6th Gen Tuning Thread

After initially thinking that I could live with drive of the 2.5i, I decided that if I was going to keep the car longer term I needed to address the "slug-like" performance.

 

So I did some timed runs and a dyno as a baseline. Stock the car runs 0-100km/hr (0-62mph) in 10.0 seconds flat.

 

I've also been working with a local tuner (Matt from KiDo Racing) who tunes a lot of Subarus. He's managed to crack the Hitachi ECU and reflashed it with an updated ECU/transmission tune the other day.

 

Here's the before/after comparison - red (stock), green (tune)

 

 

Power is up overall, however torque is a major improvement across the whole band.

 

AFR's are sitting around 12 which is nice and safe but means there's a bit more there...

 

And finally on the road the 0-100 time has dropped over a full second an it now runs 8.9's consistently.

Edited May 28, 2016 by tigger73

Would be interested to hear the impact on fuel economy

Do you have the HP increase for it yet? Sorry Can't really read the dyno graph with the KW's n stuff lol.

Did you modify throttle response as well

OK so there's actually a couple of things that has been changed. The ECU contains both the engine software and the transmission software. Both have been updated.

 

The throttle response has been improved as part of the transmission tune so that the car now feels more responsive to inputs. The transmission will rev more freely and not do the CVT drag at 3,000RPM. It will also kick down gears quicker and hold them longer if you stick your boot in. Overall it improves the driveability of the car and you actually want to give it a few beans now and then as it's actually enjoyable.

 

In terms of the actual ECU tune, the hp/kW increase is not massive 5-10kW (6-13hp) across the rev range. The biggest improvement is in the torque department as there's 30-40% increase in torque. This is where the gains are and what changes the feel of the car on the road.

 

The torque increase makes the car pull a lot more effortlessly. In gear acceleration is improved and driving along windy roads there's now decent pick-up out of the corners compared to stock which was pretty slow to get going.

 

I haven't been on the open road to do any overtaking, however I'm guessing this will be a significant improvement and able to be completed a lot more safely due to mid-range torque and general pick-up.

 

So it pretty much changes the car from bottom of class performance to leader of the pack.

 

In terms of fuel economy I think after the initial enthusiastic driving it will be better My long term average was 8.2-8.3l/100km (28.5mpg) and even doing a spirited drive through the hills and a bunch of 0-100 sprints I was still averaging 9.3l/100km (25mpg). I'm expecting that it'll probably go to around 30 or so as a long term average but will have to wait and see on this one.

Edited December 14, 2015 by tigger73

It's great that you can get this in AUS but it will never become available in the US.

More responsive throttle? Lawdy, it's already pretty responsive, touchy more like!

Touchy is a great way to describe it my dear

In terms of the actual ECU tune, the hp/kW increase is not massive 5-10kW (6-13hp) across the rev range. The biggest improvement is in the torque department as there's 30-40% increase in torque. This is where the gains are and what changes the feel of the car on the road.

 

Not only is that inconsistent (~4% increase in max power vs a "30-40% increase in torque"), but the dyno plots you posted don't support a 30-40% gain either. What your plot does show is a substantial increase in torque at the rear axle, which suggests that part of the "tune" involved increasing the transfer clutch duty cycle.

 

Edit: Examining the numeric values in the dyno report more closely discloses a more reasonable 6% increase in max torque (359NM vs. 338NM).

Edited December 14, 2015 by ammcinnis

Yes my friend picked this up also. Will have to go back to the dyno shop and get them to reprint the charts with combined torque not just rear wheels. There is the max torque figure but peaks don't necessarily tell the whole story.

 

Perhaps there is a shift from front to rear - will have to check into this further...

 

AFRs are good though - 12.0 is nice.

 

Though the real world performance on the road is a measurable difference. 1 second off the 0-60 time is a decent gain.

 

Matt does do remote tuning and had tuned cars I the US before. I'll find out what is involved.

 

 

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Edited December 14, 2015 by tigger73

Interesting results, tigger. So you're seeing about a 6% increase in torque - so a 3.6R might go from 350Nm to around 370Nm? Interesting...

Matt will be back in Adelaide on 10th of January... if you want a late xmas present

 

He does tunes for the 3.6R also.

This sort of percentage gain is about what we got from the FB20 engine in both the Forester 2.0XS an XV models. A lot of work for something the owner will barely notice within a week!

