Intake & maf dimensions

[Gaz mr-s]

I'm working on a car with the supercharged Corolla 2zz engine. It has an aftermarket intake with a Pipercross cone bedside the side vent. It shrieks!!

The engine air intake I/D is approx 71mm. The aftermarket maf pipe is 66mm I/D.

Should it be the same diameter as the inlet, & should I get ducting pipe the same as the intake?

Will it be designed in mm or imperial measurements...?? 

[mr9]

Your ducting is going over the outside of both parts - so you want the OD of both?

[Gaz mr-s]

The ducting bore will obviously be determined by the o/d of what it fits onto.

I'm trying to find out what the i/d of the maf should be & if the ducting from the air filter should be uniform to the throttle body.

I'm rather disappointed by the lack of replies....there's a lot of knowledgeable folk on here...  

[shnazzle]

Where I'm puzzled is, why is thr maf adapter small diameter? 
That speeds up the flow and when it expands back to wider, it creates a big low pressure zone after the MAF causing a butt load of turbulence. But, I have seem this design. I think the TFSI VAG engines do this.

Not on a 2zz though. 
Puzzled. I would have said same diameter all the way through. Just look at the stock MR2 airbox and pipe.

[Gaz mr-s]

Hence my question Patrick.  I'm finding it difficult to find a reference source on the web. I looked on MWR's website....they advertise a 'cold intake' for the 2zz made by PPE.

What MWR don't say, but PPE does, is that it is NOT for a std ECU, it requires a piggy-back or standalone. So going above the throttle body intake diameter of 71mm would be wrong.

So apart from the weird narrowing join at the nearside corner in the '2' with 1zz, the bore is constant right to the throttle body...?  (been unable to check due to weather)

[shnazzle]

Hence my question Patrick.  I'm finding it difficult to find a reference source on the web. I looked on MWR's website....they advertise a 'cold intake' for the 2zz made by PPE.

What MWR don't say, but PPE does, is that it is NOT for a std ECU, it requires a piggy-back or standalone. So going above the throttle body intake diameter of 71mm would be wrong.

So apart from the weird narrowing join at the nearside corner in the '2' with 1zz, the bore is constant right to the throttle body...?  (been unable to check due to weather)

That would definitely be correct. 

Going above the size of the TB intake is massively counterproductive. 

And yes I'm almost certain it's equal diameter all the way down.
Basically if you have a wider void, you want to fill it quickly, so you'll often see a trumpet shape before a box. 

I could be wrong but I vaguely remember the PPE being a narrower pipe? Did I make that up? I'd check but I'm lazy. That means airflow is sped up to fill the large plenum on the intake manifold, but measurement is off. So, very fair of them to say it needs piggyback at least. But, narrower wouldn't be as effective for 2zz as it would be for 1zz