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Old 05-12-2012, 12:53 PM   #1
CSibbs
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Default Accessport on 2012 STI and catless dp

Hello nasioc, im in the process of purchasing a 2012 Sti and was going to do a catless downpipe and a stage 2 tune.

Question is will an ots Cobb map be able to clear the cel I will get with my downpipe being catless? Or would I have to get a protune?
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Old 05-12-2012, 12:59 PM   #2
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The Cobb OTS map is for a catted downpipe ... so you will want to look at other tuning options.

Also, and this is just my 2 cents, I would go with a catted downpipe on a 2012. The newer WRX/STi are notorious for boost creep issues when running catless.

You only loose a couple HP between a high flow catted and catless downpipe, and help prevent a potential issue from occurring .. up to you though.
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Old 05-12-2012, 01:10 PM   #3
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Well to be honest the only reason I was going to go catless was because of the $300 difference. I figured since I dont have to be inspected for 4 years with a new car I can get away with catless for 4 years. But I guess I will just go with a catted dp. More than likely, invidia though
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Old 05-12-2012, 02:10 PM   #4
BigRob74
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some guys running cattless and cobbs stage 2. i have my cattless DP on the way, i cant justify spending 600 bux for a catted dp. i will see how bad the creep is, if any..
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Old 05-12-2012, 04:31 PM   #5
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Quote:
Originally Posted by BigRob74
some guys running cattless and cobbs stage 2. i have my cattless DP on the way, i cant justify spending 600 bux for a catted dp. i will see how bad the creep is, if any..
Exactly haha

Do you think it will throw a code?

Catalyst insufficiency?
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Old 05-12-2012, 04:36 PM   #6
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Originally Posted by CSibbs View Post
Exactly haha

Do you think it will throw a code?

Catalyst insufficiency?
i hope not, from what i read the AP is supposed to fix that issue..
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Old 05-13-2012, 12:25 AM   #7
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Quote:
Originally Posted by BigRob74 View Post
some guys running cattless and cobbs stage 2. i have my cattless DP on the way, i cant justify spending 600 bux for a catted dp. i will see how bad the creep is, if any..
And these are probably the same guys posting in here about blown ringlands, boost creep, and other issues. Can you try the Cobb OTS with a catless DP? Sure you can ... but I would log the crap out of it afterward, and just plan for things to not be set up right. If your going to go catless, get a tune for a catless DP ... not an OTS for a catted DP.

I realize the catted DP's are more expensive, but are you really going to sweat about an extra 200-300 bucks on your 30k-40k car?
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Old 05-13-2012, 08:29 AM   #8
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Keep in mind that a catless DP on these cars can potentially result in boost creep that cannot be tuned around. That is, you can potentially overboost even if boost control is disabled (wastegate duty is zero). That means no tune is going to fix it (the ECU has no control over your peak boost at that point) and you would have to go with a mechanical fix (catted DP, port WG, or EWG). The problem gets worse with colder outside temps, so you might find that it works fine now and then you experience the problem in winter.

It isn't an absolute certainty that you will see boost creep with a catless exhaust. But it is a much, much greater possibility that with catted. The colder the temps you see, also increase the chances. The power difference is minimal at stage 2 levels, so it makes sense to consider a catted exhaust and that is why we recommend them for any 2.5L stage 2 car, regardless of what map you are running.

Bill
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Old 05-13-2012, 08:37 AM   #9
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Leave it stock, or goodbye warranty.
If you choose to mod, don't come crying to us when it breaks and SoA won't help you.
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Old 05-13-2012, 08:51 AM   #10
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Quote:
Originally Posted by Cobb Tuning View Post
It isn't an absolute certainty that you will see boost creep with a catless exhaust. But it is a much, much greater possibility that with catted. The colder the temps you see, also increase the chances. The power difference is minimal at stage 2 levels, so it makes sense to consider a catted exhaust and that is why we recommend them for any 2.5L stage 2 car, regardless of what map you are running.

Bill
what about cars running stock intake and exhaust? i keep reading that the intake with a cattless downpipe increases the chance of creep, any truth to that? have you guys tuned cars with cattless DPs?
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Old 05-13-2012, 09:13 AM   #11
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Originally Posted by BigRob74 View Post
what about cars running stock intake and exhaust? i keep reading that the intake with a cattless downpipe increases the chance of creep, any truth to that? have you guys tuned cars with cattless DPs?
An aftermarket intake can also increase the chance of boost creep, although not to the same degree as a catless DP.

Our shops do custom tunes on a daily basis and deal with this issue all the time. Sometimes you get catless cars where it isn't a problem. Sometimes it is a major problem and there's no way you can tune around it and a mechanical solution is the only possibility. In some rare cases, you can even see it happen with catted cars. It really just depends on the car itself, the conditions its sees, and the mods (especially catless vs. catted).

Bill
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Old 05-13-2012, 09:59 AM   #12
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I have an aem cold air intake and a stock exhaust. I just went stage 2 and installed a catless dp. I haven't had any issues yet. I have no intentions on getting a full exhaust and am content with the improved sound now.

I went with a cheap dp because if it did overboost, it would been installed and returned to stage 1.

