I’m having a bit of a debate with my supplier. I purchased a Garrett GT35R turbo (T4) and a tubular exhaust manifold. If you look at the pictures, in the top picture, the top gasket is a T4 gasket used with the turbo. The bottom gasket represents the turbo flange on the exhaust manifold. The second picture I put the exhaust gasket over the turbo gasket to illustrate to my supplier that even tho the holes line up, the flange on the exhaust manifold is not for this T4 turbo. He says he installed many of these and all gaskets that have the same bolt pattern must be T4 and this will work with no problems. I feel the exhaust will “hit” the ledge of the turbo flange and cause hot spots and otherwise disrupt the smooth airflow normally acquired with tubular exhaust manifold.

I would appreciate some unbiased input.

 

Top one is a T4 undivided flange and hte bottom one is what is used on the XS crap manifolds..I think they came up with there own design on a flange..I dont think the bottom one is a TRUE t4 divided but i could be wrong, good luck with everything.

 

did you buy an ss autocrap manifold? thats what the gasket is for. if you're worried about airflow, then you should buy a manifold from turblown.

 

I don’t know if it is a ss autocrap or whatever. It was part of a kit I purchased for a well known sponsor on this site.

I have read Corky Bell’s book on turbocharger system design and several papers on hydrodynamics. Everything I read tells me this is not a good setup. My supplier says he has sold many with no problems. I’m sure it will “work” but is this normal?

 

The cheap chinese knock-off stuff is manufactured that way so they don't have to make a transition to the T4 flange from that 60mm O.D. tube they use,They just crimp the tube flat on one side and use the funny D shape flange.

 

Sadly, it is normal for the suppliers that don't build their own manifolds. It sounds like you have one of these deals. I would guess whatever Chinese manufacturer that makes these discovered that it was easier to reshape the flange into something that would "work" rather than properly shape the primaries into the proper flange.

Is it correct? No.
Is it normal? Depends on where you shop and how much you spend.
Will it work? Certainly.
Will it be optimal? Most certainly not.

Hope that helps..

 

I've been going on and on about those POS manifolds and the non-existance of a merge from the oversized piping to the proper T4 inlet shape SUCK and how SHITTY it is. Not one response in the many apoun MANY threads in my favor. Always idiots going on and on how there cheap and work great etc etc. It's finally nice to get some to recognise this huge over sight by many. NewbernD hit it exactly. Its not correct, its not normal, it will work, and its NOT optimal.

~Mike..............

 

Where did you buy it?

 

Well, I would like to give him (The supplier) the opportunity to get me a correct manifold before I mention that. I spent almost $4000 with him on a single order and I don’t think it is too much to ask that the manifold actually be built for the turbo he sold me.

I do appreciate all of your input guys. In the past month I have spent almost $9000 rebuilding my motor and converting it to single turbo. I believe there are two ways to do this: The correct way and the wrong way. I don’t like half assed builds. I just don’t feel comfortable installing that manifold.

 

Just so you know, that is technically the correct manifold for your turbo (and the guy/company that sold you it will argue this). That POS manifold was designed for T4 footprinted turbo's (what you have), they just took a HUGE shortcut and instead of making a proper taper down and squar-ing of the tubing to fit the T4 footprint, they simply made the flange fit the half assed taper of the turbing. So it is for t4 footed turbos, that footprint does NOT I repeat NOT match up to ANYTHING at all. Its a specific crappy design the manifold company came up with. It's simply a cheap manifold ($120.00 verses the usual $1000.00 or MORE for custom built tubular).

~Mike...........

 

Takes a lot of work to make the correct transition.