6th Gen Tuning Thread

What would be nice is a little more urgency off the line, however I believe there are torque limiters in the CVT transmission which limits the delivery in 1st gear from low RPM.

What I'm writing below is with the assumption that "off the line" is meant to basically just hit the gas from a dead stop, sans torque braking or any other such technique.

I doubt what you're saying is the case, because of two big reasons.

The first is that the CVT has been shown to be very stout as far as holding power. It's been over-engineered in typical FHI fashion and is more than capable of holding the torque that the 2.5i delivers. Also remember the towing capacity, that's been factored in as well when it was built! There doesn't seem to be a reason to limit torque delivery in any way.

Second, this off the line lack of "urgency" as you call it is traditionally caused in automatic Subarus by two factors:

-high-stall torque converter

-full-time awd

Basically, to put it bluntly, you have a teensy engine not putting enough torque to push the car out with the quickness. It has to send torque through 4 axles, torque that is swallowed up by the high-stall converter.

In case anyone mistakenly interprets this as a 2.5i bash by a GT owner, this is a problem on the GT as well. Outside of boost, we're stuck with a 2.5 liter NA engine too. What GT owners typically do in order to overcome this is to basically do a little bit of torque-braking; just enough to bring the revs up to stall speed and maybe build a bit of boost.

Because, it doesn't matter if you're a GT or 2.5i, taking off is going to be sluggish, up to the point the GT starts boosting.

There's one cure for this, excluding lowering the stall speed: displacement and more torque down low. The H6 accomplishes this nicely.

My GT has always felt like digging out of a tar pit, if I just roll on the throttle from a dead stop, and hardware mods do not overcome this (exhaust and ported/polished TGV deletes, etc).

All automatic Subie owners have to put up with this. It's the nature of the beast. Don't know where that leaves you but I hope it makes you feel better to know that you're not alone, and not much to be done about it.

Are the limiters completely permanent in the cvt, so Matt can't remove them? Or has he just not tried to do so yet? If you know

Nobody has cracked any of the transmission control module tuning as far as I know, and traditionally these 'limitations' have actually been imposed on the engine via tuning, by way of pulling timing to reduce power delivery. That's an aspect that can be tuned.

@fishbone very well stated.

Can only expect so much out of a 2.5 liter engine stuffed into a 3 and a half thousand pound car, mated to an autotragic spinning 4 wheels. The great news is that the CVT does worlds better than a traditional transmission, because it gets into peak torque revs much, much faster, AND stays there.

fishy have a look at this thread: http://legacygt.com/forums/showthread.php/cvt-transmission-tips-and-tricks-253599.html

There's a 3.6R owner that compares the take-off of the gen5 with auto trans vs. the gen6 with CVT and there's a world of difference off the line.

You can do indirect "tuning" of the CVT by adjusting maps in the ECU. This is what Matt/throttlehappy and likely several other tuners do.

A direct tune of the CVT would be likely required to eliminate any torque limitations. It's probably just a matter of time now that the WRX comes with CVT that the tuners will look to extract gains from the transmission as well as ECU.

One anecdotal post isn't quite enough to sway me but I accept the possibility that SOA chose to tune it down. I've already posted previously two tech articles taking apart the Subaru first gen CVT and it was described as capable of moving a Sherman tank. It has an insane amount of clamping power on the chain and pulleys which themselves are built extremely strong. Feel free to look at my post history (opened thread list). That gives me enough reason alone to doubt the CVT is asking the engine to pull back power.

But my point stands, down tuning or not you can't beat physics and for the gains it's not even worth exploring that much. With all the mods on it, my Stage 2 GT is more or less on par with just about any 2.5i Subaru until it hits boost: slow.

2 and a half liters is not enough lung capacity to get 3.5k pounds moving quick out of the hole. I'm not basing my statements on my personal experience, rather offering it to confirm what I already know.

By the way drivetrain losses can be expected to be over 20-25% on these automatic awd drivetrains. Quite significant. With a turbo the beauty is in the hole shot via a torque/boost brake but then the awd becomes a drag on the car and works against you.

Tuning wise, it should be expected to be in the ECU tuning not the TCU. It's been that way on all subarus up until this point. The TCU tells the ECU to pull power. No need to tune the TCU, meaning it's not going to be a great mystery to find if the ECU tune is accessible.

But my point stands, down tuning or not you can't beat physics and for the gains it's not even worth exploring that much.

Well, that is your opinion. Tigger has actually *done* the tune and *driven* the car after the tune and he's very happy with the result.

To everyone else bashing Tigger's decision to tune his car, YOU HAVEN'T DRIVEN HIS CAR so what makes you think you are qualified to pass judgment on the improvements he's seen? It's like writing a review and passing judgment on a movie - when you haven't actually watched the movie.

