Digsy

I've just taken my calcs a step further and confirmed your earlier post, Graham. If you work out the factor (P/T) for the standard conditions on the NASA page you get 351.736 Since R is a constant, you can incorporate it into the factor also: n= 351.736 x (V/286) becomes n = 1.229 x V Note that the 1.229 is actaully the density figure from the NASA site, so its all working so far. If we make V=0.0283m^3 (1 cubic foot) then n = 1.229 x 0.0283 = 0.0348kg and the kg to lb conversion is to multiply by 2.2, so 0.0348 x 2.2 = 0.076lb So at this temperature and pressure 1 cubic foot or air weighs 0.076lb.

Check it out (I really should be working, but this is much more interesting). To calculate the mass of air at any temperature or pressure you need: T: The temperature in K (=degrees C + 273). P: The pressure in N/m^2 V: The volume of air in m^3 And - this is the key to it all: R: Universal gas constant. But it needs to be expressed in J/kg/K and not any other unit. This value for air is 286. Then use the rearrangement of the Ideal Gas Law: n=(PxV)/(RxT) Where n=mass in kg. The reason why the units for R are so important is that normally this law is applied to a single gas, whereas air is a mixture of gases. Also, it is more usually expressed in "J/mol/K" which would give you the answer in Moles, which again is only applicable to a single pure gas. Using the value 286 rigs the equation to spit out its answer in kg. Thankfully all the information is on the Nasa page I posted earlier - except in the metric column they have @r5ed up all the units and I have just had to spend an hour working it all out. So, you can either assume fixed standard temperature and pressure and work out a fixed conversion factor of (P/T) which would look like: n= factor x (V/R) Or you can plug in whatever you think the real temperature and pressure figures will be. Sorry but I can't work this out in imperial - it was har enough in metric (thanks, NASA!)

These might be worth a look: http://wright.nasa.gov/airplane/airprop.html (WTF is a slug?) http://www.chem.sunysb.edu/hanson-foc/lesson12.htm

The density of air will depend on the temperature and atmospheric pressure (or the pressure of wherever the CFMs of air that you want to weigh are). A book or someone who knows gas laws should be able to help out.

I once had a leak on the PAS system on my BMW 3 series. The fluid was slowly leakingout of the rack, behind the gaitors at the ends. No external signs at all.

Not on a car with your age / mileage. Its just that when they are doing the timing belt the level of tear down is almost the same as for a front crank seal, so I wih I had had mine done. You got a 16000 mile UK sec car with one lady owner for 12K AND you haggled with the dealer? [envy] I would have ripped is arm out of the socket! Jesus, have YOU ever got a good deal! Well done! [/envy]

Matt Harwood of Sextons' in Maidstone. Occaisionally posts under his weekend name "Chantelle".

