6th Gen Tuning Thread

A couple points. Limited for limited, 2.5 vs 3.6 is just about $3K USD difference between the cars. A 2.5i is not going to get away with just 3 grand to have a supercharger kit profesionally installed and pro-tuned.

Fuel economy is out of the discussion altogether at that point primarily because the 2.5i is going to be required to run premium, whereas the 3.6R will run on regular, and fuel consumption is pretty much expected to go up a notch.

Cars are not an investment, they are a liability. An aftermarket supercharged 2.5i is going to drop its resale appeal like a rock; it will essentially place you in the market only for enthusiasts, and you'll never see dollar for dollar no matter what. From a resale perspective, a modded car is a bad deal.

Then the question is how the CVT holds up to the extra power. I am all for someone else finding out what the limit is

Fuel economy is out of the discussion altogether at that point primarily because the 2.5i is going to be required to run premium ...

Also, more horsepower = more fuel. Of course, this assumes that you actually use the extra horsepower available ... but isn't that the whole point of the exercise?

Fishbone I agree with what you're saying, a SC kit is not a good investment. Though I think you're making some assumptions regards fuel economy, install cost and resale.

If the 3.6 is driven hard you're going to get pretty bad economy out of it. That bit has been proven. I think the SC kit on the 2.5 would be less hungry on fuel compared to a 3.6 driven the same way. But if you're driving the car harder you're not really chasing good fuel economy - it's more about enjoying what you drive. Fuel economy would probably be a secondary consideration as long as it didn't halve the mpg.

The Raptor SC kits are designed to be a DIY job and can be bolted on in the driveway with some basic tools. Just the same you can unbolt it later when selling the car and put the tune back to "stock". You can then sell the SC kit to another enthusiast

It's the torque increase that will be the deciding factor as to how the transmission holds up. If there's some before/after dynos showing the torque change this will give you an idea on how much closer to the line the gen2 CVT is getting pushed. And to my knowledge nobody has busted a CVT yet so we're no closer to knowing what the practical limits with this transmission are either. So it is a bit of a risk yes. I believe there's SC kits been put into the FB20 motor running the same CVT with no issues but I'd expect the FB25 to be up on torque compared to the FB20.

The decision to put a SC kit on your car is never a logical decision. It's how it makes you feel. I'm sure if I put one on and it didn't break the car I'd be pretty happy... unless the transmission got cooked and then I'd be sad until I bought an upgraded CVT out of a 3.6. But then you'd definitely be better off starting with a different platform. Which is why I'm saving up now (or at least not spending much more on the 2.5) and going to tip the money into a new car instead.

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A couple points. Limited for limited, 2.5 vs 3.6 is just about $3K USD difference between the cars. A 2.5i is not going to get away with just 3 grand to have a supercharger kit profesionally installed and pro-tuned.

Fuel economy is out of the discussion altogether at that point primarily because the 2.5i is going to be required to run premium, whereas the 3.6R will run on regular, and fuel consumption is pretty much expected to go up a notch.

Cars are not an investment, they are a liability. An aftermarket supercharged 2.5i is going to drop its resale appeal like a rock; it will essentially place you in the market only for enthusiasts, and you'll never see dollar for dollar no matter what. From a resale perspective, a modded car is a bad deal.

Then the question is how the CVT holds up to the extra power. I am all for someone else finding out what the limit is

What the hell are we talking about fuel economy, resale value and investment for? I'm pretty sure the only concern I had in the original question was the CVT. Nothing that you are saying besides how the CVT will hold up to the extra power which was stated already. I will be the one to test it because I am for sure getting this kit when it's available for US customers and we will see...

Also, more horsepower = more fuel. Of course, this assumes that you actually use the extra horsepower available

I think the SC kit on the 2.5 would be less hungry on fuel compared to a 3.6 driven the same way. But if you're driving the car harder you're not really chasing good fuel economy

If you end up with 3.6 power, you will end up with worse than 3.6 economy. A high compression engine on boost must run quite rich to avoid knock for one thing. Another issue is that since the supercharger is running at all times, even in cruise, you have a parasitic loss of power you have to pay for with fuel.

The Raptor SC kits are designed to be a DIY job and can be bolted on in the driveway with some basic tools.

I have yet to buy any kind of 'kit' that was 100% complete and just bolted up as per the instructions. Some extra work is always required. Perhaps Raptor is better than this and has thought of everything. Perhaps not.

It's the torque increase that will be the deciding factor as to how the transmission holds up. If there's some before/after dynos showing the torque change this will give you an idea on how much closer to the line the gen2 CVT is getting pushed. And to my knowledge nobody has busted a CVT yet so we're no closer to knowing what the practical limits with this transmission are either. So it is a bit of a risk yes. I believe there's SC kits been put into the FB20 motor running the same CVT with no issues but I'd expect the FB25 to be up on torque compared to the FB20.

