Air box size

[TurboMatt]

I have one of the 2012 Silber kits with the big aluminum air box. I see most of the kits now are going to either small silicone tubes for 'air boxes' or I was just watching a Mtn Tek promo about their small aluminum air box. What's better? Would it even make a performance difference if I cut down the size of my air box? Mtn Tek was claiming better throttle response with no loss of top end lower. What's everyone's thoughts?

 

[meathooker]

I made my first turbo kit in 08 and the air box was bigger than the new silicon "air boxes" BD and others use. I think the smaller has better throttle response. On my car I redid the IC piping removing around 12" and the throttle response off the line and transient response is noticeably better.

To sum up: smaller the better IMO

 

[Ckale]

This is something I have been wondering about. You do see Silber and others going with the smaller silicone style, claiming for better throttle response. However if you watch some of the Aerocharger videos they are confident that a bigger airbox is the answer due to increased charge air volume. They also say that this is why stock airboxes are so large.

Some Silber guys think that the 2012 kits ran better than the 2013 kits, maybe this is why? Its hard to know due to the other changes in fuel mapping and control box changes between these years.

Here is Aerocharger's take on it. Skip to 7:37.
http://www.youtube.com/watch?v=8B4FgvOonTU

I am not siding either way, but I do find this interesting how the different companies are basically going in opposite directions in this factor.

 

[allblowdup]

The real problem that a large air box creates is turbulence within the air box. Air has mass and if you have turbulence in the airbox it will fight the movement into the throttle bodies. If the air box is design properly and is not turbulent then really there are very little issues. A small air box is difficult to make without running into turbulence. A straight tube would have very little if any. The small air if not turblent would be the best then the BD style toque tube. Better yet would be an intercooler.

 

[TurboMatt]

I just watched the Aerocharger video. The Mtn Tek video is exactly opposite.

When you have multiple companies that are on each end of the spectrum it kind of makes me feel like it doesn't really matter. It all works.

 

[akMcat]

I just watched the Aerocharger video. The Mtn Tek video is exactly opposite.

When you have multiple companies that are on each end of the spectrum it kind of makes me feel like it doesn't really matter. It all works.

This is what I was thinking, for the most part. Possibly it has more to do with the turbo size and spool characteristics. Slower spooling turbos give better response with a smaller airbox whereas quicker spooling turbos give better response with a larger airbox. In addition the airbox design could likely be optimized to provide high velocity laminar air flow to the throttle bodies, like the stock air plenum does. Likely it's a number of factors balanced to make the whole kit perform, and not a one size fits all. That's my guess.

 

[turbo pro]

I bought a 2012 silber kit for my pro and in 2013 I bought the silcon and this year I've been testing and the box is cooler charge temps just as fast spool up and on a long hill kept my motor cooler

 

[allblowdup]

Everone is kinda right. On factory air boxes there is a bunch of design critera. Two of them are a resonant chamber to aid in airflow to the engine and resonance to cut noise. The resonance aspect of the irbox does not really change with boost so a properly designed large boost box will help airflow at a given rpm increasing power. However I doubt that any of the turbo companies are making air boxes with that in mind. Most are doing what they can for packaging into the tight spaces. So having a larger air box will give a cushion to the boost pressure as the turbo pressurizes the airbox and will also take longer to fall off when the throttle is realesed. A BOV helps this alot. The problem with the silicon tube style is that it is an insulating material and does not have the surface area to expel heat that the air box would have. Having injectors in the chargetube/airbox/throttle bodies only helps the charge temp a small amount from the difference in temp from the fuel to the air temp in the box, because it is a pressurized injector there is no heat loss from latent heat of vaporization that carbs benifit from.
For hp the best will always be a oversized intercooler that is effecient. the water to air designs are the best but do make for a very long charge side of the turbo sytem. This does effect response.