Ian C Posted June 9, 2004 Share Posted June 9, 2004 Name: Decat Also known as: Double Decat CAT removal Straight through exhaust pipe What is it? The stock Supra has two catalytic converters. These do all manner of wonderful things for the emissions of the engine, but to do so they get in the way of the exhaust stream, and this reduces the flow and increases backpressure. In a turbo car, backpressure is an evil, and once you are past the turbos you need a little as possible. The restriction also increases the heat in the engine bay because one CAT is on the downpipe. Decatting simply replaces the exhaust pipes with the CATs in for exhaust pipes without CATs in. The diameter and quality of material etc. varies but they all do this one simple function. The bonus factor is that freer-flowing exhaust means a small increase in the volumetric efficiency of the engine. That means more power. Double bonus is the the turbos can flow more air so they produce more boost. That means *lots* more power. People who get decats done regularly report of the car feeling like a new one afterwards, the difference is that big. However, the increased boost is a double-edged sword, you have to watch out for boost creep, running lean on fuelling, and fuel cut kicking in. Running lean after a decat is a very real phenomena, the J-spec fuel pump isn't up to the job most of the time, and the ECU can't fuel for more than 1 bar of boost anyway, especially once the fuel cut is removed. Pros: Increases VE of engine, giving more power Increases boost of turbos, giving more power Removes heat from the engine bay Cons: Apart from some success with the first (1993.5) MkIV Supras, you will need to swap one CAT pipe (usually the centre section one as it's easiest) back in order to pass an MOT Boost creep may occur Fuel cut may occur Your fuelling may not be adequate for the extra boost Quote Link to comment Share on other sites More sharing options...
Ian C Posted June 9, 2004 Share Posted June 9, 2004 The decat FAQ now needs support FAQ entries for: Boost creep Restrictor rings Running lean/detonation Fuel pump swap/upgrade I've already covered fuel cut and fuel cut defenders. Feel free to chip in folks, and good work Darren (can you do a post about conductive garage floors next please) Oh, and will anyone be offended if I wade in and correct spelling on their FAQ entries? -Ian Quote Link to comment Share on other sites More sharing options...
Jake Posted June 9, 2004 Share Posted June 9, 2004 Fantastic work guys! We've needed a proper FAQ for ages. Bloody hell Ian, you're quite prolific aren't you! Don't you have a day job? One observation, if I may: Originally posted by Ian C Name: 12v fuel pump mod Also known as: The fuel pump mod What is it? blah blah blah .. . . . This is probably for pump longevity and maybe some NVH reasons. I don't suppose all our FAQ readers will be familiar with the meaning of NVH. Quote Link to comment Share on other sites More sharing options...
Aerotop Dave Posted June 9, 2004 Author Share Posted June 9, 2004 Fantastic efforts peeps - please keep these coming, this is shaping up nicely ++ Quote Link to comment Share on other sites More sharing options...
carl0s Posted June 9, 2004 Share Posted June 9, 2004 Originally posted by Jake One observation, if I may: I don't suppose all our FAQ readers will be familiar with the meaning of NVH. I'm not. New Vehicle Healthcheck? Quote Link to comment Share on other sites More sharing options...
Jake Posted June 9, 2004 Share Posted June 9, 2004 Originally posted by carl0s I'm not. New Vehicle Healthcheck? NVH Quote Link to comment Share on other sites More sharing options...
carl0s Posted June 9, 2004 Share Posted June 9, 2004 Originally posted by Ian C Oh, and will anyone be offended if I wade in and correct spelling on their FAQ entries? -Ian You mean Darren Blake? :D Quote Link to comment Share on other sites More sharing options...
Digsy Posted June 9, 2004 Share Posted June 9, 2004 In my defense, I had had a couple of beers and there was a Sky documentary about the history of pornography on in the background. Correct away Quote Link to comment Share on other sites More sharing options...
Ian C Posted June 9, 2004 Share Posted June 9, 2004 Noise Vibration and Harshness. I'll do a seperate FAQ entry as it's an acronym that crops up in other techie threads such as long winded and overblown crank pulley discussions Carlos - I didn't like to say Darren - I saved 21 words but had to shoot two. I've replaced them with healthy ones. -Ian Quote Link to comment Share on other sites More sharing options...
