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Discussion Starter · #1 ·
Modifications list:
ENGINE AND POWER
-Cobb Accessport V2 (Will come with the car. It has an E85 map for the current setup, a 93 map for the current setup (has many revisions and has been my main map for at least 90k miles), and a 93 map for the current setup tuned by JRTuned of Prime Motoring
-Motive Autowerks/Zerolift TGV Deletes
-NGK One Step Colder Plugs (Last replaced at 97,168 miles)
-Invidia Catless downpipe with wideband bung capability
-Invidia Q300 catback
-Fuel Injector Clinic 900cc injectors
-AEM Cold Air Intake (I will supply cleaning solution for the filter)
-Tomei Type-S Fuel Pressure Regulator
-Deatschwerks DW65c fuel pump
-IAG Air Oil Separator (installed at 76001 miles)
-Gates timing belt kit with water pump (installed at  97168 miles)

TRANSMISSION AND BRAKES AND DIFFERENTIALS
- Competition Clutch Stage 2 (installed at 100516 miles). Ran an ACT Stage 2 clutch prior for about 67-70k miles
-Kartboy short shifter (installed at 97168 miles)
-DBA Street Series all around (installed at 71,752 miles)
-Hawk Performance Ceramic Brake Pads all around (Last replaced at 71,752 miles)
-Goodridge SS Brake Lines Front + Rear
-Stoptech SS Clutch Line
-Motul RBF600 brake/clutch fluid (replaced at 100516 miles)
-Red Line 75W90 with Red Line Lightweight Shockproof Gear Oil Mix (replaced at 97168 miles)
WHEELS AND TIRES
-235/45/R17 Continental Extreme Contact DWS06 tires all around
-Rear tires changed at 81,400 miles
SUSPENSION
-Whiteline 24mm Front sway bar
-Whiteline 22mm rear sway bar
-Kartboy endlinks front and rear
-Whiteline gearbox mount bushings (positive shift kit)
-whiteline rear diff mount inserts
-whiteline positive power kit
-Group N Engine Mounts
-Group N Transmission mounts
-Kartboy pitch stop mount
-Perrin front shifter bushing
-Kartboy rear transmission bushing
-Whiteline transmission crossmember bushings
-I have a 2012 wrx

I was at my local tuner shop talking about adding some quick easy HP to my car by adding a bigger turbo but I said I did not want to add anything that my car may not be able to handle. He said I could add 50-60 hp easy. I know the WRX's engine can handle about 400hp. I was talking to a couple friends about some of the options I was thinking about for the car and what the guy at the tuner shop (TPG Tuning) mentioned. One thing we talked about was if I did add this turbo I could burn up my ringlands. Other options before that I was thinking of doing is doing a rebuild with a new rotating assembly and cams. I have 115k on the clock so it sounds like an ok idea. Right now I'm pushing 350wtq power and she runs wonderful. Also the 5 speed I have hears some bad stories about some going out with not much more power than stock. I know sometimes you may get a weak one. A part of me said be happy with the power I have and work on the look of the car. Wile I'm doing that maybe I could get a stage 2 block and just do a whole engine rebuild the right way. Adding a bigger turbo would gain a nice HP jump until something went bad. I feel like I may be jumping ahead by adding that turbo before i should. I am still a noob and I want 450 HP but all the reading I've done and people I've talked to I get so many mixed answers so I figure I'd hear what advice sone of you offered
 

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Discussion Starter · #3 ·
Yea true but I don't want to have problems,so I'm asking with my mods putting a Cobb 20g or FP Green on does anyone think it's a bad idea? I'm concerned about my rinlands and pistons. Anyone with any knowledge of building cars I'm open ears
 

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I'm open ears
I'm forced to question this though, sorry. The correct stance is to leave the car alone, and we all know it. There is no scenario where the car is modified as you suggest and reliability is unaffected. The dissonance is created by those that either ignore this or don't care, and do indeed think it's a good idea.
 

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You have 2 options. Don't do it and maybe get long life out of the car, or do it and almost certainly cut the life of the engine to nothing.

At a God honest 450whp your gonna want a built block. Your factory one may last a little while if you grandpa around and never run it out, but if that is the case why shoot for that goal.

You want 450 because you want to use it, and a factory short block isn't going to cut it. You can call up turn in concepts in Cincinnati and buy their beefy badger. That should get you some durability, and I believe they offer it as a closed deck so you shouldn't have too many issues with warping the cylinder if you get on it a lot or take it to the strip.

