Biggest turbo on stock block?

[alyolles]

No matter what turbo you go with I would upgrade the valve body. It will make a world of difference. Even on the stock turbo.

 

I have had no issues with my car at all but as stated do not drive my car hard all the time and listen to the car. Many have the VF52 and like that for a daily driver and that power level shouldn't cause you any issues.

 

What are your personal thoughts on an 18g? And what would I have to do to the trans to make it safe for a DD

[starionesir]

I'd go with the upgraded valve body and if you plan to brake launch the car get the upgraded diff bushings.

[alyolles]

I'd go with the upgraded valve body and if you plan to brake launch the car get the upgraded diff bushings.

 

Definitely don't plan on brake boosting it. So the trans is slipping if I put stock clutches in but the upgraded valve body I should be good for an 18g? If so think thats what I may do.

[starionesir]

If your going to be rebuilding the transmission I'd get a kit from somebody like ipt instead of using the stock clutches. While your in there I'd install the bushing as a preventative. You'd probably be fine with the oem clutches and the valve body but me personally would upgrade while I was there.

[alyolles]

I was browsing IPTs sight and this is all I came across in terms of clutches. Do you know if aside from the valve body this would be ok all I need? http://www.importperformancetrans.com/catalog/subaru-transmission-rebuild-kit/5eat-subaru-performance-transmission-rebuild-kit-1717.html Also couldn't I probably safely run a 20g then?

[fahr_side]

subaru didnt build the car for big turbos. they cut costs where they could and designed the parts for stock power and a pinch more for safety.

This is assuming the Legacy got a transmission designed solely for this application, which isn't the case. The transmission in this car is a bit more generic and off-the-shelf than that. I'm not sure of all the applications but it's been used in vehicles as torquey and heavy as the Infiniti QX4! Subaru doesn't have the development budget of a Toyota or Honda and pretty much take what they can get with components like these. This transmission can in fact take a lot of torque, IF it's managed properly. Using a big, heavy transmission in a relatively small, light car will lead to very harsh shift behavior and customer complaints unless it's retuned for the application. Subaru's engineers have reduced line pressures to get a nice smooth comfortable shift behavior that is appropriate for the anticipated user requirements and stock engine output. It's not that difficult to get the capacity for more torque back with the right mods, either via the transmission valving or even via TCM requests.

[MichaelLGT]

I am currently in the process of doing the same thing to my 2005 lgt 5eat replacing the stock turbo with a VF52 or BNR16g. Know any brands or vendors that sell preventative parts for my transmission? including brake boosting. thanks

[alyolles]

I am currently in the process of doing the same thing to my 2005 lgt 5eat replacing the stock turbo with a VF52 or BNR16g. Know any brands or vendors that sell preventative parts for my transmission? including brake boosting. thanks

 

IPT sells a lot of stuff http://www.importperformancetrans.com/catalog/subaru-modified-valve-body-163-1.html

[fahr_side]

Hexmods is the guy to look for in this case.

[quick4dr]

i loved my 16g for stock like boosting, however on the 5eat she is underpowered. doing it again i would go vf52 ported and cleaned up up on a simple build. or skip and go right to 1.5xtr like i think im about to (lol) give up a little spool for more mid and top pull! the right manifold and tuning will get me exactly where iw ant to be

[fahr_side]

VF-52 is a step sideways from a 16G. 1.5XTR should not disappoint though!

 

 

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[alyolles]

Worried about blowing something up with a 1.5XTR dont ya think?...

[Mike07LGT]

Worried about blowing something up with a 1.5XTR dont ya think?...

 

Not with a good tune and the engine taken care of!

[alyolles]

Good point but not gonna have money to build the block AND trans lol

[fahr_side]

I was a big believer in pushing the stock block envelope on a good tune, right maintenance etc... right up to the point I popped a HG. Now I feel like the block will do okay at 350-ish IF boost is kept around 18psi, which means running a largish turbo below it's best efficiency range. So there you have rather late spool for the actual power output and a lot left on the table all in the name of keeping the stock block. You push past that kind of power level and you are one knock event from disaster, and the stock ECU isn't quick enough pulling timing and dropping boost to catch it before something breaks. What's the point?

[Mike07LGT]

I was a big believer in pushing the stock block envelope on a good tune, right maintenance etc... right up to the point I popped a HG. Now i feel like the block will do okay at 350-ish IF boost is kept around 18psi, which means running a largish turbo below it's best efficiency range. So there you have rather late spool for the actual power output and a lot left on the table all in the name of keeping the stock block. You push past that kind of power level and you are one knock event from disaster, and the stock ECU isn't quick enough pulling timing and dropping boost to catch it before something breaks. What's the point?

 

The weakest link in the block is typically the pistons. I ran an fp red on a new block with only upgraded pistons for 60k miles with over 400 wheel on pump without Issues. As long as the tune is solid and you dont beat the crap out of it you may be good. I also launched at the track 20+ times and ran 11s in that car. If your stock block is in good shape then just make sure you use a reputable tuner and you can go pretty big i would think.

