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Thread: Hesitation and Lag after Cobb stage 2 install

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    Hesitation and Lag after Cobb stage 2 install

    Hello, I just installed a stage 2 setup on my 2011 sti hatch. Aem intake, perrin highflow downpipe and magnaflow catback exhaust. I loaded cobb ots stage 2 maps. Since then I get some hesitation where its seems like the car loses power or catches when just cruising. It happens a second then will engage again. I dont notice it happening when I am on the throttle. Its just a random lag for a second when maintaining speed and happens randomly. Any suggestions would be helpful.


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    System Operator IGOTASTi's Avatar

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    @HolyCrapItsFast will know where we should start.

    Without you, we cease to exist. Without your support, we stop growing. Without your involvement, we remain at a standstill.
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    Meat Product Toy Spamby's Avatar

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    Does this happen when your just cruising along, higher gears, feathering the throttle to say maintain speed on a slight incline, around 2700-3200 RPM's ? This could be the infamous stumble if that's the case.

    I don't think Cobb's OTS maps support the aem intake anymore. Your maf scaling may be a tad off because of this.

    Just me spitballing.


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    Quote Originally Posted by Spamby View Post
    Does this happen when your just cruising along, higher gears, feathering the throttle to say maintain speed on a slight incline, around 2700-3200 RPM's ? This could be the infamous stumble if that's the case.

    I don't think Cobb's OTS maps support the aem intake anymore. Your maf scaling may be a tad off because of this.

    Just me spitballing.

    Yeah just cruising and maintaining speed. I know the lag you speak of happened before I got the cobb and didn't with stage one. As soon as I installed stage 2 this lag started happening and feels different. Pulled maps for aem intake right off cobb a website. Any ideas on how to fix or what normal maf should be? Still working through all the stuff on the cobb so trying to figure out what I'm looking for on the maf side of things.


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    Also have seen a decrease in gas mileage. It's gone down to as low as 15.9 when I used to sit at about 20 for city driving and like 22-23 for highway.


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    Drinks beer! HolyCrapItsFast's Avatar

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    Did you use the AEM specific OTS map from Cobb? If so then this really shouldn't be happening. As Spamby suggests it could be the 2500 rpm stumble that is plaguing 2008 and up Subies everywhere. If that is the case then only a tune can fix this.

    Just for shitz and giggles you may take this time to check for intake leaks and exhaust leaks, They can have a profound influence on fuel trims.

    If you don't feel like spending the cash on a tune then go back to using the stock intake and revert to an OTS map that is suited for the stock intake. The stock intake is better in any case IMO. an after-market intake is not going to get you anything significant as far as power goes and in many cases, even makes things worse. Unless you are using a larger non-stock turbo that requires you to change the size of the MAF housing, an intake is never recommended.



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    Meat Product Toy Spamby's Avatar

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    Let's see, car drives like crap after install of new stuff?
    Retrace your steps and make sure everything is kosher with your added parts and anything in the area of work.
    Poor fuel economy, hesitation and lack of power sounds like you may have leak, post maf. Easily done since you messed with/replaced the factory unit with a CAI.

    Check your couplers
    Check the maf to ensure it's installed tightly and correctly.


    Holycrapitsfast will most likely want to look at logs. Boost leak test will need to be done if the logs point to that.


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    Meat Product Toy Spamby's Avatar

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    Holy just beat me to it. Lol... 19 seconds


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    Basic Member Jruss's Avatar

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    Re: Hesitation and Lag after Cobb stage 2 install

    I am actually having a similar issue. I have a Cobb downpipe and an AEM CAI. At first I mistakenly loaded the Cobb Stage 2+SF map (don't ask how). The amount of bucking and lag made the car undrivable. I then loaded the correct map, Cobb Stage 2 +AEM intake 91 octane, high wastegate. I noticed a significant change having the right tune and I felt the full power of stage 2. Even though this is a night and day difference, I still have hesitation and lag around 2500-3500rpm when accelerating. This has me convinced it is the tune. While these OTS maps fit a wide variety, you need something more specific to your car when you go stage 2 and beyond to really dial it in. I personally don't think the Cobb OTS AEM stage 2 maps are very good. The stage 1 maps we're great unfortunately. I am still going to double check and clean my MAF, but there isn't any boost leak or exhaust leak in my case. My next step is to reach out to Torqued Performance or find a local dyno.


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