proud new H6 owner! - Subaru Outback - Subaru Outback Forums
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post #1 of 7 (permalink) Old 07-10-2013, 01:35 AM Thread Starter
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proud new H6 owner!

well, I guess the title is still in my wife's name, but I'm gonna be the one fixing stuff on it and asking all the questions on here!

Just bought a 2005 LL Bean Outback yesterday with 118K on the clock. Really happy so far, super clean, fun to drive, etc etc.

My first questions:

I do notice a little whine to the engine, not terrible but I wanted to confirm. Kinda like the whine of a newer motorcycle I guess.

The PO removed the air scoop in the front saying it improved breathing and gave it better power?? is there any truth to this idea?

Lastly, and maybe the most dangerous of all the questions, just how important is the premium gas? We've already cheaped out without regular once on the way home (before my wife new it was imperative...)

What are the actual damages that may occur? or is it just lower power?

Thanks, looking forward to years of just chatting it up on here with no actual problems

The only form of self expression left in Boulder these days is what colour your Subaru is!!
---Mark Byers

2005 Outback H6 LL Bean
1993 Legacy L
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post #2 of 7 (permalink) Old 07-10-2013, 07:16 AM
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Just throwing a rock in the bush, but with the car having 118k on already, how sure are you that the PO put in premium up till now and would it really matter?

This is the extract from the owners manual:

"The 2.5-liter turbo engine and 3.0-liter engine
are designed to operate using premium
unleaded gasoline with an octane rating
of 91 AKI or higher. If premium unleaded
gasoline is not available, regular unleaded
gasoline with an octane rating of
87 AKI or higher may be temporarily used.
For optimum engine performance and
driveability, it is required (for 2.5-liter turbo
models), and recommended (for 3.0-liter
models) that you use premium grade unleaded
Be sure to use premium unleaded gasoline
of 91 AKI or higher for a 2.5-liter
turbo engine model. If other gasoline
(lower than 91 AKI) is used, knocking,
reduced output and poor accelerator
response will result.

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post #3 of 7 (permalink) Old 07-10-2013, 08:05 AM
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The reduced acceleration is no joke. Regular unleaded will also run somewhat hotter and your MPG will drop a bit.

But, I haven't heard of anyone cracking a piston with it yet. So it's up to you.
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post #4 of 7 (permalink) Old 07-10-2013, 08:36 AM
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that aftermarket intake is letting you hear more noise - likely not doing anything positive for you either as the stock intake IS a 'CAI', cold air intake.

Time Flies Like an Arrow,
Fruit Flies Like a Banana!
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post #5 of 7 (permalink) Old 07-10-2013, 11:27 AM Thread Starter
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interesting, my wife read the manual about that, but I didn't notice the part about it being "mandatory" for turbo and "recommended" for 3.0.

The PO says he used nothing but premium, but he only had the car for 6 months. Who knows what was used before...

I'll see what we think of the performance while we run out this tank, then assess again with a new tank of liquid gold We're about to take a road trip to the East coast so we'll have a few tanks to test on highway driving!

and the intake hasn't been so much replaced as it was just removed and left off. I guess it may be taking in warmer air from the engine compartment that way? maybe I'll just put that back on...

The only form of self expression left in Boulder these days is what colour your Subaru is!!
---Mark Byers

2005 Outback H6 LL Bean
1993 Legacy L
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post #6 of 7 (permalink) Old 07-10-2013, 01:13 PM
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I would try and get the original ducting back on the intake before the road trip. You'll have a quieter ride and possibly better gas mileage.

The prior owner failed HS science. Hot air is less dense meaning less oxygen per volume so the engine generates less power sounds like he thought removing ducting work and feeding hot engine bay air to the engine would create more power. LOL He probably reduced his power 2-10% by doing that. Get the original ducting back in the car so your feeding it cold outside air not hot engine bay air and you will probably see better mileage for sure have a quieter ride.

As they say you can't fix stupid... In this case HS science did have its value.. How to get the most power from your car #1 don't feed it hot air! Feed it cool air.
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post #7 of 7 (permalink) Old 07-10-2013, 09:37 PM
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I can save you a lot of time calculating.

The H6 runs sluggish on low octane compared to the zippy acceleration on high octane. The fuel economy is actually better on high octane. I saw an easy 2 mpg increase with 93 over 87.

Flush all the fluids that you are unsure of being on schedule. Add a full bottle of Sea Foam or Techron to the tank when you fill up to clean the fuel system. Make sure the air filter stays clean. Cabin Filter ought to be checked.

Don't let the oil get low.
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