Thanks 3.0R-AUS. I've taken my local Subaru service advisor for a spin around the block and he was quite surprised by how much an improvement over stock the exhaust/tune makes. He likes my choice in wheels too

I've come from the VW world of tuning and there you get both transmission tunes and ECU tunes. The DSG transmission tunes will adjust things like shift points and how long the transmission holds a particular gear under light throttle, plus you can shift the launch control RPM and how hard/quick the twin clutch clamps/changes gears. You can only do so much from modifying the tables in the ECU.

I agree that the 2.5i is never going to be a track day weapon - I didn't ever buy it for that. After tuning mods though it will not be that far behind a stock 6 cylinder in terms of straight line performance and will handle a lot better due to the reduced mass up front.

It's not about making the fastest car on the road - more about making what you have as good as it can be. If it gives you a sense of satisfaction and a smile on your face when you drive it that is what modding cars is all about.

I have posted up all the before and after timed results. Yes 2.0sec is a decent gain in performance. About half comes from the ECU tune and half from the adjustments to the transmission (indirect).

It's certainly not a fast car by any means but it does liven it up a bit. I've also run this back to back on the same dyno as a range of other Legacy including tuned GTs and 6's so I am under no illusion of where it stands in terms of performance credentials.

However for anyone with a 2.5NA it certainly is worth consideration. Especially where people are spending similar $ on a front lip or grille.

Sent from my iPhone using Tapatalk

Can someone lead me in the right direction for upgrading my brakes? Lol jk

Sent from my iPhone using Tapatalk

Right lets just put things into a bit of perspective here. A few of us have spent a couple of hundred bucks on our cars to make them go a little better.

I'm really not sure what the fuss is about. Did you think we paid too much? Was it not good value? Or do you think we should have spent the $ on lighting upgrades like all the other gen6 owners on here

If you had a car that was running 10sec 0-60(mph) and for a few hundred bucks you could get an 8 sec car would you do it? I know I would.

Even if I did run my car down a 1/4 mile I'm sure you'd question whether it was wind assisted or if the track had a slight slope on it. I know how my car runs. I have comparison dyno results and 0-60 times to support it so I'm not going to bother. I'm not chasing 1/4 mile times. I'm really looking for better on-road pick-up and general drive-ability which I have achieved.

I know my GTech GPS timer is probably only good for 0.1sec accuracy. There is an error on lead-in that it doesn't catch the first metre or so, however all the runs have been done with the same device on the same road and I've found it quite repeatable/consistent. You can do a bit of research on the GTECH unit here: http://www.gtechpro.com/ss_fanatic.html

Also the dyno that I run my car on is used by the local Subaru independent workshop to do all of their dyno tuning - mostly WRXs. It is probably a harder to please dyno than most, however I have found the dyno numbers and my 0-60 times lining up pretty well. Any improvements on the dyno are reflected on the road and vice versa.

I'm really not sure why you're reading this thread. Are you actually interested in getting an ECU tune on your 3.6R? We'd be interested in getting your feedback and perhaps even some timeslips from before/after if you'd like to share.

Why are you on this thread? What are you trying to prove... That he's lying and took the graphs off a different car? If you consider yourself to be a "car enthusiast," rule number one is to not cut down other people's builds. All I've read from your posts are how everybody is blowin hot air and are full of it.

I didn't believe him either when he claimed his gains.. But I didn't come on the forums and rip on him all day because I have nothing else better to do.

I have the tune as well, it's not as developed as his but I have improvements in mine.

Go waste your time on another thread

Sent from my iPhone using Tapatalk

It is all good. This is the internet and a forum and everyone has a right to have their opinion. But at least keep it on the subject not personal.

This is tiggers thread and he is the Op and the one in charge.

http://uploads.tapatalk-cdn.com/20160616/c5df8c1e02c1cfbdc9877d1da06fe6d4.jpg

A 2.0 second improvement in 0-60 is phenomenal. Its probably the equivalent to adding 80-100 rwhp on a 3500 lb car.

On a 175 hp car, it doesn't take 80-100rwhp to gain 2 secs 0-60 mph. As you go faster you get diminished returns. Torque plays a much bigger factor than hp with 0-60 times.

Prior 170hp Auto Legacy's had 0-60 times of 9 seconds. I ran my 170hp 6MT 2.5i with G-TECH my best 0-60 was 7.45s with a high rpm launch. One of the car magazine posted 7.5s 0-60 out a 6MT 2.5i Forester. It is not unreasonable for 170ish hp car to have a 0-60 time 8 secs. I am sure maximize the torque and optimizing what they can in the ECU that affect the CVT is making the major difference in his improve 0-60 times. Cobb had thread on NASOIC about tuning on the F20DIT CVT Forester XT's, they found they were able to great improve the CVT response and track time by just playing with the CVT setting in the tune.

^correct, It's less about how many ponies are under the hood and more about the torque pushing the car

Sent from my iPhone using Tapatalk

On a 175 hp car, it doesn't take 80-100rwhp to gain 2 secs 0-60 mph. As you go faster you get diminished returns. Torque plays a much bigger factor than hp with 0-60 times.

