Subaru WRX Forum banner

Cobb stage 2 question

5K views 5 replies 4 participants last post by  RoboTuner 
#1 ·
Hey, greeting from Kansas everyone. So I bought a 2016 STI the other day and the guy before me had a Cobb SF intake, ETS extreme cat back and a Cobb accessport currently running 91 Stage two. My question, is it safe to run a stage two like that with no fuel upgrades and with a stock down pipe? Or should I just run that 91+SF? I would rather not mess up my car. Any advice is very much appreciated.
 
#2 ·
Your fueling system by all means can supply plenty of fuel to the engine at Stage 2. However a stage 2 generally is designed to work with an aftermarket CATTED downpipe.

You can run a Stage 1 map safely on that setup
OR
Throw on an aftermarked catted DP and enjoy the power bump safely

:)
 
#3 ·
Or you can run 93oct on your stage 2 91oct map and let the ECU do its job. You shouldn't be using 91oct in an STi anyways, if the manufacturer wanted to do that they would have from the factory. You can always run 93 on a 91 map, the OE dp won't hurt anything...might just kill the cats faster and have slightly reduced spool over what the map COULD do.

OTS maps are lean anyways so why worry about piss water 91 and if you're making power. If you are really worried about reliability then call around the reputable subie performance shops in your area and get a protune for 93oct and the parts you have. If you are using a 91oct map because you don't find 93oct at most gas stations then that would be a different story. Otherwise, 91 is utter crap for "reliable fuel".
 
  • Like
Reactions: GSMNZ
#4 ·
Or you can run 93oct on your stage 2 91oct map and let the ECU do its job. You shouldn't be using 91oct in an STi anyways, if the manufacturer wanted to do that they would have from the factory. You can always run 93 on a 91 map, the OE dp won't hurt anything...might just kill the cats faster and have slightly reduced spool over what the map COULD do
It's not a good idea to run a Stage 2 map on a stock downpipe because the Wastegate Duty Cycles are tuned for a much more free flowing exhaust which allows for much faster spool but also completely changes the relationship between the boost control system and boost. It will likely never be able to reach target boost because WGDC will be much too low.... or worse?
 
#6 ·
Knowing you don't get good fuel then yeah, use the Stage1 map (double check to verify it supports the SF). Get used to it and take logs and hit up some of the e-tuners for a "reliable stage1 map" using your logs. Getting a wideband A/F would be ideal, with that and logs you can get a solid map for your setup for much less than a dyno tune and it will be more realistic to what your engine would see every day, not to mention if you ask for something on the conservative side you may even see better MPGs.
 
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top