Suddenly more responsive motor. XV 2014

[gregjet]

OK I have a strange thing happening. Just bought a "new" Subaru XV 2014 manual demo with only a couple of hundred K's on it. Runs smooth and economical on the highway trip home but quickly found that to do right angled corners I had to put it in 2nd or it just wouldn't accelerate out of the corner. I bought in Brisbane and local dealer ( Bundaberg) only had the auto and I hated it so much to drive I can't even begin to say how much. Couldn't make it accelerate out of corners at all.
Anyway, I changed to oil and filter at 1000km and it ran a bit smoother but at about 2000km I put a K&N filter in it .
It now will accelerate quite well ( OK it isn't a WRX) in 3rd gear around right angle corners. I am talking seriously noticeable change. Before it simply wouldn't accelerate around in 3rd, now it does.
This leads me to some questions:
Is it just me? Maybe just a placebo to justify buying the K&N. I should point out that I raced motorcycles for a few years and am reasonably sensitive to power changes.
Is it the new better breathing air filter? I also hole-sawed some 30mm holes above the grill where the air is taken from to help get some cool air flow but that is not gigantic.
Has the software on the Suburu got a table that changes the EFI/spark timing when it gets to a certain mileage? My BMW F800R did. Up to 1200km ( I think that was the distance) , would not rev over about 60% of it's rev range. once passed that it would. Also had more power and better low end after that as well.
Has the motor just freed up with wear in?
Anyone else noticed this.
BTW on a completely separate note. Is there a table on this forum that shows which model motors are in which cars. People keep quoting engine model numbers in the threads and I haven't a clue which is which.

 

[Robbks]

I'm tipping the dealership only ever ran 91RON fuel it.
And you're probably now using 95 or 98.. and the car can run the timing it needs to make power without pinging

I don't like K&N filters, they end up killing your AFM by coating it in oil.

I'm also a big fan of those early oil changes on a new car, I'd do another at 5000km aswell.
also don;t be too kind to it while it's running in,
I've got a long explaination if anyone is interested, but basically "new" components are a little more malleable than old ones, "pre-stressing" them now will give a longer service life than one that is infrequently stressed.
the old addage of clearing out the cobwebs still holds true.

 

[Ratbag]

Running in procedures discussed here:

https://offroadsubarus.com/showthread.php?t=5124

Personally, I have never seen any evidence of any benefit/s accruing from using higher octane fuel than what the engineers designed it for. Result of a number of 'experiments' over the last 35 years that I gave kept detailed log books for all our cars.

Changing the plugs as per service schedule and reasonably proper servicing is far more beneficial, IMHO.

 

[Robbks]

Since about 2004, Subaru's software engineers appear to be blind and deaf.
The majority of Australian Delivered Subaru's suffer badly from overly advanced ignition timing tables for the "rated" fuel.

As a result the coarse adjustments (IAM- Ignition Advance Multiplier) pull out a lot of timing to keep the motor from pinging itself to death., the fine learning tables attempt to put some of the timing back where it can, but often are at their maximum limit, but still low on the total timing that the engine can safely run without knock.
So you end up with a very compromised and dis-jointed "total timing" map by the time the car has had some time to learn it's way around.
This results in poor throttle response, poor economy and a less than smooth or linear power delivery, noticed moreso in the NA engines

As an example, my 2006 3.0R-B Liberty was run on 98RON (95 recommended) and the IAM ideally will target a value of '1'
this allows the ECU to run 100% of the timing values in the timing advance table.
However, even on the best fuel available from the bowser, the car still pinged audibly and the IAM was reduced to 0.3, yes 30% of it's programmed ignition timing.
It resulted in the lifeless, surging, fuel guzzling performance alluded to above.

Having the car re-tuned (to suit 95RON) at a small cost, to fix the timing map increased available torque over the entire map, with a huge 100% increase at 2000rpm,
20% better fuel economy, smoothness restored and much faster in-gear acceleration.)

while you "shouldn't" need to run higher octane that listed, sadly, modern Subaru's are tuned by 5 year old children, running 98RON ensures the best protection against big end failures due to constant knocking, but having them tuned is almost a necessity.

