casioqv

It wouldn't hurt if you coated the gaskets with the same non-hardening sealant used to join the two block halves, but it's probably not needed as other people said.

You're right, I was mixed up on the definition of positive and negative caster. If you interchange them in my previous post, you will see what I meant and what I was asking.

If you can run slightly lean without predetonation, it will improve fuel economy, but it's still a bit risky and increases emissions. There is an excellent graph in the book "Bosch Fuel Injection and Engine Management" by Charles O. Probst that shows how fuel mixture affects fuel economy. If you have low octane fuel, a turbocharger, or high compression there isn't much chance of running lean without predetonation.

By radius do you mean caster angle? Does the subaru really have positive caster from the factory? That would be entirely pointless, I wonder why they would do such a thing. It would make the car wear tires faster, understeer, and feel unstable on the freeway. So can the factory camber and caster problems be fixed just by ovaling out the holes in the front strut tower, and moving the top strut mount as far inward and forward as possible (if the vehicle is at the stock height)?

I'm used to driving volvos which have an electric 5th gear button on the shifter, and 4 real gears. In my XT with push button 4WD I always want to go 1-2-3-4-4WD!

You should be using redline 75W90 NS, or MT-90. The regular 75w90 has friction modifiers for limited slip differentials, that cause your syncromesh to engage slower, and grind. You could also try the redline MTL, which is more similar to the ATF in viscosity, but might be bad in temperatures over 90F (32C).

I don't think he's lying, but I would like to see some more information. If you drive 45-55mph and are very gentle on the throttle, many cars will give incredible fuel economy improvements. I would get a graduated cylinder full of fuel, and drive at a perfectly constant 55mph on level ground (measured with a GPS) while the passenger times how long it takes to use a specific amount of fuel. It could be dangerous to have a cylinder of fuel in your cars cabin, but I'd bet the fuel economy would be over 40mpg. It's basically impossible to always drive like that. Unless you live in Nebraska, sometimes you have to stop or turn. I would really like to see someone try this, and report how the fuel economy differs over the range 40-80mph with 5mph intervals.

Why do you say the distance is not linear? The rolling circumference of the tire is a fixed ratio relative to the factory tire rolling circumference. The odometer is geared at the factory to record a specific number of tire rotations as a mile. As the vehicle moves one tire circumference per axle rotation, you just multiply the mileage the odometer reads by the ratio of the tire circumferences and you have the actual distance travelled. There is no calculus necessary. As you said, the odometer can be fixed by adding a reduction gear box to the odometer cable. A reduction gear box can only change the speed by a linear factor. Also, polynomial interpolation (fitting a curve to a set of data points) is not calculus, it's statistics. I use a cheap $75 GPS to calculate my fuel economy, as it will also record my average speed so I can calculate how that affects the fuel economy. It's pretty sad, but you don't actually need a degree in a subject to teach it. Often the teachers level of proficiency in the subject in high school, is just what they learned in high school and nothing more. A good portion of the science taught in high school is just plain incorrect.

Did you read the entire thread? Did you read the link I posted earlier? You can't just say "it doesn't add any more air" without any explanation whatsoever, when I provided references written by well known mechanical engineers that design turbocharger systems professionally and say just the opposite. This effect has nothing to do with intercooling. Cold idle enrichment is to provide the proper stoichiometric air/fuel ratio at cold temperatures when the fuel condenses instead of atomizing properly. When a multi port fuel injected engine is fully warmed up, the atomization is very complete and this is a non-issue, even if the intake charge is still very cold. Again, don't take my word for it read it in the book "Bosch Fuel Injection and Engine Management" by the late Charles O. Probst, SAE.

If you're going to argue semantics... From the American Heritage Ductionary: Motor n. - A device that converts any form of energy into mechanical energy, especially an internal-combustion engine or an arrangement of coils and magnets that converts electric current into mechanical power. My point was that if you're locking the subaru transmission in 4WD and using a divorced transfer case, and entirely replacing the suspension/subframe you lose any advantage from the car already being 4WD, as you don't really use any of the factory 4WD parts. Sure a subaru is light, fuel efficient, and strong enough, but so are most passenger cars. I don't think it compares very well to those european cars I listed, but that's mostly a matter of opinion.

