what's your airbox mod?

[F17BAD]

In the rr air box thread the open filter has a massive fan blowing on it and with a open bonnet so no hot air is around the filter.

It then gives better torque than a standard box, but the torque is matched by a modified top half air box. I can't see the cone filter getting any more gains than that on the road.

Why even waste money on a cone filter? When you get same results as a modified top half air box.

I'm then adding two 100mm cold feeds to that box. You telling me I won't see any gains?

I think someone has had a heavy Xmas and is not thinking things through.

i would bet you that u see no gians nor feel any gains

id agree i wouldnt spend money on a cone if i dint have to, but somethimes its the only route to take

[tweed]

I doubt ill do it in all honestly as I'm still gonna vr it, but if the Hellas come up cheap ill give it a go.

And yeah that grill  what a joker  only opened the box two weeks ago.


When I vr mine I want it loud and already got a simota carbon loud box on it only like vr6's for the noise so its got to be loud.


But I do stand by what I say! I do think it will give more than 1bhp and that's slower than 100mph.

If I had a turbo yes I would go out and buy a cone filter because that is the only way to go. But certainly isn't on a N/A

[tweed]

I've done 10,000 in 2 years and 3 months 

And I think that's to much.

[VW BUSH]

Reckon a 16v needs about .92 Cubic m/s at full chat, VW must have made it at least 90% efficient in the factory.
To increase intake pressure (without going on about bernoulli) a turbo needs to pump more than this figure.
What hope does an 80mm bit of pipe have?
To put it into perspective .92 CmP/S is about 5500 lts per min, the engine is drawing this in on its own.....
My maffs is a bit out granted as im suffering a port headache but you get the picture

I think the OP would be happiest with a cone filter or a giant hole, just for the sound and the backfire on engine breaking, did me for years

[tweed]

Have you read this thread?

I'm on about two 100mm feeds.

And why work cubic m/s at fall chat?

Why not work it out in litres at 4000rpm?

To get boost you need to go from 1 atmospheric pressure to 1.01 

1 atmosphere is 14.6 psi

Most standard turbos are 7psi. I'm sure most people are running 12psi.

So you only need 1 psi to get air inlet pressure.

What bhp gains do you recon you would get from say 0.5psi to 1psi

[tweed]

To make it easy for you a 4 cylinder 2.0 engine will use 1 litre of air every 1rpm.

[VW BUSH]

3373 lpm at 4000 rpm with an efficiency of .85........
Why not try four 20 cm pipes, you may need a dump valve with all that boost your building

[tweed]

N/A engine at 4000rpm will have minus - pressure, a vacuum because its sucking air.

Lets just say it -7psi at 4000rpm. Now I ain't believing that I will get boost, that's just plain stupid.
Why you are thinking that is beyond me?

I do think that I can lower the vacuum inside the air box with a big cold air feed. So the engine doesn't have to suck in as much air.


And at 4000rpm the engine will be sucking 4000 litres of air. That's 66.6 litres a second.

How are you working your math out?

[VW BUSH]

N/A engine at 4000rpm will have minus - pressure, a vacuum because its sucking air.

Lets just say it -7psi at 4000rpm. Now I ain't believing that I will get boost, that's just plain stupid.
Why you are thinking that is beyond me?

I do think that I can lower the vacuum inside the air box with a big cold air feed. So the engine doesn't have to suck in as much air.


And at 4000rpm the engine will be sucking 4000 litres of air. That's 66.6 litres a second.

How are you working your math out?

Volumetric efficiency of 85%, just one of many variables when calculating air flow and fluid dynamics.
The one of the variables you are playing around with by flowing an air box or intake manifold.