tigger73

Post up some votes only need 2 more then off to another Challenge..

 

Sent from my SM-G930P using Tapatalk

Yes for all those that want to participate in this thread, if you're not going to take photos then you can at least vote (just thank the post with the photo that best meets the challenge criteria). Once a photo gets 4 votes that photo is declared the winner and a new challenge set.

If you think you can take a better photo then get out there and post up a better shot!

Full rules for the photo challenge are listed in the first post, though recently we've been a bit more lenient in the time constraints for each challenge

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

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.

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.

Have a look at post #45 - it has dyno chart with derived torque values. It's not 100% accurate but it's an indication of engine torque figures.

0-60 improvement from stock is 2.0sec. I have not put the car down 1/4 mile but have run against a 10Hz GPS timer over multiple runs on the same stretch of road in both directions.

In other threads people complain that there is no data. Here I'm providing data (at my own cost). I have given you an explanation/interpretation of the dyno charts.

The real world drive-ability of the car is grealty improved. 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.

If there was launch control or some capability to allow the car to hook up a little faster I 'm sure you'd see 0-60 times in the low 7's.

Jeez, did you wash and wax your Legacy at the airport??

No unfortunately black cars only look good when they are spotless so my car gets washed weekly and occasionally a quick touch-up in between.

Discussed previously. That is torque at the rear axle, not at the crankshaft.

I like your explanation. It's a little more concise

OK, so can you explain how the dyno graph on pg 1 of this thread shows what seems to be an NA 2.5 engine putting out a baseline of 249 ft/lb and an after run of 265 ft/lbs? The engine is rated at 174 ft/lbs of torque and given a 20% driveline loss, you would expect somewhere around 140 ft/lbs at the wheels. Does your dyno need calibration or am I missing something?

Torque at the driven wheels and flywheel torque are two totally separate measurements. They are related, however will depend on gearing ratio, wheel diameter, and a bunch of other factors including how the CVT transmission is programmed.

Fundamentally, Torque = Force x Diameter

Like I said previously all the figures from my dyno charts are wheel torque values. You can get the dyno operator to generate a "derived torque" that is a calculated value based on trying to convert back from the measured toque at the wheel to a flywheel torque value but it is based on a lot of assumptions about mechanicals of the vehicle which may or may not be correct.

So any attempts that you make to relate the wheel torque values to engine torque that a manufacturer claims is just hypothetical.

What I can do is compare my before and after value for real measured torque at the wheels and these values do have meaning and can be used for comparison.

Any dyno operator that tells you the engine torque value is either making a lot of assumptions or has done all the calculations for every change in diameter and force exerted at every point along the driveline. In the real world nobody does this so the only meaningful value is the measured torque value at the wheel which is what is in the dyno charts I posted.

To participate you just need to go and take a photo that meets the challenge.

It's really that simple.

http://uploads.tapatalk-cdn.com/20160615/3854557e0499d7392dd018a9b20e438a.jpg

Sent from my iPhone using Tapatalk

Yes the dyno graphs tell you what is reaching the wheels. I know with the CVT transmissions there are limiters put in particularly in 1st gear moving off from stationary.

Sent from my iPhone using Tapatalk

How does a transmission ... any transmission ... increase engine torque at the crankshaft?

You tell the transmission to allow more through

The torque is there it's just that it's not getting delivered to your wheels/road where it matters.

Sent from my iPhone using Tapatalk

If you could get a 20% improvement in acceleration why wouldn't you do it?

Understand the warranty argument. It is a risk but the rewards are a more engaging/enjoyable car to drive.

Torque values on the dyno chart are actual measured torque at the wheel/tyre. There is no way to measure flywheel torque easily without removing your engine from your car. It will depend on engine RPM and what gear you are in to calculate a flywheel value. There are inherent errors in doing this that is why measured torque at the wheel is the figure that my dyno centre provides.

You run into the same problem trying to compare power figures to manufacturer flywheel figures when you have driveline losses on a car/dyno.

