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replacing turbo. should I go VF40 or VF52?


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trying to decide what option to go with. I want to retain power levels similar to stock, stock look, ideally stock heat shield too.

 

currently 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.

 

VF52 is sounding more and more appealing. Cost difference is about $450 between the two turbo options because if I go VF52 I have to do a tune vs just keeping the stock tune if I go with the VF40.

 

Reliability and maybe a little more pull in higher RPM's are my goals. I was thinking about having a 14.5psi tune done since that seems to be what a stock STI runs.

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I thought you were dead set on staying stock...
Obligatory '[URL="http://legacygt.com/forums/showthread.php/2008-gh8-238668.html?t=238668"]build thread[/URL]' Increased capacity to 2.7 liters, still turbo, but no longer need spark plugs.
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Well that is a stock upgrade. IMO go with the VF52 it's just as much as the VF40 but if you would like to go past stock in the future all you would need is some new injectors and a nice tune and you can get some nice power from the VF52.
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I still think of the VF52 as a stock upgrade considering its an oem part for the STI.

 

I've been researching lately why Diesel turbo's last so much longer then gas ones and the reasons I've been finding lead me to believe a larger turbo may be more reliable. My goal is achieve somewhere between stock LGT and stock STI power with a turbo that spins slower then the VF40

 

Anybody know if the VF52 will fit under the VF40 heat shield?

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The VF52 is an OEM part for the WRX, not the STI. Still an upgrade from the VF40 though, for sure.

 

It should fit under the heatshield fine. Replacing the downpipe is what usually causes folks to cut the heatshield. Seriously though, heatshield fitment should not be a concern that plays into this decision...

"Bullet-proof" your OEM TMIC! <<Buy your kit here>>

 

Not currently in stock :(

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08+ wrx = VF52.

 

No idea what the STI uses, never really cared to find out.

 

EDIT: check out this site: http://cars101.com/

 

Seriously, it has LOADS of accurate subaru info. Should have definitive answers for "what turbo did XXX model year of XXX model have" etc.

"Bullet-proof" your OEM TMIC! <<Buy your kit here>>

 

Not currently in stock :(

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08+ wrx = VF52.

 

No idea what the STI uses, never really cared to find out.

 

EDIT: check out this site: http://cars101.com/

 

Seriously, it has LOADS of accurate subaru info. Should have definitive answers for "what turbo did XXX model year of XXX model have" etc.

 

 

'cmon man.

 

 

04-08 wrx got the td04, 09+ get the vf52. 08+ wrx have the same fitment IC as us.

 

04-06 STi got the vf39, 07 got vf43, 08+ got vf48...all the same fitment

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VF46? Stock turbo for 07-09 LGT, shouldn't require a tune, might be better reliability?

 

wrongggggg. putting a vf46 on a vf40 equipped car will require a retune simply due to the different wastegate actuator. or you can switch over the actuators....i think

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supposedly VF46 does actually require a tune so between VF46 and VF52 it seems like VF52 is logical if I'm going to invest in a tune. VF40 is the only no tune bolt on option.

 

I wonder how reasonable it is to expect a shop to be able to dyno tune a car for reliability and shitty gas when they specialize in making cars as fast as possible?

 

hmmm....decisions...

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supposedly VF46 does actually require a tune so between VF46 and VF52 it seems like VF52 is logical if I'm going to invest in a tune. VF40 is the only no tune bolt on option.

 

I wonder how reasonable it is to expect a shop to be able to dyno tune a car for reliability and shitty gas when they specialize in making cars as fast as possible?

 

hmmm....decisions...

 

 

performance modifying subaru = reliability decreased. 91 oct tunes are common, and preferred if your area of the country has that as premium

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supposedly VF46 does actually require a tune...

Depends on the combination of restrictor pill and actuator you use. It is possible to run the VF-46 on the stock tune if you keep the VF-40 pill but I can't remember now if you keep the VF-46 or use the VF-40 one. Search.