1 - I've heard i need to do a full oil change every 2500 miles or so, if i want to keep it healthy and running. Now thats not a problem, just what oil is recommended? I don't want to scrimp on the important stuff like oil, so please recommend whats best for a long life! At the risk sparking disagreeing and general bad feeling, a 2500 mile oil change interval is totally OTT IMHO. The guy who told you this, he wasn't called "Bush" was he? In reality you could change the oil every 1000 miles if you were paranoid about it, but if the car is standard (no mods), been treated well (turbos allowed to cool down before key-off etc) then you should in theory be able to get away with the manufacturer's recomended service intervals (more of this later). HOWEVER, as a general rule turbo cars do work the oil harder, so an "interim" oil change midway between scheduled services isn't a bad idea. 2 - I'm nearing the end of 59k miles and i got some money knocked off for a cambelt change. Is the light going to come on at 60k? I was going to take it to http://www.jpsmotorsport.com in Bletchley which are about 10 miles from me - is this a decent place to go? Can they do a decent full service on the car, with oil change, cambelt etc? How much did you get knocked off for your cambelt change? Rough price for Toyota todo it is £160 depending on your area. Almost anyone could do it but make sure they use the right tool to get the crank pulley off (NOT a blow torch, right Rob?) Just as an aside - my 1994 NA has done 45000 miles and has a weepy front crank seal already. When I had the timing belt changed I wish I had asked for the front crank seal to be done too. Its not much extra work when the front end is already stripped out. The book on your car will say 6000 mile service intervals. This changed in 1994 to 9000 miles as part of a policy decision by Toyota. We are reliably informed that a 1993 car will run happily on a 9000 mile schedule (this would make your interim oil change every 4500 miles). 3 - Where is the best best place to get the most-fitting blanking plate for the Stereo. I have a £500 Pioneer sitting here which i want to put in, don't want a panel that will look like a totally different colour plastic etc underneath! Don't UK spec's have a single DIN hole as standard? If not then Toyota have a proper part to blank off the lower half of the slot. Otherwise there are several generic plates or cubby holes available from all good ICE installers (Matt!) Someone will be along soon to give you the details (Matt!!) 4 - Is the factory fit alarm Cat1? I've been told it is, but i personally have my doubts that it would be..... Aparrenalty it is. Someone who knows car security can give you more details (MATT!!!) 5 - Other than oil, is there anything (im a total novice here) that every informed Supra Mk4 owner needs to check on a regular basis, on addition to the usual car stuff (fluids and so on). PAS pump noise, squeaky tailgate rubbers, allow turbos to cool down before key off, dont thrash it from cold, front suspension bushes / bolts coming loose, some reports of valve stem seals going. No real major mechanical foibles really. Check fluids and pressures as you would any other car. 6 - Finally, how simple is it to get to the rear and front speakers to replace and can anyone quote sizes and how deep the gap is behind them? Don't know the sizes off the top of my head but rears are quite easy to replace with more decent kit. Fronts are tiny compared to the size of the grille and a bit of a pig to replace. Again, plenty of good advice to be found here from people who have done ICE upgrades already (M A T T ! ! !) And...welcome to the BBS!!

Sounds like a dodgy earth somewhere in the lighting circuit, linking the brake light and sidelight earths. Is there any moisture around the tail light multiplug?

That's neat - looks like it has a sight glass tube on the side so you can see how much oil you are carrying over. Any more details on it?

Does it say "LH" on the opposite wheels? Sorry - couldn't resist :D

I've had input on a couple of these: One on a rig and one for a production engine. No idea about generic aftermarket designs, though. Yes, they can fit into the camcover breather line. Both the ones I have worked on had entries for breather gases/entrained oil at the bottom and exits for air at the top (connected to pre- and post-throttle breather points in the air intake hose). The volume needs to be as large as will package (does not need to be cylindrical), with an oil drain at the bottom connected back to the oil pan. Sometimes the drain entry to the pan is below the level of the oil so that the drain cannot communicate directly with the breather volume inside the cylinder block. The rig engine one made stuff all difference, but the one that I worked on for production had a marked effect on oil carry over. IMHO the tend to be a bit temperamental. Do you suspect you have an oil carry over problem?

Well, like I said, if you have det bad enough you will be able to hear it with the naked ear, but if you suspect you have borderline det or pre-ignition then take it to a tuners' to get it checked out. Just thinking aloud, maybe knock events are recorded in the ECU, so you may be able to interrogate that. Maybe someone else can confirm or otherwise...?

