2008 gh8

[fahr_side]

Yeah, it's not a Legacy GT but it has the same powertrain bar the turbo. If you can't deal with that, go read something else.

 

Some history:

 

Stage1 tune at 15,000km by Eric Minehart at Torqued Performance. Really nice and smooth tune, no knock at all except for the FLKC you see from slight overboost. Ran on Redline 10W-40 synthetic from second oil change and never used a drop between services.

 

Added BNR 16G turbo at 30,000km, supported by GRB fuel pump, FP turbo oil line, banjo filter deletes and 3-port BCS. I started with a stock GRB downpipe because I was in warranty and although the techs at Subaru never noticed the turbo had been swapped, they definitely would have spotted a shiny aftermarket DP. This time I self-tuned with the help of a much more experienced friend who tunes on the Syvecs ECU for the most part. Then I tried a gutted stock DP which was horrible, leading to the following additions over the next couple of years:

 

Invidia catted DP

Custom 76mm midpipe with resonator

Custom 76mm axleback with Dynomax super-turbo muffler 17665

Tomei EL header

Perrin turbo inlet

Spearco TMIC soon swapped for...

Perrin TMIC

PTP turbo blanket

Innovate Motorsports LC-1 wideband O2 kit

Solid Modifications vent pod

GrpN engine / trans mounts

Per-gear boost control

tinywrex launch control and flat-foot shift patches

 

At the end of that I was at about 310whp from 18psi on 98RON with zero knock, zero oil consumption and stock-like driveability. At around 80,000km the turbo rear seal started to leak a little and for the first time I would have to add a little oil toward the end of the service interval. Around this time I had the coolant overflow from the expansion tank for the first time at a track day.

I had the turbo rebuilt with new bushings, seals and a billet 18G compressor. Rather than fit larger injectors I opted to add a Snow Performance meth injection kit with my own homebrew failsafes. Of course the trans did not seem to like this very much, started complaining with some noises, and so:

 

18G billet compressor upgrade

Snow Performance Stage 2 meth injection kit

EDM GRB 6MT

GRB stock clutch

GRB driveshaft

GRB shift mechanism

GRB starter

Hardrace 6MT transmission mount

Suretrac LSD for R160

DCCDPro center diff controller

Turbosmart Kompact BPV

 

I was still running at 18psi in higher gears and 20psi in 1st and 2nd, no oil use since the turbo rebuild and about 330whp.

 

Having seen my mod budget depleted from the above the engine decided that this would be the perfect time to rebel and it started puking it's coolant out of the tank every time it was pushed over about 1bar. There was no trace of oil in the coolant or coolant in the oil. I tried to find any other reason for this besides a blown head gasket, like weak radiator caps, loose hoses etc. but finally a gas test on the air in the radiator sealed it's fate. At 90,000km the car went into a friend's shop and didn't come back until six weeks later. Having the heads off revealed not only was the gasket leaking on one bank but the head itself was cracked. I had ordered a set of 99.55mm Manley pistons, thinking that at 90,000km I would not have to go larger. Wrong. One bore was quite oval and that needed to go to 99.75mm. More time wasted. To top it off, one of the pistons had a broken ringland that had gone unnoticed in use. That's what you get for driving around with a blown gasket while trying to convince yourself that the problem is elsewhere. It took six weeks to finish the overhaul because it was the middle of the racing season and my builder was too busy for cars without hard deadlines on the jobs.

 

Manley 99.75mm forged pistons

ARP L19 head stud kit

Siruda 1.00mm head gaskets

Stock size ACL bearing set

Gates kevlar timing belt kit

OEM water pump

Infamous Performance secondary air system deletes

Two low-mile heads, new valve seals, valves lapped, clearances reset

72* thermostat

Mishimoto radiator hoses

Koyo aluminum radiator

 

Now I run the motor on a 50/50 blend of Redline 10W-40 synthetic and 40WT racing synthetic. I still have to put about 300cc in by the time 3,000km rolls around and of course it sounds like a busted old tractor unless really hot. Winter tune at 19psi in higher gears and 21psi in 1st and 2nd. Virtual Dyno plot says...

