got my cobb last week and downloaded the maps onto the car. Installed the stage 1 91 on the car and actually noticed a nice gain in hp. happy with it so far and have not even tried the stage 1 93 octane. ( supposed to be a 15% gain in hp)
The question i have is about my knn drop in filter that I have on the car. I am being told that the car could have too lean a setting where the car has to compensate and I might be doing some damage to the motor. I was also told to put back the stock air paper element back in the air box.

Is this true .....do I have to watch for some readings in the air/fuel mixtures. Still learning how to read some of the data logging on the car but how can I actually tell if all is good.

 

you should be more then fine. A drop in filter wont lean it out too substantially.

 

Use the HKS Foam filter

 

they flow almost the same wiki. Leave the modding questions for those with experience please

 

Whoever told you that shouldn't be aloud to hold a wrench. No drop in filter should cause you to run lean, or rich for that matter. The MAF (Mass Air Flow Sensor) is located behind (or after) the stock air box, and the MAF meters the volume of air that is being fed into the engine. The K&N (or HKS) filter will have better flow rates than a typical (stock) paper filter, thus more air is getting into the engine. The MAF recognizes this, and thus more fuel is injected into the combustion chamber to balance out the A/F ratio and keep you closer to stoich (ideal A/F ratio). This combination of added air/fuel results in more HP, hence the reason to ditch that stock filter, and pick up a few ponies with either the K&N or HKS filters. A true CAI (Cold Air Intake) will result in bigger gains because you are now pulling in colder air (which is more dense than warmer air), and thus more fuel has to be provided, to again, get you closer to stoich, resulting in more HP. Regardless of the tune from your COBB AP, the MAF is still doing it's job and correcting the A/F to compensate for the increased flow rate.

Bottom line - Keep the K&N, and the few extra ponies you gain with it

 

to answer your question:
nope, youre fine running the drop in filter.


Totally unrelated question:
why would you use a 91 octane map if you are running 93 where you live? Maps only take a few minutes to swap out, and I'm unclear on the advantages of going the route you have taken thus far.

 

Cool thanks that good news

As for the Fuel question: I'm running with 91 octane. Out here in Toronto, Canada 93 IS avaliable but not as often as I'd like. Only one gas station carries ( to my knowledge) 93 and that is Sunoco. Funny thing is I think they got bought out by Petro Canada as all the gas stations I have passed by that used to be Sunoco are getting redone. Petro Canada does not sell 93 Octane

 

Ok great this is good news as I was a bit concerned.
Its funny...the guy at Cobb headquarters out in Plano,Texas was mentioning these lean levels. I hear what you are saying but he mentioned to keep a watch on the fuel trim levels ( long term and short term) and if that the read outs are over or + 8 or Under - 8 then you are in a safe range. Says that the closer you are to 0 on your fuel trim levels the better I am trying to get started on learning how to data log so I can make sense of the data when trying to read it but guess its gonna take a few times to get familiar with it. He basically told me that after you flash the ecu the car runs much leaner levels and that the programme was written with a stock filter in mind. using any aftermarket filter may lean your car out to unsafe levels. Thats why I got concerned. Regardless I think your explanation on MAF does make sense but I wanted to be absolutely sure.
Thnx

 

I downloaded the 2010 ralliart stage 1 91 octane map and installed it on my car and had absolutely no gas pedal response from the engine at all. I reinstalled the stock map and now everything works. My question is can i run the 2009 stage 1 91 octane map on a 2010 ??? Or can someone that was the non downloaded 2010 stage 1 91 octane map saved email it to me ??

 

My car runs a hair leaner with my K&N installed. I used to smell ALOT of raw gas whenever I was coming to a stop at a light (both with windows open and closed). Since I dropped the filter in, the raw gas smell isn't nearly as potent. I usually can't smell it now unless my window is open.

PS - I have not cat. so that's why I smell raw gas.

 

Others have had this problem. Call Cobb tech support and they will send you an updated map.

 

Folks I've done extensive testing with panel drop in filters and the results are surprising. Using a wideband O2 sensor and just swapping the filter from stock to a K&N saw a full ratio change in AFR. The stock filter produced a 10:1 afr at WOT throughout the rev range. Just swapping the filter to the panel filter saw the ratio change to 11:1 AFR. Now thats scary that a replacement panel filter IS having such a big effect on AFR's!

 

I think you also have to keep in mind there is a learning period after you swap out anything. To get a true reading you should disconnect the battery, swap the filters, then reconnect the battery and get 25-50 miles on the car. Then you can run the test with the wide band and compare the findings. If you were running a stock paper filter for months and tested the A/F ratio you should be relatively close to stoich. If you swapped out to a HKS or K&N filter, you will run a 'little' lean for the first 25-100 miles until the ecu learns that you are consistently getting an increase in air volume.

 

Has anyone tested this theory yet?

We have many owners here in Australia who have noticed measurable fuel savings after replacing panel filters with performance filter and the fuel savings remain. This suggests the AFR is leaner and remains leaner.

Would love to see if this has been comfirmed 100%.

 

I downloaded the Stage 1 93 Octane map and tried it out yesterday. My heart always pounds when I am switching maps cause it always asks me to make sure you have a battery charger attached! I have heard that if you are in the middle of switching a map and the battery dies out on you you will have a damaged ecu and that you car would be undriveable! You have to get your ecu re-set by cobb?
Anyway..... did the download yesterday and tried the car out. It is a nice jump in hp on Stage 1 93 v.s Stage 1 91. Just had a question... If I have a Stage 1 93 on my ecu map and need to fill up on 91 octane ( for reasons like avaliability) do you think its a problem for the car? Just curious.