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#6611 of 19336 Re: Stock 2003 2.5L pistons vs updated oversized pistons [locke2c]
May 18, 2006 (2:54 pm)
Thanks for the reply. My Impreza Outback Sport just had the #2 & #4 pistons replaced and the Subaru mechanic told me that the diameter of the updated piston is a bit larger and also that the skirt is moly. It even said oversized on the W/O. I was also talking to a customer service rep and was told the skirt is longer. This to me doesn't make any sense unless they replace all four. I'm now quite concerned about the longitivity of the motor especially since the other side wasn't even taken apart to verify the condition of those two pistons. Having two different types of pistons can't be good.
#6612 of 19336 Hesitation and Surging
May 19, 2006 (9:44 am)
Good news. I have a 2005 OBXT MT and it has always been plagued by mid-throttle acceleration hesitation and surging and holes in power delivery. Many people have posted these same problems in this forum. Early on I visited the dealer about it and was told to "buy better gas". Yeah, what a gas alright. I have been pestering the dealer about it and today their lead technician revealed that within a few weeks Subaru will be releasing an ECU upgrade and the necessary hardware/tools to enable this upgrade to be done at the dealer (about 1 hour). I'm optimistic and will post the results when my upgrade is installed. Have faith.
#6613 of 19336 Re: does your engine shake? [jeqq]
May 19, 2006 (10:15 am)
I'm not a mechanical engineer but I'll try to explain. I believe that "1st" order is the rotational balance and "2nd" order is the reciprocating balance. I once found a good website on this but I've lost the URL. Anyways, there are only two naturally 2nd order balanced reciprocating engines: any even-cylinder flat "boxer" engine and the inline six engine. The boxer engine is naturally balanced because the reciprocating masses are always moving in opposite directions. Note that there are other flat engines but these are actually 180degree V engines. The inline six is naturally balanced because of its geometry. A V12 is just two inline sixes joined together. Almost all other engines require balance shafts/masses to approximate 2nd order balance. The old favorite V8 is balanced if it is a "cross-plane" V8 (what most of us know) and if balance masses have been added to the crankshaft. The downside of this V8 is high rotational inertial (i.e. doesn't rev well) and that header tuning is difficult because of uneven firing order within each bank of 4 cylinders. V8s of the type "flat-plane" (i.e. Ferrari) are a different animal and are basically two inline fours joined together, and are performance oriented, not smoothness oriented. So, your best balanced engines are boxers (Subaru, Porsche, BMW bikes) and inline sixes (BMW). As displacement increases, the limiting factor on a boxer is its width, unless you increase the number of cylinders, and then length becomes a problem. As displacement increases, the limiting factor on an inline six is height and length, unless you change to a V12. That is why you see very few transverse mounted inline sixes. I think Subaru has chosen wisely with their 4 and 6 cylinder boxers. JMHO.
May 19, 2006 (1:27 pm)
Thank you for the input. I plan to see a Subaru dealer that I trust to have them look it over. I figured while I am there, they can finally replace the abs-brakes chip that Subaru sent as a recall (or a service to their owners). The car has plenty of pep, just think it used to have a little more.
Otherwise, love the car. Since I do a great deal of highway driving, was getting annoyed with the road noise (especially with the Yoko ES100s). Highly recommend the Micheline Pilot Exalto PE2s!!! Not as good a handler as te ES100s, but much nicer ride and quieter!
#6615 of 19336 Re: chugging and pinging [ateixeira]
May 19, 2006 (11:20 pm)
Yes, and if that does not work it might be the knock sensor going haywire. Mine did not throw a code when it started acting up, but oddly, it only did so after the crank sensor started to fail. The crank threw a code and was replaced, but the problem only became slightly better (mostly mine was wanting to stall and ran VERY rough at under about 1500 RPM) until I replaced the knock sensor. If you do not or have not add any injector cleaner, you might try that as well since pinging is often a sign of dirty injectors.
#6616 of 19336 Re: does your engine shake? [larrycrowell]
May 20, 2006 (4:49 am)
thanks everybody for the explanation.
So if I understand this correctly these engines are smooth while driving. At idle they will sometimes have to find there equilibrium/balance.
#6617 of 19336 Re: chugging and pinging [xwesx]
May 20, 2006 (9:47 am)
Thanks Juice and xwesx. I've reset the ECU, but I haven't driven enough yet to know if that's the fix. If not, I'll try the knock sensor. I add injector cleaner regularly so I'm not worried about that. I'll check back when I know more.
#6618 of 19336 Re: does your engine shake? [jeqq]
May 20, 2006 (11:52 am)
If your Subaru boxer were rotated by some external motor instead of running, you would find that it would be essentially without vibration. This would not be so for an inline 4, for example. Vibration at idle is probably caused unequal power impulses in each of the cylinders; it is somewhat difficult to get exactly equal miniscule fuel amounts to each cylinder. More rotating mass would damp out these impulses but at the expense of poor "rev" performance; less rotating mass would enhance the vibration. Guess they try to strike a balance in their design.
May 21, 2006 (8:59 am)
Does anyone know how to fix an air leak around the driver's mirror on a 2002 Outback Wagon?
#6620 of 19336 Re: Air leak [jfgolf3]
May 21, 2006 (9:48 am)
I had this, and from what I read, an issue for the MY. Mine was replaced. No amount of silicone spray, or extra padding was able to alleviate it. The whole housing was improperly fitted. The new gusset works flawlessly. Search the threads, I believe there should be some about it.