Hello all,

For a long time now i am an avid Fiat enthusiast from the Netherlands and last year i went on a holiday to Italy with a Punto mk1 75. Absolutely loved the car and its performance, sadly i killed the engine and will have to replace the cylinder block. I put the dead Punto in storage for the time being and for this year i bought another mk1 which was only 200 euro's.

Why i stick to small Fiats

• Price/performance
• Excellent parts availability and cheap
• Well equipped
• Light weight / Good fuel economy
• Easy to work on
• But most important of all, the Fiat FIRE engine

I have driven other makes and models too and like Citroen/Peugeot as well, Japanese cars are fun but a struggle to maintain here.

Since i now have two Punto's i feel more freedom to tune or modify the second one. This one is a 1.2 16v with 85hp.

Brakes, shocks and exhaust were totally shot, so replaced all of that with shiny new stuff and since i like a little stiffer setup i went for a sport kit (-40mm).
Clutch is also gone and the infamous rust on the bottom panels will need welding too. This will be done later and i will do write up on that in a separate thread.

The problem
Upon checking the air filter i noticed the air filter box was cracked and all the inlet hoses were also starting to perish. So another opportunity to tune things up

Since it will be useless to hunt scrapyards for these parts (which most likely will have similar wear) i decided to totally redo the intake with performance parts, which believe it or not is cheaper than buying the broken parts new from the dealer!

On Aliexpress i bought some hoses a pipe and cold air intake style filter for under 70 euro's. Nice, nice.

This is how it looks now:


The front scoop is currently not installed but will be done later.

Crankcase breathing is often overlooked and i want to improve this too. An oil catch tank will be added later to keep the inlet clean, but for now i am wondering why the current breather pipe (just below the throttle body) is also connected to the inlet manifold.

Anyone can explain this? and should i keep this or modify?


Cheers, Jochum

Connected that way so crankcase fumes are burned in the cylinders rather than released into the air we all breath. Crankcase fumes do harm our environment.
Being connected after the throttle plate is good because it means throttle plate stays clean.
My recommendation is leave it as it is, it won't cause any running problems unless your engine is very very worn , in which case you have bigger problems.

Nice picture if engine looking good.

Love the Fiat F I R E.

jackwhoo said:

Connected that way so crankcase fumes are burned in the cylinders rather than released into the air we all breath. Crankcase fumes do harm our environment.
Being connected after the throttle plate is good because it means throttle plate stays clean.
...

Click to expand...

If so, I don't understand why there is also a connection to the air inlet (original situation).

Is (or was) this tube also part of a PCV valve? (will have to check the old parts).

Sorry I looked your photo and could only see crank breather pipe connected to inlet manifold.
Is your car crank breather pipe now just connected to inlet manifold?

I don't think your engine fitted with pcv valve and you would have see one taking it off.

I will make a few pictures of the old parts when i'm at the garage, better to know for sure i guess.

I always in favour of making sure too.
Photos would be great.

The connection to the air inlet - the airfilter housing..? That may be a warm air take-off.

If there's some valve or flap at the rear/underneath the airbox .. it's a take-off.

Well here it is (finally)






So, no valves, just a straight connection.
Now i gave it some thought and figured it out (i think)

The pressure and vapor from the crankcase is drawn out of the engine because the inlet is always under vacuum. Pressures naturally will want to equalize, thus the vapors will move to the inlet. However in idle condition (throttle closed) there is not enough flow in the inlet tube to provide a sufficient vacuum. Fiat therefore also made a connection before the throttle body so that vapors are able to flow.

What do you guys think? If so than i only need a simple tube to the inlet. One thing is worrying me though, what will happen if a scoop is installed and the inlet is slightly pressurized?

Glad for the added pictures.

The crank breather connection on vacuum side of throttle body is most likely through a calibrated orifice , suitable for handling normal volumes of crank case fumes.
if the volume of fumes increase to more than the calibrated orifice can handle, the hose to air intake pipe prevents crank case pressurising.

An oil catch can connected the breather that used to connect to air inlet pipe.

Or put a simple tube to inlet recreating what Fiat original system.