slo5oh

a quick google search... and Stolen from http://www.newton.dep.anl.gov/askasci/eng99/eng99234.htm All substances, gases, solids, and liquids, including water, are compressible. Some substances just require more pressure per change in volume to compress than others. The numerical value of the compressibility depends both on the temperature and on the pressure too. That is how hard you have to squeeze at one pressure to obtain a certain fractional decrease in the volume is different than at some other pressure. The same for two different temperatures. Under most "normal" lab conditions however solids and liquids are usually considered to be incompressible. Some of you seem to be experts on the subject. Some seem confused. Inside your combustion chamber will be both air and fuel. If a little water slips in you will be fine and it will turn to steam either before, during, or after the ignition of that cyl. If more gets in it will "bog" your engine down and the mixture will not ignite correctly. If quite a bit gets in you will seize the engine. It takes quite a bit. Depending on the size cc of the heads, and how the piston is seated in regards to the top of the block you will have more or less space known as your combustion chamber. If you exceed the size of your combustion chamber you will hydro lock. I've personally poured a mixture of brake fluid and water down a carb on a chebby 350 to clean the carbon from the tops of the pistons. I wouldn't do it now a days since it would probably destroy the o2 sensors. But, holding my idle at 3000 rpm I poured an entire 44oz cup down the carb in about 60 seconds. And as for an exhaust valve being bent by this situation... It does sound far fetched, but I've seen stranger things.

And you can maintain that speed? Jeeps have the aerodynamics of a brick. I had a 89 with the 4.2 carbed engine. It made gobs of TQ, but I could only run 5th on the freeway for downhills and flat surfaces.. any sort of hill and I would have to put it in 4th. I was also running oversized tires, so maybe that was part of it. Mine too had 3.07s. And the best mileage i ever got was around 14mpg.

Shell gas?http://www.local6.com/automotive/3378460/detail.html

My parents have a 99 honda with the 4cyl and while I don't know the RPM, I do know my father with a lead foot usually gets between 30 and 38mpg... his honest average at about 35.

Engines will use the most fuel at peak TQ. Obviously under full throttle. You are dead on with your jeep example. The only flaw is that nothing cruises on the freeway at 1600rpm. Even the stock gears in my mustang kept me at about 1800rpm at 70mph in 5th. Our cars tend to run too short of gears. I know my soob pushes 3500 rpm on the freeway (of course I'm doing 80). I would probably get 30mpg if I were doing 40mph everywhere. The taller (smaller number) you can get your gears and still maintain freeway speeds the better mileage you get. Of course the reverse is that the lower your gears (bigger number) the better the car "feels" driving around. It will feel like you are making more HP.

Damn... Didn't want to start a fight. The last couple posts peg internet information as a whole. Be careful what and who you take advice from. My experience is with high HP 5.0 ho engines, supercharged and N/A. I've seen sooo many people put a 160 (stock is 195) t-stat in and have all sorts of overheating issues in the summer months. Usually the 160 is not blamed since it was put in months earlier. What it comes down to is that, fans or no fans, the cooling fluids don't spend enough time in the radiator to cool off sufficently... so unless you were doing 50mph on the freeway you would always overheat. Honestly in my soob I'm not looking to make 10 more HP or 10 more TQ... although another 10mpg would make me nut. With a simple basic understanding of engines, electronics, and mechanical parts I know that heat is your enemy. Cooler engines last longer, cooler air is more dense, cooler electronics burn out slower (they all eventually burn out). I know the engine needs to reach a certain temp to run at it's peak. I opted for a set of cast iron heads on one engine in place of the normal alum heads to keep temps in the combustion chamber up... (where the juice likes it) In defense of Blitz: I read Everything you posted and with my 10 years of tweaking assorted 200 to 600hp engines I'd agree with all of it. The phynolic spacer story amused me, hell it reminded me of a friend that ported his own intake and hogged the thing out sooo bad he probably lost 40lb of TQ, and no way did he gain any HP. There's a little thing called "intake port velocity" that he mangled. But his pride would not let him remove it and start over. It takes balls to admit you spent time and money on something and it failed. I still have some 3" black PVC I bought 2 years ago and was planning on using to bypass the stock breadbox intake... never got around to it though. I'm no pro engine builder... just a garage fiend with friends-a-pleanty. Some of them are smart as hell, some are... well... not. But I learn from them all. Blitz seems to know what he's talking about. Since it looks easy enough to get at the t-stat I will try swapping to a 160 whenever I get around to draining the cooling system.