 

[Ratbag]

Gidday Rob

I don't experience any of those problems (ever ... ) with my 2006 N/A Forester.

Pulls like a bull in mating season at low revs; and revs its rings off at the drop of a foot. Sure, it's no E-Type Jag, but it performs more than satisfactorily for what it is.

Perhaps peculiar to the H6 engine/s?

 

[Robbks]

no, not H6 specific
talk to any tuner and see how bad most of them are.
even my MY03 2.5 Lib pulls timing.

you'd be suprised at what you see if you plugged it into and ECU Editor/ diagnostic program to show you the learning tables.

problem with most of the factory tunes too is that the ECU ignores the knock sensor once the rpm's rise,
this leaves you at 5500rpm+ with a bad tune and the ECU not listening
on an engine that has square (2.0, 3.0) or oversquare (2.5, 3.6) bores, this makes timing absolutely critical to keep them in one piece.
Subaru's have a bad reputation for blowing big ends and ring-lands
All caused by pinging from excessive timing.

 

[Ratbag]

Rob, if it were any better, I would probably lose my licence ...

My issue with your statement is that it assumes that every single Subaru engine (ECU) hasn't been programmed competently. IF this were the case, at least half the ordinary owners world wide would be screaming the house down. Instead, most of us are quite amazed at the torque that (say) the EJ-253 can deliver, with 80% of its maximum from around 1200 rpm, holding above this until 90% at its red line at 6300 rpm.

I am personally staggered that any 4 cylinder engine can deliver a flatter torque curve than a 1970-90 V8!

 

[ateday]

Interesting discussion. Now my 2 bobs worth.
My MY03 Forester, owned since new, 331000 kms on the clock, minimal oil consumption of about 1-2 litres between changes, economy has been 8.9l/100 kms over the entire 331000 kms, original motor, heads never off, tappets done probably twice, has run on E10, 91 (mostly), 95 and 98 occasionally. Never specially tuned but serviced regularly and now oil and filter changes every 5-6000 kms. Can of UEC (Austech Chemical variety at $45 a dozen, yes $45 a dozen) every 10-12000 kms.
Certainly not a rocket but reliable and adequate power. Moves well in the appropriate gear with enough right foot and gets to 6250 in 1st and 2nd easily.
Perhaps I am just lucky and got the good one..

 

[Robbks]

I've got a 2.5 Na in my MY03 Liberty and it's not a "bad" engine
Lazy like an old Toyota, but reasonably torquey and smooth enough
but when I run logs on it, it does pull timing at peak torque.
it's economy is woeful on 91RON,
It does have a happy balance on 95RON, and there's no measured benefit on 98
but the ECU is still not 100% optimised
the average joe probably doesn't feel it, notice it or care. but it's there and knowing about it bugs me.

I've still never seen a dyno chart (rolling road or calculated "on-road") showing this V8 like torque curve

 

[Ratbag]

^ the search engine is your friend, Rob. ATM, my head and body both hurt ...

 

[gregjet]

Ok This has raised more questions than answers.
First I DON'T use 98RON in normally aspirated cars unless they have an OLD head chamber design and have a high compression ratio. This car , IF it has a decent modern head design, should run perfectly fine on 91. 98, particularly BP and at least one other ( which one I forget), is designed for high activation fuel/air mixes like turbo's and supercharged, or ridiculously high compression ratios. Found this out the hard way when I was racing production motorcycles. It changed during the year I was racing a VTR250 and all of a sudden it wouldn't start properly, idled aweful and run like it had the brakes on. Did some research and found they had reformulated 98. Changed to 95 and bike ran properly. I use 91RON exclusively in the car until someone shows me real evidence that 95 is beneficial. Even my current motorcycles both run on 91 and they have 10.5 and 11 to 1. Hyosung motorcycles run WORSE on higher octane fuels and they have 11:1 compression ratios and combustion chambers designed by Hyabusha engineering.

