general questions about tuning

[josh_cooper]

Im currently looking to buy a cobb access port and ive been reading alot of information on them. I read some magazine articles explaining how you should buy colder plugs and an air oil seperator. Therefore i was wonder if its absolutely necessary to do that before i do stage one? Any information would be useful im just looking for opinions as of now.

[maus]

If you are going just stage 1 those things aren't necessary. All you would need is an AP. What year WRX do you have?

[josh_cooper]

2011 also when i want to do stage 2 does it matter what dp i get?

[Calvinball]

I believe that Cobb's maps are specifically designed for downpipes with a cat.

[Sinister]

Yeah.... but a lot of people run them on cars without.

[SleepyWRX]

would there be a way besides protuning to get around the catted side of the tunes? or our we mostly just stuck with it?

[EJ257]

would there be a way besides protuning to get around the catted side of the tunes? or our we mostly just stuck with it?

Depends. If you experience boost spikes due to the catless downpipe, you can modify the tune to make up for that. If your car starts boost creeping, that's a mechanical problem and can't be "tuned around".

[SleepyWRX]

Oh that's understandable. Thank you.

[teflon_jones]

What DP you choose matters more in terms of what ones are most effective in that they have the best designs. The ones with cast iron merge collectors are the best to keep EGTs up, which used to just be Cobb and TurboXS, but in the last couple of years a number of others have started using them including CNT, Invidia (I think?) and others. I would also definitely get a catted DP because it will help prevent boost creep, allows you to pass visual emissions checks, and you're not going to hurt your performance at all by having a cat in there. The DP will flow more than you need for stage 2 levels with a cat in there.

I'd stick with the simple bellmouth designs too and not the ones with divorced piping that merges further down the pipe. And having a divorced wastegate is also something that has never been shown to make any improvement, though some companies advertise them as being important (of course they do, they built the part and are trying to sell it!).

[EJ257]

What DP you choose matters more in terms of what ones are most effective in that they have the best designs. The ones with cast iron merge collectors are the best to keep EGTs up, which used to just be Cobb and TurboXS, but in the last couple of years a number of others have started using them including CNT, Invidia (I think?) and others.

Post-turbo EGTs don't really mean much. The only thing you really need to consider with post-turbo and temperatures is heat soak from the downpipe on the TMIC.

I would also definitely get a catted DP because it will help prevent boost creep, allows you to pass visual emissions checks, and you're not going to hurt your performance at all by having a cat in there. The DP will flow more than you need for stage 2 levels with a cat in there.

Not all catted downpipes are created equal. Catalysts closer to the turbo restrict flow more, but do a better job filtering emissions. Downpipes that have the catalyst further down the stream aren't as restrictive, but don't filter emissions as well. At S2 power levels, the restriction may be somewhat negligible, but I would take a catless exhaust over catted any day of the week; I run an EWG, so boost creep isn't an issue for me, however.

[SleepyWRX]

I've read in my engineer book (all I do is read these kinds of.books) it truely does. The point of the exhaust is to expel the exhaust gasses as quickly as possible. And as well a catted exhaust system actually sucks some exhaust back into the engine. Thus hurting performance as-well-as hurting your turbo. That it is why believe it or not turbo charged vehicles are recommended straight pipes. But ill never straight pipe my scooby cause that sounds like crap. And only get a divorced wastegate if your pushing 20+ lbs of.boost.

Not trying to demeanor your response...... Or be a duche canoue :c I assuring you I'm quite the gentlemen. Just sharing my knowledge.