It sucks that there is no consistent and going stage 2 is a bit of a gamble. Some cars have issues, others don't.
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Old 05-13-2012, 11:27 AM   #13
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Increasing exhaust back pressure is a means of reducing the chance of boost creep. So, just as a catted DP reduces the chance, the stock catback (vs. aftermarket) will reduce the chance (maybe to a lesser degree than the catted DP). So, a catless DP with aftermarket catback has a greater chance of the problem than a catless DP with stock catback. But, generally, a full turbo-back catted aftermarket exhaust has a very minimal chance of boost creep which is why we recommend that combo for stage 2 (vs. any catless configuration).

Bill
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Old 01-29-2013, 08:55 AM   #14
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I'm running catless dp full 3" tbe straight pipe cobb stage2 intake on my 2012 STi with no problems
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Old 01-29-2013, 10:21 AM   #15
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Quote:
Originally Posted by gilroy408 View Post
I'm running catless dp full 3" tbe straight pipe cobb stage2 intake on my 2012 STi with no problems
Some won't have any boost creep issues with a catless DP + intake - it depends a lot on your climate. In fact, you could have no issues at a higher temperature (or a less noticeable overboost) and then significantly overboost if the temperatures were to drop quite a bit. So, as a fake example, you could run fine at 60 degrees, but severe overboost at 20 degrees.

Boost creep usually occurs at higher RPM, so you might not be exceeding your peak boost target, but your boost may not taper at higher RPM like it should. That would be a case where things might appear to be fine, but you are actually overboosting at higher RPM. Data logging is the best way to see how things look.

Bill
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Old 01-29-2013, 12:36 PM   #16
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My vf52 which is essentially the same turbo with a different cold side hasn't boost creeped with a catless downpipe, aem intake and in -30C weather. And yes I do data log. But I do have a torqued performance tune. Not cobb. According to Eric @ Torqued Performance he says he hasn't seen anyone boost creep with a stock intake and catless downpipe. And the ones that do creep are Invidia and Tsudo downpipes with a Cold air intake.
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Old 01-29-2013, 12:53 PM   #17
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My vf52 which is essentially the same turbo with a different cold side hasn't boost creeped with a catless downpipe, aem intake and in -30C weather. And yes I do data log. But I do have a torqued performance tune. Not cobb. According to Eric @ Torqued Performance he says he hasn't seen anyone boost creep with a stock intake and catless downpipe. And the ones that do creep are Invidia and Tsudo downpipes with a Cold air intake.
With actual severe boost creep, tune is irrelevant as you will overboost even at 0% wgdc. We have definitely seen cases of boost creep with stock intake stage 2 GR WRX, but certainly not anywhere near as common as aftermarket intake with stage 2. It is a combination of factors (not one thing) that increase the chances of boost creep on a stage 2 car: 1. aftermarket intake 2. DP design (some designs appear to be worse than others 3. catless DP 4. cold outside temps 5. higher atmospheric pressure (i.e. those near sea level). That doesn't mean if you have some of these factors, that you will see boost creep. It is more the combination of these factors (and severity of each where applicable). For example, at our Portland OR Cobb location we see many more cases of boost creep than at our Plano, TX location and that is due just to environmental factors.

At 0% wgdc, about the only thing you can do as far as the tune is concerned when boost creep is still an issue is to modify the throttle mapping to close the throttle at WOT to try to mitigate it.

Bill

Last edited by Cobb Tuning; 01-30-2013 at 09:33 AM. Reason: clarified statement about boost creep and tuning
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Old 11-24-2013, 03:02 PM   #18
GotBoost94
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Thats weird my friend runs catless DP on his 09 WRX with the stage 2 accesport tune and he has no engine code issues
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Old 11-25-2013, 01:55 PM   #19
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Thats weird my friend runs catless DP on his 09 WRX with the stage 2 accesport tune and he has no engine code issues
As stated above, if you (or your buddy) choose to run a catless downpipe it doesn't mean that you will 100% have boost issues. It just means that you are more likely to have boost issues. It is possible your particular car may run fine. On the other side, if you run a catted downpipe it doesn't mean that you will never over boost. Just that it is a lot less likely that you will have boost issues. Every car/turbo reacts a little differently. Then you throw in environmental factors and you have a lot of variables to deal with. We recommend running a catted turbo-back exhaust with all Stage2 maps because that is the combination that has provided the best and most consistent results.

On another note, just because a car is not throwing any engine codes does not mean the car does not have any issues. The vast majority of check engine lights are emission related and very few have anything to do with the performance of the motor. Datalogging is the best and easiest way to determine if your car has any boost and/or knocking issues. If you are not familiar with the datalogging process, you can watch the video below.

The best way to determine if you are hitting target boost is to watch the TD Boost Error parameter. This parameter is your target boost (including altitude and temperature compensations) minus your actual boost (negative values mean you are over the target by the amount while positive values mean you are under). Ideally you want this value to be between 0 and 1.0 at wide open throttle (WOT), but -1.0 to 1.0 is acceptable assuming that you donít have any significant knock corrections. Overboosting is more likely to occur in higher gears and with colder outside temperatures, so be sure to verify boost levels during these conditions.

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Old 11-25-2013, 02:05 PM   #20
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Listen here fellas...I ran a catless dp with Cobbs stg 2 ots map and spun a rod bearing about 10k miles into it...just because it doesn't happen right away doesn't mean it wont down the line...if Cobb's map says "for use with catted dp" USE A FREAKIN CATTED DP!!! It's my fault this happened and you'll only have yourself to blame if it does...I don't blame cobb in any way lol
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