I have never heard it ping at all. Remember this is a new model and the ecu faults may be sorted or no longer relevant .
Can I surmise that the XV has a fuzzy logic expert system learning ECU? That could explain why the change happened, especially if the adjustments occur periodically, instead of continually as the data is gathered. The ECU, surely by now, will be a high rate 16 or 32 bit smart system. If it is learning all the time a garbage table will sort itself out sooner or later so long as you don't go swapping fuels all over the place or commute from Jindabine to Eden all the time.
Can I assume that the throttle reset procedure is the same as most learning ecus. Start without touching the throttle. Let it idle until it heats up and the fan starts ( OR a set time period) then turn it off without touching the throttle. Some also have a TPS total arc read procedure.

Funny my Rodeo turbo diesel 4cyl had a torque curve that was a flat as any V8's...lol.
A V motor will always deliver a smoother torque curve admittedly but the multi cyl boxer would have to come second.

BTW I use RP7 on my K&N filters. Won't clog things and is actually stickier to dust than oil. You have to wash it more often BUT it washes easier than oil. A trick I have used since my dirt motorcycle days.

 

[ateday]

Having made my 2 bobs worth a day or so ago my ancient MY03 Forester does at times ping on 91. Usually under load at low rpm. Rapidly cured by a gear change.
Also has little torque under about 2500 rpm and, from new, has been VERY unforgiving at low rpm when taking off from a standing start.

 

[Ratbag]

Gidday Greg

Interesting comments and thoughts. Thanks.

Even the ECU in my '93 Impreza tuned itself constantly (EJ-18) . That's what it said in the OM, anyway.

It also performed flawlessly on 91 RON for nearly 18 years and 240K kms. Like my other cars, I have done the experiment of running the tank almost dry, then using 3-4 tanks of higher octane fuel. No noticeable difference in drivability, power or economy ...

Ditto with our 2.2L '94 Camry.

Both our SG and SH Foresters perform flawlessly using 91 RON, both EJ-253 donks.

The SG gets in the mid 7.xL/100 kms on the open road, and the SH (auto) around 8.5 to 8.9, fully loaded. Both are poor if used solely for shopping trips, but considerably better than a friend's 2.7L Grand Vitara or 3.8L Statesman ...

Personally, I see no reason whatsoever to interfere with a working system!

 

[gregjet]

Don't know if this is covered anywhere else in the forum, as I haven't a clue what to search on, but I like to chuck this into forums involving auto and motorcycle engines.
Alcohol in fuels.
If you own a carburetor model there are good and backable reasons to avoid alko mix fuels. The prime ( but not the only) reason is that ethanol reacts with the zinc and copper in the jets and other bits,as well as crabs with pot metal ( as opposed to aluminium ) bodies. Fuel injected smart ECU engines , ESPECIALLY if they have plastic tanks, not only have no ill effects for the alcohol but can actually perform better than straight petroleum fuel. Most EFI throttle bodies are straight aluminium nowdays so they don't have a problem. Mythbusters did a beautiful little experiment where they run several cars on "gas" and then increasing amounts of alcohol ( dukes of Hazard moonshine myth) and the smart fuel injected cars actually ran on moonshine. The research I have seen on alcohol fuel mixes are actually more likely to retain their RON over time. The aromatic hydrocarbons breakdown and lower the effective RON but straight alcohol in actually very high "octane" rating and doesen't break down as fast ( actually very slowly). You can run it in very high compression motors and gets less pinging, which is why alcohol fuelled dragsters were a HIGHER class than petrol cars.

 

[ateday]

Interesting.
If you read road tests of cars in Brazilian motor magazines there are interesting results on different fuels.
Automobile fuel in Brazil ranges from 100% petrol to 100% ethanol (and diesel of course) in, about, 5 or so blends at 5 or so prices to match and cars come in models to suit.
Usually in a published road test is a comparison with, usually, two fuel types.
What is common is that an engine using, and tuned for, alcohol performs much better than the same motor using petrol. The trade off is that it consumes vast amounts more.
Personally I have found bugger all difference in economy or performance using, as stated above previously, fuels from E10 to 98. Perhaps around town E10 is less economically efficient than straight petrol, regardless of it being 91, 95 or 98.
Economy depends pretty much upon how much of a hurry I am in and right foot pressure. Even across the Simpson I maintain a maximum consumption of about 14 l/100 kms and that is grossly overloaded.

