Building a new Manifold-help and advise

[Mir]

Hi Guys,
 
I am in a process of building a new manifold for my 20B FD. The currently manifold is not up to the "required" job .
 
I need an advise regarding the diameter of the pip work on the manifold. When I removed my current manifold, I discovered a round black ring on the exhaust port side of the manifold. Does that mean it is not up to the job and there is a room for improvement or that is just about right?
 
Any help is appreciated.
 
Mir

[JayDee]

50 mm will do for your power levels!! Worry more about length and wastegate pipe position

[Grant Monkhouse]

I would have thought that the exhaust needs to be the same diameter as your exhaust port, if it is smaller it would restrict flow a little maybe? And would get hot around these areas.

Are you building a single or divided fanimold? Not that it will spoil the spool up of a 20B.

[clive]

Sounds like it just had an exhaust blow, if so you would only need to check the face is flat and put new gaskets on, espesialy if this is an otherwise reliable manifold with no warpage, clearance or cracking problems that befall so many Rotary manifolds.

Pictures of the black mark may help us to help you.

Not sure if you realise but this will be a big task without a workshop with fabrication / jig facilities

[Grant Monkhouse]

I do believe there are 2 triple rotor manifolds available. Single scroll and twin scroll. T4 footprint. May be easier to purchase one of them? Or are you after one for a T6 footprint?

[HaywardRotary]

The flange that is bolted to the engine should be port matched to the engine block so that there is no step into the manifold or it should and could be slightly bigger on entry into each of the runners.
Regards
Carl

[Mir]

Thanks for the in put guys! I appreciate that! I am on the case anyway and I will be uploading pics accordingly!

Cheers

[m1tch]

Tim @ RX motor\'s 20b manifold on the short block triple looked erm \'interesting\' but it worked really well :rollin

[SiH]

I do believe there are 2 triple rotor manifolds available. Single scroll and twin scroll. T4 footprint.

How does a twin scroll manifold work on a triple rotor?

[Grant Monkhouse]

By splitting the centre exhaust into 2, One to the front rotors exhaust and one to the rear rotors exhaust.

I think cummins have done a triple scroll exhaust housing for one of their turbos but it is huge and wouldn\'t fit in a car. I will try find the pictures tonight of them as I\'m on iPhone at the moment

[Mir]

The thread is coming soon regarding my 2012 plans for my Fd!!!

Mir

[m1tch]

The manifold should look like this for your 20b:

[m1tch]

You could always look at what a banned member has done with their 20B:

http://www.jpoc.co.uk/forum/index.php?showtopic=13347&st=80

[Mir]

You have installed some serious ideas in my mind. Ummmmmm!!

[Turblown]

By splitting the centre exhaust into 2, One to the front rotors exhaust and one to the rear rotors exhaust.

I think cummins have done a triple scroll exhaust housing for one of their turbos but it is huge and wouldn\'t fit in a car. I will try find the pictures tonight of them as I\'m on iPhone at the moment

Can\'t say I\'ve done that, but probably a waste of time. There is so much exhaust energy on a well built 20b that it really doesn\'t matter. All you need to do is keep the bends gentle, and don\'t use a collector that has bad entrance angles.