Subaru Ascent and Boxer Engine

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I was looking at an ad for the Subaru Ascent and they were extolling the virtues of the Boxer engine. Are the last 5 years of Subaru Boxer engines reliable? I recall the old ones might have had head gasket problems. I see Subaru refuses to give up the Boxer. Any other issues?
smile.gif
Thanks.
 
If by "old" you mean greater than 10 years old, then yes, there were some HG issues on the non-turbos. Then there were rod bearing issues on the like '12-'14 STIs. Some of the first year FBs had minor oil consumption issues. However it seems all of these are generally behind Subaru.

I'm getting ready to buy an Ascent sometime in the next year as well, I have no worries.
 
This is a brand new engine, the FA24DIT, the larger cousin to the FA20DIT that first arrived in the states in the '14 Forester XT.

The FA20DIT had many software teething issues that lasted the first couple years of production (mostly fixed throughout the first year, however). Hopefully everything they learned on the FA20DIT can be transferred to the FA24DIT.

Having purchased one of the first FA20DIT-powered Foresters I was lucky enough to be Subaru's guinea pig for those first couple of years. Everything is good to go now, but I won't be a first-year adopter ever again! If I was in the market for something the size of an Ascent, I'd wait until the third year of production, since that seems to be when Subaru figures out all of the issues AND incorporates customer feedback into the first refresh.
 
Like gathermewool, I bought a '14 FXT new and went through some software stuff...first hard starting, then a mysterious CEL code (P0300?) that seemed to have no basis in the actual performance of the engine. Both fixed by software.
The LSPI recall was probably the biggest deal regarding the engine...some folks got new engines, some got new plugs, some got thorough cleanings (I assume for carbon buildup on the intake valves unrelated to LSPI). I know there were software changes, too, but LSPI is fundamentally a hardware issues...although I believe that it can be reduced somewhat by running the engine a little rich in low RPM, high torque conditions.
Other than running a d1G2, d2, or SN+ oil, I really don't think there is much to worry about with the Subie DIT engines.

My CVT has been a bigger problem, had a part replaced around 80kmiles after I kept throwing codes and the car felt funny going in reverse. The warranty had been extended to 100kmiles on many (all?) Subaru CVTs by that point, but I am getting close to that mileage and hope it breaks soon if it's going to break again!
The FXT CVT (high torque version) was modified to include a new filter during the '15 model year run and this change cannot be retrofitted....I assume that the Ascent tranny design has taken advantage of this field-based learning.

I am waiting for the announcement that the 2.4l DIT in the Ascent has been tuned for use in the WRX STI...

BTW, I keep saying I will never be a first year buyer/beta tester, but my '06 RAV6 was also the first year of a new model...and had tranny issues...sigh.
 
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First year guinea pig for new Subaru motor configuration and potentially block size 2.4?. All recent Subie motors are 2.5 or 2.0.

Subaru does not have a good track record for first year major engine designs/configurations but quickly corrects them. The upside if it turns out bad they replace the blocks typically with campaign warranties.
 
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Originally Posted by madRiver
First year guinea pig for new Subaru motor configuration and potentially block size 2.4?. All recent Subie motors are 2.5 or 2.0.

Subaru does not have a good track record for first year major engine designs/configurations but quickly corrects them. The upside if it turns out bad they replace the blocks typically with campaign warranties.


There are multiple variants of the 2.5 and 2.0L; however, the 2.4L FA24DIT is new this year.

The big difference between the FA24DIT andFA20DIT is the bore of the cylinders.

If Wikipedia can be believed, the engine spec's:

FA20DIT:
Bore: 86 mm
Stroke: 86 mm
CR: 10.6:1
HP: 250 @ 5600 RPM (258 ft-lbs @ 2k RPM)
Super square...

FA24DIT:
Bore: 94 mm
Stroke: 86 mm
CR: 10.6:1
HP: 260 @ 5600 RPM (277 ft-lbs @ 2K RPM)


So, the new FA24DIT is has a larger bore to gain it's larger displacement, but makes similar power and has the same compression ratio as the FA20DIT.

Might mean less stress on bearings (design dependent, of course), but we'll see how the ringlands hold up...
 
Is the engine for the Ascent going to be DI with turbo?

Well, maybe the good thing is it will have lots of room under the hood for working on it. Regardless, these things will sell as fast as they hit the parking lot.
 
Originally Posted by gathermewool
Originally Posted by madRiver
First year guinea pig for new Subaru motor configuration and potentially block size 2.4?. All recent Subie motors are 2.5 or 2.0.

Subaru does not have a good track record for first year major engine designs/configurations but quickly corrects them. The upside if it turns out bad they replace the blocks typically with campaign warranties.


There are multiple variants of the 2.5 and 2.0L; however, the 2.4L FA24DIT is new this year.

The big difference between the FA24DIT andFA20DIT is the bore of the cylinders.