Mmm. I know people have broken the stronger CVT fitted to FXT and WRX models simply by spooling the turbo too hard and at too low rpm. Aren't superchargers celebrated for that ability to produce high torque at very low rpm? Again, if you're looking to approach or beat the 3.6R output then Subaru's fitting the beefier trans to that model might be a hint the small one won't survive. I'd wait for someone else to test your theories out.

I've seen a few XV models with the AVO turbo kit do okay but as you mention those are FB20 units not FB25.

I'm sure if I put one on and it didn't break the car I'd be pretty happy... unless the transmission got cooked and then I'd be sad until I bought an upgraded CVT out of a 3.6. But then you'd definitely be better off starting with a different platform. Which is why I'm saving up now (or at least not spending much more on the 2.5) and going to tip the money into a new car instead.

The beefier CVT will very likely not play well or at all with the existing TCU in your car, and the TCU from the 3.6R etc. will have a different CANbus address than yours. Plugging it in (assuming the connectors are the same) will result in a CANbus error that will limit you to 50% throttle angle, which makes your blower kit kind of useless. It might even refuse to engage any drive range. More research is advised.

What the hell are we talking about fuel economy

Because it was brought up:

For me the 2.5 base model was AUD$30,000 and the 3.6R $45,000, however the kicker was the extra fuel consumption of the 3.6

Like fahr_side already said, mpg will be worse and a higher grade will be required, so all in all now you have a car that you're spending more money on gas. It's as if you guys don't want to hear the cons at all. We're just having a conversation, you're under no obligation to really take to heart anything that is being said should you choose not to.

Though I think you're making some assumptions regards fuel economy, install cost and resale.

That may be true, but you can't really counter what you think are assumptions, with bigger assumptions. An aftermarket supercharger added onto a NA engine is almost never less hungry on gas for the reasons fahr_side already called out. It will need more gas of a higher octane. Even the kit being DIY, these kinds of installs are rarely turnkey, and the modding bit isn't DIY. You're very, very optimistic in your prospect of installing a supercharger kit which I would attribute to lack of experience. Which is fine, but what's in it for you is to be receptive.

And to my knowledge nobody has busted a CVT yet

Several have failed at stock levels. I've been following this thread on it

So at this point as far as the topic of supercharging the 2.5i, it's going to be a waiting game that will be educational for everyone. However, the first order of business for anyone going down this path would be to make sure the car is more stable than stock first: upgrades to suspensions and braking. Otherwise you're going to have a somewhat fast boat.

I'm not going to quote you line by line, however fuel economy has never been a concern for me. I get a company fuel card so it doesn't effect me at all. If you read on the next sentence that you quoted, the company I work for has limits on what vehicle stated fuel consumption it will allow. Hence why the 3.6R was off my shopping list due to the stated mpg being above the limit. I needed to have a vehicle under 9.6l/100km and the 3.6R is 10.3l/100km. This is mainly to stop people running big V8's and costing the company a lot of $ in fuel.

Regarding the CVT transmissions thanks for the Gen5 thread. However I believe a number of the issues with the CVT in gen5 cars have already been fixed/resolved.

"Service Bulletin # 16-90-13 Design Change to Lock-Up Type Torque Converter Torque Converter Bulletin Description: This bulletin announces the availability of a countermeasure torque converter assembly to address a customer concern of very low engine RPM when coming to a stop. The condition is similar to coming to a stop in a manual transmission equipped vehicle without depressing the clutch pedal. Thrust washer wear inside the torque converter torque converter can cause restriction of the oil passage used to bleed off lock-up clutch application pressure. The result is either a delayed (momentary low engine rpm) or no lock-up pressure release. The thrust washer has been changed from a solid bushing-type to a needle bearing type. "

There also appears to be issues where people take their cars to a generic service center/mechanic and they accidentally drain the CVT oil out and replace it with standard engine oil. This tends to reduce the life of the CVT drastically.

Like I said before, can you please point us towards the thread that details issues that we are going to have with our cars. If there's issues with older gen CVT's that have been resolved it doesn't help bringing up this type of mis-information. We really need to know if these problems still exist or whether updated parts are being used in our cars which resolves the earlier issues.

Obviously we've done a lot less miles than some of these cars that are having problems and we'll only really know if the problems have been fixed properly once the cars get 100,000+ miles on them.

I'm not going to quote you line by line, however fuel economy has never been a concern for me. I get a company fuel card so it doesn't effect me at all. If you read on the next sentence that you quoted, the company I work for has limits on what vehicle stated fuel consumption it will allow.

Oh I get it. You're essentially buying a car that on paper matches their rules, but in practice would break those rules if you were to install the supercharger kit. In essence, it doesn't matter because you get to fly under the radar, that is lie to them

So mpg WOULD matter even in your situation.

