Installing parts outside of a toon

I do NOT recommend installing ANY parts outside of a toon.  It is never a good idea.  Ever.  End of story.

  The only benefit is "cost saving" by not purchasing another toon.  A toon is made for the specific mods and condition the vehicle was in during the tooning process.  When you are removing and reinstalling parts you can have install errors, induce a leak or a number other issues.  There may have even been a small leak or some other minor issue during the initial toon, which may get corrected during the install of new parts.  So there is a chance the car may run considerably different than it did before.   

If you put the car back together and something is off, you are going to email your tooner and start asking questions and wanting him to look at logs, which he will likely charge for.  So in the end the best practice is to gather all your parts and install them all at the same time and get tooned once.  I know many people can't afford to buy everything all at once, but for most stock turbo mods anything you would have to buy would accrue minimal interest on a credit card compared to paying for multiple toons. 

Pretty much the only part that I would say can be installed without a toon is a catback exhaust.  

All of the differences between vehicles is the whole reason OTS maps don't work very well and that we toon the cars in the first place.

• Boring/honing the cylinders can lead to variance in engine displacement
• Decking the block and heads removes material and can lead to changes in compression ratio
• After market pistons and rods are different sizes, shapes and weights than OEM components and can lead to changes in rotating mass
• Changes in displacement, compression ratio and rotating mass all effect how the car needs to be tooned.
• I would never advise anyone to run the same toon, even if you're not changing any other part besides replacing the short block.  

The gear ratios in the ECU need to be updated via an updated map.

• Fixes gear display on dash to match STi gears
• Fixes gear position logging parameter to match STi gears
• Correct gear position reading allows all "per gear" compensation tables to work as intended.
• Whether or not additional mapping changes are needed is a hard question to answer.  I don't believe I've ever had to drastically change mapping after a swap.  But if the clutch on the WRX tranny was slipping at all the car may overboost with a newer clutch.  
• I charge $25 for updating the map. 

How do I know if I need additional tuning?  

• Data!  Be proactive and be prepared.  
• Before  the swap, do a cruise log, 3rd gear log and a log of random boostage in various gears. 
• Put boost, DAM, FBKC, FLKC, AF Correction 1 and AF Learning 1 on the 6-gauge screen. 
• Snap a pic of the AP screen after each log so you have min/max values for everything.   
• Once the swap is complete, load up the updated map from your tuner, then repeat the same logging and monitoring process you just did pre-swap.  
• If the boost levels, knock values and fuel corrections are all in line to what they were before the install, then you’re good.  If the post swap data has overboosting, excessive knock, DAM drops or huge fueling corrections, then it’s likely going to need some tuning.  
• Since you logged pre and post swap, you already have data ready for for your tuner to check.

Do I recommend installing an intake outside of a toon?  

• No.
• The intake is the main part that should absolutely never be installed without a toon. 
• The MAF sensor in the intake pipe measures the airflow and provides fuel to the car based on the MAF scale in the ECU.  So in essence the intake controls the fueling over the whole powerband of the vehicle.  
• Every intake has a different MAF scale.  There is a plot of a 2015 WRX stock intake vs ETS intake vs CobbSF intake at the bottom of the page.  The % difference between the MAF scales will equate to the % difference in your AFR and/or AF Corrections.
• Running an intake on the stock MAF scale or another intakes MAF scale will not fuel the car correctly.
• If you're going to stick with Cobb OTS maps, then just get the CobbSF intake.  
• When companies say "our intake doesn't require a toon" they really mean "the fuel corrections/learning are within a range that we deem acceptable to run without a toon".  
• I've been in California for 20 years and before that I lived in AZ.  So I have always dealt with crappy 91 octane.  But most intake manufacturers live in states that have 92 or 93 octane.  So they don't really care about 91 or ensure that they thoroughly test it on 91 octane without a tune.  I bet you can check every intake maker's website and not a single one will have a dyno chart on 91 octane.  
• Mishimoto actually took my advice and added a disclaimer on their intake "Mishimoto does not recommend using the intake with 91 octane fuel and no tune.  Using the intake with 91 octane and no tune may damage your engine."  Although it's basically hidden.  It's not on the main page with the intake features, you have to click on "Tech Specs" and then it's at the bottom of the page.  But C+ for effort.  
• The main issue is that 99% of aftermarket intakes are larger than the stock intake, this means that the air fuel ratio (AFR) at wide open throttle will lean out if you install it on the stock toon.  Anyone that has logged a stock vehicle on the stock toon on 91 octane has seen that the cars already knock excessively and the DAM is almost always below 1.  
• Leaning a car out that is already knocking will just make the car knock more.  Installing a part that will cause more knock is a horrible idea.  
• When Cobb carried OTS maps for other manufacturer intakes they had OTS maps for the ETS and Mishimoto intakes....and both say their intake doesn't need a toon.  Cobb would not have wasted the time to make separate calibrations if it wasn't necessary.  

The stock boost controller is a 2-port EBCS and operates at 10 hertz.

The aftermarket EBCS' are 3-port and operate at 30 hertz.  

The variation in the frequency between the two solenoids is the reason you get the flutter sound with an aftermarket EBCS.  The flutter can be tooned out by adjusting the frequency.

Do I recommend installing an EBCS outside of a toon, no.  

Running an intercooler without a toon is mostly pointless.  Almost all the gains from an intercooler come from being able to toon the car with more boost, timing and a leaner AFR.  There are many different intercoolers with different cores, different pressure drops, different efficiencies, etc etc.  

Can an intercooler be run without a toon, yes.  Is there any guarantee that the boost and fuel trims will stay in check, no.  

Do I recommend installing an intercooler outside of a toon, no.  

Headers change the diameter, length and shape of the piping that is feeding the turbine wheel.  The turbine wheel is what drives the compressor wheel and ultimately makes boost.  

Can a header be run without a toon, yes.  Is there any guarantee that the boost and fuel trims will stay in check, no.   

Do I recommend installing a header outside of a toon, no. 

Can an AOS or CC's be installed without a toon, yes.  I have tested both the street and comp AOS' and neither changed the fueling or boost by a significant amount.  

BUT, like it says in the first paragraph on this page, installing any part opens yourself up to induce leaks or other issues.  If an AOS line is kinked, hooked up backwards, PCV hooked up backwards, PCV failed, etc etc...then these issues will not be easily visible by indications on the AP gauge screen.  

Do I recommend installing a AOS/CC's outside of a toon, no.