Custom Inlet Manifold
Turbo Mini Forums

Ill be (hopefully) starting my custom exhaust manifold and downpipe soon, i was just wondering if there would be any benefit in doing a custom inlet at the same time? Maybe increasing the runner length? Or making the path straighter?

I had a look through Paul S's thread but that covered efi, I know the principles are the same but the carb restricts the shape and design a bit, especially using the standard plenum.

Any thoughts?

Cheers,
Mike

http://www.turbominis.co.uk/forums/index.p...tid=469104&fr=0

If your talking turbo and a carb dont mess with the metro log manifold imo... I would guess at it aiding the fuel distribution some what

Yes i moved to the darkside

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The worst bit about the Metro turbo are the manifolds. They were designed for ease of packaging and before the science of wave action in engines was understood. In fact, the science suggests that the problem with the 5 port head is not the lack of inlet ports, but the poor manifold design.

Lift the bonnet of your daily and it's not uncommon to see long inlet runners.

I'm building a manifold with 300mm inlet runners at the moment. It could easily be used with a carb.

Saul Bellow - "A great deal of intelligence can be invested in ignorance when the need for illusion is deep."
Stephen Hawking - "The greatest enemy of knowledge is not ignorance, it is the illusion of knowledge."

Okay, so it's not just a case of longer is better though is it? Arnt there special 'tuned lengths' that are more optimal than others?

http://www.turbominis.co.uk/forums/index.p...tid=469104&fr=0

What are you trying to achieve? Do you want the the most powerfule and most efficient engine you can get? If so chuck the carb in the bin.

As you are keeping the carb, ask yoursekf, is it worth spending time and money making somthing that is essentially an unknown, to get unknown gains?

Reality is, the metro turbo manifold both fits and works, why re-invent the wheel when you're not trying to break any records?

Paul, quite rightly, is exploriong the possibilities of the 5-port. this is his pet project and he has lots of tools (including engine sims and CFD) to get what he wants. Unless you have similar tools and LOTS OF TIME then IMO you're wasting your time.

Fastest 998 mini in the world? 13.05 1/4 mile 106mph

Edited by Paul S on 24th May, 2012.

Saul Bellow - "A great deal of intelligence can be invested in ignorance when the need for illusion is deep."
Stephen Hawking - "The greatest enemy of knowledge is not ignorance, it is the illusion of knowledge."

Some useful information here:

http://www.team-integra.net/forum/blogs/mi...lculations.html

Saul Bellow - "A great deal of intelligence can be invested in ignorance when the need for illusion is deep."
Stephen Hawking - "The greatest enemy of knowledge is not ignorance, it is the illusion of knowledge."

On a practical note,I have one of Matty's splendid fabricated exhaust manifolds,but had to switch to an n/a inlet manifold to get at the fixings.Performance seems at least as good,if not better,but I changed lots,so not a contolled test.

'Where does the engine go?'

Thanks paul, that's an interesting read.

Will I'm not after an out and out racer no, but i dont have an inlet manifold at present anyway, so for the price of a metro turbo one i could make my own, it can't flow any worse...

I'll get the tape measure out tomorrow and see how long i could get with a carb and plenum on.

http://www.turbominis.co.uk/forums/index.p...tid=469104&fr=0