Durty-Sanchez

$151 from Subaru.. although if you harass them and cry poor that you need all 4 they can often be had for $110

Clearing out the camera and thought i'd share the damage.. Although the impeller fins look corroded I suspect the corrosion set in after they were torn off by whatever went through it.. you can see only 2 fins remain, and they're completely bent under by whatever that was.

Forum debates ftw! This is true, non-laminar airflow being introduced to the compressor blades will cause inefficient compression through the turbo, however being an off-boost situation it may not be of any significance.. whether or not it offsets the denser airflow I couldn't say. My original rant was to dispel the rumour in a prior post that a BOV recirculates hot air back through the system, which isn't the case. IMO plumb back has more advantages over venting if you overlook the woo-ing effects the audiable portion of the vent has on the female species.

Probably not.. but it is worth replacing the factory BOV as it tends to leak after a while. Replaced my 15yr old unit and gained 3-4psi. It wont whistle at the skanks the same as a manual would though (if atmos venting)

Without being "that forum guy" here are some links to help (sorry, I was one of those white lab coat guys for 6 years).. in any case, I give you the Reverse Brayton Cycle aka the Gas/Air Refrigeration Cycle aka Bell Coleman Cycle: Gas Refrigeration Cycle Brayton Cycle And one more link, which shows that the cold discharge, when re-compressed and discharged again, continues to drop in temperature, as used on aircraft

Ahh.. then why do we run an intercooler if for "a substantial transfer of energy (Heat) there must be a change of state"? Temperature drops through an air-air intercooler of anywhere from 30-50°C, which is more than enough to cause these effects from a adiabatic expansion. Granted there will probably be cooling in the intercooler itself, but I am assuming that the turbo is still supplying pressure to the system, so most of the adiabatic cooling is taking place outside of the vent hole (BOV). To simplify (apologies for the rant), if you increase pressure the temperature goes up. If you then decrease the pressure the temperature goes down. If you increase a fluids pressure then decrease it back to its original state, the temperature will be the same as before you started. Now increase the pressure (higher temperature), then remove heat from the system (intercooler), then decrease the pressure.. the temperature drop is the same as before, which leaves you with air cooler than you started with because you took heat energy out during the heat exchange (intercooler stage). Perhaps you may have overlooked what is really going on here.. have a read up here. Example: Coke - Coke is bottled with plenty of fizz in it. The bottle itself can be considered a thermodynamic system as the working fluid (the trapped gas/fizz) is trapped within the bottle. The disolved gas expands and escapes the liquid until the bottle reaches a equilibrium pressure whereby no more disolved gas can escape (hence why when you look at a new bottle of coke it's not fizzing inside). This pressure increase leads to an increase in temperature (as given by the ideal gas law). Now take your new bottle of coke (in equilibrium) and put it in to a fridge, or even just leave it at room temperature. As heat is exchanged from the bottle to the surrounding atmosphere the temperature of the gas decreases.. now open it. As the trapped gas (under pressure) needs to do work on the atmosphere in order to expand it must decrease it's heat energy.. however, much of that heat energy has been removed through the heat exchange process. This is an adiabatic process as there is not enough time for the heat to be exchanged in to the trapped gas. The result? The temperature drops below the ambient temperature, which you can prove by looking at the top chamber of the bottle where there is now mist, which is water vapour in the air that has dropped below dew/condensation temperature. Find a atmospheric venting BOV on a car under load (i.e. on a dyno) and you'll see the same condensation forming as the BOV vents.

Not at the time the recording was taken.. sometimes it got so bad that it did throw a CEL while driving, otherwise the error code remained in memory. Those blips you see there caused the ECU to throw a huge WTF and 'tard the timing for safety

Should have taken some photos when doing the knock sensor today (big thanks to a mate of mine who did all the work). Here's a happysnap of the audio coming through my knock sensor before the swap. You'll see those big noisey spikes (sounded like I had water in my ears).. that was how crapped it was, was sending the ECU nuts and setting the CE light/retarding timing. Might do an after shot too that shows the difference.. In any case, remove the I/C and the two bolts that hold the heaterhose/ICV hoses on. You'll need a 12mm socket, bendy bit, and extension.. and crap loads of patients. Be careful not to thread the bolt when putting it back in, you'll need it to be on an angle as you start to feed it in as the intake pipe prevents it from being 100% vertical. G'luck!

I got mine for $105 from Subaru, that was with a discount though.. usually they're $151 I think. Try pick-a-part, or they look fairly generic so a knock sensor from another make might be ok. They're a bastard to get to..

Yea BOV needs to be post-cooler in order for sh*t to happen that way.. if it's pre-cooler the air coming out is (assuming no heat exchange) the same temperature..

