Cold air intake mythbusted

[Jerez]

Very interesting vid.
Decrease in power with performance airfilters
So, with ram air scoops at hight speeds I should be getting about a 1% increase.[video=youtube]

 

[Gregmeister]

This IS very interesting. I have done comparison runs with airbox on and off on my '92 325i and saw a definitive 10KW @ flywheel increase in power with it off, with no ECU correction. Not sure what a CAI would show. I would suggest that the results vary between engine setups. Some cars react better or worse to certain mods. Do the dyno tests for the mod as scientific method would dictate and THEN make a decision on the way forward.

 

[Jerez]

So do these work or not, I'm really confused by this. I've always changed my filters and more recently went for the stage 2 RPI ram air scoops larger elbow and BMC airfilter which in the running world is a pretty decent setup but to be really really honest, I can't feel the difference.For me it's not about the numbers on the dyno but the feel of the car.

10% increase on your 325i which I'm assuming is a 126 kw version is impressive.
Or will the best results be gained from an induction kit exhaust and software?

I don't know... Someone's laughing all the way to the bank

 

[Gregmeister]

Before the teardown on the 325 we did several dyno tests, including removing the rear of the exhaust system and airbox in different combinations and found that there was little to no gain removing the exhaust system, but better results with the airbox removed and exhaust system on. But it also depends on what you start with. The airbox was a standard unit with a pretty used standard air filter. Interestingly, we managed a few runs of around 131kw at the wheels (airbox off), which was certainly impressive for a standard 325 with slightly shot rings and valve stem seals with 244k km on the clock. How and why, I do not know. To see/ feel any real performance gains on a modern engine will, as you propose, take more than just the cold air intake mod. Possibly a software tweak would more than likely be required to better utilise the mod etc. Again, it would seem different engines/ setups react differently to certain mods, and the only way to learn what works is trial and error, and for that you need the appropreate measuring equipment.

 

[Josh-ZN]

Possibly a software tweak would more than likely be required to better utilise the mod etc.

i think you hit the nail on the head with this one.

 

[moranor@axis]

what part of the exhaust did you take off... from the branches back?

 

[Gregmeister]

what part of the exhaust did you take off... from the branches back?

rear section only:

 

[maximus]

Are these guys Australians?

 

[Jerez]

That is being tortilly currect @ Maximus :rollsmile:

 

[moranor@axis]

what part of the exhaust did you take off... from the branches back?

rear section only:

rear has the biggest impact on sound but the smallest on performance this is why they put a huge box at the back... if you removed the mid section you would have seen a larger difference...

Are these guys Australians?

why mate?

 

[maximus]

That is being tortilly currect @ Maximus :rollsmile:

:rollsmile:

 

[UpNcOmiNg!]

I dont know if I can agree with these findings.

I put a Simota on my mouth once and I noticed a 12% gain on the rear. It rear wheels, just rear. Quite impressive if you ask me.