Mesh over turbo

[silverzx]

Everyone says its uber restrictive, why.

Explain.

Layman’s terms accepted.

[Jake]

restrictive... yes. Depends what mesh you use though.

It will restrict it as it reduces the surface are of the inlet.

[1616six]

I had a sieve over mine & it literally halved the PSI I could boost up to, took it off & it was a different animal.

[r3k1355]

You get it on some stock applications, I guess some manufacturers are frightened about people feeding small animals in there or something??

IIRC one of the older Merc C230k's had two or three different pieces of mesh in the induction system.
Rip them out and it makes a noticeable difference in performance.

[silverzx]

I get this, how can I explain to someone whos stuborn and in simple terms that it's super restrictive?

A friend of mine runs mesh on his 235BHP TD04'd Glanza, I can't convince him to remove it!

[Jake]

Tell him to suck air through a straw.... Then but his hand over the end of it and try again.... The same effect his turbo is having.

[ginge191]

ORRR... Do it yourself, suck through mesh, then suck through an open filter.

[Tom]

Completely depends on the mesh surely?

Do you mean literally a naughts and cross type thing over the turbo, literally 9 squares, or in effect a piece of plastic with a load of needle holes? Obviously complete opposite ends of the scale but im just making a point.

[Jake]

Completely depends on the mesh surely?

Do you mean literally a naughts and cross type thing over the turbo, literally 9 squares, or in effect a piece of plastic with a load of needle holes? Obviously complete opposite ends of the scale but im just making a point.

You would be surprised how much restriction it still causes.

[Dave]

On a stock T2 blower boosting around 22psi at 5k I think I calculated the air being sucked into the blower inlet was approx 150mph. Imagine holding a sieve out the window of a car doing 150mph, you wouldnt hold onto it it would just catch the air and whip it out your hand, the same is happening on the entry of the turbo. Now imagine that with a td04 which is supposed to flow alot more... may seem like there's little restriction when you blow through it, but imagine intensifying that air then any small restrictions become huge.

I know ruan was banging on about this for ages and it took me a while to get my head around it, but you want to aim for zero pressure acting on any surface, so the goal would strangely be to reach 0 psi boost, which would achieve maximum flow (Turbos wouldnt like that though). The less boost, the more air is being taken into the engine. The less vacuum you have on the inlet of the turbo, the more flow you will allow it, same goes for the exhaust etc which is common practice.

[darrenjlobb]

Over the tiny area of a turbo inlet, it would be massively restrictive, if you had a area the size of say a HDI panel filter of mesh, it would be fairly fine, but tbh, ANY air filter material over the size of a turbo intake will be hopeless..think of the surface area of your average "cone" filter / stock airbox compared to the intake hole on a turbo!

[Ruan]

Turbochargers really struggle with ANYTHING on the inlet. That's because the airspeed going in as Dave says is incredibly high, trying to blow through a mesh filter is pointless since you can never simulate the conditions that are going on inside a turbocharger.

This is a brand new Garrett 4th gen GTC turbo - they run with insanely small compressors (44mm exd) yet will do 180hp with ease...



Notice the massive step up to the air intake hose connection? That's because if you put a hose the size of the compressor inducer on there, it'd seriously struggle for air - that's because as you increase hose size, the airspeed will drop. Naturally if you make it the same size as the compressor inducer all the way down, your airspeed would be the same all the way down the pipe! Meaning that you're trying to accelerate air upi to 150mph in a hose - errr not going to happen, so you end up with a big vacuum on the turbo inlet, causing restriction.

If however the mesh had lots of surface area - i.e. like a cone filter! It'd be fine, that's the whole point of the cone shape - it gives lots of surface area to pass and filter air through. If you just put a tea strainer over the turbo inlet, I'd say probably 1/5th of the area over the inlet is metal - that means you've increased airflow a significant amount through those tiny holes in the sieve... You're probably trying to get the air through those teeny tiny holes at 170mph or so...

[toseland]