I am thinking about putting a TII engine into my FB and figured I'd post here since you guys are familiar with the motors. Are there advantages with using one series over the other?

I know they came with different turbos and different ECU management but I am going to upgrade the turbo and run a stand alone ECU so those don't matter.

I am mostly interested in knowing if internals are better in one and if one has a better throttle body and intake, etc. I will also be using secondary fuel injectors
so is one motor easier to fit them in?

I probably am showing my little knowledge but need a starting point.

Thanks

 

the series 5 has .5:1 more compression which helps with response, also has a better turbo design and manifold. some series 5 have thicker dowel pin boss for the rear iron giving them a higher ceiling for reliability with higher power levels.

series 4 is better for reliability due to it's lower compression. basically it's a little bit tougher to blow up if your tuner is mediocre.

i would go with a series 5 myself but they aren't as easy to get a hold of, though about half of the engine is shared with the FD3S in components. rotors and housings are interchangable between S5 and S6.

 

I don't know honestly, I'm intrigued on which turbo educated people will advise you on. I'm actually doing an s4 TII swap into my s5 n/a. I've got a lot of reasons but one is because it is easier to remove the emissions on a s4 engine than on a s5 because of aux ports... but then again turbo engines are 4 port.. I'm retarded.. nevermind.

 

s4

 

s5 also has a "better" intake manifold.

 

I've never done this swap ...what front cover is used?

 

if your upgrading the turbo and using an aftermarket turbo manifold as well as using a stand alone ECU the S5 is the way to go as the chrome on the housings is superior to those of the s4, the better compression, and the rear dowel pin is casing is thicker like Karack said. The only reason to stay with a s4 is if your going to use a stock ECU because it is easier to remove the OMP and premix for reliability and the emissions system is easier to remove and simplify and in this case you can swap a s5 turbo manifold and intake manifolds because they are interchangeable

 

Oh man, all this S5 is better stuff, I better rethink the amount of work it takes to put an S5 TII in my S4.