Upgrades vs Lifespan and Reliability

I've been lurking and learning for a while on the forum. I'm about ready to get my first Legacy GT. I'm curious about how power upgrades affect reliability and longevity?

 

1) Given mods to ~300 whp/wtq, what has been people's experience with affects on the car's reliability and lifespan?

2) How about 350whp? Is there a relative point at which parts break or wear out considerably sooner?

3) Given a power upgrade to the 300+ range, what else should be upgraded to maintain reliability (clutch, CV joints, wheel bearings)?

 

I had an 02 Audi S4 at one point with turbo upgrades. Although it was a torque monster and a hell of a lot of fun to drive, it was just too maintenance intense and I'd rather not repeat that experience.

I'm pretty happy with my wagon. I just put a new ej257 short block in it and the basic required parts. I plan to drive itfor at least another 150,000 miles.

 

They say 350whp is the max you want for a stock block. On a Mustang dyno I made 280whp with stock fueling.

 

A decent clutch and better brakes are all you really need to stay healthy at your power goals.

 

You know about the hub issues other than that keep the oil topped off.

what else should be upgraded to maintain reliability (clutch, CV joints, wheel bearings?.

 

Wheel bearings

 

Your questions don't matter and I'll tell you why. Before you go stage 3 you need to go stage 2. A downpipe and a tune are going to yield the biggest results with this car dollar for dollar while retaining oem driveability and use. Anything beyond that adds more support parts, more maintenance and more work.

 

IF after you go stage 2 and get a huge bump on powa, you still want more and to spend more money, you continue to research stuff.

 

After all... Stage 2 parts are a prerequisite for stage 3 anyway. My 2c. You will likely find Stage 2 to be plenty for you for a while, hopefully for the duration of ownership. It would most fit your maintenance parameters.

 

EDIT: At stage 1/2 I plug the laptop into the car once a month to once a season in a DD. At stage 3+ I plug the laptop in EVERY tank or every weekend. Whichever comes first.

Thanks for the info. I'm pretty confident that I like the 300-325 whp range in my daily driver. Like I said, I felt right at home in the S4 with the K04 turbo conversion and supporting parts. I never had it dynoed, but it had more than enough power for my needs. If I was in crawling traffic and needed to jump quickly into another lane, I just put my foot down and I was there without hesitation, sometimes losing traction in all 4 tires if I wasn't careful. As with any German car, though, especially a modified German car, it just required too much fussing. At that point in time, time-money-responsibility ratios allowed me to have a great time spending my evenings tweaking things, but not so much anymore.

 

As I've gotten a bit older, I still like some kick under the hood, but I don't have much time to allocate to wrenching on cars in the garage and I'm much more concerned with reliability and maintenance. That's one of the main reasons I like my Subarus. I have beat the hell out of my Subarus and they are almost indestructible, given basic maintenance. I also drive long distance occasionally and I can't afford to have things snap, pop, or break out in the middle of nowhere. I'd rather build to a power level where I can essentially "set it and forget it", but I don't have much experience with the XT's or GT's, so I don't know where that magical threshold lies.

 

I'm not really planning a progressive stage build. I will be deciding on the master-plan beforehand, buying all necessary parts for that build, and then having them installed with a buddy for a turn-key package. I would love to install everything myself over a few months, then tweak things and slowly enjoy the build, but I don't have that luxury much anymore.

You can't set it and forget it beyond stage 2. Your goal is either less than 270whp or you need to plug in the laptop once in a while. Stage 2 is prep for anything else. The only thing you would be doing "more" would be a second tune if you added more later.

 

It sounds like you are going to do what you are going to do. Good luck! I look forward to your build thread.

ah, that is definitely good to know. Thanks for the info. If the 270hp range is the safe limit of "set it and forget it", then that's where I'll set my goal. I would just like to have a good idea of where the 'safe-ish' power level is for it to be used as, more or less, a regular car. Also, if for some reason I have to let someone else drive my baby (God forbid one of my friend's wives), I don't want to have explain spooling, which switches to flip at which time, how to monitor boost, oil pressure, etc.

 

I'm not trying to be a neglectful owner, but I need to be realistic about my lifestyle and habits for the next four years. I'm trying to collect data for a "preponderance of evidence" in making my decision about the build. I'm sort of planning it like an engineer lays out a construction project. Study the data, lay the blueprints, assemble it.

 

I'm curious about your thoughts on turbos. I'd like to install a small mass BB twin scroll turbo, probably blouch 1.5xt-r (with header, up pipe, down pipe). I despise banjo bolts, friction, and I like how twin scrolls respond. I figure if I have it tuned very conservatively and focus on lower end power and spooling, it shouldn't be terribly maintenance heavy.

