2019 Subaru Ascent Mid-sized SUV - True 3-row vehicle

It's been stated in multiple places: the 2.4 DIT is rated on 87 octane gas.

Just because they say it in literature doesn't mean it wont knock still, which is what Perscitus just told us, where he saw it knocking with 87 and 89.

With my 2.5i Outback, since it was knocking so badly on 87 yet was fine on 93, I dug up all of the owners manuals and made sure the car was actually rated for 87 gas. Surely enough all the literature said 87 only.

Right now on stock tune, on the outback, my IAM is around 0.125, if you know know anything about Subaru tunes, you know that a turbo EJ25x wouldn't be alive much longer with that IAM .

I think I spelled it out rather clearly above. Data logged/monitored the dealership demo car with AKI87 and 89 and BOTH showed fair bit of FKC noise. I have no interest in this vehicle, just wanted to see how the base t00n behaves and if Hitachi, Subaru and the unnamed thid-party which builds the stock calibrations (on a contract) learned anything from Liberty/Legacy DIT, last FXT days and then 2015-2018 Levorg/WRX/S4 days. Evidence? Ive given up on providing any on this site and others years ago. People can come to their own conclusions and spend their own time monitoring and logging Ascents if interested.

Some of the knocks could be caused by LSPI. That’s a new phenomenon for Subaru because that primarily happens with Turbo 4’s that are running 0w20 oil. They’re designing SN+ as a stepping stone to SP grade oil to counter it. I wouldn’t be surprised for them to push 0w16 once they figure out LSPI.

And what would the point be to get to a 0W16 (would be 0w15) from a 0W20? A 0w30 is better than a 0w20 for a turbo engine.

The point is for fuel economy I guess. I’m not saying I’m a proponent of lower weight oil. Just saying that’s the roadmap. There is already 0w16 out there, and roadmaps point to long term 0w8.

Oil starvation is killer for a turbo. The FA24 is the first non 5w30 Subie turbo...

One could argue that the machining process is so exact you don’t need the thicker oils to fill the gaps as much and the 0w20 is more “effective” - we’ll see in a couple years I guess?

I don't think you mean oil starvation with thinner oil, I suspect you talking about the film strength of the lighter grades of oil.

This, which is why I switched to 0w30 for the the outback even though it calls for 5w30. If I could get non Mobile 1 0w30, I would switch the LGT to it too.

Thinner oils actually reduce the amount of wear and tear that happens on cold starts because they flow better (water oil is better then no oil during cold starts, which one could argue is what causes the most wear and tear on an engine).

I don't understand what LPSI has to do with oil viscosity. LPSI is from making high boost pressure at low RPM, which can create very high cylinder pressures that lead to LPSI. The 5th gen GT low mount turbo can do this from doing WOT at low rpm high boost at high loads. (ie flooring 6th gear at 55mph). DI with higher compression only exaggerates the issue. Modified FA20DIT WRX's can break the connecting rods from doing WOT at low rpm at high loads.

I did a little investigative work on the Pennzoil website. They amongst other oil companies are pursuing SN+ solely to counter LSPI. I don’t know if they’re putting some type of friction modifier or additive in it to make it SN+ but the issue was starting to be a problem per their website when manufacturers started changing from NA 6’s to Turbo 4’s - not just Subaru, everyone.

Thinner oils typically have a (worse) NOACK value which is a representation of volatility. Perhaps the thinner oil can not effectively cool the engine as it is intended to do so. Cooling and lubrication. The result is a hotter cylinder which could lead to more preignition.

I guess I could buy into additional heat/ reduced cooling with the lower viscosity oil. The cylinder temp are pretty high already in the combustion process. The peak temperature has to be higher than 1400 degree that EGT in the exhaust manifold are at WOT.

BTW Pilot, I do not know what you do to your posts but I can not quote them.

LSPI has been discussed for at least 4 years on North American Subaru forums and maybe 6+ years across the ponds.

And of course a few more years over on the Mitsubishi, Mazda, VAG forums.

What I saw wasnt LSPI.

There are even t00ning strategies and yes also mechanical mods and oil/fuel additive choices to try battlying it. The t00nong starategies employed by both Subaru/Hitachi and the aftermarket to try to limit/eliminate most of it on the FA20DITs and FA16DITs... so the same could translate over to the FA24DIT.

