Distance Commuter

Increase tire pressure. It's a standard technique among high-fuel-economy folks. We usually put our tires at least at the max sidewall rating; some of us go higher than that. For 4wd Subies, maybe 5-10% higher in front vs. rear tires if that's what your oem spec's say. Below is quoted from http://www.carbibles.com/tyre_bible_pg2.html For the first two years of our new life in America, I'd take our Subaru for its service, and it would come back with the tyres pumped up to 40psi. Each time, I'd check the door pillar sticker which informed me that they should be 32psi front and 28psi rear, and let the air out to get to those values. Eventually, seeing odd tyre wear and getting fed up of doing this, I asked one of the mechanics "why do you always over-inflate the tyres?" I got a very long and technical response which basically indicated that Subaru are one of the manufacturers who've never really adjusted their recommended tyre pressures in line with new technology. It seems that the numbers they put in their manuals and door stickers are a little out of date. I'm a bit of a skeptic so I researched this on the Internet in some of the Impreza forums and chat rooms and it turns out to be true. So I pumped up the tyres to 40psi front and rear, as the garage had been doing, and as my research indicated. The result, of course, is a much stiffer ride. But the odd tyre wear has gone, and my gas-mileage has changed from a meagre 15.7mpg (U.S) to a slightly more respectable 20.32 mpg (U.S). That's with mostly stop-start in-town driving. Compare that to the official quoted Subaru figures of 21mpg (city) and 27mpg (freeway) and you'll see that by changing the tyre pressures to not match the manual and door sticker, I've basically achieved their quoted figures. So what does this prove? Well for one it proves that tyre pressure is absolutely linked to your car's economy. I can get an extra 50 miles between fill-ups now. It also proves that it's worth researching things if you think something is a little odd. It does also add weight to the above motto about not trusting forecourt pressure gauges. Imagine if you're underfilling your tyres because of a dodgy pressure gauge - not only is it dangerous, but it's costing you at the pump too. Fuel economy message board - http://www.gassavers.org

I, too, fear and suspect that vibration and lack of metal are hurting the engine. But anyway,... Don't misunderstand me re. the cooling thing - I'm not suggesting to try run the engine colder than the intended design. I'm suggesting we try run them closer to intended temps, and with more even temps around the block, by slightly improved cooling. If during idling the water coming out of the radiator isn't quite cool enough to cool the block, the temps will go up. The thermostat still mixes hot and colder coolant as needed as it adjusts itself, trying to maintain the temp balance. But it can't achieve the balance if it only has hot water to work with. When the block temp goes up, the fan kicks in, and then the t'stat gets what it needs - but there was a delay. During the delay, things got hotter. "Pre-emptive" or pro-active cooling at the radiator while idling makes sure the t'stat always gets water that's been cooled somewhat. Dig?

Why Subaru didn't upgrade the cooling? Dunno. I think it doesn't matter. Whatever is needed to remedy the hg leaks, they didn't do it - I think there's no value in us assuming that any solution we think of has already been thought of and properly tested by Subaru. Obviously they missed something somewhere. I kinda suspect that poor switching of elec. rad fans is responsible for troubles throughout the industry. Back in the "old days" the fans were mechanical, and spun always, even with a fan clutch. And I think there were fewer hg failures - but that's just me guessing. Yes, my thoughts also. The block casting looks pretty much like a shell surrounding a series of explosions. Also as a non-engineer, it looks like it needs more metal. But as you say, that's a harder fix to add, and also harder for Subaru to add, having already designed, tested and built the engine. But shucks, the fan modification should be easy to do. Testing would need a bunch of Sub owners to do the mod, and even then we'd need to hang in there for a year o so before seeing results.

How about radiator fan switching? Most fan switching is based on readings of coolant temperature. In other words, the fan won't come on till some sensor detects a temp outside its allowed limit. If designed too close to the limit, it could allow excessive temps in some local areas - like the 2.5's failure area which sees less coolant anyway. My own car has fan switching by temp sensors, PLUS fan operation triggered by the brake light circuit. That way when the car is stopped the fan is running on low speed. This gives a constant breeze over the radiator. The temp gauge is far steadier than it ever was before I added the brake switch-fan circuit. The circuit includes a delay to reduce on-off cycling due to brake pumping, stop and go driving, etc. Remember, the rad fan enables the thermostat to do it's job. If the coolant coming out of the radiator is too hot the t'stat can't keep up with the engine's heat output. Yes, the temp sensors are designed to meet the engine's needs - but improved cooling might just be enough to overcome the potential for failure. I've always felt that a warme3d-up engine idling without any airspeed over the radiator is building up potentially harmful heat. And, that's a mod that can be added at fairly low cost. Ideally, Subaru would add switching to run the fan in park and neutral if the engine is running. I think that's a bit tougher to do as a DIY modification.

I'm also thinking cooling passages. The pics of block near the start of this thread show a much shallower cooling passage around the failure area. The machined/milled groove is much deeper on the non-failure side. Not having been inside one of these motors myself I don't want to try to guess where one could cut away more metal to create a larger passage. I'd be very wary of weakening the structure. My feeling is that a larger block casting would give everyone more to work with.