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Discussion Starter · #6 ·
Thanks XJ that's what I needed to hear. I was getting a lot of mixed answers and want this done properly and I just knew bolting that on would be a terrible idea but you know I'm still a noob and trusting a reputable tuner shop should be something I can do. Another question I have is I was looking into doing a rebuild,picking out a nice rotating assembly and cams. On a mustang dyno I hit 350 hp and 350 wtq. My question is can my stock block handle this rebuild bored .030 over? Then I was going to put on the Cobb 20G turbo. Is this possible to do and run and handle it with nopb? I have a buddy that likes v8 power and builds trucks he seems to feel it will work nopb. What do you think
 

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I was looking into doing a rebuild,picking out a nice rotating assembly and cams. My question is can my stock block handle this rebuild bored .030 over? Then I was going to put on the Cobb 20G turbo. Is this possible to do and run and handle it with nopb? I have a buddy that likes v8 power and builds trucks he seems to feel it will work nopb. What do you think

Short answer, no.



One thing, with that turbo you will be losing power with aftermarket cams. The stock cams will generally be the best choice for anything up to 550-600whp. That Cobb 20g won't move near enough air at 7000rpm to make use of more aggressive cams. You would be losing a lot of power down low and only have marginal gains in the very upper rpm range. For the vast majority of people that isn't a very good trade off.


On the subject of built blocks, a rebuilt/built engine is going to be FAR less reliable than a stock block assembled by Subaru in a factory. If you have disposable income and are only looking to use the car for weekend duty then it is an option.. but I certainly wouldn't have Billy Bob who builds v8s in his backyard touch the inside of a Subaru engine. I would only consider purchasing an already assembled blueprinted block from a very reputable Subaru engine builder/machinist (ie. IAG).

As far as boring the Subaru block 0.03" over, I wouldn't unless you're dropping aftermarket sleeves in it. 0.03" will leave you with virtually no cylinder lining left. Any significant cylinder pressure will cause it to mushroom out at the top over time until it fails. The very most you should ever bore an ej255/257 is .5mm, and I wouldn't even do that if you're looking at running over 26psi or increased compression ratio. .5mm over should be alright for a moderate boost stock compression ratio 400-450whp, but I don't see a point in taking that much off unless your cylinder walls are all jacked up, and if that's the case I would just pick up a clean set of used case halves for $350-$400 instead. Of course if you're changing the pistons I wouldn't use stock bore pistons either since you will have no way of getting the piston to wall clearances right. Your best bet is to take off as little as possible and pick the alloy of your pistons based on your power goals. For example, I chose to go with 99.54mm (0.04mm over) 4032 alloy pistons for my engine. Anything beyond 500whp I would definitely ditch the stock sleeves and/or have inserts pressed in to reinforce the tops of the cylinders regardless of bore.
 

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MainFrame said:
One thing, with that turbo you will be losing power with aftermarket cams. The stock cams will generally be the best choice for anything up to 550-600whp. That Cobb 20g won't move near enough air at 7000rpm to make use of more aggressive cams. You would be losing a lot of power down low and only have marginal gains in the very upper rpm range. For the vast majority of people that isn't a very good trade off.
26X duration cams shouldn't be too bad in terms of reducing low-end. Unfortunately, they're just as expensive as the big boys, so most people don't get them, so there isn't a lot of data with them. Also, I don't recall ever seeing a before/after with just those size cams to see what the powerband difference was.

I agree that on a 20G, cams wouldn't be the wisest way to spend your money. If you wanted more power, something like a rotated GTX3071R would be better. I don't know why anyone would go with a stock-location turbo when they are pulling the motor to install a built one in its place; the price difference isn't all that much (you can sell any stock-location parts to help recoup), and you can have a much more efficient-running turbo.
 

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Discussion Starter · #9 ·
Thanks for the info everyone. If I would have any work done with the engine I would have TPG Tuning do it they are the best around where I live. Maybe I should just be happy with the power I have she runs great and I don't want just a weekend driver. All the options I come up with don't seem to be the right one. I figure the bigger turbo would be hard on the pistons and rings so I figure a rebuild new rotating assembly would help but no go. Honestly I have a new problem I think slowly coming up. I think I have a synchro or 2 going bad when I run through the gears at high RPM sometimes I will get locked out of 3 rd or 4 th so I been looking into a 5 speed rebuild since this just happened again today. This happens maybe 2 times a month. Any of you know any reputable people that rebuild and build up trannies. I'd like to do this first considering this situation just happened again today. Everything else's can be on hold this this is fixed. I'd like my 5 speed to be build up to be just as strong as the STI 6 since it's crazy expensive to swap it and a big ass job
 

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$poolnWRX said:
I'd like my 5 speed to be build up to be just as strong as the STI 6 since it's crazy expensive to swap it and a big ass job
Just do the swap. Like with a rotated turbo build, you're not looking at much difference. Even with a stronger gearset (PPG, Albins, etc.), you're still dealing with an inherent weakness in the transmission, which is the case.
 