Here's a good reason to stick with a plumb-back setup (sorry for those who've heard me bleat on about this before, seems older posts were lost in forum fails). In anycase, you can take my word for it or onwards science geeks for todays lesson in BOV thermodynamics.. The Turbo/IC/BOV thermodynamic system is very similar to that of a refridgerator, so much so that air being vented from your BOV is cold - very cold (well at least colder than the surrounding air). In some cases it could even be well below 0°C. How?.. well.. (numbers refer to crude MSPaint PV diagram below) 1. At first we have some air sitting around outside at a given ambient temperature. The turbo sucks this air in and compresses it through an adiabatic process (a process that adds no heat energy to the system). Yes the air does heat up, but that is because of the increased pressure (as given by the ideal gas law). For simplicities sake, no heat is exchanged from the turbo to the air. Looking at the 1st law of thermodynamics (dU = dQ-dW or the change in the systems internal energy, in this case the airmass, is related to the increase in its temperature - the work done by the airmass) we see that no heat energy is added, but work is done on the airmass by an external system (the turbo), so the internal energy of the system increases. (note, dW is only positive if the airmass does work on its surrounds, if work is done on the airmass by something external then dW is a negative value. Negative minus a negative is positive, so dU is positive). The final result is that the airmass is hotter, of greater pressure, and occupies a smaller volume than before.. you'll see the path it takes as the compression stage of our thermodynamic cycle. 2. Straight out of the turbo the air is then passed through the intercooler, or in other words a heat exchanger. The heat exchanger is designed to remove heat from our system, so we get a negative dQ in our thermodynamic equation and the overall energy of the airmass decreases. The air itself loses heat energy and the pressure of the airmass decreases. The volume however remains the same (roughly), so this is a constant volume process. This is usually the point where the air enters the engine and that'd be the end of this part of the cycle.. however, the case of a BOV venting causes something else to happen. 3. When your BOV vents you then have two systems suddenly combining - one at a much higher energy than the other. From the 2nd law of thermodynamics these two systems have to reach an equilibrium, which can only be done if the pressurised airmass (from the BOV) does work on the ambient airmass. Because the ambient airmass is so large in comparison, it will see very little in the way of changes, however the BOV airmass will do something quite interesting. Because of the speed of the BOV releasing this is considered an adiabatic expansion (no heat is exchanged from the BOV air to the atmospheric air), so the only method by which the BOV air can release it's energy is to do work. The work the BOV air needs to do to expand in to the outside atmosphere is roughly equal to the work done by the turbo to compress it in the first place.. however the intercooler has already taken away some of the airs internal energy. The result is that in order for the BOV air to expand fully in to the atmosphere it has to borrow from its internal energy - or heat - meaning its temperature drops below ambient. 4. So the air shooting out of your BOV is actually cold, much colder than the surrounding air (depending on how efficient your I/C is). This happens regardless of whether or not your BOV is plumb back or atmospheric venting.. however you wont get any benefit out of it if you vent it. Might as well plumb it back in and cool the airflow through the system for that split second! This is, of course, one cycle of the vapour compression refridgeration cycle. Your fridge does this repeatedly to cool the refridgerant down to well below freezing and keep your beers cool. Anyway, hope that was somewhat interesting for someone, and next time someone claims that the BOV air is hot so you're better to vent it you can pwn them with science.

Check for damaged radiator cap or if your overflow tank has itself overflowed.. if the later then it could be a sign that you need to investigate further.

I bought a CD short block for $50, already honed (but needed doing again).. you'd get one for under $100 somewhere

Oh.. and dont worry about insurance, 2x careless = 2x writeoffs.. insurance paid out both times

They may not take his licence depending on the seriousness of the charge. I've had careless driving x2 and they only took my licence once (the first charge). Tips from my expensive lawyer are to go do a driving course before the court hearing to prove that he is sorry and actively changing his ways. Then ask for an increased fine in lou of losing his licence.

Check the rocker cover gaskets for signs of leaking (a steam cleaned engine ruins this..). Look for any visable AFM damage (they're sensitive wee things), error codes too if you get the chance.

If it's the secondary it'll be loose like a palmy girl. They start to leak over time like the crappy (identical?) primary bov's.. pull it off and check it for holding pressure. If it's not that then check for split hoses both inside and outside the black box (of doom). Those are the usual suspects, every now and then it may be one of the sensors, valves, or the solenoids.

Here's a question.. back in the day of 91 and 96 the price difference was around 5-6 cents. When they brought 95 they dropped the price so the difference was only 4-5 cents. Within weeks it was back up at 5-6 cents. Just on my way past the stations today I notice that the difference is now 9 cents.. what gives?

Maybe.. without knowing the electrical characteristics of the coil-on-plug devices it's hard to say if they have a suitable charge time to be used with a wasted spark setup (although I'm sure Reuben and friends have done it with their single turbo setups and have no problems). The cheapo way is just split the two ignition signals from the ECU in to two, so you have 4 signal wires again, run them to the coils and go for a thrash. If at high RPM/boost you have missfiring then chances are you've run out of time to charge the coils. Best way would be to get the manifold based coils (as Mr. Fuji had intended it to be). At least that way you dont need to worry about expensive coilpacks (x4) dying every 4 years

As the engine speeds up the time period between ignition events decreases, however the charge time of the ignition coils remains constant at all speeds. Therefore the ECU is responsible for determining the dwell time, or the amount of time between ignition events.. and of course if the ECU c0cks it up and doesn't give a long enough dwell time to charge the coils then you get a crappy spark

Take off the plastic scuff plate (2 bolts at the back, 3 at the front, and screws in the wheel arch) and see where it's dripping from. My bet is split hose.. keep the coolant topped up and get it looked at asap. If the coolant can't pressurise and boils it causes corrision to start.

Anyone passing through Helensville on the way to Welly/Palmy/Masterton? Got me a large hairdrier needing a ride..

It's all in the firmware.. it calculates the load based off rpm/airflow, then makes corrections for manifold pressure. The cuts/failsafes kick in if manifold pressure is too high, if the load values are too high (i.e. reach the limits of the map or the load limit), if rpm is too high, or speed is too high.. those are the only cuts I can remember finding but that's from the top of my head..

One cut is load based, so if say your "load cut" is 90% then if the load on the engine (as calculated by the ECU) exceeds 90% it will cut out. You might be at 20psi in 2nd gear and the load will be at 70% - you're fine. But if you're at 15psi in 5th gear you might hit 92% load, and it will throw a cut in. In any case, I would say that if it is a cut then it's the ECU protecting the engine, so i'd leave it there..

Was it consistantly at 5500rpm? If not then check the error codes again using the under-dash connectors.. the AFM code might come up. If it was consistant then you're probably hitting the boost cut..