 

Prior 170hp Auto Legacy's had 0-60 times of 9 seconds. I ran my 170hp 6MT 2.5i with G-TECH my best 0-60 was 7.45s with a high rpm launch. One of the car magazine posted 7.5s 0-60 out a 6MT 2.5i Forester. It is not unreasonable for 170ish hp car to have a 0-60 time 8 secs. I am sure maximize the torque and optimizing what they can in the ECU that affect the CVT is making the major difference in his improve 0-60 times. Cobb had thread on NASOIC about tuning on the F20DIT CVT Forester XT's, they found they were able to great improve the CVT response and track time by just playing with the CVT setting in the tune.

Good points.

Well, that is your opinion. Tigger has actually *done* the tune and *driven* the car after the tune and he's very happy with the result.

Yes that's correct, it is my opinion but you must also realize it's also tigger's personal opinion that the gains are satisfactory.

My point was completely different, though, and for whatever reason it's apparent I failed to be clear enough in what I was trying to convey and I'm OK with that, I just wanted to make it clear that I wasn't bashing or putting anyone down. My only aim was to share information.

Could be they don't want the insurance bill of a WRX/STI.

Just saw this

:lol:

Any list of reasons and considerations as to why someone would buy a 2.5i or 3.6R Subaru should start with that point right there.

The WRX and STi are one of the most expensive cars to insure because all the white rim sunglass wearing douchebags that won't even acknowledge other Subaru owners on the road, wreck them left and right or get ticketed twice a week, so they killed the deal for everyone else. If you're in your 20s or early 30s, expect to pay through the nose. It's one of the reasons I went with a Legacy instead.

I realise that I haven't posted up all the 0-100kph (0-62mph) times in this thread - there's most of the data in my build thread.

Anyway here's the table of all the times:

I've highlighted the best times as well as the bottom line is the average of all runs on each day. Improvement over stock is 2.0sec.

Here's the screenshots of rev2 with headers. No I didn't make these numbers up. This is the raw data. Make of it what you will

And here's the best run including graph:

http://uploads.tapatalk-cdn.com/20160226/97c49fc9e546c284e47dfe2e9588e9b5.jpg

http://uploads.tapatalk-cdn.com/20160226/f5d66696bdf6802c29876389357a0b79.jpg

You can see that the G-tech probably doesn't quite capture the precise start of the run, however it is pretty consistent so if you're just comparing the relative numbers then it's a valid comparison.

If you want better figures then you need to spend more and get a Vbox, though the best Vbox only has a 20Hz GPS engine.

I am all for modding cars but I am not going to mess with my Legacy. There just isn't a track record with the new 2nd Gen CVT and if I really want to drive something reasonably quick, I'll break out the 2002 Acura CL Type S... saying HP is not as important as Torque is rubbish... if you want good acceleration, it is a combination of engine power, ability of the trans to effectively put the power down, and how good the tires/suspension are....

when I put headers on the Acura, not only did I get 30HP more, it moved the power peak from 6100 all the way up to 6700rpm and made an already rev happy motor even more so... IE building power all the way up to very deep into the RPM range with a small fall off by the time you get to WOT shift point of 7100rpm... it shaved an significant amount off of the 0-60 times and a bit off of the 1/4mile

A 2.0 second improvement in 0-60 is phenomenal.

I'm glad you agree that Tigger has had great success!

Yes that's correct, it is my opinion but you must also realize it's also tigger's personal opinion that the gains are satisfactory.

Tigger is not using his opinion to put down other people on this thread, so he is not being offensive nor rude towards other forum members.

Other people are using their opinion to accuse Tigger of lying.

There is a big difference.

Tigger is not using his opinion to put down other people on this thread, so he is not being offensive nor rude towards other forum members.

 

Other people are using their opinion to accuse Tigger of lying.

 

There is a big difference.

Tigger is not too concerned about the doubters in this thread. He is actually a little bemused at the number of people that are showing such a keen interest in modifications to a Gen6 2.5i.

Tigger is hypothesizing that either these people are:

a) a closet 2.5i lover

b) worried that a 2.5i may some day be quicker than their car

c) have nothing better to do with their time than continue the myth that there is no point modifying a 2.5i

Tigger doesn't mind that people ask questions or seek clarifications. After all this is a forum and a place for people to learn - you don't ask you don't learn. Though he is a little disappointed that when he takes the time to write a detailed explanation to a question someone has asked, that the response is either not read or completely ignored.

Tigger thinks that it would be a shame if this thread was filled up with off-topic posts rather than exploring the possibilities/opportunities for improving the performance of the gen6 2.5i. This was his intention of starting this thread and he would actually like it to keep on topic.

Tigger is pleased to see some other forum members starting to tune their gen6 2.5i also and hopes that they will be able to achieve similar results.

Sent from my Pixel C using Tapatalk