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26X duration cams shouldn't be too bad in terms of reducing low-end. Unfortunately, they're just as expensive as the big boys, so most people don't get them, so there isn't a lot of data with them. Also, I don't recall ever seeing a before/after with just those size cams to see what the powerband difference was.

I don't know why anyone would go with a stock-location turbo when they are pulling the motor to install a built one in its place; the price difference isn't all that much (you can sell any stock-location parts to help recoup), and you can have a much more efficient-running turbo.

I would think s1 cams wouldn't be bad for >400whp, but when I was filling Mike McGinnis in on my engine build he said I would be way better off with stock STI cams than the 272s I have. I asked him about 264s and he said stock was best for anything under 600whp. Then you have the whole cost/benefit issue you brought up. Cams are $1000+, then tack on another $600-$1000 for the valve train. Plus apparently now GSC, Kelford, and Cosworth all have some serious issue with chewing up the lobes. https://forums.nasioc.com/forums/showthread.php?t=2642831

Totally agree with the stock location sentiment. Rotated turbos are cheaper, there are tons more options, it's easier to work on, they spool faster, AND make a good deal more power in the top end.. efficiency is king.





I'd like my 5 speed to be build up to be just as strong as the STI 6

Impossible.
 

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MainFrame said:
I would think s1 cams wouldn't be bad for >400whp, but when I was filling Mike McGinnis in on my engine build he said I would be way better off with stock STI cams than the 272s I have. I asked him about 264s and he said stock was best for anything under 600whp. Then you have the whole cost/benefit issue you brought up. Cams are $1000+, then tack on another $600-$1000 for the valve train. Plus apparently now GSC, Kelford, and Cosworth all have some serious issue with chewing up the lobes. https://forums.nasioc.com/forums/showthread.php?t=2642831
When I pull the motor, I'll be looking at going with a 400whp turbo (GTX3071R / EFR7163) on pump gas. I will probably spend the money on the S1 cams (and the associated costs associated with it).

Dom's thread was before the new billet GSC cams; I don't believe the new ones have had issues like the last ones. I could be wrong, though.

While I somewhat agree with Mike, I think there needs to be some clarification. For people seeking big power, the $1000+ spent on cams and valvetrain modifications isn't worth it, when you can just choose a bigger turbo and get better ROI (at possibly the same cost as the smaller turbo). That said, when powerband hunting, I think a mild cam is a worthwhile option.

This is probably the most desirable powerband I've ever seen in a Subaru:


2007 STI (single AVCS) with Kelford 264 cams (link)

Obviously, there are a lot more modifications on that build, but you can't deny that's impressive. Yes, JR made 1200+whp on his Subaru, but I would rather have this.
 

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EJ257 said:
This is probably the most desirable powerband I've ever seen in a Subaru:
Yes, dyno numbers vary, so take the absolute values with a grain of salt, but these are DynoJet figures...

Show me another Subaru with:
550wtq/400whp @ 3750 RPM
625wtq/500whp @ 4250 RPM
>500whp for ~2750 RPM

This would be incredible to drive on the street.
 

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I've heard several builders mention that D25/W25 heads benefit most from added lift vs. the duration of a mild cam.

I can't imagine that powerband is the result of ONLY a cam and not some mild PnP.

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zax said:
I can't imagine that powerband is the result of ONLY a cam and not some mild PnP.
Per the build thread:
Kelford 264/260 Duration, 10.70mm/10.20mm Lift.
Stock heads.
I would agree that lift is probably the biggest factor, but the duration helps keep the powerband where you want it for street driving.
 

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Edit: NVM, I was reading the horsepower as the torque curve. It's what I expect out of OEM heads.

You say that's a perfect torque curve, but I'd want a bit more drama. Horsepower peaks then holds for 3000rpm. Not my cup of tea.

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zax said:
You say that's a perfect torque curve, but I'd want a bit more drama. Horsepower peaks then holds for 3000rpm. Not my cup of tea.
Street car, which is what 90% of what people on the site would be using the car for. That is enough power to likely break traction on even high-end summer tires, even at 255/35/18 (closest match to 225/45/17 that comes factory).

EJ257 said:
Yes, JR made 1200+whp on his Subaru, but I would rather have this.
EJ257 said:
Yes, dyno numbers vary, so take the absolute values with a grain of salt, but these are DynoJet figures...

Show me another Subaru with:
550wtq/400whp @ 3750 RPM
625wtq/500whp @ 4250 RPM
>500whp for ~2750 RPM

This would be incredible to drive on the street.
Please show me a better street powerband.

In addition to what I mentioned above, 450+whp for 3500RPMs.
 
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