blitz

Drive smoothly and move with traffic, just stay out of the fast lane. Driving sporty is more fun, but it cost more money. If you can afford it, no prob. The auto-trans models do, but it doesn't de-couple any rotating mass from the system (rear axles, rear diff, driveshaft, and transfer-clutch all still rotate when the vehicle moves) so it doesn't really do a whole lot. What I forgot to mention is that those heat-ranges I quoted are from more than plug manufacturer websites, they're actually from my '02 owners manual as well.

Always start with the recommended heat range and only switch if you have reason to believe that a hotter or colder plug would be of benefit for a specific reason. NGK Iridium IX (#BKR6EIX-11) are way less expensive and will be more durable. Great FAQ & tech tips at: http://www.ngksparkplugs.com/products/cars_trucks_suvs/iridiumix.asp?nav=11420&country=US About the only thing you can do to get better mileage is to keep the tires inflated and don't drive real fast. Both the AWD and the extremely over-square bore/stroke dimension (thermal loss) conspire against great mileage. It's doubtful that the plug change itself will have any measurable effect on fuel economy.

The 16 is a hotter plug than the 20. In fact, 16 is the hottest plug in the Denso iridium range according to the Denso site. All the documentation I've seen shows 20 to be the recommended heat range for the 2.5 (for a Denso plug). http://www.densoiridium.com/findmypart.php If using an NKG plug, the correct heat range is a "#6" in their system. By going to a hotter than recommended plug, you'll probably end up with spark knock if you drive normally. The ECU'll retard the timing and you'll end up with elastic throttle response and worsened fuel economy. A hotter plug would be beneficial in an engine with really worn rings, if you idle a lot or drive like an old lady.

Bingo. With a good set of winter tires and open diffs, you never find yourself inadvertantly trading any forward momentum for sideways momentum. :cool: I gotta fit a manual override FWD/4WD switch to my ride on account of that rear clutch (4EAT) having some treacherous characteristics in turns.

Everybody with a Subaru should spend a little "slide time" in a vacant lot at least once every winter. It really is fun, it's a great way to better appreciate the Subaru capabilities, and mostly, in an emergency driving manuever, might save a life or three. Just make sure it's a lot that you know to be free of blocks.

I don't have a problem with Denso per se, I think they make a fine product. I've run their standard U-Groove plugs for almost 200,000 miles in my last car (not one set, I changed 'em regularly). I'm just making the observation that the iridium tips melted on my iridium Denso's. I think there's a limit to how thin the electrode can be made. Also the Denso Iridiums are way expensive. Phase I 2.5 = earlier DOHC version. Phase II 2.5 = later SOHC version

I've been running the Denso IK20 in my phase II 2.5 for about a year (10k miles). After taking a look at their condition recently, I was shocked to see that the iridium tip had become molten on two of the four plugs. Two of the tips had changed appearance from a flat, precision machined look, to a shiny little ball of slag. I chalk it up to the long and extremely thin (.4mm) tip. Next summer, I'm going to swap them out in favor of NGK Iridium IX with a shorter and thicker (.6mm) tip to see if that remedies the situation. I've never heard anyone else voice this complaint.

Novus plastic polish system: http://www.noscratch.com/novus/ For a fogged or yellowed polycarbonate lense, start with #2, then finish with #1.

The "cheap" way around that was the knurl tool for the piston skirts to expand little indentations and bumps. It could buy another 30-40k miles of driving on the old pistons. It's interesting to see all these problems that automakers had pretty much worked-out long ago popping up again in the quest for emissions and efficiency. e.g. sludging, piston slap, lean stumble, etc.

My '02 uses the old fashioned screw and locknut type adjustment (no shims). I had the covers off at 20k miles to check the clearance and found it had opened by only .001 over spec. I adjusted 'em back down anyway since I was already in there.

Ahh... this was a concern of mine. I'm aware of the tensioner noise thing but wasn't sure if there was any way to positively differentiate it from the piston noise. I would've thought for sure that the tensioner would begin making noise from the get-go rather than needing a short drive for the noise to develop (as on my car), but maybe I'm wrong?

I'm not sure it gets cold enough often enough here in Detroit to justify a block heater (the coldest it got during the recent cold snaps was -1F). The first two winters I ran mobil 1 5W-30. This winter I tried to thicken it up just a bit by mixing (2)qts. 5W-30 with (2)qts. 0W-40, but it didn't seem to make any difference in the noise. To anyone with a slapper: does the noise continue to get worse every winter (as the mileage accumulates), or does it level off at some point? This is my third winter with this vehicle, and the slap has gotten proggressively louder and longer each winter. This car is a blast in the snow, it's like a friggin' go-cart. I love dusting Mustangs, Camaros, and 2WD pickups from light to light.

Relax dude. no one wants to see you fall out of the sky. Being conservative at 10,000 feet is generally not considered to be some form of character weakness. :cool: The quote was for a stock 2.5 which is pretty much what Eggenfeller has been using as of late. Other than a hand-built intake manifold, they don't soup 'em up. They offer a supercharger option, but it's setup to compensate for altitude rather than increase HP over stock by boosting over Bar. Most of the companies that make adjustable cam gears for Hondas and Toyotas, etc. don't cater to Subaru. This is the only source I've been able to find to date: http://www.speedstash.com/camgears.html#subaru, but there's nothing there for a 2.2 tho.

Mmm... but it's the heat in the piston itself which is transferred through to the oil via under-crown splash (I do realize heat is also transferred to the oil via the heads). I have pondered the oil viscosity thing before, but haven't experimented. So do you 'spose an oil that exhibited somewhat greater viscosity during the warmup would help? I'm listening, but definitely not looking!!!

