replacing turbo. should I go VF40 or VF52?

[nwsurfwakeskate]

^^^ So my 194K motor is running better then New, compression check, cylinders; 1) 145psi, 2)150psi, 3)145psi, 4)147psi.

 

Mike

 

That makes me think your test was run different. Hot vs cold. Maybe different throttle position. Newer battery or external 12v source. Maybe difference in climate too? Idk.

[Max Capacity]

Like others said, don't worry about the number's. Let it go.

 

Find a good Tuner and dyno in your area and you'll be happy.

 

Remember to keep an eye on oil comsumption.

 

I guess you already removed the cat from the up pipe, correct ?

 

You should also think about a new oil return line for the vf52, and a nice DP.

 

Remove the filter from the banjo bolt on the back of the passenger side head.

 

What do you have for tuning ? Cobb AP or a lap top ?

 

Use the next month to plan everything so it goes smoothly.

 

Oh just reviewed your first post, "have a VF40 with 123k miles on it and its leaking a little bit of oil. I want to change it out before it blows up. I'm running a stock tune. Perrin uppipe and a CBE."

 

 

A little more boost then 14.5 would be nice too, I was at 19psi for a while, but the OEM tmic would like it to long.

[nwsurfwakeskate]

I have also done the bulletproof TMIC mod recently. I guess I'm more evidence that they can blow even under stock daily driver conditions.

 

The very next thing I'm going to do is the Infamous IP&T filtered oil supply line kit. wasn't planning on doing the AVCS line because it looks like a bitch to get to and I don't really see the need but the one going to the turbo for sure looks like a good idea to replace. It seems like a simple enough mod too since all you have to do is cap off the old line.

 

I was thinking 14.5psi would be good for awhile when I switch the turbo. If it starts to feel slow then maybe change the fuel pump and injectors and retune for more power. I like keeping everything in its normal operating range rather then trying to max everything out. maxing out the fuel system sounds like a good way to end up with detonation. I've already had 1 injector fail. Seems like the stock LGT injectors were somewhat problematic.

 

Do you guys think it makes much difference if I change the clutch before or after a tune?

 

I've got about 60K on the ACTHD + Streetlite combo. It feels decent still but if you overheat the flywheel it slips pretty easily. My guess is the flywheel probably needs a good resurface. My thought was change it out with an OEM WRX flywheel and clutch kit.

[bmx045]

you do know 13.5 is stock psi, right

[nwsurfwakeskate]

yes I know. but stock boost drops significantly in higher rpms. I'm thinking 14.5 peak but higher average boost. make sense?

[BarManBean]

no.

 

Edit: you are being way too paranoid due to all the failures you read about on the forum. Get a tune to 16-17 psi peak boost, which will still be very conservative. Also ask your tuner to dial everything back a couple degrees from what he finds to be max timing. Call it quits and run your car till it rusts out on you, continuing regular maintenance as you've done in the past.

[bmx045]

you still won't gain much of anything. hell, stage 1 accessport tunes are 15-16psi.... there's no point in peaking at 14.5, might as well peak higher earlier so you achieve greater accel, the vf40/46's fall on their face above 5k. if i were you i'd get a vf52, downpipe, and a tune, and call it a day. it'll be reliable and spunky on the street.

[Max Capacity]

I can attest to this (rode shotgun) wicked fast wagon, the power feels more linear. the vf40 feels like it just sits you back but then falls flat.

 

CT08SpecB said the same thing when he drove the car.

 

To quote bmx045 The vf52 has plunty of spunk for a DD.

[SSpeed]

When you said the turbo is "leaking oil", where exactly is it doing this?

 

Why did you start another thread with basically the same question? Sounds like you've already convinced yourself and are just trying to validate your answer.

[HAMMER DOWN]

That makes me think your test was run different. Hot vs cold. Maybe different throttle position. Newer battery or external 12v source. Maybe difference in climate too? Idk.

 

One you shouldn't every do compression test cold. You motor don't run cold. It runs "HOT" as in 196F-210F. I do the same way that ALLDATA state in the manual of the 2005 Subaru Legacy F4-2.5L DOHC Turbo.

From ALLDATA;

 

INSPECTION

 

CAUTION: After warming-up, engine becomes very hot. Be careful not to burn yourself during measurement.