 

 

I wonder how long it will be before the oil consumption will get bad enough that I overhaul it again, and whether I should go then to 100mm pistons or buy a new shortblock. Maybe next time I'll go with Mahle 4032 pistons for tighter clearance and less of the tractor noise. I think I'm not going up further in power as I've been in a few 400whp GH8s and they just feel disconnected and floaty on the awful roads here. DMV here are dicks and will not let you change the engine number on your registration without a letter from Subaru guaranteeing the replacement is exactly the same spec as the original, and they won't provide one of those unless they supplied and installed the parts.

 

More images on photobucket if anyone gives a shit: http://s464.photobucket.com/user/fahr_side/library/

[AMileHighLGT]

The forged pistons will increase the wear on the cylinder walls- especially at the top and bottom of the bore. One of those drawbacks you have to deal with when you go forged. Do you daily drive it?

[Rhitter]

The forged pistons will increase the wear on the cylinder walls- especially at the top and bottom of the bore. One of those drawbacks you have to deal with when you go forged. Do you daily drive it?

 

Any ides how much it increases the wear by? Like 100k you need a rebuild or sooner?

[fahr_side]

It's my DD, yes. I think the oil consumption will get a bit excessive beyond 30~40,000km on forgies but if you can live with that or have the right AOS solution, it will run a lot longer. We will see.

 

Other mods, so you don't assume I'm that idiot that runs around with 350whp on stock suspenders and stoppers:

 

Suspension / steering

 

Koni Sport LGT adjustable inserts / rear dampers

JDM GRF springs

JDM alloy front LCAs

Hardrace GroupN front LCA bushings

Whiteline steering rack mount bushings

Whiteline 24mm front swaybar / bushings

GRF front top mounts

Whiteline rear subframe bushing inserts

Whiteline rear differential mount inserts

Whiteline 22mm rear swaybar / bushings

Kartboy front and rear endlinks

4-row power steering fluid cooler

 

Brakes

 

AP Racing CP5200 front calipers (custom brackets)

330x28mm 2pc front rotors

FHI 2-pot rear calipers (custom brackets)

BR9 290x13mm vented rear rotors

Project-mu HC-CS pads

Braided steel brake lines

ATE Super Blue brake fluid

 

Wheels

 

Enkei SC-23 17x7.5J ET48

Bridgestone RE-11A 225/45-17

 

Enkei PF-01 17x8J ET45

Advan AD08R 235/45-17

 

Cosmetic

 

2009 grille

Replica 2009 rear spoiler

Replica STi front lip

Hatch chrome trim deleted / painted body color

De-badged

Rally Armor mudflaps

GRB carpet (black)

STi carpet mats (can't find WRX ones)

GRB shifter surround trim (couldn't source '09~ WRX one)

[MrTris]

Any ides how much it increases the wear by? Like 100k you need a rebuild or sooner?

 

There's too many factors that come into play to actually put a solid number on it, but, yes, by 100k, a forged motor would definitely need rebuilt. And by rebuilt, I mean new case halves and all. Or sleeved and closed-deck mod'd.

 

It's my DD, yes. I think the oil consumption will get a bit excessive beyond 30~40,000km on forgies but if you can live with that or have the right AOS solution, it will run a lot longer. We will see.

 

How can an AOS reduce your cylinder blow-by? If the pistons are wearing down the cylinder walls, crosshatching, and making them out-of-round, an AOS really can't do much to change that.

 

[AMileHighLGT]

There's too many factors that come into play to actually put a solid number on it, but, yes, by 100k, a forged motor would definitely need rebuilt. And by rebuilt, I mean new case halves and all. Or sleeved and closed-deck mod'd.

 

 

 

How can an AOS reduce your cylinder blow-by? If the pistons are wearing down the cylinder walls, crosshatching, and making them out-of-round, an AOS really can't do much to change that.

 

The cylinders will wear down, which allows more blowby as the rings have a harder time seating to the cylinder walls. There's nothing an aos will do to stop that.

 

MOST motors that have forged internals are racecars. Those go maybe no further that a few hundred miles before they are torn down and rebuilt

[MrTris]

The cylinders will wear down, which allows more blowby as the rings have a harder time seating to the cylinder walls. There's nothing an aos will do to stop that.