I needed to have a vehicle under 9.6l/100km and the 3.6R is 10.3l/100km. This is mainly to stop people running big V8's and costing the company a lot of $ in fuel.

So a modified 2.5i that no longer meets the manufacturer MPG would have to be disclosed and subject to approval.

Like I said before, can you please point us towards the thread that details issues that we are going to have with our cars. If there's issues with older gen CVT's that have been resolved it doesn't help bringing up this type of mis-information. We really need to know if these problems still exist or whether updated parts are being used in our cars which resolves the earlier issues.

You're in fairly uncharted territory as far as Subaru's 2nd gen CVTs behing supercharged engines goes, but I offered up that link because it has a wealth of data. If you decided none of it is relevant, okay.

That said, we already have a lot of data gathered which is still solid point forward, although unrelated to specifically the 6th gen. For example, we know what mpg would look like, and we know what the CVT is designed like and what type of holding capacity it could have. If you look at other manufacturer's vehicles with similar if not identical designs, you can already connect some dots. For example the Nissan community has had coupe owners that supercharged/turbocharged some Coupe Altimas. This resulted in them boiling the CVT fluid and killing transmissions at a non-trivial rate. This has resulted in power having to be pulled back, which basically defeats the purpose.

You can reach out to the communities should you decide this information is relevant. I used to be quite involved with Nissanclub.com, where I read some of these stories. There's more at Nico Club and the like.

If you're only interested in data strictly on the CVT 2nd gen and 6th gen 2.5i, you're on your own.

If you want to read up on some tech articles about Subaru's CVT unit, here's some sources you may like

http://legacygt.com/forums/showthread.php?t=230379

TL-DR: it is being described as being beefy enough to stuff into a Sherman tank; insane amounts of clamping power for the pulleys that are holding the drive chain connected. Does this mean it's enough to hold the power that the engine would subject it to? Don't know.

Oh I get it. You're essentially buying a car that on paper matches their rules, but in practice would break those rules if you were to install the supercharger kit. In essence, it doesn't matter because you get to fly under the radar, that is lie to them

So mpg WOULD matter even in your situation.

 

 

So a modified 2.5i that no longer meets the manufacturer MPG would have to be disclosed and subject to approval.

 

 

 

You're in fairly uncharted territory as far as Subaru's 2nd gen CVTs behing supercharged engines goes, but I offered up that link because it has a wealth of data. If you decided none of it is relevant, okay.

That said, we already have a lot of data gathered which is still solid point forward, although unrelated to specifically the 6th gen. For example, we know what mpg would look like, and we know what the CVT is designed like and what type of holding capacity it could have. If you look at other manufacturer's vehicles with similar if not identical designs, you can already connect some dots. For example the Nissan community has had coupe owners that supercharged/turbocharged some Coupe Altimas. This resulted in them boiling the CVT fluid and killing transmissions at a non-trivial rate. This has resulted in power having to be pulled back, which basically defeats the purpose.

You can reach out to the communities should you decide this information is relevant. I used to be quite involved with Nissanclub.com, where I read some of these stories. There's more at Nico Club and the like.

If you're only interested in data strictly on the CVT 2nd gen and 6th gen 2.5i, you're on your own.

 

If you want to read up on some tech articles about Subaru's CVT unit, here's some sources you may like

http://legacygt.com/forums/showthread.php?t=230379

 

TL-DR: it is being described as being beefy enough to stuff into a Sherman tank; insane amounts of clamping power for the pulleys that are holding the drive chain connected. Does this mean it's enough to hold the power that the engine would subject it to? Don't know.

I guess this is why you have over 10,000 posts. Thanks for the link to that thread though because I like to read anything Subaru CVT related even if it's not the same gen as ours it's always good to know but I'm the one who wants the SC kit, tigger already ruled it out so all the explaining about gas mileage is irrelevant, I could care less about that. Would you let someone talk you out of doing something to your car if you knew it was possible? Of coarse there will be roadblocks, I never said this would be some easy peasy install and when it comes to cars things break with no modifications. So if I totally screw the CVT up, that'll be my excuse to throw a 6MT in it

Thanks fishy for your clarifications. My car runs more efficiently now its tuned, however it always depends on how heavy you are with your right foot as to what the real world fuel economy figure you actually achieve.

The issues with 2nd gen CVTs in 5 year old cars is a concern, however as I said what's most important to us with a 6th Gen Legacy is what redesigns/changes have been made to the transmission since these failures. Like I posted above there have clearly been some redesigned parts.

Again Nissan CVTs with supercharger horror stories is the reason why we should be concerned but doesn't provide any direct information on what 6th Gen owners could expect (unless the CVTs are shared between Nissan and Subaru).

If there is any information that is directly related to what we can expect that would be a lot more useful. Kayslay seems to be happy to be a test bunny so he will be doing some pioneering work which hopefully everyone that comes after will have the benefits.