Obligatory '[URL="http://legacygt.com/forums/showthread.php/2008-gh8-238668.html?t=238668"]build thread[/URL]' Increased capacity to 2.7 liters, still turbo, but no longer need spark plugs.
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It's a lot easier to tune for simple reliability than it is to tune a car to run on the ragged edge of reliability while making lots of power.

 

In all honestly, I don't think the VF52 is really all that more reliable than the VF40. It's just that it's newer than the VF40, thus had less time to fail. Plus whenever anybody upgrades to the VF52, they tend to remove any of the issues that caused the VF40 to fail.

 

Your current VF40 is in the 125k range and hasn't failed yet - thus, by that logic, with a new VF40 that will probably last as long, your car is going to be at the 250k mark.

 

Regards,

 

Paul Hansen

http://www.avoturboworld.com

http://www.facebook.com/avoturboworld

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Here's another potential curve ball..

 

VF40's and VF46's are essentially obsoleted by the VF52 from my understanding. Is this true or are VF40's still being manufactured?

 

By purchasing a new VF40 am I getting a possibly lower grade old bottom of the parts bin part as opposed to a new production VF52 possibly better quality VF52?

 

agreed the stock VF40 has made a good run at 123k miles and still feels lively. I'm just a little concerned that I am the exception and that the replacement turbo could actually be worse then what I have.

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Here's another potential curve ball..VF40's and VF46's are essentially obsoleted by the VF52 from my understanding.

 

This "understanding" you speak of. I do not think it means what you think it means.

 

Is this true or are VF40's still being manufactured?

 

Not true AND no.

 

By purchasing a new VF40 am I getting a possibly lower grade old bottom of the parts bin part as opposed to a new production VF52 possibly better quality VF52?

 

Can't answer. Question makes no sense.

 

I'm just a little concerned that I am the exception and that the replacement turbo could actually be worse then what I have.

 

Then get a vf40/vf46 and you will have the SAME you have.:redface:

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VF52 is a nice upgrade. The VF40 heat shield will need to have a small notch cut into it as the actuator on the VF52 lines up a little differently. 5 minute job, no biggie.

 

As for the tune, I would have a good shop dyno tune it as they normally would but have them dial back 3 degrees of timing and 1psi less boost peak and taper. You'd have the same power under 3500rpms but once past 3500rpms you'd be down 10-30whp from the "ragged edge" tune. That would give you a huge margin on safety (you'd have a safer tune than stock). Your engine bay will look 100% stock, you will have greater power than stock, and have a simple reliable setup. Go for it.

My '05 LGT

My '07 Supercharged Shelby

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You've got what, 130k miles? I'd be thinking about a new short block, and not just a new turbo. Our pistons aren't that good to begin with, and yours are getting long in the tooth, as the saying goes.

 

Vf52 will get you more power, but could push your motor over the tipping point. Just my $0.02.

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You've got what, 130k miles? I'd be thinking about a new short block, and not just a new turbo. Our pistons aren't that good to begin with, and yours are getting long in the tooth, as the saying goes.

 

Vf52 will get you more power, but could push your motor over the tipping point. Just my $0.02.

 

:rolleyes: All depends how it's maintained. Back in Spet.2011, at almost 174k, I did compression check, cylinders; 1) 145psi, 2)150psi, 3)145psi, 4)147psi. Check shaft play on my turbo, there is non. http://legacygt.com/forums/../images/smilies/eek.gifhttp://legacygt.com/forums/../images/smilies/cool.gif My OCI avg.15k with Amsoil 0w-30 SSO & Ea oil filters. Running Cobb stage1 93 map, max boost is still 16.2psi. Original motor & turbo are running like new.

 

Almost 194k on my 05 now, 20k at stageII @ 18.5 psi. original motor & VF-40 turbo are still running like new.

 

Plan on upgrading turbo in late Spring early Summer. By then I will be over 200k. My waste gate flap valve is off center. With 15k OCI, it will be ironic that I replace my turbo for this. And have zero shaft play on the turbine shaft.:rolleyes::spin::spin::spin::rolleyes:

 

http://i99.photobucket.com/albums/l293/HAMMERDOWNGT/Subaru/0906112134.jpg

 

Mike

Mileage:331487 Retired/Sold

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