB seems insignificant and I can't imagine it causing any performance loss whatsoever.

 

[hypnoticpimp]

Thats what I thought... I was confused because I called RRE to ask them how much to make a custom 2.5 upper pipe thinking this was the best thing to do, and unexpectedly the guy tells me that it wouldnt be worth it and it would be a complete waste of time so......I came on here to reasure myself...

 

[Supa Dexta]

2.5" is just sort of the standard for most people, and then onto 3" for the big boys.. Most of the time it gets swapped to 2.5 when installing an fmic, or smim or something. If your pipes fit the way they are, you can leave them as be, but if you need to change them up in the process of other upgrades, may as well do it properly.

 

[romeen]

IMO, 2.5" is not necessary for most street turbos. It is not even close to being a restriction and the bigger size will decrease the air velocity. This is probably what RRE was getting at.

However, in your specific case since the outlet of the IC is 2.5" it would probably be better to keep the piping a relatively constant size. Either that or have the IC modified so the outlet is 2.25". I think the 2.5" UICP is the way to go given your setup.

 

[biglady112]

I have a 16g and a non-turbo 90 throttlebody. I run 3" tubing/piping from the j-pipe all the way to the throttlebody. My intercooler inlet and outlets are 3". My car runs great.

I would either keep it even from your first transition after the turbo or the same all the way through. On most smaller turbos. But flaring larger and larger throughout is not a bad idea either.

Steven

 

[hypnoticpimp]

Great, I decided to go with a 2.25 lower pipe from dejon tool and cusom 2.5 inch upper pipe to mate perfectly with my 2.5 inch 1g tb