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Discussion Starter · #1 ·
Hey All,

So I recently purchased my first Subaru, it's 2003 WRX, I would like some advice on the valve train and tuning. This WRX I bought came with the following already installed.
VF48 Turbo
1000cc Injectors
Wahlboro 255
STI intercooler
Cobb SRI w/box
Perrin hose after MAF (sorry don't know the proper term)
Catless bellmouth DP (invidia I believe)
3in TBE
3 port cobb EBC
Catless up pipe

It also recently had new heads with ARP studs and cometic gaskets

I was told it was running a 'good' street tune (I know) but was a little rich.

My 2 questions are what do you guys recommend for tuning, and are additional supporting mods needed?
And do these cars commonly need valve lash adjustments? I know the heads were recently done but previously on cars ive worked on alot of times the most improvement I got from a valve adjustment was after a another valve adjustment or head replacement since things settle.

Sorry for my lack of knowledge I've built many cars in my day but I am new to forced induction and Subarus.

Thanks!
 

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Can't quite speak for the valve adjustment but you should find a reputable tuner in your area and take it to them to look over it and then give it a fresh tune. How do you know it's running rich? Did it come with an accessport? You'll likely need to buy one of those unless you want to open source tune which is a little more complicated for subie newbs.
 

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I would find a performance shop and have them go over it verify what if any tune is on the car and have it adjusted accordingly. What do you consider rich? 10.8 to 11.1 on wide open throttle is normal and safe. Turbo cars run a little richer than a normally aspirated engine so what's rich for a na car may be ideal for a turbo application.

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Discussion Starter · #4 ·
I was told it runs a little rich, I believe the street tune was pretty conservative just to get it going and keep the injectors at partial duty and keep it from going lean, all the work was done fairly recently, I'd like to do a Cobb tune w/access port,

You guys think I need any other supporting things before that?
 

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There aren't really any other supporting mods that you would need.. I would check into which 1000cc injectors they are. Hopefully Injector Dynamics. There are a few brands (DW) which I would replace if they were on my car. You would see some gains with a good aftermarket intercooler, but it's not necessary.

In most cases buying a modified Subaru turns into a nightmare, but it's possible that the previous owner knew what they were doing.. if that's the case then the car should run pretty well with those mods and a good tune. I'm wondering what caused the heads to need to be replaced though.
 

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Discussion Starter · #7 ·
There aren't really any other supporting mods that you would need.. I would check into which 1000cc injectors they are. Hopefully Injector Dynamics. There are a few brands (DW) which I would replace if they were on my car. You would see some gains with a good aftermarket intercooler, but it's not necessary.

In most cases buying a modified Subaru turns into a nightmare, but it's possible that the previous owner knew what they were doing.. if that's the case then the car should run pretty well with those mods and a good tune. I'm wondering what caused the heads to need to be replaced though.
I am actually very familiar with this car, it was purchased from a long time friend and alot of the smaller things I actually did before it was mine (spoiler painting, coilovers, stereo install).
The injectors are in fact Injector Dynamics, the car was built very well with excellent attention to detail AFAIK, really tasteful modding imo.
The car started overheating last summer and the car was driven home, water pump and thermostat were changed and then driven more (we didnt know it was headgaskets because we didn't see any smoke or milky oil) still overheating so we changed the radiator and hoses and flushed coolant some more. Still overheating so took it to a shop, in the time it had been driven trying to solve the issue the heads had warped, thus new heads. All professionally installed at a local performance shop with all OEM stuff, that was probably 9k miles ago.

P.S. You dont like DW? I had some on my Integra and never had a problem.
 

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Discussion Starter · #8 ·
Actually it may have just a Cat back, if my understanding of the WRX's exhaust is correct it would go Invidia Downpipe into a catted mid pipe. Would this be a hindrance with the larger intake items, intercooler, and larger turbo? I'm not radically opposed to cats, but I don't need them where I live.
 

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P.S. You dont like DW? I had some on my Integra and never had a problem.
This is one of the first mentalities you're going to have to get rid of. Just because something worked well on your Honda ( A car that's basically impossible to explode), does not mean it's a quality part.

I had a buddy that made an intake for an integra out of PVC pipe with foam stuffed in the end in high school and his car never had a problem, lol. See what I'm getting at?
 

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Discussion Starter · #10 ·
This is one of the first mentalities you're going to have to get rid of. Just because something worked well on your Honda ( A car that's basically impossible to explode), does not mean it's a quality part.

I had a buddy that made an intake for an integra out of PVC pipe with foam stuffed in the end in high school and his car never had a problem, lol. See what I'm getting at?
Absolutely, greatful I have Injector Dynamics then :)

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You dont like DW? I had some on my Integra and never had a problem.

Nope, not at all. At one point I had purchased a set of Dontwerks 1300s for my WRX. Upon install one of the was sticking shut, so I sent them back for replacement. After three or four months I received the replacement set, which this time had two injectors which weren't working correctly.. Once again I sent them back. After another long wait I got another set of non-working injectors. This time I called DW and told them at this point I just wanted a refund since none of their injectors seemed to work properly.. plus I didn't feel like waiting another four months to try another set. They apologized for the long wait, explaining that they were swamped with returns and were having difficulty fulfilling all the warranty replacements in a timely manner.. at the same time they told me that they did not offer refunds to customers who received defective injectors. They were adamant that their policy was that their warranty covers replacement ONLY. They assured me that the next set of injectors they were going to ship me would be thoroughly tested prior to sending them out to make sure I didn't once again receive a defective product. I reluctantly agreed because I felt like I didn't have any other choice unless I just wanted to eat the cost and order a different brand.. that, or I could sell them to some unfortunate soul who didn't know any better (which ethically, I would not do). After another unreasonably long wait the injectors showed up, and to no surprise they also had a bad injector that was sticking open this time. At this point I was more than ready to let my negative experiences with both their products and their customer service publicly known.. I called, and this time demanded a full refund. I told them I had absolutely no interest in trying another set of their injectors. After a long discussion they finally agreed to send me a refund. Months and months went by, no refund. I emailed them a few times and they kept saying that they had sooo many returns to process that they just hadn't been able to get to it yet. In the end it was 14 months from the time I shipped the fourth set of injectors back to them that my refund showed up.

During this time period I knew five locals who were using the same DW1300s, and by the time I had received my refund all five of them had experienced injector failures.. two of them resulting in catastrophic engine failure. To this day I am convinced that they were simply taking the warranty returns, cleaning them, and shipping them out to the next unsuspecting customer.


Other than my personal experiences with them, I have seen several other people with DW injectors (a few of them on this forum) having issues ranging from hesitation on throttle tip in which could not be tuned out (likely due to fuel pooling in the ports caused by poor spray patterns), random misfires, to other complete injector failures. All of which were solved by switching manufacturers.



Actually it may have just a Cat back, if my understanding of the WRX's exhaust is correct it would go Invidia Downpipe into a catted mid pipe. Would this be a hindrance with the larger intake items, intercooler, and larger turbo? I'm not radically opposed to cats, but I don't need them where I live.

Having an aftermarket high flow catalytic converter at your power level won't make a noticeable difference. The added restriction will make a bigger difference as power levels increase, but with such a small turbo I wouldn't bother replacing it.
 
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