Why wouldn't I want to use a $3 special from a local autoparts store? If they work in every other car....

Has anyone played with running a lower temp t-stat? I'd like to see my normal operating temp lower then it is. p.s. what is the stock t-stat temp?

I agree. See if you can get it to reproduce the problem by hosing the engine bay down. If you can I'd wait an hour for it dry off then tell them to take it into the dealer and do the same thing for them. My best guess is there's a short in the wiring harness. If they can't find it... they can just change it. You could spend days testing each wire (I know, I have)... and since it's shorting out the system you'll probably never get a computer code on where the error is. The simple solution is to change the main engine harness.

I just went through this on a differnt car. You are right on the universal. The only difference is that the universal does not have a plug on the end, so you have to cut and crimp on your existing harness plug.. From what I have seen every company out there reboxes the Bosch O2 sensor into their own box. I bought A/C Delcos... and whoa... strange... they had a bosch # and even said BOSCH on them. :)If you want your new o2s to last you stay away from Shell Gas. They have sulphur in their fuel and will cause premature failure of your entire exhaust system... and mostly your o2s.

My brother had a late 80s soob that sounded like a diesel. A few mechanics told him he needed a new engine. He kept driving. 2 years late he found a new mechanic for his general stuff and the new mechanic told my brother he could fix it. The mechanic replaced his oil pump and the diesel noise went away. That engine went well over 300k before my brother sold it.

Don't fret over what the dealer said. The best cooling additive I've ever seen is redline water wetter. It really does what it says. I ran a supercharged mustang with a blown head gasket using 100% water, no anti-freeze and a botte water wetter. I never boiled over. I had to wait a month or 2 before I could rip it down to swap out the gasket. If you're wondering why I didn't use anti-freeze... it plays hell with your bearings if it's leaking into your oil. Water on the other hand, in small amounts, will heat up and evaporate out of your oil.

I'm uninvited.... with my '98 2.5RS... but average with mostly freeway... 25ish average on the mazda zoom zoom type road... 23ish best ever... 28.1 Something I've noticed.. gas mileage sucks at over 70 freeway speeds... it's like these cars were built to get great mileage between 50 and 60mph... that's how I got the 28 tank. Took a trip through Yosemite, beautiful drive, spent most of my time between 40 and 50 and probably would have pulled 30mpg if it weren't for the 80ish getting to Yosemite and coming back.

****!! you're a hottie!!! You show your left side a lot. Is there only the one dimple? I knew a girl in Sac with only one dimple. She hated it, but I thought it was sexy. In your opinion, where's the first major bottle neck in these engines? Forgive me, but my last 10 years has been spent tinkering with 200 to 600 hp mustangs. On those cars I can tell you the headers are the first thing that need to go. Ford pinched all the tubes coming straight out the heads so you can get a socket on all the header bolts. Great way to save time, right?

Test your voltage at your battery. Test the resistance of your ground. I'd tell you how, but I got a C in electronics 10 years ago, and don't have my multimeter in front of me. Electricity is fun, and it's a new adventure every time I figure it out again. The last line, in that last post, reminds me of one of my brothers friends. He bought a license plate ring that says "yes, I am a rocket scientist". Some people are too smart for thier own good. God blessed me with other problems. Naimly the curiosity of a Kinder.