 

MOST motors that have forged internals are racecars. Those go maybe no further that a few hundred miles before they are torn down and rebuilt

 

See, that's what I thought, which was why I asked.

[fahr_side]

How can an AOS reduce your cylinder blow-by?

 

 

It won't, but at least you won't have as much knock due to oil in the combustion chambers and you'll lose less intercooler efficiency with less gunk in it.

 

Note I said 'run', not 'run without blow-by or oil consumption'.

[fahr_side]

Happy happy joy joy. Out for a fang in the hills and get a CEL for P0030 and P0134. That's O2 sensor no activity and O2 heater borked. I've seen both of these codes on various Subarus but never both at the same time. LV is also a horrible mess with knock everywhere, IAM at 0.56 or so... ugh. Car runs okay but on throttle the turbo whistle is much louder than before, like I'd installed a shorty intake. Not screeching, but loud. Car ran smooth, AFR was good, but poor power on throttle. Reset ECU to see what would happen, codes came back very quickly but knock and low IAM did not reoccur.

Pulled the O2 sensor out to find it looks like this!

Oops. Where have the caps from the sensor gone if not into the turbine? Oops. Pull the turbo off and lo, the missing bits are stuck in the throat of the exhaust housing volute. Sitting in there they make a nice Bubb Rubb style whooo whooo sound.

At least the cover parts didn't crash the turbine, but the turbine has cracks forming in the hub anyway. No excess play in the bearings and wheels come nowhere near touching the housings. On the other hand, there's quite a bit of oil seeping out the front cover, indicating my need to add oil recently may not be from the motor eating it.

The oil was just due for a change at 5,000km and a look at what came out of the pan didn't show more than the tiniest amount of glitter. I think this is okay as the shortblock was only built 10,000km or so ago and this is only the 3rd oil change. Seems normal to still have a tiny amount of sparkle when the engine is this fresh from being built.

 

I guess I've been pushing the EGTs a bit higher than is safe, causing the sensor covers to crack apart and the turbine to overheat. Oh well, this is why I use my own car as a test mule rather than push the envelope on customer rides... Turbo is out for an overhaul and car sitting for a week. I may look at using a larger exhaust housing or go EWG as pulling boost back down is most unappealing.

[Max Capacity]

You got lucky.

 

That could have been real bad.

[AMileHighLGT]

Screeching. Lack of power. Before you said anything else I knew turbo, but that a/f sensor scares me!

[fahr_side]

Turbine wasn't even damaged by the shards but was cracked from overheating. It's coming back tomorrow with new bearings and seals, plus a new 9-blade turbine.

 

EDIT:

All buttoned up again, with new 9-blade turbine.

[fahr_side]

We had some fun with the turbo swap. Swapped the turbo to find oil still dripping onto the up-pipe after a hard pull or two and figured the rebuild didn't go right. Pulled the turbo off again and sent it back to the vendor. They swapped a few seals and sent it back again. Still seeing clouds of oil smoke off the header. Pulled it out again and noticed the oil line that used to feed the turbo, the one that's been capped off since I installed the FP oi line, is also coated in oil despite being higher than the bottom of the turbo. Yep, the oil line developed a crack and would weep oil after the engine heated up fully.

New n/a style AVCS line in place now with no branch for turbo feed. The fact that the line was capped and no longer had the piece above it fixing it in place probably allowed for enough vibration to fatigue it.

[Max Capacity]

Cracked oil line, that's a new one.

 

Good Luck going forward, sounds like it's running pretty well.

[fahr_side]

It's going great now, thanks. Very impressed with the new turbine aero. WGDC is down around 10% from full spool to redline, for the same boost targets. EGBP should have dropped a lot, but I will cobble together a way to measure that soon.

[fahr_side]

After some development work on another project I decided to change the meth system up a little. I had been triggering meth to come in at 14psi boost and taper delivery up to the max of 20psi. After some study I decided that throttling these pumps, even via PWM, is not the way to go, and leads to poor atomization. At that point I'd set the system to come on at full flow immediately at the trigger MAP level. Once you decide to spray at full flow at all times, it makes sense to then reduce the load on the controller and increase voltage at the pump by using a relay, especially when the controller is in the cabin and pump behind the front bumper. Now the controller triggers a relay and the relay output drives the pump via a much shorter run direct from the battery.

