How should I rebuild my 2008 Spec B?

[White_Wolf]

Hello everyone. I'm sorry for posting what must be a common topic here!

 

I am looking for advice or other threads to dig through to figure out how best to rebuild my '08 Spec B. I've definitely been searching but I thought I'd ask outright, too. I bought my Spec B two years ago and had my local Subaru shop do the head gaskets and piston rings immediately. Last week I think it spun a bearing and died on the highway, but regardless, there's a shit ton of rod knock now and I need to rebuild it.

 

The engine was originally modified and tuned by a member here, then sold and... unmodified... by the owner I bought it from. A lot of supporting mods were removed, the engine was put on a 'stock' tune, but the guts stayed in. It was a mess trying to figure out what was going on in there.

 

I'd like to start essentially from scratch. I want to build it right. But I don't have an unlimited budget, and until it died, it was my daily.

 

So I'm looking for advice on accomplishing one of two different goals. Either rebuilding it and getting it running for as cheap as humanly possible and hating how much potential is left on the table (realistic), or building it smart from the beginning and having a reliable (lol) and fun daily driver (god I want to do it so bad). I am not shooting for crazy HP numbers, 350 would make me happy. 450 is about the max I'd personally want to daily drive. I just want to do it the right way and be happy about the build. I have an unreasonable love of this car and the Legacy/Spec B in general and I want to get another 10 years out of it at least.

 

I'm fairly well versed on the supporting mods, but I don't know much about putting a block together. I do have a BNR 18g turbo wrapped up sitting in a box in my garage that was on the car at one point, but the previous owner put a stock turbo that is on the car now. The stock turbo maxed out at 7psi with whatever tune was on the car.

 

Thank you for taking the time to read this, and I would appreciate any advice you may have.

 

<3

Edited August 23, 2021 by White_Wolf

[TorqueLegend]

450WHP sounds like very powerful to daily drive..

 

From what I've gathered from my personal research in looking to mod out my LGT, if you want to go all out you're going to spend like $7K(on the low end) prob more like $10K+ to get the mods to support a bigger turbo. To go with that new engine you'll may need a side of bigger injectors, 3" Turboback exhaust, (catted is fine), prob an E 85 conversion kit, fuel pump, AOS, catch can, TGV delete, maybe even a better TMIC and with that turbo a new intake if you're trying to get above 350 and that's not to mention the Cobb AP and the protune and most likely other things that my uninformed ass is missing.

 

Someone else will have a more valid opinion than I but for what its worth, I would prob sell that 18g turbo, use the funds to acquire a gently used stock turbo and just start slow, maybe a nice catted DP and catback exhaust to go with an AP and tune. You can prob get close to 300 WHP without too much fuss, keep the stock intake and TMIC and then maybe get a nice set of rims and tires if you don't already have it.

[Bobsyouruncl]

Correct me if I'm wrong but 350 wheel is a wild build with a top mount. Anything more iirc requires going front mount. Then your talking more than just "bolt ons?"

 

You really need to start with your budget and work from there.

 

Think about doing things that require pulling motor or trans while it's out.

 

350 is about the threshold for an OE block iirc anything under that it can handle just fine from what I read. I'm not expert tho so take that with a grain of salt.

 

You can do 300 with stock manifolds, up pipe (catless which you should have),aftermarket DP, stock cat back, new TMIC and a "mild" turbo: VF 52 or equivalent. You will be stretching the limits of stock injectors and pump.

 

Your 18g should do 320-350ish with Injectors, fuel, DP, new TMIC from what I've seen. The turbo is a sizeable chunk of your budget so if you can use what you have and it's in good shape you may as well. That 18g can potentially get you close to what you want.

 

You don't "need" an AOS, many people run without one but they are nice and can potentially mitigate some knock and oil consumption risk. They are $400ish so not exactly cheap. I highly recommend IAG street from my limited experience vs my friends with a competitors.

 

Shooting for 300 whp might put you between 9-11k all said and done.

 

When I did my build I went full send on replacing almost everything down to the avcs cam bolts. You don't have to do that but you should clean everything oil touched very thouroghly. If you cant open it up, clean it and put it back together you should replace it.

 

This was my experience https://legacygt.com/forums/showthread.php/new-07-spec-b-owner-possible-turbo-failure-need-education-286096.html

Edited August 24, 2021 by Bobsyouruncl

[White_Wolf]

Thanks for the responses so far!

 

450whp was just a reference for top end. I'd much rather be in the 325 - 350 range, with 350 as a very soft target. HP numbers aren't really that important to me. I'm more interested in good engineering and a drivable tune.

 

Like I said, I'm familiar with the supporting mods and what it'd take to get there. I have most of the mods already either on the car or in my garage.

 

I'm not sure what to do about a new block, though. Do I grab a new oem short and just run stock internals? What would be worth upgrading inside the block for a 325 - 350whp daily while I'm assembling a new engine?

[Bobsyouruncl]

Thanks for the responses so far!