Honestly though. Subigal, what sort of gains did you see with that pipe? The factory setup impressed me, short of the big bread box feeding the TB. Skanky, a good ground or a pefect ground, you will not notice any difference. I had friends that built street racers (400hp) engines and were all anal about running a big phat ground strap. Other friends and I have ran upto or past them still using a stock ground strap on a supercharged 5.0.

Any pictures of you? I'd love to see a subigal!

If you have not, change your trany fluid. I would spend the extra $30 and replace it with redline synthetic (or what ever flavor you like). It's obviously coming from the trans. I've seen engines with bearings that go out and they will shake like hell, in or out of gear. After that trip pulling that trailer you probably burnt the hell out of your trany fluid. If it's never been changed it's way past due anyhow.

Forgive my lack of ... ehumm... subaru experience and knowledge. I have a '98 2.5RS and I bought it from a dealer with a hair over 60k. I'm now at 106k (2 years later) and it's been a great car. I don't know if your 99 has the same 2.5 as mine, but when I first got it I ran it for 3k and when the oil change was needed I thought I'd treat it to the same thing I've always given the mustangs. Redline 5-30. A few weeks later when I started it up on a real cold morning and took off with no warm up t rattled like a baby's toy. Piston slap... bad. I lived with it, just did my best to warm it up in the mornings so that wouldn't happen. 4 months and 10k later I was looking to change the oil. I've always loved redline, but I remember a friend of mine telling me he got better oil pressure with mobil 1 synthetic in his mustang. Hell i'll try it. It's been over a year and a half later and I have not (knock on wood) had to listen to any piston slap since my soob started drinking mobil 1. I even ran 2 cycles of 0-30 weight I got on clearance at wal-mart for $1 a bottle... I bought all 20.

I bought my '98 2.5RS with just over 60k and I'm at about 106k right now. Just did the timing belt (old one looked beautiful though) last weekend and fixed a leaking front crank seal.

If this is a factory service manual I should be able to find it at a library... right? I can go to the library and copy pages from it. Does anyone have the book that covers the 98 Impreza? Would you be willing to scan those pages?... at least the engine mechanics (should be 10 to 20 pages at most). I think the copy rights don't allow those pages to be sold, but given away is fine. If someone will do that I'll be happy to stick them on my website for anyone to download.

Reading several of the newer posts I read that there are problems with the DOHC 2.5 engines. Can someone elaborate?

Purolator One with the synthetic element... that's the same filter in the black box at Wal-Mart called a "super tech" for under $2.

for $4000 I'd expect the dealer to drop in a NEW engine and TRANS.... and while I'm waiting the cute girl that answers the phone better give me a hummer. I haven't been taken by a mechanic since I was 20. IT cost me about $1500,and 2 weeks without my car, to find out that my timing was off by about 20 degrees in a mustang. Man I wanted to beat the snot out of that guy. Since the day I wrote that check I've never had anything other than oil changes, brakes and tires done by anyone else.... and even for the oil changes and brakes I would ONLY take it to a shop my friend worked at. Did I mention that I still want to beat the snot out of that guy? Way I see it you have 2 things you can do. #1) Learn from your mistake. I know this is kind of obvious, but you'd be surprised. Ask around your local area and you will find a mechanic that's honest, there's always one. Then, be good to him. Still shop around for prices on repairs, but so long as he's in the ballpark with everyone else stick with him. Some mechanics will tell you a low price then do half the work and call about "other" problems to raise the $. We always call these the "muffler bearings" costs. There is no such thing as a muffler bearing. #2) Take your invoice to several different shops and see what they charge for the same thing. If the dealers cost is way off, as I'm sure it is, you may be able to sue and get some back or at least call the BBB on them. What I would do, since it was a dealership is have a custom sticker made up for your back window that explains "XYD Subaru Dealership Service Department ROBS IT'S CUSTOMERS BLIND!" I thought about doing this to the guy that worked on my mustang, but he's a small shop with no advertising, so I'd probably bring him more work.

Just buy the Super Tech one from wal-mart... under $2 and give you all the goods.