 

I'd also been using a kind of failsafe system where the tank level sensor would both drive the red LED in the cabin, and also trigger an electronic timer relay to shut down the BCS in the event the level sensor circuit was closed for 30 seconds continuously. IOW, if the tank is nearly empty, boost control is disabled and boost limited to actuator pressure (1bar) which is in the safe area of the tune. The problem with this was that the red warning LED would flash on and off when the tank level dropped a little and sloshing let the sensor float bounce around. I've chosen to re-purpose the timer relay instead to prevent the red LED lighting until the sensor circuit has been closed continuously for 30 seconds.

 

 

After more experimentation on another project I also decided to drop the injection threshold to 8psi. It's quite a surprise how much more of the timing map can be bumped up, which makes acceleration in part throttle much snappier.

[Max Capacity]

Can you get a large capacity tank...

 

I'm impressed, nice job there.

[fahr_side]

Thanks. I'm using the stock washer tank. 6L lasts quite a while on the street.

 

 

Sent from some electronic device.

[fahr_side]

Well, my relay idea had a flaw. I had mounted the relay in behind the battery out of the way, in the fender area. Over a month or two since installing it there's been some corrosion and this was the result:

 

 

Upshot of that was the pump coming on at random times but not lighting the green LED in the cabin. I noticed there were occasions when cold idle was a bit rough but didn't think too much of it until one morning it started up on three cylinders and AFR was pegged at 9.5, even with the fuel trims full lean. After a moment it smoothed right out and ran normally but regular LVs taken throughout the day showed the fuel trims bouncing all over the place and AFR about a point richer than stoich at some times during cruise. I'd never seen misfire count before but it was going up to 7 or 8 on all four cylinders. I started thinking about ignition or fuel pressure woes, or AVCS solenoids.

 

Next morning my wife noticed the car was making a buzzing noise while parked and supposedly asleep. A quick check revealed the meth pump was running full blast, had been for some time, and the whole 6 liters of fluid in the tank had been emptied, presumably into the intake manifold. Luckily we caught this before the battery went flat, since I live on a hill and would just go bump start the car down the hill in that case, leading to some very bent rods.

 

So I spent all day yesterday draining first about 4 liters of water out of the sump, then the oil sitting on top of it, pulling the plugs, draining or siphoning the water out of the turbo, intake, intercooler etc., then turning the motor over to eject the water through the plug holes. That done, refilled with clean oil, put everything back together, and she started right up and ran perfect first time.

 

Yes, I will be changing the oil again in a day or two once the engine has been heat cycled a few times and yes for the meantime it's being babied.

 

EDIT: Dodged the bullet this time. No further issues.

 

Next up:

 

Blouch 1.5XTR turbo

GRB intake manifold

TGV delete / gutting

GRB stock TMIC

GRB stock Y-pipe, intercooler brackets etc.

Keep stock GH8 fuel rails as GRB are known to cause a stumble

DW750 injectors

DW65c fuel pump

Omni 3bar MAP sensor

Grimmspeed intake

[fahr_side]

I wanted to use both the Blouch 1.5XTR turbo and a top-mount intercooler. In the past I had used a surfboard-sized Spearco TMIC and hated everything about it, especially how much of a pain it was to remove and replace, and how that needed to happen to do anything as simple as access the clutch fluid reservoir, check the transmission fluid etc. Therefore I decided to go with a GRB TMIC, which meant switching to a metal manifold. This is what I ended up with:

 

GRB Intake manifold

GH8 control valve for brake booster re-purposed as PCV

GRB coolant header tank

GRB coolant hose bracket

Samco GRB coolant hose to radiator top

Samco GRB coolant hose to radiator cap

Samco GRB coolant hose to turbo

GRB BCS bracket, used to also mount the MAP sensor and one fuel vapor purge valve