 

450whp was just a reference for top end. I'd much rather be in the 325 - 350 range, with 350 as a very soft target. HP numbers aren't really that important to me. I'm more interested in good engineering and a drivable tune.

 

Like I said, I'm familiar with the supporting mods and what it'd take to get there. I have most of the mods already either on the car or in my garage.

 

I'm not sure what to do about a new block, though. Do I grab a new oem short and just run stock internals? What would be worth upgrading inside the block for a 325 - 350whp daily while I'm assembling a new engine?

 

 

Read this:

https://crawfordperformance.com/blogs/tech/everything-you-need-to-know-about-your-subaru-engine

 

Call the guys at flatirons tuning and ask them what they think. I bought most of my parts from them and spent a lot of time with them on the phone and they were always very helpful.

 

New short block, pull heads and take to good machine shop for cleaning, machining inspection and replacement of valve train parts as necessary.

[whitexc]

As someone going through this process right now, the best thing you can do is have a plan. There are so many parts available for these cars it's easy to get caught up in throwing parts at something that Subaru may have done right. My goal is longevity. The last thing I want to do is wrench on this car all the time. That put me in new short block, heads checked and reconditioned as necessary and a good rebuild on my OEM turbo. I'm not looking for dyno numbers.

 

Spend your money fixing and replacing things that need to be done while the engine is out. Mounts, stops, seals, hoses. Stick or auto? What is the clutch like? You can spend a ton of money reconditioning these cars due to their age before even thinking about putting more power down. Best of luck and keep us posted.

 

I spoke with and purchased a bunch of parts from Crawford. They were very good to deal with.

[Code]

Realistically if you want a 350whp legacy you’re going to spend a bunch more than you think. Suspension, brakes, and tires should be included to keep it safe. You already need a motor so there is 5k ish right off the bat. Add an entire fuel system, intercooler, turbo, exhaust, engine management, tuning, clutch, intake/inlet. 5MT? You’re playing with fire! That much power will find anything that is weak. I make 375hp/425tq at the wheels and it took a lot of dough to do it reliably.

 

Edit- you have 6mt so just a.clutch.

[seanyb505]

If cost is legitimately important to you, I'd lower your hp goal. A simple stock looking rebuild can end up around $3-7k depending on how much work you do, and that's not really throwing a lot of 320hp+ parts at it.

 

I've no doubt my stage 2 build only makes 260-270hp but it's still fun on the way to work, and has been reliable.

[JoeInOregon]

Oem short block, head work jmp vf52, fueling ,downpipe, uppipe, intake, e85 kit, clutch, good buy 10k easily you will hit 300 probably but should be reasonably realiable.

 

Unless you you the work yourself motor install included this is going to cost you absolute minimum 6.5k and that's just doing short block and head work......10k will get you a fun car and it will probably cast you more before it's over

 

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[seanyb505]

Man I thought I did mine about as right as I could afford and it was was $10k. But that included exhaust from the header back and a number of grimmspend pieces.

[JoeInOregon]

Man I thought I did mine about as right as I could afford and it was was $10k. But that included exhaust from the header back and a number of grimmspend pieces.

Admittedly I left a few things off the list but cheapest quote I got for oem short block was 6.5k hell just the Cobb access port is 650, it adds up so quick but ya a nice complete build would ring at least 10k best I can tell, clutch and flywheel another 850 just in parts , I did used parts , new clutch and flywheel , new Cobb access port and intake, used turbo, used fueling and uppipe , new down pipe and I'm at ok 4k or so already

 

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[JoeInOregon]

Admittedly I left a few things off the list but cheapest quote I got for oem short block was 6.5k hell just the Cobb access port is 650, it adds up so quick but ya a nice complete build would ring at least 10k best I can tell, clutch and flywheel another 850 just in parts , I did used parts , new clutch and flywheel , new Cobb access port and intake, used turbo, used fueling and uppipe , new down pipe and I'm at ok 4k or so already

 

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No motor work

 

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[NORULZleggy]

Look I just went through this process. I have 4500 miles on my built. I did take about 2 full years buying parts, and finding deals, and having a plan. With two kids in daycare. Bought my 06 LGT 5MT for 2400 with a bad motor (Trashed motor) from a 34 year old lady. Car had sat for 7 months at an air force base.

 

I made a plan over two years, saved money, found deal on this site and specials across the web. Not including my parts, I spent 8900 with buying the car, and getting the motor installed.

 

I did not mention I got a OEM VF52 and STI short block at a steal from subaru along with other parts from them.

 

I make 315/328 to the wheels and my 5MT is holding my power back. My heads are worked, I have a REAL Radium full fuel system, injectors, big pump, custom lines, blah blah blah and so much more.

 

No one suspects my cars move out so quick, but it's scary cause I need Big brakes and a 6MT to really make it killer. I did replace all brakes and rotors and line with quality stuff, and it sill needs better.

 

Just do not go CHEAP on these cars or they will hate you for it. 320-350 AWHP is nice in these cars.