The best thing to do is compare figures at the wheel. You can't easily compare to manufacturers engine specs as there is no practical way to rerun these tests.

Sent from my iPhone using Tapatalk

Great to see that someone in the US has taken a leap of faith and got their car tuned. At the moment I believe there's only really remote tuning options available for you guys.

The stock tune file in the US must be quite a lot different to the file we have in Aus so it sounds like this will be separate development.

My first tune file was good, but the second was an improvement again. When I spoke to TH he said he's extracted about as much as he can from the Aus Liberty 2.5i. Though a 2 second improvement in 0-100 is definitely noticeable.

I was in my dealer the other day pricing up some brake pads/rotors and took one of the service advisors for a spin around the block. He couldn't believe the improvement over the stock car as it is definitely a lot more urgent - particularly in manual mode.

dying to mount these ASAP

...and we're dying to see these mounted up too

****** beautiful !! 255 it is!!!!!

You'll need at least 8.5" wide rims to fit these.

Well after reflashing my car back to a known good tune I was still down on power. So next step was to reset the fuzzy logic in the CVT transmission.

There's a specific procedure to get the CVT to "forget" it's learned settings. So after running through this procedure I went and re-ran my 0-100's and wow I picked back up the 0.6sec that I'd "lost".

I'll post up in a separate thread a "how to" but we now suspect that the power was down since the dyno tune earlier in the year when I'd run a tank of 91 octane fuel.

Life is good again having full power/torque back

Recommendations on rim widths/tyre sizes: http://www.tyresizecalculator.com/tyre-wheel-calculators/tyre-size-for-rim-size-width-calculator

7.5": 215-225

8.0": 225-235

8.5": 235-245

9.0": 245-255

You can go one size larger/smaller on above, however you will end up with the sidewall either being stretched or a slightly bulge

I'm running 18x8.5 and have 245/45R18 tyres. Personally I have found with the extra width and better rubber (Goodyear F1 Asymmetric 2's) there's a big step up in grip.

It's going to depend on what is available in the rim design that you're looking at. You could go 19x9 ET45-50 and run something like 255/40R19's.

I don't think with the power in the Legacy 2.5 that you'll be breaking traction...

Sent from my iPhone using Tapatalk

I don't think these have been done on a gen6.

Personally if I were going down this path I'd be going 19's as this design makes the wheel look smaller than it actually is.

There's a lot of rim and not a lot of spoke in the RPF1 design.

Well I've been having a love/hate relationship with my car for the past couple of months. Haven't posted an update for a while so I thought I'd give a quick recap of activities.

Took my car in for the Electronic Park Brake recall and got a free wash + vacuum

Have been lugging a fair bit of gear around for work and thought the car wasn't as quick. Did a timed run out on a flat section of road and ran 9.0sec for the 0-100 (a full second slower) so figured it must have been the full tank of fuel and 100kg of gear that I was lugging around in the boot.

Had a tweak of the tune done for 95 octane fuel, re-ran the car on the dyno and redid my 0-100km/hr (0-62mph) times.... only for the results to be worse than before. That was after emptying the car of all excess items and running the tank down to 1/4 full. Power was down on the dyno and 0-100 was worse by 0.6 sec (went up from 8.0 to 8.6 sec).

So the last week or 2 there has been a lot of head scratching going on. However I then realized that when I'd taken my car back in for recall on the electronic park brake, the service guys at the dealership must have connected my car up to the computer and overwritten the tune in my car.

Anyway so now I'm going to get the tune file rewritten and reflashed to my car and then rerun the tests.

And I won't be taking the car back to the dealer any time soon either as I'd specifically asked the dealership if the update they were doing for the electronic park brake was going to effect the ECU software for the engine tune...and they'd said definitely not

Have a look back at the start of this thread as there are a lot of wheels/offsets posted up with pics.

The 18x8 ET40 would be very close to being a flush fit. You only have to measure out 15mm from stock wheels to work out where they are going to sit.

Sent from my iPhone using Tapatalk

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.

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...

Sent from my iPhone using Tapatalk

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

Sent from my iPhone using Tapatalk