I probably could have been more clear there. In normal ignition, when the spark ignites the fuel / air mixture, it does so in one place - at the spark plug tip. The flame front advances across the combustion chamber at a finite speed, so the whole process from spark to "all fuel burnt" takes a short space of time. However, as the flame front expands, the cylinder pressure rises and temperature increases. With conditions condusive to detonation, this pressure / temperature rise can be enough to spontaneously ignite the fuel / air mixture in a region where the "normal" flame front has not reached yet: hence two (or more) sources of ignition, and two or more flame fronts, each expanding and heading for each other with desasterous consiquences. Det / knock / pinking makes a noise which you can hear. You could also hook up a visial display to the stock knock sensor (we use normal oscillascopes here). You could also hear it if you fed the signal through an appropriate amp and into a pair of headphones. The possibility of a custom made in-car display that talks to the standard knock sensor has been discussed here before. You could probably also hear it with a stethoscope or something similar - although this isn't much good for tuning! What we do here is map engines for fuel / spark by watching for knock events on the scope and listening on headphones. The guy running the engine dyno literally has two dials in his hands: one for spark advance and one for fuelling and he twiddles each one until he gets the best power from the engine at a given speed without knock, then he moves onto the next set speed, etc, etc. He ends up with a fuel / spark map (this is a gross simplification because some engines need many maps, but the principle is similar). Once the normal map is defined, the engine can run on "auto/auto" (auto spark and auto fuelling based around the nominal map but supervised by the O2 sensor and the knock sensor). The problem with testing a knock sensor, or with mapping an engine up to the limits of det, is that you actually have to make the engine det, which is not a good thing even in small quantities.

Detonation occurs when multple flame fronts develop in the combustion chamber, usually because the engine is running too hot, boost pressure is too high, too much spark advace, AFR is too lean or octane is too low. Detonation usually occurs after the spark fires, and the sudden rise in cylinder pressure as the flame front expands causes the remaining unburnt fuel/air mixture to combust of its own accord. The two (or several) flame front collide and the resulting shockwaves knacker your pistons / rings / combustion chamber / valves etc. Detonation (or knock) is characterised by the metallic "pinking" sound when the engine is under load. OEM knock sensors use peizo-electric transducers (a material that changes physical shock into an electric current) to sense the vibration caused by the flame fronts colliding. This is why the mounting of a knock sensor in the engine is so critical: There must be a clear path through the engine structure for the shockwaves to travel. Pre-ignition is a simpler problem where something in the combustion chamber ignites the fuel / air mixture before the spark fires. This can be an almost normal combustion process (one flame front) which is ignited by a hotspot in the combustion chamber, like a hot carbon deposit or a sharp edge or burr which cannot dissipate heat from itself. The combustion event will obviously be mis-timed in relation to the "optimum" spark event so the engine will lose power. However, if the normal spark event occurs soon enough after the pre-ignition, you can end up with multiple flame fronts and detonation. HTH.

Its definately a durability issue. Lots of engines used to have exposed timing drives until industry durability targets and service intervals got pushed up. On engines destined for the US of A if you have a timing belt go the manufacturer will fall foul of thier emissions legislation too (the timing drive is considered an emissions-critical part). Of course, poking fingers into a running timing drive is a bad idea

Guess that's a limitation of the version of the EPCD that's in circulation. That part number doesn't even appear on my CDs (JDM or UK). Sorry for the mis-information. Supra Pilot: Here's the parts list for the teming belt tensioner bits, as I have them.

I'll check it out tonight (if I remember).

The "half to bottom to half" is the amount of oil pumped to the top of the engine, which drains down after you stop the car. Can't account for the overfill after 4 1/2 hours though! Are you sure the ground is level where you measure it? Maybe your engine makes oil! Watch out mate, OPEC will be onto you soon!

My PAS pump makes noise on cold start too. Supras seem to have noisy PAS as standard.

Mine doesn't creak either but I've got to get some of that stuff!

I always go around my bolts twice whenever I re attatch the roof. I can usually get another half turn or so on each one after the roof has settled into place. I didn't do it once because I was in a hurry and the difference was obvious - lots of creaking.

Sounds like he has standard JDM brakes but 17" wheels to me. Its one or the other - worn pads or fooked calipers!

Assuming your pads are standard Toyota parts, they have noisemakers built in to alert you when they are low. Once they contact the disc, the make noise almost continually. If you check you should find you have about 1mm of pad left somewhere! Theye is another thread running about pad part numbers.

Front: T04465-14081 Rear: T04466-30030 These are May 1996 onwards parts, but they fit my 1994 car OK.