So if I totally screw the CVT up, that'll be my excuse to throw a 6MT in it

So I'm not the only one who has thought about throwing a 6MT on the 6 Gen Legacy. I want a stick more than anything. Does anyone have a clue about swapping a 6MT into the car/what it would do/how would it hold up/cost/is it even possible? Any performance gain?

Gen6 Legacy is available with 6MT in some countries (e.g. Canada). Not sure what would be involved with a conversion but it should be technically possible.

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Again, CANbus issues. You will need to research which parts are different between CVT and 6MT platforms but you can expect most or even all of the following have to be swapped to avoid limp mode:

Body Integrated Unit

ABS computer

Instrument cluster

HVAC cluster

Look up the price of those parts and cost of getting them from Canada before getting too excited.

Of course you'd also have to wire the car as a manual and succeed in flashing a manual ROM to the ECU, which isn't always possible. Look at the price of an ECU as well, just in case. Then there's the pedal box, shifter mech, trim parts, clutch cylinders etc.

Now note that swapping isn't easily reversible and greatly reduces the used value of the car unless you run into someone with preferences as esoteric as your own.

I've done loads of swaps on earlier cars and even pre-CANbus stuff will surprise you with how much needs changing. Throw in modern networked electronics and it gets really expensive, especially when the parts are not just chilling in a local scrapyard.

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Yes so though technically it's possible from a practical point it's likely to be cost prohibitive. Unless you live close to Canada and can find/buy a wreck at the right price. Not sure what would be involved in moving a wreck across the border. I can see a few hurdles...

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Yes so though technically it's possible from a practical point it's likely to be cost prohibitive. Unless you live close to Canada and can find/buy a wreck at the right price. Not sure what would be involved in moving a wreck across the border. I can see a few hurdles...

I just so happen to live in a state that is connected to the Canadian border What type of hurdles can you think of? I'll have to look into this.

http://m.autotrader.ca/results?ms=pv&make=Subaru&mdl=Legacy&loc=M9C5J1&prx=-1&yRng=2015%2C2016&trans=Manual&hprc=True&wcp=True&inMarket=homeSearch&u=1 There's a few for sale in Canada. I'm sharing the link because I've never seen a picture of a 6 gen legacy with a manual. If you haven't either, here you go.

I never actually saw what it looks like either, but if you go on parts.subaru.com you can look everything up to see what parts will be needed (obviously only for part #'s though unless you want to pay top dollar) we would somehow have to find used parts for cheaper

And then we want to see the supercharger kit put on it Robbie

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Hey Robbie there may be some 2.5 guys that would like your old transmission so you may be able to subsidise some of the costs that way...

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Hey Robbie there may be some 2.5 guys that would like your old transmission so you may be able to subsidise some of the costs that way...

 

 

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I read somewhere that they're not interchangeable

I'm seriously debating dropping the STI standard into my 3.6r.. There's talk in the Subaru world that it's not too bad of a swap. I'll most likely have a shop sponsor me to do all the labor and i'll provide the parts, save me a few grand atleast.

Hardware is Lego (albeit expensive Lego). It's the CANbus electronics that will make the most trouble.

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I read somewhere that they're not interchangeable

Now what you likely read was its not a simple change. Hardware-wise it's likely bolt-off and bolt-on but it's the software that may become tricky.

Now please understand that nobody has actually attempted this on a gen6 so they may not know 100%. There's a bunch of well-meaning people posting their opinions in this thread which may or may not be based on facts.

If you were keen on going down this path then I would certainly be looking into the potential issues that they have raised as it may be a show stopper (or just make it very expensive).

You also may have to go outside of Subaru service/dealer network to get this done as they probably won't be able to help you. They can look up your VIN and quote you parts for your car as it left the factory but this type of modification would be outside their scope.

So find a good/reputable independent workshop that specialises in conversions and get the facts from them. If you're looking at getting an oil cooler for the transmission the independent workshop can probably do this install for you also.

For those in the U.S. Interested in getting the tune!

I am now on week two of the TH tune. The process for reading the ECU and sending it off to Matt was a piece of cake. Matt got the tune to me within 12 hours and then I started the process of flashing the ecu. Saving and downloading the tune was a learning process (for me). The program is free and pretty easy to use once you get the hang of it.

I am not all about MPG but it is a nice bonus, I have noticed a difference in MPG. Before the tune I was averaging around 28MPG and after the tune I am getting around 32-34MPG (mix of highway and city).

Throttle response is better, more even through the 1k-4K range, the "dead zone" is less noticeable. You can feel the torque a little more now hammering it in 1st or 2nd gear.

The shifts are noticeable quicker and smoother.

Matt said there is still much more to be discovered on the tune, so the more people with the tune means the more time he will spend on improving the tune!

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