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New WRX owner, 08 with a lot done to it.

4K views 38 replies 14 participants last post by  03bugeyeDude 
#1 ·
Hey Guys. I just picked up an 08 sedan and the previous owner did a lot to it. Not sure if he did it right or wrong so looking for any advise of concerns, things to look out for, parts to swap etc. So far it is driving great pulls hard. Was previously in a VW GTI so it is a big difference. This is the parts list that I found in his for sale ad but I actually got it from a deal so couldn't confirm all of it.

This car has lots of great upgrades the upgrades as follows: VF52 turbo Full Perrin exhaust Perrin TMIC, Tanabe sport springs, Prosport dual gauges, Rota wheels,K-Sport front and rear breaks, K-Sport front and rear slotted rotors, Rallyart mud flaps, Kartboy short shifter, 650cc fuel injectors, Cobb tuned (I believe stage 2 per the access port), Walbro fuel pump, Typhoon coldair intake, cusco front strut bar, Perrin shifter bushing, HKS SSQV
 
#3 ·
It did come with the car. Pretty sure the previous owner has a custom tune on it that I know nothing about. I was looking to swap out the BOV as a friend of mine said the HKS is a cheap one. looking for suggestions on that. What are the issues with the Intake. I have been trying to find more about it, looks like it is one of the better ones, MAF is close to stock and all that.
 
#4 ·
Well, if its been custom tuned then the intake can stay. But, changing the BOV wouldn't hurt anything...change it to one that can recirculate. Cobb or Turbosmart....some people also say Forge.
 
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#7 ·
Any BOV can be recirculated very easily regardless of make or model and HKS makes a quality product. I ran a Greddy 'open vent' for a short time on my MR2 yet the engine would almost stall because the stock ECU was made to calculate the incoming air flow from the BOV, This was the 'flapper door' aka VAF (volume airflow) type meter and the MAF (Mass Airflow) sensor is not much different. In reality if someone wants the "sound" of an 'open vented' BOV they will need to convert to a MAP (manifold absolute pressure) sensor.

Mass flow sensor - Wikipedia, the free encyclopedia
MAP sensor - Wikipedia, the free encyclopedia

;)
 
#8 ·
This is assuming you know how our boost system works and assuming its easy peasy to switch it over. The Subaru is a closed loop boost system and the MAF likes it to remain that way. There is a MAP already on the car...but, its not used in the traditional sense on these cars. To switch the tune to Speed Density (MAF and MAP) based tune isn't something most people need at a stock level tune. Hell, its only really needed on a rotated turbo setup. But, some tuners have been doing it to cars past stage 2. Because it offers some more options. Again...not something most people need at stage 2 or below power levels.

Here is some reading: How Subaru's Factory Boost Control System Works
 
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#9 ·
I actually do understand forced induction engines ;) yet now I have doubts you understand them. If there is a MAP already on the car in what way is it not used in the "traditional sense" and why is it there (if it really is?). Frankly I am surprised and amused that some people do not KISS yet make a mountain out of a mole hill.

I have NO EXPERIENCE with turbocharged engines accept....




 
#14 ·
I'll say this...you have no experience with a flat 4 engine and flat 4 engines are not like a traditional inline 4. Plus, some turbocharged cars have no ill effects from running a open loop boost system. A Subaru isn't one of these cars. It has to be modified to either be blow thru MAF or tuned for Speed Density. Neither is required for a stage 2 or lower car. The MAP on the Subaru's isn't how the ECU is determining the fuel/air mixture. Its MAF fuel based and the MAP is used for monitoring. Which is why its possible to do a speed density tune which would allow for a BOV/open loop boost system and have no ill effects. Its a waste of money at lower power levels. Where money can be better well spent on other options before you'd even need to actually go with a Speed Density tune.


This is what your comparing right now...
<img src="http://unbankingunbelievable.files.wordpress.com/2013/09/apples-and-oranges1.jpg" />
 
#15 ·
It's exactly as Kirt said. The car is designed up oneside and down the other to work with a MAF, not a MAP. Yes it can be converted but it's far from a simple thing. Most people just throw on atmospheric BOV's and call it a day without even understanding the difference between a MAF and a MAP sensor. You can tune for an atmospheric BOV, as Kirt said, by converting to a blow thru MAF or tuned for Speed Density. That's not simple and it also wastes precious intercooled, pressurised, intake air to make a high pitched fart sound.

No more arguments based on appealing to your expertise. We discuss as equals. We're all still learning in one way or another. Posting this or that you did in the past doesn't make you infallible. Stay on topic. The topic is not the expertise level of the other poster.
 
#17 ·
If you can find one replace that HKS with a factory unit. I'm not a huge fan of aftermarket air intakes, but if the car is tuned properly for those upgrades then you should be okay...For the record I am originally from Clearwater, FL so I know the area you live quite well.
 
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