Aftermarket catted downpipes are just as illegal as their catless counterparts.Originally Posted by Mikie13
This is a discussion on Looking to go Stage 2... NEED HELP!!! within the Engine Modifications forums, part of the Tech & Modifying & General Repairs category; Originally Posted by Ryno10rex Don't want to Hi-jack this thread but have a question.. If i were to go catless ...
Some may disagree with me by saying you need to follow map notes to a T, but I'm more in the thought that Cobb says you *have* to use a catted DP because that complies with federal emissions regulations and basically means they don't support you breaking laws by using catless...they are just specifying it to cover their asses.
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2005 STi WRB w/Silver BBS Stage II OpenSource tuned by: Mattypants @ WTF Tuning
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"If I have 10 ice cubes and you have 11 giraffes, how many pancakes can fit on the roof? Purple, because aliens donít wear hats" -Ying
And yeah as EJ and MF said, it's illegal period to mess with any pollution control device so it has nothing to do with them covering their asses. They specify it because having a cat (even a high flow one) makes a BIG difference in the behavior of the engine versus an open pipe with that source of backpressure removed.
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I'll say first that I don't understand why anyone would - in addition to making no real extra power and having a smelly car, there is no guarantee that a protune will be able to eliminate boost creep. If you can't cough up a little extra for a cat, don't mod. your car.
Boost creep is hit or miss. Cobb has it in there because they don't want to have to tweak maps for 100's more users who would have issues without a cat, and furthermore they know they can't tweak it far enough in all cases to solve the problem. Otherwise they would have a map for a cattless DP, as they always did for 2.0l. It isn't like an intake or something that will cause variation in A/F and knock. With boost creep you have it or you don't and you know it if you do.
That being said, you can drive around boost creep especially if you have a boost gauge. Don't start a pull on the highway in 4th at 2k RPM and go to redline etc.. Run lower gears out to the top, and downshift as necessary to keep the RPM up if you are going to floor it. You are basically trying not to stay in one of the higher gears WOT for too long.
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The whole driving around boost creep info is more than enough to make me spend the extra $200.. I guess I was looking to free it up as much as possible but I'll take this as lesson learned from the veterans of the hobby
I've been trying to do my own research off Cobbs website reading their dyno maps. For me to run 17 psi is it necessary to have an EWG, and a 65c fuel pump? I'm looking to reach ~300 hp and by January my mod list will be: Spt boost gauge, Spt Cat-back, catted DP, Cobb AP and short ram intake.