I'll just comment on a few bits from the quoted post. For better or worse, I CAN remember driving two mid- '70's econoboxes (4-spd standards) , among other cars. '76 Corolla, '75 Datsun B210. I think FWD lets you cram the whole drivetrain into less space, leaving more room for passengers in a car with a smaller overall size. Smaller size = less steel etc. so you save weight, and still have a roomier passenger compartment. Lots of modern cars have very low aerodynamic drag. Often you can see the spec for that on cars.com (drag coefficient). But there's a style-demand thing going on; if you want the car to look macho like most SUVs do then the designers go for a taller boxier style, big vertical grill/headlight area, and a more vertical windshield instead of a shallow slope, and the drag coefficient goes up (more resistance). For a fairly aerodynamic design, see the 2nd version Prius. A very shallow windshield slope, not very tall, and no big frontal area pushing agains the air. I don't recall seeing anything saying that FWD reduces rolling resistance. Maybe in that pulling creates less resistance than pushing the front tires into the roadway? But I think that in pulling with fwd, you're trying to lift up the front so you're constantly exerting that upward pull energy. Maybe it's an even swap. In any case I suspect that rolling resistance comes in way below air drag and lots of other mechanical issues, in overall mechanical energy lost or needed. Some of those old econoboxes really were boxes. Chrysler's K-cars and the VW Rabbit and the Chevette come to mind. But some were pretty sleek: Mid '70's Corolla and the ubiquitous Datsun (Nisan) B210. Especially the hatchback versions; those were pretty much a fastback like the old muscle cars - the roof curved and sloped right down to the trunk edge; the glass was in line with that. As I recall, those little things got about 30 mpg.

I agree. But then sometimes people tell me I'm boring them, so what do I know?...

Yes, I'm with Commuter on this one. Here's another view of the same thing: When you look at examples of change in drag for some different changes in speed you see how dramatically it increases. The "cube" factor for air drag and the percentages of increase hold true regardless of your speed. So - - Increasing speed 20-40 doubles your speed (2X). ~~ That's an 8x increase in air drag (2x2x2). Increasing speed from 40-60 is a 50% increase in speed (1.5x). ~~ That's a 3.375X increase in drag; nearly 4X from the 40 mph drag! Increasing speed from 60-80 is a 33.3% increase in speed (1.33x). ~~ That's a 2.37X increase in drag. Increase from 20 to 80 is 4x the speed. 4*4*4 = a 64X incrase in air drag - yikes. Unfortunately it's true. Put your open hand out the window at highway speeds and you'll feel it. That's what your engine is pushing against, except the car's frontal surface is more like 5x6 feet or something like that. So I'm also with uniberp, who posted the first answer in this thread - the lowest speed where you can be in the top gear without engine lugging etc. will be the most efficient speed. It's all downhill from there. I usually drive 70 anyway. I pay for it at the pump.

Emily, Can you post a link to a good chart or table defining/describing the different engine types (not just the '99's)? I've been hanging here for a while on and off, and can see that the folks referring to these things must be getting their information from somewhere... Thanks!

Yes - I did. Thanks. Can you recommend someplace that lists the different engine types and years etc?

The thread Its time for a new SooB by nomoaudi had some good things to say about the H6 vs. the 2.5. Is there anything on the horizon as a replacement or real improvement for the 2.5? Or do we have to choose between an old and lower powered 2.2 and the big H6 if we want a truly long lived engine? I've been spoiled- been driving rwd Volvos since '95. The whole drivetrain usually lasts 300-400K miles. But they stopped making them.... So I've been lurking here.

You may be receiving a settlement offer anyway. If police were present or if ID numbers + insurance info was exchanged, lawyers may end up calling you for a release. As follows... I was once the front car in a four-car pileup in RI. In that case it was the last guy who was ultimately responsible - as he hit the car in front of him and pushed them all into the next car ahead. My car was fine really, I was a bit shaken but that was temporary. Old black bumper cover looked like it did before, it had miscellaneous minor dings here and there. After a few weeks I got a call from a law firm. They wanted to know about any damages or medical costs. So I had a dealer look at the bumper and he wrote it up, something like $300-400 to replace the cover. When I told the law firm the amount they asked me if I'd be willing to sign a release and they would send me a payment of $1000. They wanted the release - their guarantee that I wouldn't come back with a whiplash claim or some other issue a few months later. I'm sure I could have squeezed them for more than the $1000 but I didn't feel greedy; I felt lucky! I signed that release real quick and received payment. Among other things I bought decent lawn mower with some of the $$; I'm still using that mower.

Just plain old flat-out against federal law to remove or disable emissions equipment. Period. I'm old enough to remember the air on the highways and in cities before cat converters. Absolutely toxic. There are reasons we spend money putting them on our cars and they're good reasons. I also hate spending a few hundred dollars now and then to replace one of those buggers. But I do it.

JB Weld. Just kidding - sorry that happened to a car you know. Your daily driver??

I'm a big fan of self-service junkyards. Maybe not ideal for a motor or tranny but they are great for all those little things you might want. If you do find one that has a good motor they might help pull it for a fee; depends on the yard. Or bring a couple friends. You just have to call and ask around locally and go in there. Have a small bag of tools with you and more in the car; any yard-picker worth his salt has what's needed to get the parts off the cars. Many times they'll say "no" on the phone due to insurance + legal stuff but if you show up you're fine. I know a couple good ones in CT and MA but that's kinda far from you. If you can get to Southington CT see Chuck & Eddie - look 'em up.