 

[guzzla]

I am personally staggered that any 4 cylinder engine can deliver a flatter torque curve than a 1970-90 V8!

I could start quoting heaps of them. Most of the newer generation European manufacturer 4 cylinder turbo engines have flat peak torque ranging in the area from 1250rpm to 5000rpm from where they start hitting peak power spread over a 1000rpm range. And they feel like it when driven. An average example is my VW 1.4 turbo with 200Nm of peak torque from 1400rpm to 4000rpm and 90kW peak power from 5000rpm to 6000rpm. The best spread of torque and power I've seen is on the 2L BMW turbo.

The 253 Subaru engine you've got might seem a good engine of it's type after Kimberley sixes or 1.8 boxers or even 2.2 Camry slugs but compare it with a nice healthy 2.5 N/A four as found in the Mazda 6 with 138kW and 250Nm and 253 boxer's 121kW and 226Nm is very ordinary. And the proof of it is in the driving with the heavier Mazda 6 far out performing the Forester / Liberty with that engine.

And I really agree with Rob - Subaru really didn't do a good job factory tuning their engines if my 2.5 turbo international award winning engine is any example. Compared with the perfect tuning of my VW 1.4 turbo the Subaru engine is a disgrace - lag, flat spots, jerks, sudden spikes in power and unpredictable throttle response - just like every other example of it that I have driven. An after market reflashed tune helped improve it but it is far from perfect. At least it doesn't ping, gives wonderful peak power, has been 100% reliable to its present 288,000km and only recently started using minimal oil - less than a litre over its 12,500km service intervals.

 

[Ratbag]

Guzzla

For a start, I would have thought it pretty clear that I was talking about N/A engines ...

Secondly, last time I counted (about 35 years ago ... ), I had driven well over 1,000 different makes and models 1,000 or more kilometres each. Given that, and holding a National Heavies licence, it is respectfully suggested that I am a fairly experienced driver, and therefore somewhat unlikely to fail to notice an engine behaving in any kind of erratic manner - be it a Kawasaki 750, or a 3 cylinder diesel tractor, or a Subaru ...

Thirdly, I have not experienced the sort of behaviour you are inferring is the lot of every Subaru owner for all time. Not once with any of our three, not under any circumstance - not paddling down to the shops; not in stop/start traffic; not towing; not punting along country roads; not loaded; not unloaded; ... not ever.

Perhaps yours does these things. Perhaps it does them because of modifications you have made, and your car doesn't appreciate being fiddled with by amateurs. I really can't say.

However, what I can say is that I am unlikely to make sweeping generalisations based on a sample of one or two vehicles ...

 

[guzzla]

I'm not questioning you vast experiences of vehicles over the years Ratbag but have you driven any Mazda 6 (or Honda Euro to name another example of a great NA 4 cylinder engine - they both make the NA Subaru engine look ordinary) or any of the new smaller capacity 4 cylinder turbos?

And I have now driven 7 different Subaru turbos in 2 and 2.5 editions in Imprezas, Foresters & Libertys in stock and modified forms and know mine is typical. And the reflashed tune is far from amateur - it is the Ezy-Flash Pro tune done by Chip Torque at Nerang and did nothing but improve the engine. Which just goes to reinforce what is being said here - Subaru haven't tuned their engines properly and it shows.

 

[Ratbag]

Actually, what you have stated referred to turbo Subarus ...

How many people have been killed because their Subaru suddenly stopped dead in dangerous circumstances?

Other brands which have done exactly this? I can name one ...

Performance is a consequence of many factors.
I would not trade the proven safety of both AWD and Subarus for an extremely marginal perceived difference in performance (personal experience ... ). Haven't driven the Mazda, have driven the Honda - nice car, but not quite in the same price bracket. It also isn't as stable as either my '93 Impreza or even my Forester, IMHO, even on a totally dry road ... I haven't driven the Honda at the extremes, but also do not need to.

 

[Ratbag]

Just BTW, you consider Chip Torque at Nerang are not amateurs, yet the engineers at Fuji Heavy Industries are, by necessary implication ...

What a peculiar perspective ...

But whatever rocks your boat ... .