 

 

 

1. Remove the collector cover.
   
2. After warming-up the engine, turn the ignition switch to OFF.
   
3. Make sure that the battery is fully charged.
   
4. Release the fuel pressure.
   
5. Remove all the spark plugs.
   
6. Fully open the throttle valve.
   
7. Check the starter motor for satisfactory performance and operation.
   
8. Hold the compression gauge tight against the spark plug hole.
   

NOTE: When using a screw-in type compression gauge, the screw (put into cylinder head spark plug hole) should be less than 18 mm (0.71 inch) long.

 

 

1. Crank the engine by means of the starter motor, and read the maximum value on the gauge when the pointer is steady.
   
2. Perform at least two measurements per cylinder, and make sure that the values are correct. Compression pressure (350 rpm and Throttle fully open):
   

Standard: 981 - 1,177 kPa (10 - 12 kg/cm2, 142 - 171 psi)

Difference between cylinders: 49 kPa (0.5 kgf/cm2, 7 psi) or less

 

FYI my motor only cranked 286rpm not 350. As others stated, 120 or above is good & what most important is the difference between cylinders.

 

Mike

[nwsurfwakeskate]

Unfortunately I have no idea how the test was done on my car. The guys at Outback Auto aren't very detailed in the results they show their customers.

 

Still though they seem like a good shop in general. Plan on using them for more work in the future.

 

I'm surprised the test is supposed to be done with the throttle open. I was googling compression tests last night and most of them seemed to call for the throttle plate to be closed. huh...learn something new every day.

[HAMMER DOWN]

That makes me think your test was run different. Hot vs cold. Maybe different throttle position. Newer battery or external 12v source. Maybe difference in climate too? Idk.

 

Unfortunately I have no idea how the test was done on my car. The guys at Outback Auto aren't very detailed in the results they show their customers.

 

How can you type in RED above, when you don't even KNOW how the shop did your car's compression test:spin::spin:.

 

Good luck, Mike

[bigjweb]

http://www.fredbeansparts.com/index.php/subaru-legacy-gt-vf-series-replacement-turbocharger.html

Or here. $200 cheaper

http://parts.subaru.com/parts/2005/SUBARU/LEGACY/?siteid=215892&vehicleid=1430733&diagram=7523261

[jack3000]

I have a 2008 legacy gt with invidia cat back exhaust, cobb downpipe, cobb sf air intake, invidia uppipe, and a cobb v3 accessport. My car has not been professionally tuned, only tuned to a stage 2 cobb tune via the accessport. I am think of eventually upgrading to a bigger turbo, and was wondering what else I would need to get to make the car run properly with the upgraded turb. Also, I don't really know what turbo to get? Please help me out and give me some suggestions

 

Thanks

[Max Capacity]

jack3000 you need to talk with a Tuner before you do anything else.

 

A vf52 is a nice bolt on up grade, the stock heat shield needs some cutting for the waste gate arm, but other then that its a direct bolt on. Yes I bolt the turbo to the up pipe.

 

Read my sig line, that's on stock fueling.

 

 

I use www.tuningalliance.com for all my tuning needs. They can also guide you to the next step. Find a Pro to give you the correct answers to your questions.

[Dujo]

Jack. You need to do a lot more reading before you make any decisions. Stage 2 really is a sweet spot on these cars. When you start getting into stage 3 with a turbo swap, you start needing to replace a whole lot of restrictions in the system. Intercooler, bypass valve, EBCS, turbo, fueling (injectors and pump), clutch (or auto trans valve body), etc etc. Of course a stage 3 car really ought to consider suspension and brake upgrades as well. You need to decide what your goals are and how much you are willing to spend toward them and make a plan from there. A VF52 is a nice mild turbo upgrade. You can get away with less of the suporting mods if you need to, but they still go well with that turbo. A Blouch Dominator 1.5XTR is going to need a lot more. And then there's everything in between. Good luck. Welcome to LGT.com!

[ttnio]

I have a 2008 legacy gt with invidia cat back exhaust, cobb downpipe, cobb sf air intake, invidia uppipe, and a cobb v3 accessport. My car has not been professionally tuned, only tuned to a stage 2 cobb tune via the accessport. I am think of eventually upgrading to a bigger turbo, and was wondering what else I would need to get to make the car run properly with the upgraded turb. Also, I don't really know what turbo to get? Please help me out and give me some suggestions

 

Thanks

 

Welcome!

 

With all those goodies your gt have,you should take get it tune.

 

Your pro tune is less money than getting a bigger turbo.

 

Perhaps you wont need no more mod. Less mod less problem... hehehe

[fahr_side]

What you need to know is here: http://legacygt.com/forums/showthread.php/turboi-wiki-twist-178684.html