If you're going to modify a subaru that much, where you have a divorced transfer case, custom built suspension, custom axles, and custom subframes front and rear there isn't anything "subaru" about it's offroad abilities. You could start with any passenger car, and get identical results. I would choose something with a strong lightweight unibody, a durable motor with lots of torque, and good rollover protection. Probably a Volvo 140 with a B20F engine, a mercedes W115 with an OM616 engine, or a 1.6l VW diesel 2 door wagon would be a better canidate than a Subaru. What's great about a subaru is that they are cheap, fuel efficient, handle like a car, and are reasonably good offroad. If you modify it like that, you lose all of those benefits except the offroad abilities.

Why will it not add additional fuel? Please explain. If the flapper in the air "mass" meter is stuck all the way open at WOT on a stock engine, and the fuel system cannot add any additional fuel, wouldn't cooling the air charge cause the engine to run lean, and increase the chance of predetonation? I do not think that the stock fuel system is unable to adjust for varying flow rates, as that would cause very serious problems in any turbocharged engine. I found an excellent article online that shows how to calculate the change in air mass due to an intercooler: http://www.gnttype.org/techarea/turbo/turboflow.html Please read the section on volumetric efficiency, and explain logically (in the context of the article, and my previous explanation) why you think that an intercooler would not increase the amount of air (and therefore fuel) entering the engine. The book "maximum boost" that I mentioned earlier is also an excellent source of information, and clearly explains what I am talking about. I do not think that it is possible, or safe to effectively modify a turbocharged engine for additional performance without understanding exactly what you are doing, and what the effects will be. I may be a dork, but my engines last a long time, and generate more power without blowing up. The ideas I am expressing here are not unusual or radical, they are clearly explained in every book I have ever seen regarding turbocharger system design, and can be found in any basic textbook on classical physics or engineering thermodynamics as well.

The ecu doesn't need to read the temperature difference to increase the fuel flow to the engine. The flapper-type air "mass" meter measures the volume of air being sucked into the turbocharger. From this it estimates the air mass using the PV=nRT formula I gave earlier, and injects the correct amount of fuel. The ECU doesn't need to know what the intake charge temperature is to provide the correct amount of fuel, it just needs to know the mass of air so that it can maintain the correct air fuel ratio. As I explained previously, an intercooler will cause additional air mass to enter the engine at the factory boost. Before the turbo this additional mass is measured as additional airflow. Where you might get into a problem is if the ECU isn't capable of measuring the increased airflow, and adjusting fuel accordingly. Some flapper type air "mass" meters do not function on wide open throttle, and the ECU just flows a set amount of fuel for each RPM based on the stock boost. This is true with the Bosch L-jetronic system, which the EA82T system seems to be based on. I'm not sure if it's the case with the EA82T.

I disagree, the pressure drop across the intercooler is a property of the physical configuration of the intercooler, not the amount by which the air is cooled. A sufficiently large intercooler (such as a custom made Spearco intercooler that is larger than the radiator) will have both less pressure drop across it, and greater cooling. Such custom made race intercoolers have negligable pressure drop, and are able to get the intake charge cooled down to very near the ambient temperature. The wastegate on the turbo keeps the pressure before the intercooler at it's preset value, so an intercooler with less pressure drop will flow a greater mass of air. While the mass air flow is not entirely linear as in the PV=nRT equation, it is certainly not fixed as you are implying. If it were fixed, any reduction in charge temperature would need to be accompanied with a pressure reduction by an equal factor, that would be fixed for all intercooler configurations in all vehicles. This is clearly not the case. For example, My Volvo 740 Turbo has a very large intercooler from the factory (18.5x17 inches of frontal cooling area), and no pressure drop can be measured across the intercooler (a factor of under 0.05) without a very high precision boost gauge, while the temperature reduction across the intercooler is over 100 degrees C (a factor of about 0.25). How could a power increase be caused by a reduction in charge temp without an increase in fuel or air mass? A reduction in charge temperature will decrease the chance of predetonation, but more air and fuel are required to create additional power. Edit: It is possible for a particular intercooler to have enough restriction that the reduction in pressure equally cancels the cooling effect, resulting in the same mass of air entering the engine. Again, this would require pressure and temperature changes by an equal factor, which would require an enormous pressure drop, or very little change in temperature. This would have to be an extremely poorly (or cheaply) designed intercooler. I don't know if that is the case with the WRX intercooler or not, but it is certainly not the case with any large front mount intercoolers I am familiar with.

What intercooler were you using? Is it top or front mounted? A top mounted intercooler would get almost no air flow on a dyno unless it had a fan installed to force air over it, while on the road it would get considerable airflow without such a fan. Is it possible that your intercooler was simply heatsoaked from lack of airflow, and not operating at all on the dyno?