DIY Matched Inlets/Polishing? (172 Cup)

[PeteCup]

Not done this before but i might give it a go, i'm a high precision CNC setter/machinist. So i'm after some info, its my understanding that the aim is to match the ports on each end of the inlet manifold and to polish the insides? Are there any guides around for removing the inlet manifold? I know its not rocket science but guides always make the job easier.

Also will i need new gaskets? As i wont be able to get any in time (will be doin the inlets Monday)

Is there any other points that i need to know?

 

[GarethM]

there's a guide for removing them in the guides section.

best to get new gaskets too

 

[Johnc172]

There's a guide on how to remove the inlets in the guides section, pretty easy to do, just one pain in the ass bolt!

Interesting to see how you get on mate!

 

[Turkish]

Awaits pictures of highly polished "mirror finished" inlets.

 

[PeteCup]

Must have missed the guide, will check it out. Is it a good or bad thing to mirror polish? (on the inside of course) Never been quite sure.

 

[Nrj]

bad,

the inlets will loose there natural venturi effect,

 

[franx]

bad,

the inlets will loose there natural venturi effect,

yep i think the surface has to be rough to some content due to the "pulsing" thing going on in the system..
BenR knows; maybe you can get in touch with him !

 

[Henry22]

roughness is to prevent fuel beading in the inlet, only an issue after the injector..

 

[Daz Clio Cup]

roughness is to prevent fuel beading in the inlet, only an issue after the injector..

but before the injector helps to mix the air with the fuel if it's a bit rough. ( sandpaper rough, not OEM casting!) just don't mirror polish the inside near the injectors. Trumpets on ITB's are always polished

 

[Henry22]

roughness is to prevent fuel beading in the inlet, only an issue after the injector..

but before the injector helps to mix the air with the fuel if it's a bit rough. ( sandpaper rough, not OEM casting!) just don't mirror polish the inside near the injectors. Trumpets on ITB's are always polished

Before the injector there is no fuel!! :rasp:

 

[Daz Clio Cup]

but before the injector helps to mix the air with the fuel if it's a bit rough. ( sandpaper rough, not OEM casting!) just don't mirror polish the inside near the injectors. Trumpets on ITB's are always polished

Before the injector there is no fuel!! :rasp:

Very good however the air does need to be turbulent before the injector so when it gets to the fuel it mixes well and doesn't drop out of the airflow and puddle on the bottom of the inlet manifold runner.

 

[Henry22]

The step on the manifold to the head should aid this too..

Matching inlets makes a debaitable diference, theres so many variables thats its very difficult to understand unless you have a degree in the dyamics of the subject!

I say get rid of the thing altogether and get some throttle bodies!

Failing that get a big f**king turbo some anti lag and steel bottom end.. and possibly some life insurance

 

[PeteCup]

Will have a word with my mate who owns a head working place before i do anything and see what he comes back with. Cheers guys.

 

[Daz Clio Cup]

The step on the manifold to the head should aid this too..

Matching inlets makes a debaitable diference, theres so many variables thats its very difficult to understand unless you have a degree in the dyamics of the subject!

I say get rid of the thing altogether and get some throttle bodies!

Failing that get a big f**king turbo some anti lag and steel bottom end.. and possibly some life insurance

I did get itb's! The guy who bought my old manifold said it made about 15 bhp