I've been reading through all the post and most are saying the stock airbox is good for 4/500hp.

What I found is my car dynoed at 208kw atw with exhaust and Haltech ECU and Haltech's own car also with exhaust and ECU dynoed at 210kw.

Now the interesting part is, when Haltech dropped in the HKS pod filter on their car, it went up to 226kw. I'd tried changing the pipe between the turbo and airbox, but didn't make a difference.

Now does this mean the stock airbox is quite restrictive or am I missing something?

 

stock airbox i believe is good up to 400whp or with the stock turbo. U can use the intake on the stock turbo and yield some gains wit a tune. But on the stock turbo most ppl use the drop in K&N.

 

Yeah I'm currently using the stock box ... but Haltechs car gained 16kw when they added the HKS pod filter. I want to know why is that when everyone is saying the stock airbox isn't restrictive?

 

You will get some gains with it with a tune like mentioned above as the HKS does flow better, but the HKS intake doesnt filter that well. Id just go with a drop in with a good flow rate (K&N, Monster Sport, Works, etc). That way you should get some small gains and keep the filtration high. You dont want crap from the air getting into your engine and scratch up your cylinder walls.

 

WEll, the rest of us don't make that much power, and that power gain is slightly skewed by the hood being open and the car stationary. When driving, the hood is closed, so the intake sucks in hot engine air as opposed to fresh, cool, external air. Add to that the fact that the HKS filter doesn't really filter anything.

 

And the HKS pod filter is a joke. I have wondered for years why they continue to sell such restrictive filters. I guess they make a bunch of money selling foam.

 

Vishnu Stage Two GT30R kits use the stock airbox and make 400 to 450 awhp.

As far as the HKS Super Hybrid filter, it seems to work good.

 

stock airbox is good for up to 450ish hp

 

Also, just throwing the intake on without a retune would result in a leaner condition, which in turn makes power (but can be dangerous).

 

Yep, but this was definately tuned as it was the vendors own car.

 

good air filters make power. I dont have one and people with ss manifold and hks rs intake consistently make more power than me. If I did not hate the sound, it would have been one of my first mods. you might investigate aps intake as it an open element filter that gets cold air.

 

karman hz logged with utec of stock air box w/ oem felt filter:
https://www.evolutionm.net/forums/at...chmentid=72429

karman hz logged with utec of K&N cone filter:
https://www.evolutionm.net/forums/at...chmentid=72430

the stock setup flows as much as the car needs to inhale
stock turbo, 20psig, 272i/264e cams, 3"tbe

 

A dyno of an intake only shows you how it reacts on the dyno.

1. The stock intake has a high pressure snorkle forcing cool air into the filter.
2. The stock intake isolates the maf and filter from the low pressure air movement in the engine bay.
3. The stock intake keeps hot engine bay temps out of the air stream.
4. If you tune with an open filter you will see as speed rises and air pressure changes the tune changes. Meaning you can tune in 3rd gear but it will be different in 1st and 5th gear.
5. Dyno's do not represent the airflow at 100mph on a track.
6. Dyno's often happen with the hood up so the airflow is inaccurate.

 

That is very interesting guys.

I just got my hands on a dyno chart of the two cars, same mods except for the difference being the higher one has the HKS pod filter and mine with the stock airbox.

With the pod filter on the dyno it makes more power, but the power drops off towards the end, where as with the stock box it holds the power.

 

there u go