Gt3 manifolds/headers

[996er]

Hi there I have the opotunity of fitting some GT3 manifolds to my 996 it's the 3.4 standard other than a modified air filter. Do you guys think it's worth doing, would I see any gains ... Many thanks

[Loren]

I do not think GT3 headers will fit a 996 engine. They are completely different engines.

The GT3 and Turbo share the same engine mechanics - based on the air cooled 964 engine. The 9x6 series Boxster and Carrera use a then newly designed water cooled engine.

[996er]

Oh interesting. A local Porsche specialist in my area has offered me a pair of GT3 manifolds for my 996 .. My be they are not GT3 and he is trying to dress it up a bit.. Anyway if they seem like free flowing manifolds would i see much differnce in performance being that i still have the standard exhausts after that..thanks

[phillipj]

Even if you do find that the headers will fit you car you will only see hp gains if you add "high-flow" mufflers, 100 cel cats and a flash of your ecu.

The headers alone will not give you any noticable improvement..

[996noob]

Even if you do find that the headers will fit you car you will only see hp gains if you add "high-flow" mufflers, 100 cel cats and a flash of your ecu.

The headers alone will not give you any noticable improvement..

I've researched this and have determined that the bolt pattern on the GT3 header to engine flange is totally different from the 3.4/3.6 engine of the 996 C2/C4/C4S.

They won't fit.

However, the mufflers MAY fit, but I am still trying to find conclusive evidence whether they do or do not.

[996er]

Hi there i haven't tried them yet but i bought them, they are for a GT3 Mk1 and the Porsche spaecialist says they will 100% fit he is actually fitting them for me in a couple of weeks so i'll keeo you posted.. I must say they look very similar but the ports look bigger and better welded more smoother. The point where they all branch into one is alot bigger too, thanks for you interest..

[phillipj]

if they fit they are not GT3 headers. By your description they are X 51 headers. Your Porsche "specialist" may be not telling you the whole truth

[996noob]

if they fit they are not GT3 headers. By your description they are X 51 headers. Your Porsche "specialist" may be not telling you the whole truth

I agree. The bolt pattern on the exhuast gasket and mounting flange is totally different.