Nope, hardly news to me. I've been to the Eggenfeller site many times. http://www.eggenfellneraircraft.com Here's a direct quote from their site regarding typical operational RPM. Take it for whatever your life is worth: "QUESTION: Are there any placarded "non-operation" RPM zones? You mention that you typically run 3800-4200 RPM for continuous operation--and for takeoff and emergencies, you can run 5300 RPM for short times. If I choose to run the higher RPM for "longer" times, do I jeopardize engine reliability (i.e., does reliability drop off quickly) or does it just shorten the TBO?" "ANSWER: No placarded zones. Reliability and TBO is reduced by drawing more than 75% continuously in any engine." "QUESTION: If my car ran at 5600 RPM I would be concerned. The Subaru is essentially an auto engine even after it has been converted for aircraft use. Should I be concerned about this?" "ANSWER: We don't operate @ 5600 RPM but high RPM is an excellent way to get power from a well balanced engine with a short stroke for a SHORT DURATION such as for takeoff and initial climb. In the GlaStar, we get plenty of power @ 5300 RPM. This RPM is used for takeoff, and climb is @ 4800-5000 RPM. " "The Subaru is no ordinary car engine. There is a main bearing every 2 inches and this, together with a balanced flywheel and lightweight pistons, provides for an easy turning engine. It is not a coincidence that we only work with Subaru engines. Drive a Subaru and wind it to 8,000 RPM, it will be smooth as silk and you will understand that 3800-4200 for continuous use is not a problem."

'02 OBS, 37k Miles Alright, I have the cold piston slap which is gradually becoming louder with miles accumulated, no surprize there. But what I've noticed is that the slap doesn't occur when the engine is started, but rather it develops as heat is built into the cold engine by driving gently, and reaches peak intensity about the time the temp gauge reaches it's "normal" reading. From that point, it slowly diminishes as the engine warms further, and is gone after another 2-5 miles of driving (depending on ambient temp). Geek type question: Why the buildup of the slap noise during warmup? I'd think the piston, being the primary recipient of combustion heat during the warmup cycle, would expand faster than the bore during that period and therefore be subject to a snug, bore-fit. This puzzle rattles in my head at least twice a day during the winter.

Had some more thoughts. Not sure what kind of altitude you routinely see in that sort of craft, but I would think that as atmospheric pressure drops as a consequence of altitude, accelerative velocity in the manifold and ports will suffer proportionately ...so if the air lags, make the cam lag too. You might be onto something. Also, continous full-throttle operation at 5500 RPM seems like it would place a fair amount of strain on stock internals as well as generate a butt-load of heat into the piston crowns, ring-lands, oil, and exhaust valves. Part-throttle operation at 4500 RPM on a continuous basis shouldn't pose a problem.

Just noticed the aircraft requirement, so I guess the Cobb header is out, but I'd imagine that you've already got a decent-flowing custom exhaust installed. The only disadvantage to the Cobb cam (or any other stage 1 cam) is the higher lift which works the valve springs harder. This I think might neccesitate a periodic valvespring changeout interval to retain reliability in flight. The engine might respond to a little bit of cam-retard if you combined it with having the heads done (including a multi-angle valve job). The only way to know for sure would be to have access to some dyno time. A dozen pulls to try different combinations would show you the way.

I speculate that some meat could be added to the lower end of the torque curve by advancing the stock cams a couple degrees, which would benefit a relatively heavy, 4EAT equipped vehicle, but the tradeoff would be a power fall-off above 5000 RPM. I don't see any benefit of going the other way (retarding the stock cams) in hopes of finding better breathing up top. As Legacy777 mentioned, your best bet to get the motor to breath freely is the Cobb street cams combined with an intake, Cobb header, and a decent exhaust. If you want to go further, have the heads done. Further yet? ...Cobb club-racer cams. There's a lot of power to be had, at the expense of some engine longevity.

I've run the Denso U-Groove's in a previous vehicle (Mitsubishi) for 176k miles (a fresh set every 20k miles) with excellent results and subsequently tried 'em in my '02 OBS with equally good results. These are about equivalent to the NGK "V-Groove" coppers I'd guess. Anyway, in my efforts to try to crispen the soggy throttle response, I swapped in some Denso Iridiums. Now while I'm not sure that I noticed any real improvement in the way the car ran, I did pull em' out after about 8k miles just to have a look-see, and I noticed that a couple of the plugs appeared as though the long, needle-thin (.4mm) center electrode turned to a ball of molten iridium at the very tip. Mind you, the plugs themselves (ceramic insulator, ground electrode, etc.) showed no indication of heat-range abnormalities, only the very tip of the center electrode. It's my belief that there is a limit to how long and thin the center electrode can be made before heat cannot escape and a "plasma" condition occurs. I got me a set of NGK IridiumIX to swap-in next. These have a slightly thicker (.6mm) and measurably shorter center electrode, which ought to sink heat more effectively. Also, they were a heck of a lot cheaper.

Alias20035, I believe that those limits that you describe are for towing. With engine not running, the trans pump isn't supplying any lube to the rotating mechanisms and hence the speed/distance limit to avoid tranny damage. I'm pretty sure the car could be driven indefinitely with the fuse in (FWD mode).

No one's mentioned this yet, but you might want to have a look underneath to check for the possibility of a broken front sway bar.

I hear ya brotha!

Not yet, but I will soon. It's building full pressure in the top hose now, so I think everything's kosher.

The problem I was having was an inability to build full pressure in the cooling system which resulted in a constant stream of bubbles (boil) out of the overflow tank. (see thread: "Oh Crap, bubbles in the overflow tank"). I was concerned that I might've had a head gasket problem. Actually I have no operational problems whatsoever, the vehicle runs fine. In fact it's never run better.