Those that have driven the Ascent, does it shut off the motor at stop lights? I was standing next to a brand new Highlander (oddly enough was poop brown like the Ascent too), and it was shutting the motor off after about 10 seconds of idling.

Personally I hate the feature period, the amount of gas it saves will never cover the cost of a replacement starter. Thus hoping Ascent doesn't have it!

Those that have driven the Ascent, does it shut off the motor at stop lights? I was standing next to a brand new Highlander (oddly enough was poop brown like the Ascent too), and it was shutting the motor off after about 10 seconds of idling.

 

Personally I hate the feature period, the amount of gas it saves will never cover the cost of a replacement starter. Thus hoping Ascent doesn't have it!

Eh, I don't know about that. The Fords I drove that had that feature were so smooth, the first time I had one, it took nearly a day for me to realize it was doing it. It's starting a warm motor, and the lag is so minimal, it doesn't seem it's putting a real load on the starter. I definitely noticed a good amount of fuel economy improvement when driving around Philly compared to when I turned it off.

Eh, I don't know about that. The Fords I drove that had that feature were so smooth, the first time I had one, it took nearly a day for me to realize it was doing it. It's starting a warm motor, and the lag is so minimal, it doesn't seem it's putting a real load on the starter. I definitely noticed a good amount of fuel economy improvement when driving around Philly compared to when I turned it off.

After SBT replied curiosity got me and I did some research, gains seem to be between 2-10%. Complexity does go through the roof with additional and different batteries, stronger motor internals and stronger starters.

Edmunds covers it well: https://www.edmunds.com/car-reviews/features/do-stop-start-systems-really-save-fuel.html

This, which is why I switched to 0w30 for the the outback even though it calls for 5w30. If I could get non Mobile 1 0w30, I would switch the LGT to it too.

 

Thinner oils actually reduce the amount of wear and tear that happens on cold starts because they flow better (water oil is better then no oil during cold starts, which one could argue is what causes the most wear and tear on an engine).

I agree that the figure to the left of the W shall be low which denotes the viscosity when the oil is cold, but to the right of it then having a high value is usually better since the oil film will normally be thicker and that means less wear and lower oil consumption.

Just realize that the oil selected by the manufacturer is also part of the designated lifetime of the engine.

Those that have driven the Ascent, does it shut off the motor at stop lights? I was standing next to a brand new Highlander (oddly enough was poop brown like the Ascent too), and it was shutting the motor off after about 10 seconds of idling.

 

Personally I hate the feature period, the amount of gas it saves will never cover the cost of a replacement starter. Thus hoping Ascent doesn't have it!

I have that on my Outback and I hate it.

At least there's a button where I can switch it off.

It does have the vehicle hold, so once stopped it doesn't move until you push the throttle. That was interesting the first time we drove it.

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I agree that the figure to the left of the W shall be low which denotes the viscosity when the oil is cold, but to the right of it then having a high value is usually better since the oil film will normally be thicker and that means less wear and lower oil consumption.

 

 

Just realize that the oil selected by the manufacturer is also part of the designated lifetime of the engine.

A while ago I remember reading how the difference between 5w30 and 5w40 was very negligible in viscosity at 212*F. I don't have time to find the exact thread but I think it was this big book: https://www.ferrarichat.com/forum/threads/motor-oil-all-chapters-inclusive-copy-and-save-this.136052/

I have that on my Outback and I hate it.

 

 

At least there's a button where I can switch it off.

Does it stay off when you turn it off, or is it like TC that turns back on every single time you start the car?

It does have the vehicle hold, so once stopped it doesn't move until you push the throttle. That was interesting the first time we drove it.

 

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Auto engages the brakes you mean?

Originally Posted by kukabuka on that site which shall not be named:

I picked up a red Ascent Touring on Friday. Everything was great until it wouldn't let me park in the garage because of a phantom obstacle. I'm new to eyesight, so I don't know what it's problem was. I will be disappointed if I have to disable electronic nannies every time I try to park at home.

 

 

Coupled with the SIA QA issues with the Honeywell-supplied turbos and the FKC / FLKC orchestra when data logging a Dealer demo running AKI87 E10 and AKI89 E10 - leave only the S-AWD to provide any level of confidence before the new car smell wears off and daily family hauler status is unlocked.

Park in reverse. Problem solved.