GRB evap solenoid valve

GRB BPV return hose

GRB PCV hose assembly

GRB PCV hose bracket

GC8 PCV hose connector 3-way

GRB PCV hose

GRB PCV hose

GRB PCV hose

GRB purge valve

GRB purge valve hose assy

GRB coolant and PCV hard pipe

GRB cast top coolant pipe

GRB vacuum hose intake pipe to metal pipe

GRB various vacuum hoses

GRB metal breather pipe

GRB GrpN BPV

GRB TMIC driver side bracket

GRB TMIC pass side bracket

GRB complete intercooler

GRB TMIC Y-pipe

Turbosmart soft 90* elbow for GRB

GRB throttle body top and bottom warmer hoses

OMNI 3bar MAP sensor for 2JZ

GRB Green Bracket Of Death, pass and driver side

GRB splitter

Grimmspeed CAI

 

 

 

Results are about 388lb/ft and about 375whp @20psi with meth on. Working on some stumbles at tip-in while in neutral or with clutch in. Nothing is really helping this, so I'm waiting for different injectors (new EV14 Bosch injectors from DW). Need an AOS solution now, Crawford on order.

[heiche]

been waiting to hear some details about your 1.5XTR project. How does it feel driving it? (aside from the tip-in issues you're working on)

[covertrussian]

That compressor wheel and nut is gorgeous, I'm actually surprised more turbos don't use something that aerodynamically smooth.

[fahr_side]

been waiting to hear some details about your 1.5XTR project. How does it feel driving it? (aside from the tip-in issues you're working on)

 

I like it. Boost threshold is a tiny bit higher than on my previous 18G setup, but response is very similar. Maybe it comes on 2 or 300rpm later than before, but power onset is very linear. Blouch did a stellar job with the wastegate flow and actuator on these units, though the coolant return pipe routing is a disaster if you're using a TMIC. If it turns out I have a boost leak I'm sure I can improve both spool and response further.

 

The wife thought I'd done an engine swap without telling her (I swapped a few of my previous cars). Only downside (aside from the tip-in and oil use issues) is now I have the car trying to wheelie at full chat and the front tires scrabbling a bit for grip, which wasn't a problem before.

 

Efficiency (compressor, intercooling or both) is clearly improved as I can run a couple of degrees more timing than before even though airflow and boost are both higher. It would have been much easier to do a GS or PW TMIC but I didn't like the length of the hoses needed to mate with an STi style turbo, and I like things under the hood to look stock. I could probably gain a little more with a slightly larger meth nozzle as I'm still using the Snow #5 item. The #6 is about twice the size, too much for this application.

[rebourne]

What's the duty cycle on the 750s at this power level? Your top feed? Have you swapped the injectors out or solved the tip in stumble?

 

Do you have a plot of the 18g vs the dom?

 

Can i ask anymore questions, or am i out of tokens? Lol, good stuff, thanks.

[fahr_side]

What's the duty cycle on the 750s at this power level? Your top feed? Have you swapped the injectors out or solved the tip in stumble?

 

 

 

Do you have a plot of the 18g vs the dom?

 

 

 

Can i ask anymore questions, or am i out of tokens? Lol, good stuff, thanks.

 

 

 

The current injectors are the nasty Deatschwerks top-feed 750s made from old 380cc stockers. I think mine were just trashed when DW got them since they're very noisy. IDC will top out around 95%, but remember I am using meth too. AFR without the meth on would only be around 12:1...

 

 

 

I haven't done a full 4th gear pull from 2k0rpm to redline to make a proper comparo yet. I will only get to that when the new Bosch EV14 750cc injectors are in, hopefully sometime this week. I am blowing a cloud of black soot at full load, even my WBO2 says AFR is good at around 11.3:1, which says to me the atomization is piss poor. Hopefully the new squirters will bring the end of the tip-in woes too.

 

EDIT: New injectors made the idle smoother but did zip to improve tip-in until adding more pulse width. More fuel with the modded injectors just had it coming out the tailpipe part-burned. Now I'm adding up to 1.5ms where another car with the plastic manifold only uses a max of 0.5ms extra. Perhaps the difference is in the volume or flow characteristics on the alloy manifold are that much different.