Exhaust manifold crack symptoms

[peanut]

When accelerating from under 3000 rpm in 6th I get a jolt/judder with a dip in power.Worse going up hill.
No engine light/fault codes.
This has slowly got a bit worse.
If I use @50% throttle it does not happen.
It is less noticable in 4th or 5th .
I have had my mobile connected via OBD and have tried to see if there is any variation in boost or MAF but have not been able to see any. Boosts to @ 10 psi.
I have a Delphi reader so are there any sensors I can look at to see if there is a crack.
450 with a Roadster engine swap so @ 87000 miles.
Also are all manifolds the same ?
Thanks

[peanut]

Update- I have located a crack in the manifold.
Are there any compatibility issues between 450/roadster manifolds/turbos ?
Thanks

[Mr Gus]

There is some info on evilution

search "manifold"

This page however may answer some queries itself, some pages are subscription...

https://www.evilution.co.uk/index.php?menu=info&mod=561

[137699]

If you have a cracked manifold, the "solution" is a new turbo.


You are highly unlikely to find a used manifold that isn't cracked already & don't be tempted to buy one of those cheap Chinese ones off ebay, they're often very poorly manufactured.

[EmilysDad]

If you have a cracked manifold, the "solution" is a new turbo.


You are highly unlikely to find a used manifold that isn't cracked already & don't be tempted to buy one of those cheap Chinese ones off ebay, they're often very poorly manufactured.

While I realise that it's not the best solution, but there is always the option to weld it .... I've welded cast iron various times with success, you just need a LOT of heat in the manifold before you weld it

[peanut]

If you have a cracked manifold, the "solution" is a new turbo.


You are highly unlikely to find a used manifold that isn't cracked already & don't be tempted to buy one of those cheap Chinese ones off ebay, they're often very poorly manufactured.

I assume you mean a turbo attached to a manifold?

[peanut]

While I realise that it's not the best solution, but there is always the option to weld it .... I've welded cast iron various times with success, you just need a LOT of heat in the manifold before you weld it

My welding skills are very basic so not an option .
Thanks for all the help.

[mikerj]

I'd be willing to bet that most of these manifolds have some cracks in them, they have to be fairly bad to create a problem.

The majority of Roadsters have the 80bhp engine and the manifold and turbo are a bit different to the lower powered 450 ForTwo engines. Perfect if you have a Brabus ForTwo, but whilst it will physically bolt onto a 60bhp engine the exhaust flange is larger so fitting the ForTwo exhaust may be problematic, and if using the Roadster turbo you'd need a matching intake (TIK) pipe.

There are a few 60bhp Roadys, but they are quite rare.

[peanut]

So it looks like its not a straight swap to swap to a roadster manifold turbo.
I am now sure my roadster engine is using a 450 manifold/turbo including the TIK.
From reading forums I thought the external dimensions of the turbos were the same .
Is reusing my turbo onto a different manifold an option?(keeping costs down).
I thought you could use a roadster TIK on a 450 to improve breathing meaning the external size is the same.
Thanks

[mikerj]

External size of TIK is the same, but if you used a Roady turbo with the 50/60bhp TIK it would really choke it.

The external dimensions of the turbo are very similar, the most noticeable difference is the larger exhaust flange as I mentioned, though I think people have managed to bodge a standard ForTwo exhaust onto the larger turbo flange.

The other thing is that the Roady turbo has a higher boost threshold than the 60bhp one, i.e. it doesn't start making boost until a higher RPM. The gear ratios in the Roadster are different to match this.

I rebuilt a Roadster engine for my ForTwo and used it with the original ECU and gearbox for a while and they are not a very good match, felt like I was forever hopping up and down gears. A Roadster gearbox (and ForTwo Brabus ECU) transformed it. I cut the exhaust flange of an old Roadster exhaust and welded it to my ForTwo exhaust so it all bolts together nicely