I don't disagree with what you're saying, though I think when you combine it with the adjustments to the CVT it does make a larger difference. I was expecting around 0.5sec improvement in the 0-100 which would correlate with the moderate increase in the power curve, however I got more than double the improvement in 0-100 I expected and that really surprised me.

Yes, half of what the customers reported was the improvement in the transmission behavior, basically not acting like a soggy pudding.

 

 

Sent from a device using some software.

Do want

Perhaps there is a shift from front to rear - will have to check into this further...

 

AFRs are good though - 12.0 is nice.

 

Though the real world performance on the road is a measurable difference. 1 second off the 0-60 time is a decent gain.

 

Matt does do remote tuning and had tuned cars I the US before. I'll find out what is involved.

 

 

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Glad to hear you are happy with the tune from Matt and the car behaves quite differently when compared to stock

is this an accessport tune?

Glad to hear you are happy with the tune from Matt and the car behaves quite differently when compared to stock

 

Yes I'm happy at this stage, though Matt has promised me there is around 1 second more to be found. If he can do this then it will be a significant improvement for a NA car and will drop the 0-100 into the low 8's / high 7's. Can't have the XV drivers being faster than the 2.5NA Legacy/Liberty...

 

 

is this an accessport tune?

 

Yes this tune was done over the OBD port. Direct flash tune - no hardware changes or tuning "boxes". Time to read/write the ECU would be 10 minutes tops. Took longer to go through the adaption run to check that the tune was operating correctly.

Edited December 28, 2015 by tigger73

using the same reg fuel or did you have to jump to premium? I ve always found MPG s increase with this type of tune.(Usually 1 or 2 MPG More). Although you have to drive it normal to see it, LOL. If you are still using reg fuel there should be more power to gain if you get a tune for higher octane...

using the same reg fuel or did you have to jump to premium? I ve always found MPG s increase with this type of tune.(Usually 1 or 2 MPG More). Although you have to drive it normal to see it, LOL. If you are still using reg fuel there should be more power to gain if you get a tune for higher octane...

 

I do run my car on premium fuel (95 premium vs. 91 regular unleaded), though I believe the tune is for the regular unleaded. I haven't noticed any improvement in fuel economy yet, however I've done mostly city driving and my previous long term average included quite a bit of highway miles. Also I'm probably a little heavier with the right foot now that there's better pick-up....

 

Also I get a fuel card for work so fuel economy doesn't really come into the equation - it's more out of interest and I definitely don't drive to get the best MPG. I'll see what Matt says about tuning for 95 octane. I know he also does quite a few E85 (85% ethanol) tunes, however availability of fuel is more difficult especially in rural areas... and is not covered by my fuel card or stocked by my company fuel card retailer so I'd have a hard time convincing the big boss it was necessary

We run Premium in our Subies. I see a BIG difference in cold starts (been 10-20F in the early mornings lately) and we seem to do a little bit better on average mpg. Okay, let the debate begin.

We run Premium in our Subies. I see a BIG difference in cold starts (been 10-20F in the early mornings lately) and we seem to do a little bit better on average mpg. Okay, let the debate begin.

 

 

What kind of "difference" on cold starts?

 

 

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The engines both crank normal, albeit a little slower. When using Regular (85 here), there's noticable lag in starting. Our XV is pretty bad with super cold starts on regular. It will stumble for a few seconds and act like it's going to stall. My Legacy doesn't do that, however it will pause for a split second after cranking and then the motor will start running. - Hard to explain, sorry. With running Premium (91 here), no pause in my Legacy and the XV doesn't stumble.

The numerous US FB25 engines I have tuned in Foresters etc have always shown a 20% increase in fuel economy. The FB20 Impreza/Crosstrek guys have even seen 40+MPG's when tuned even on 87 fuel

 

Yes I'm pretty sure there is an improvement in fuel economy as the "cruising" figures are better around town. However with the increases in throttle response and driveability it's more fun to give it a bit more poke with the right foot so I'm yet to better my old long term average. Also I haven't done any long country trips either which bring the average down.

 

As I said before my goal was not fuel economy - more for driver enjoyment. I've had a company fuel card for 10+ years so it's not really a consideration what mpg I'm getting. It's more out of interest and for planning out fuel stops on occasions.

 

The reason I run premium is that the regular 91RON fuel here can be a bit dodgy and also because my company card will accept it. I figure the premium fuel is better for the engine and if my company will allow me to run it I'll fill the tank with premium.

 

It's not that cold here in the mornings so I can't really comment about cold starts. Though the old octane discussion is really better had over in the "What do you put in your tank?" thread.