If Wikipedia can be believed, the engine spec's:

FA20DIT:
Bore: 86 mm
Stroke: 86 mm
CR: 10.6:1
HP: 250 @ 5600 RPM (258 ft-lbs @ 2k RPM)
Super square...

FA24DIT:
Bore: 94 mm
Stroke: 86 mm
CR: 10.6:1
HP: 260 @ 5600 RPM (277 ft-lbs @ 2K RPM)


So, the new FA24DIT is has a larger bore to gain it's larger displacement, but makes similar power and has the same compression ratio as the FA20DIT.

Might mean less stress on bearings (design dependent, of course), but we'll see how the ringlands hold up...





So to confirm, is the FA24DIT the same block as the FA20DIT but with a different bore and other changes?
 
I can't say for sure. My post is based solely on my reading - keeping tabs on the various sites talking about it since before it was introduced.
 
Originally Posted by gathermewool
I can't say for sure. My post is based solely on my reading - keeping tabs on the various sites talking about it since before it was introduced.




I did some checking but I haven't found anything to verify this. I does make sense from a Subaru perspective. It would save money by not fabrication a whole new block.

I did read that the connecting rods were strengthened.
 
Originally Posted by PimTac
Originally Posted by gathermewool
I can't say for sure. My post is based solely on my reading - keeping tabs on the various sites talking about it since before it was introduced.




I did some checking but I haven't found anything to verify this. I does make sense from a Subaru perspective. It would save money by not fabrication a whole new block.

I did read that the connecting rods were strengthened.


I read about the beefed up connecting rods, too, but I don't remember if that was conjecture or from a legit source.

Also:

Same or very similar turbo between the two, as well: an MGT22, if I'm not mistaken. I don't know exact turbo variants, but I do believe they're very similar.
 
Originally Posted by Snagglefoot
I was looking at an ad for the Subaru Ascent and they were extolling the virtues of the Boxer engine. Are the last 5 years of Subaru Boxer engines reliable? I recall the old ones might have had head gasket problems. I see Subaru refuses to give up the Boxer. Any other issues?
smile.gif
Thanks.

Try to avoid first year in general. Even if it is proven engine, and it is not, there will be other "infant" issues.
However their Ascent commercials are coming straight out of KGB propaganda kitchen.
 
Originally Posted by edyvw
Originally Posted by Snagglefoot
I was looking at an ad for the Subaru Ascent and they were extolling the virtues of the Boxer engine. Are the last 5 years of Subaru Boxer engines reliable? I recall the old ones might have had head gasket problems. I see Subaru refuses to give up the Boxer. Any other issues?
smile.gif
Thanks.

Try to avoid first year in general. Even if it is proven engine, and it is not, there will be other "infant" issues.
However their Ascent commercials are coming straight out of KGB propaganda kitchen.


You obviously don't know what "LOVE" is!
 
I was a little surprised that they didn't put the flat six in these.
The turbo four should work okay since Subaru has plenty of experience with these.
The flat engine is a Subaru trademark going back to the first real cars Subaru sold in this country more than forty years ago and will be around for probably as long as there are Subarus.
 
The boxer engine is Subaru's identity and their tradition. If they ever had to switch to a inline or v engine it would be one from Toyota.
 
Pim, I just threw up in my mouth at your last sentence.

Sure, boxers have had issues with engineering like HGs, having to split the case, and engine width, but they also have plenty of benefits. Low CG, inherently balanced, great exhaust note, extremely short so it can be moved back for optimal weight distribution... I hope the Boxer lasts as long as the ICE does.
 
^ Well Toyota and Subaru did work together on the BRZ/FR-S engine. That's the one without fuel dilution and intake valve deposit issues because Toyota saw fit to add port injection.
grin2.gif


In regards to guinea pigs/early adopters, don't forget that this is also the first Subaru turbo that I'm aware of that specs 0W-20. Let's hope they got it right!
 
Originally Posted by gathermewool
Originally Posted by edyvw
Originally Posted by Snagglefoot
I was looking at an ad for the Subaru Ascent and they were extolling the virtues of the Boxer engine. Are the last 5 years of Subaru Boxer engines reliable? I recall the old ones might have had head gasket problems. I see Subaru refuses to give up the Boxer. Any other issues?
smile.gif
Thanks.

Try to avoid first year in general. Even if it is proven engine, and it is not, there will be other "infant" issues.
However their Ascent commercials are coming straight out of KGB propaganda kitchen.


You obviously don't know what "LOVE" is!

What love man?
Their Ascent commercial goes this way: You watch your kids die, then your spouse then you die, unless of course, you get Ascent. In reality they put Falken tires on it, which after 10k will probably do 200ft instead of what car and driver measured (178ft). Those commercials do not have anything that draws on Subaru legacy, it is pure fear mongering.
And Subaru customers take that so literally that every time I see one in rear view mirror I step on the gas as I know probability of them having worn out tires is like 99%. Considering "power" they packing, getting away is really no sweat.
If they just kept dog, kayaking commercials only, not not this "your family will die in miserable death" commercials.
 
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