Hi I have searched around but cannot find the information I am after I currently have 2 ht12 (s5 turbos) and I would like to know what turbos are a bolt on upgrade replacement for these I am currently thinking the t25/t28 will do it but can some of the members point me in the right direction????

the stock FC turbo is an ht-18s, the FD uses 2x ht-12's



the ht12's are close to a gt25, although you need to measure it to find out which one



the FC's ht18 is basically a small shaft t4. since the turbine housing is proprietary, its common just to replace the compressor wheel, or compressor wheel/housing/backplate. its even been done to bore out the turbine housing for a larger t4 turbine wheel. you can even use a garrett center if you like.



since the stock turbine housing and manifold are the limiting factors, it makes balancing the compressor and turbine is important. the other thing to realize is that its not a big HP setup.



it seems as if the simplest setup is to replace the stock compressor wheel with a V trim. this makes the turbine and compressor wheels almost the same size. with a freeflow exhaust, stock, or other smaller intercooler, 280-300hp is doable at around 12-14psi.



you can try to get more out of the stock based turbo, but it gets time and money intense, and at that rate you might as well upgrade to a full t4

If your looking to beef up or reman the factory twin's, contact BNR.



http://bnrsupercars.com/