 

Feel free to school me.

If you are going beyond stage2 (downpipe/tune) you should be monitoring boost and afr. If you are going beyond stage2 you should be monitoring learning view and log occasionally.

If you are going beyond stage0 you should be seriously hesitant to hand the keys over to anyone who may be dumb enough to put 87oct in it.

If you are going to go with a blouch 1.5 you are going to spend thousands of dollars. You also need injectors, fp and quickly a clutch.

If you are going to go stage 3+ you need to consider stage 2 first and think about if it is worth the money/maintenance to go further compared to stage 2.

 

What do I REALLY think? You need to stop looking at parts for a moment, post up in your regional forum area and get a ride in some modded Legacys. You may find that stage 2 is fine or that it falls on its face up high too much for you and you hate it. Only one way to really know for sure, thats have it yourself but a ride and some suggestions from local members would go a long way toward making that decision. I know it did for me.

 

I loved my small turbo but ran it on e85 most of the time. I've since gone bigger in my weekender and stuck it out at stage1 with the OBXT. For me the sweet spot is either stage 1/2 or go big. 1.5xtr is a sweet turbo btw. Love the graphs and dynos.

You need to stop looking at parts for a moment, post up in your regional forum area and get a ride in some modded Legacys.

This is great advice. A Subaru is not an S4. Beyond Stg2 they really can get quite fussy and you want to do constant follow-up and checking that everything is running right. As LALGT mentions, everything you need for Stg2 you will need for Stg3, so there's no waste of funds on parts you'll change out later.

If Stg2 doesn't do it for you, read this.

Even if stage 2 doesn't do it for you, I'd say go with it for a while so you can get a feel for the characteristics and make informed decisions on exactly how you want to reach the next level. fahr_side's writeup is stupid-good for laying out different options. You won't know which you really want to take until you understand where you're "starting" from before taking the plunge.

 

For example, I thought I would want to push somewhere around 350-375whp/tq when/if I go stage 3 based on my experience with my 07 STi. After driving around with a vanilla stage 2 setup on my '10 lgt, I have discovered I'll be happy with < 350whp but I want to flatten out the VERY peaky characteristics of the stock setup. That is going to greatly influence my choice in turbos. I wouldn't have known that had I not taken the time to drive around stock, then stage 1, then stage 2 for a while at each phase.

Also - im a big fan of making the car handle with increased power. So, i would also think about some sways and endlinks once you figure out what you are looking for. They make a very noteworthy difference, and help you control some of the power you're after.

That's a bit broader view of the same idea... Don't try to solve problems before you know if they exist. There's plenty of stuff to improve that will actual matter to you. As you bump up powa, you're bound to discover other tweaks to get you the driving experience you're after.

Thanks for all of the info, help, and advice. Part of my plans are based on driving other people's modified OB XT's and Legacies. I test-drove 11 modified legacies over a month before I started looking around here and joined the forum. Some of them were for sale, others were just cars that I was allowed to drive. I think I've identified what characteristics I like and don't like. In particular, I think I've identified what stock components I'd like to replace immediately.

 

In general, one thing I love is the feel of a flat torque curve under my foot in traffic. Obviously, with the compression of these engines and their design, a flat torque curve isn't going to happen. However, the last setup I drove had a twin-scroll turbo that felt really good and was pretty close to what I like. No peaky on/off feeling like the stock turbos. In the various tunes and setups that I've driven, no matter how the electronics and fuel delivery are modified on the stock turbos, power always 'peaky' to me. The ball bearing turbo immediately felt nicer and more responsive under my foot and the twin scroll was just pleasant to drive (unfortunately, not for sale, though).

 

I'm really not concerned with huge peak numbers or giant power. I just like a comfortable, reliable car with plenty of power under my foot in traffic. I really like the feel of that twin scroll turbo, but if there is no way to tune it down to a very conservative power level, then I'll stick with stock or a BNR16G hybrid. I was planning on starting with a cheap GT that will probably need the turbo replaced. I'm going to be replacing a lot of engine and suspension components anyway.

 

In any case, reliability and drivability are paramount. The thing that I really like and has really impressed me with my Subarus is how they can be absolutely used and abused (with basic maintenance, though) and remain reliable into several hundred thousand miles. That is most important to me. If I want a car that is souped up with huge power that is an unreliable pain in the ass that requires constant maintenance, then I'll go back to an S4 or CTS-V.... haha.

