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-   -   K&N Drop In Filter Question (

Sub14WRX 01-31-2014 02:31 AM

K&N Drop In Filter Question
Alright, so here we go.
I was thinking about buying a Cobb SF Intake and OTS Stage 1 Tune.
When I talked to my tuner about it, he said that in his opinion the Cobb SF Intake is harder to tune with because it does something with the A/F or something like that. He suggested to me that I buy a K&N Drop In Filter and that I could still use the Cobb Stage 1 Intake Map and run fine.

I just don't see how thats possible.
I may just be dumb, but what is your input guys!?

psinuse 01-31-2014 05:09 AM

Listen to your tuner.

brfatal 01-31-2014 12:43 PM

Only if your tuner is tuning the car for it. You shouldn't use it with Cobb's OTS maps. Cobb has stated several times that drop-ins are not always safe with their maps and this has been backed up by logs.

arcticscythe 01-31-2014 04:39 PM

Always trust your tuner, If you cant trust your tuner then its time to find a new tuner.

As far a panel filters are concerned drop in panel filters experience similar air turbulence as stock so that may be why your tuner prefers a clean drop in filter to the Cobb SF part. I had a really dirty stock paper filter and i switched to an AEM panel a few months ago. I am currently running a stock tune but I will be moving to a stage 1 on or around the 15th of February. I will have more information when I can begin logging with the AEM panel filter but as far as I can tell it allows for a tiny bit more airflow with less pressure from the intake system. I did a write up on the AEM drop in panel a few months back and I've been very satisfied with it. Here's a link to my write up.


To answer your question, Easy is in the eye of the beholder, if your tuner has an easier time working on a stock air-box with a particular brand of filter then that's what i would stick with. Personally i feel like the ECU was able to adjust to the new filter rather quickly and while it may not be explicitly supported by Cobb im sure that the ECU would learn the new filter just the same. besides your intake isn't a hindrance until you are at or beyond stage 2.

TLDR - do what your tuner recommends, always good to do your own research but i trust my tuner to make the right decision about my car : )

brfatal 01-31-2014 05:04 PM

[url=]Blown engine after 20 miles on COBB stage 2--UPDATE - Page 5 - Subaru Impreza WRX STI Forums:[/url]

[quote=Cobb Tuning]
I'd also like to address a few other things in this thread as well to maybe help others in the future. In our experience, the 2008+ cars are very sensitive to air intake changes. For example, I have personally diagnosed cars with aftermarket panel filters that knocked using our OTS maps. Once the filter was replaced with the stock paper one, the car ran perfectly. With any OTS map, it is very important to follow our map notes and modification requirements. We spend days on the dyno making sure these maps run well, but there are small variances in how the cars come from the factory. We make various maps to try to cover these cases (different octane levels, HWG, LWG, etc), but a small change like a panel filter can have a big impact on performance and safety of your car.

itiswhatitisnt 03-18-2014 02:31 PM

So in short...using a K&N drop in filter whilst using a COBB Accessport stage 1 is bad for the car? I am running stage 1 no intake, stock filter. Only COBB Accessport for now.

itiswhatitisnt 03-18-2014 02:33 PM

[quote=itiswhatitisnt;441881]So in short...using a K&N drop in filter whilst using a COBB Accessport stage 1 is bad for the car? I am running stage 1 no intake, stock filter. Only COBB Accessport for now.[/quote]

However, before my COBB Accessport I did use a drop in filter made from K&N for 10k miles and had ZERO issues.

arcticscythe 03-18-2014 03:06 PM

**BAD** is relative, the best scenario for your engine is a perfectly clean OEM paper filter. Because we live in the real world we are faced with different levels of BAD.

Any change to the intake systemshould be followed by an ECU reset, that would allow it to re-learn the new airflow patterns for a given filter, unfortunately the stock tune is only capable of learning to a certain point so an ECU reset wouldn't help if you built a completely open intake unit.

I am personally running an AEM drop in panel because my paper filter was muddy, I have been running it for about 5k miles and it seems to be holding up well. It is definitely not recommended by cobb for their stage 1 tune but the difference in airflow is negligible.

arewmors 03-19-2014 05:31 AM

You should make sure to do data logs if you run a drop in filter like that and make sure it is running well. We've had members have a car running rough and/or throwing bad data from multiple logs. I wouldn't recommend the use of one. Not every car will react the same either. One car may run many miles with no issue and others right off the bat. So if you decide to use it, continually do data logs and look at the info to confirm your car is running well. If you are unsure what you're looking at in a log, send it too Cobb for them to assess and let you know how it looks.

LW_Black4 03-19-2014 04:58 PM

[quote=arcticscythe;430226]always trust your tuner, if you cant trust your tuner then its time to find a new tuner.[/quote]

+1 :)

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