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Help all new to this... Have 2013 wrx

2K views 5 replies 3 participants last post by  arcticscythe 
#1 ·
What exhaust mods will i need a tune with?

Will i need a tune with a nameless axle back exhaust....
 
#4 ·
You do not need a tune for a Cat-Back exhaust. There are a few other mods you can get away with without a tune (for example, a new Bypass Valve... however not a BOV) but generally speaking most bolt on tunes require a tune.

Do not listen to people who say you do not need a tune for an intake. It will change the relationship between your MAF reading and how much air is actually going into your engine. This is ok when in Closed Loop Fueling (aka not under boost) because your car is always striving to compensate to reach 14.7 AFR.... however when your car goes into boost, Closed Loop fueling is applied, which means your car will take the MAF reading, and add a specific amount of fuel based on a few basic environmental compensations...
This is not good because you could either
a). Go rich, not too big of a deal, your azz will get dirty around exhaust and you might eventually foul up plugs
b). Go lean, big deal, under boost, going lean makes you significantly more prone to detonation (aka knock) which is what destroys our engines
c). Both, in different areas of MAF range.

Putting an intake on with a bigger tube, is exponentially worse, because it completely breaks the relationship between MAF reading and actual air mass, since you have much more air moving at a lower speed. This will cause CELs, idle issues, driving issues, and would reek serious and dangerous havoc on your AFRs.

Here's some common mods you NEED a tune for:
INTAKE < absolutely need a tune
Downpipe
Intercooler
Turbo
Turbo Inlet
Boost Controller / Wastegate Actuator / Wastegate Actuator Adjustment / ANY boost controller VAC lines / MBC
Headers (not technically required, but it will change how your turbo spools and you can't gain all the extra power without a tune)
Injectors
Intake Manifold
Fuel Pressure Regulator
Cat Delete
TGV Deletes
Air Pump Delete (only to turn of CELs and take car out of limp mode)

Am I missing anything? Probably.
 
#6 ·
Depends on what you intend to do, For rally and other off road events 16 is king because you can run taller sidewalls and get more flex/grip. For street use 17 is great because there are lots of options that are very lightweight. IMO you should leave your wheels alone and invest that money in some quality rubber to wrap around your stock wheels.
 
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