 

It looks like mild Stage 2 is probably the best for my needs

I'm interested to know which twinscroll setup you drove and loved so much because in all honesty, I've never seen one on a 2.5 Subaru that was worth the extra cost. Older EJ205/207, hell yes. EJ255/257, not so much. I've just never seen one that offered vastly earlier spool than a single-scroll version with the same power potential to really make it worthwhile.

 

It's not that hard to get a flat, broad torque curve. You need to buy a large enough turbo, then tune the boost to a mild value in the midrange and then increase steadily from there through to redline. Not many people do that, choosing instead to have it come on hard and fast in the midrange, but it can be done and it is glorious. Problem is, supporting a big enough turbo to do this successfully gets expensive, and we also walk into the reliability issues again, attendant fussing etc.

 

For you, if grindstone simplicity is your overriding need, I think a good solid pro-tuned stg2 is a good option. I also dislike it because of the big spike of torque you noticed, around 3k0~3k5rpm, and then it falling over much like a turbodiesel.

 

For a simple and reliable DD, leave as many parts stock as you can. A nice set-up is a BNR16G and catted downpipe / catless up-pipe (if you get an earlier model). Stick with stock fuel, intercooler, catback exhaust, intake and so on and be good for 280~300whp and a wide torque curve. Upgrade to an OEM WRX clutch and flywheel when the stocker starts slipping. Spend the money you saved on hardware on a solid pro tune. Properly set up like this you can get away with strict service interval and good fluids for a long time. As suggested before, you'd want to just plug in the laptop at the start of every season (changing weather can show up issues with your tune) and check to be sure everything's running okay, before something bad happens. You can just take a snapshot of parameters and post them here for analysis.

Ah, that is some good advice. Thanks, fahr_side. I know my wish-list is a little unusual compared to most tuner owners, but you give me hope that it's not completely ridiculous. I really do just want a low/mid-range focus with a mild tune. The aftermarket turbos (particularly ball bearings) seem like they can really help in that area.

 

I've been watching cars for a few months and have observed several 05 GT's in reasonable shape sell for the $6000-7000 range online. Given a little patience and time, I'm pretty sure I can snag one at that price, which leaves room for parts. I'm still kicking myself for not jumping on a well maintained 05 5MT with 93,000mi that a lady sold for $6500 before I called her back. I've also been watching Craigslist for parts I might want. It's pretty amazing what shows up sometimes.

 

The twin scroll was actually on an Outback XT, so maybe I shouldn't have referenced it. I figured they are similar enough to compare. I wish I would have gotten more info on it, but I really didn't know what it was (or any of the other modifications). Honestly, it may not have been the turbo at all, but that's what stands out as being different to me. A guy in camping with the group next to us at a festival had a pretty awsome salvaged 05 XT that he had essentially turned into a Mad Max style personal rally car. He ended up letting me take it for a short spin in the woods with him, which was like driving a go-cart. I had never heard of a twin scroll turbo, but it felt pretty great (maybe the turbo, maybe something else he did). I looked it up when I got back home and ended up finding references to twin-scrolls on this forum. None of the other Subarus I've driven have felt that smooth in power delivery. Very impressive. I doubt I'll run into that guy again anytime soon to get notes on his build. However, after looking into it, the Blouch seems like a solid twin scroll with some nice looking dyno graphs to back it up.

 

You'd recommend stock fueling and intercooler at that level? I had added injectors, pump, and a Perrin TMIC to the build list. If they're unnecessary, then I'll leave it be. On previous cars, I have tended to err on the side of going overboard on fuelling because those components don't seem to like to run at 80% or above reliably.

 

If I just have to adjust things seasonally, that is perfectly acceptable. I just don't need to be constantly fiddling with it and worried that I need to adjust every time I fill the tank.

As a few people mentioned before, getting a broad flat torque is entirely possible BUT it means leaving power/torque on the table.

 

If you set a lower boost target at the ~3k rpm range you'll suppress the big torque spike. The drawback is that you won't get huge torque number and you'll be below max HP in the 3-4k rpm range.

 

In general, once you start going significantly beyond stock, its going to need more care like your Audi. That's likely to be true for virtually any car. The OEM designs the whole package to work together, the more you exceed those specs the more likely things are to break.

 

There are OEM 300+ HP cars out there, but they're significantly more expensive (such as a stock S4 or CTS-V). Ultimately, the decision comes down to how important money and reliability are to you.

 

Main issues at Stage 2:

Transmission wears faster, either upgrade clutch or valve body (5EAT).