[fahr_side]

I have tuned well over a hundred EJ series motors to all kinds of power levels, and I'm probably the most OCD tuner out there. Yes, the 2.5 pistons are the weak link in terms of what breaks under common and specific conditions, namely knock. OTOH, I've seen quite a few stock motors spit out head gaskets while having perfectly good pistons. That IMO is just the limit of the stock head bolts to keep the heads on the block long-term beyond a certain boost level.

Sure, there are a few people who can put down 350~400whp on the stock block, but they are the minority and my anecdotal experience says they aren't standing on the loud pedal long or often. YMMV and all that.

I no longer accept stock block cars for tuning past a certain point as every single one of the owners thinks that they will be in that minority that beats the odds. You wouldn't believe the nonsense I hear from would-be customers; Oh, I want to run this 35R because it's sitting on my shelf gathering dust... maybe if we hold the boost down a bit... You will promise the motor will last another 100,000km eh? How about putting that in writing? I promise I won't turn up the boost on the manual boost controller I'll sneakily install the week after I get the car back... much.

[Mike07LGT]

I have tuned well over a hundred EJ series motors to all kinds of power levels, and I'm probably the most OCD tuner out there. Yes, the 2.5 pistons are the weak link in terms of what breaks under common and specific conditions, namely knock. OTOH, I've seen quite a few stock motors spit out head gaskets while having perfectly good pistons. That IMO is just the limit of the stock head bolts to keep the heads on the block long-term beyond a certain boost level.

Sure, there are a few people who can put down 350~400whp on the stock block, but they are the minority and my anecdotal experience says they aren't standing on the loud pedal long or often. YMMV and all that.

I no longer accept stock block cars for tuning past a certain point as every single one of the owners thinks that they will be in that minority that beats the odds. You wouldn't believe the nonsense I hear from would-be customers; Oh, I want to run this 35R because it's sitting on my shelf gathering dust... maybe if we hold the boost down a bit... You will promise the motor will last another 100,000km eh? How about putting that in writing? I promise I won't turn up the boost on the manual boost controller I'll sneakily install the week after I get the car back... much.

 

Great info! Thanks for the post! And I agree 100%. If your building a new motor for a big turbo its a different story. If your trying to throw a big turbo on a motor with 100k miles or more then you arr certainly playing with fire/gambling. Just make sure you have the funds for a rebuild if you go any bigger than a vf52 is what it comes down to. If you want the most power out of a big turbo then expect to pay to play

[alyolles]

Getting a different answer from everybody lol but all great points.

[xtea]

Lots of power equals playing with fire. Not everyone is going to get burned.

 

Buy a used 52 and tune it for e85. If that doesn't tickle you enough and you decide you don't care about your engine then sell the 52 and put something bigger in. You won't lose much except the value of the tune.

 

I'm currently tuning for the 52. I debated the 18g, vf52, and hta68 with my tuner and he suggested the 52 for my purposes, e.g. daily driver, lets keep the engine alive, most driving under 5k, tuning for under 20 psi, fast spool.

[boxkita]

so why do you care how big a turbo you can put on the stock motor with 5eat/ A bigger turbo spools slower on the low end and makes better on the upper end. Unless you thrash your 5eat or drive exclusively in sport mode hammering every shift, your turbo will always be off-boost.

 

Rather pick a turbo that matches your driving style and adjust the engine parameters to match. You'll have much more fun with a very streetable car. This is where a tuner would really help put together a package to match.

 

In direct answer to how big, well, how much money do you have? You could mount any size turbo if you wallet is deep enough. Would it be fun? No, unless burning money is fun...

 

What you might be happier with is a turbo that spools quickly to max torque and has good power to the limit of the transmission, which is 5k? JMP was working on a turbo that hits full boost at 2k, that would pick some hair on your corn flakes.

 

Keep in mind a big turbo upgrade comes with supporting mods, otherwise, you've wasted your money. you need to do the rest of the mods so you don't blow something.

 

For every Phil Fry (who blew his HG at 82k) talking about no problems, there are dozens who took shortcuts on their turbo upgrade. Unless you are an engineer of BAC2.5 cailber or similar, realize there are no shortcuts. Every post on here that starts with I did "x' and it works fine, you should find ever post they made and read thru what "it works fine" actually means to them.

 

I could tell you a HTA68 would be perfect, however, I'm lying. It would suck for you. As it requires alot of supporting mods to work well. My car ran 29k miles with nary a hickup, then the radiator had an issue and the HG eventually blew. However, in the short term it did run, it was a spectacular ride. Would I recommend it to anyone else? No.

 

Reading your other threads, http://legacygt.com/forums/showthread.php/big-problem-apparently-stock-vf40-turbo-241212.html?t=241212, this one has really good advice. Why you ignore it? Send you vf40 off to JMP and let him upgrade it. You'll be happy you did.