End tanks on the TMIC eventually separate (combination of high mileage at high boost)

No, I wouldn't suggest buying an expensive twinscroll turbo and associated header (+ maybe downpipe) and then hobbling it with stock fuel. Pointless. A TS header alone is close to $1,000. TS turbos are usually a few hundred $ more than an equivalent single-scroll and just net you a few hundred rpm earlier spool. The Dominator series are STi-fitment so you'll need an intercooler to match that. See how this adds up?

On stock fuel you're limited to about 300whp. A $700~ 16G will do this and spool almost like stock.

 

Very good chance that Outback ran so well because it had a good tune, and the right mix of supporting mods. A lot of owners manage to put together a collection of good parts that don't match each other, or ruin a good build with one ill-chosen part.

You wouldn't believe some of the random parts I've seen cobbled together on one car, or some of the bloody awful tunes I've seen from some 'pro shop', and the owners have no idea why an otherwise solid car runs like crap.

I think the 16G might be a good compromise. I'll be missing the linear feel of that twin scroll with no rubber-band acceleration (gas pedal to the floor, nothing, nothing, snap), but a good tune should ease my longing.

 

I think what I may do is find a build i really like and copy all of the components. Not exactly 'original' but I'm all about functionality.

 

I'm still amazed at what pops up on craigslist. Every performance upgrade I search for pops up with several listings. There's a BNR16G with '400 miles' for sale right now for $200 nearby. I was originally considering a brake upgrade and the first search result was a complete 04 STi brake system with calipers, rotors, and all lines for $800 from a wrecked car. The $100 Perrin TMIC seems to have gone quickly.

I think the 16G might be a good compromise. I'll be missing the linear feel of that twin scroll with no rubber-band acceleration (gas pedal to the floor, nothing, nothing, snap), but a good tune should ease my longing.

 

I'd say get a ride in a properly tuned 16G car and see for yourself. A LOT of tuners do this 4G tuning strategy which results in what you describe. I'm a disciple of tuning for earliest torque, even if that comes at the cost of spool. My playground is tight mountain pass roads with steep drop-offs and drainage ditches that suck in cars with unpredictable power delivery... you mis-anticipate, you go in a ditch or off a cliff.

You will also want to upgrade your engine and transmission mounts to the GrpN parts, and fit replacement bushings or void inserts to the rear differential mounts to remove 'rubber-band' effects from the driveline. The stock parts are soggy and allow the drivetrain to wind up before transferring torque to the wheels. Huge improvement to response and predictability with very little penalty in NVH.

 

I think what I may do is find a build i really like and copy all of the components. Not exactly 'original' but I'm all about functionality.

Good idea, but not every set-up is value for money. A lot of people spend a lot of cash doing something a much cheaper set-up can reproduce.

 

There's a BNR16G with '400 miles' for sale right now for $200 nearby.

Sounds good, go check it out. Here's some useful info.

Not to mooch off of other people's blood, sweat, and tears in their trial and error..... but is there someone's build on the forum that you would recommend mimicking?

Not to mooch off of other people's blood, sweat, and tears in their trial and error..... but is there someone's build on the forum that you would recommend mimicking?

 

These setups are so simple and common most people don't bother with a build thread.

 

BNR16G or VF52 turbo

STi or DW65c fuel pump

Kludged stock intercooler OR

Perrin or AVO intercooler

Catted or catless downpipe

WRX flywheel

Full-faced single-plate clutch

Pro tune

Just a thought (if money is an issue). You could skip the clutch and wait till it lets go... Might buy you some time (alot of time depending on your driving style).

Stage 1/2? LMAO. Why not have a stage 2.75 or 1.53. Upgraded panel filter could be stage .25

Not to mooch off of other people's blood, sweat, and tears in their trial and error..... but is there someone's build on the forum that you would recommend mimicking?

 

The bnr HTA68 really seems popular for a solid stage 3 build. Lots of users including myself have this. It's a nice solid build that many have done with good results. Pushes the stock block almost to the limit

The bnr HTA68... Pushes the stock block almost to the limit

... on E85, and needs injectors.

 

68HTA is a really nice turbo for use with E85. Long-term use of E85 may cause some issues with fuel system soft parts degrading but in terms of shortblock longevity, it certainly reduces your chances of losing a piston to detonation. Of course the block is going to wear faster at close to 400whp than at 300whp.

 

If you're sticking with gas, there are better turbo choices IMO as the HTA wheels are definitely optimized for higher pressure ratios and don't really do their best work at the sort of boost pressures gasoline will tolerate.

What would be your recommendation for a gas only turbo?