Ian C Posted June 11, 2004 Share Posted June 11, 2004 So far the list, as I see it, looks like this. I can edit this post as things get written: To Do: Boost Controllers High and low impedance injectors Hybrids Induction kit BOV/Dump valve Turbo timer EGTs Intercoolers Basic Performance Upgrade (BPU) AFC E-Manage Fuel pump upgrade Adjustable FPR Piggyback tuning Race Logic Traction Control Wheel spacers Suspension - lowering, stiffening Alignment spec LSD (Limited Slip Diff) NVH Done: FMIC The solar sensor Misfire under boost Fuel cut Fuel cut defender Double decat 12v Mod Charcoal canister EGR TVD/Crank pulley Speed de-limiter Boost Gauge Quote Link to comment Share on other sites More sharing options...
Ian C Posted June 11, 2004 Share Posted June 11, 2004 Name: Speed delimiter Also known as: Speed Limit Defender (SLD) Speedo convertor What is it? The Japanese import verion of the Supra is limited to 180km/h, which is 112mph. The SLD bypasses this limit so that you can go faster than 112mph. It usually also serves the function of converting your speedo so that it reads in mph rather than kph (and the odometer counts up in miles). Pros: You can go faster - woohoo! Your speedo reads in mph Your odometer counts up in miles Cons: A good SLD has no cons. This is because it takes the input from the vehicle speed sensor and sends three outputs. One output is unchanged and it goes to systems like the speed sensitive power steering and the active spoiler etc. A second output is scaled so that it reads mph instead of kph - this goes to the speedo and the odometer. A third output goes to the ECU and this is clamped at around 111mph, which stops the ECU from ever engaging the speed limiter function. A crap SLD has various cons. Usually it's electrical-quality related, a lot of problems are caused by poor construction or wiring as the ECU starts seeing a zero speed signal. The main problem with poor SLDs though is if it acts as a speedo convertor as well. Usually they emit only a scaled Vehicle Speed Sensor output to everything, meaning all the speed-dependant systems like the power steering and active spoiler (and especially the autobox!) get an incorrect speed signal and behave eratically. Quote Link to comment Share on other sites More sharing options...
Ian C Posted June 11, 2004 Share Posted June 11, 2004 Name: Boost Gauge What is it? A gauge that displays, usually in PSI or Bar, the amount of boost pressure your intake manifold is seeing. Why do I want one? The first bit of performance tuning you'll probably do to your Supra is increase the boost in some fashion. This can be by a bleed valve or a boost controller affecting the wastegate, or by a decat and/or performance exhaust pipe affecting the flow of the turbo. You *need* to know what's going on at this point, cause the fastest way you can destroy an engine is to run too much boost. Another factor is that the stock sequential system can go wrong in various ways, or the airflow path to the engine can fail, usually due to hoses being loose, split, or plain old missing. The boost gauge lets you monitor the behaviour of the system across the rev range, which aids in troubleshooting the problem no end. Especially if you are asking questions in a text-based forum. Pros: Shows you how much boost the engine is seeing Acts as a diagnostic tool Cons: You have to fit it somewhere. Either replacing the clock or a heater vent (depending on the gauge size) or getting an a-pillar pod, that sort of thing. Quote Link to comment Share on other sites More sharing options...
Clarkey Posted June 12, 2004 Share Posted June 12, 2004 This is fantastic! The D's B's! Muchios Gracias!! Quote Link to comment Share on other sites More sharing options...
Dragonball Posted June 13, 2004 Share Posted June 13, 2004 Loads of this on the other site - will post link later when i can find it - sorry if not applicable here - hope useful elsewhere! On Buying a soop - What should I check when looking at a Supra to buy? -Have someone cold start the car while you stand behind it watching the tailpipe, and look for gray smoke with a blue-ish tint (easiest to see in direct sunlight) -Let the car warm up and continue to stand behind the car checking for smoke -Now move to the front of the car, and open the hood. Listen for bad noises (Noticeable Injector Ticking is Normal) -Now go back and watch the tailpipe for smoke, have someone blip the throttle, while you watch for smoke, let it idle between the blips -Now do the same but have them mash the gas and rev it up till like 5000rpm or so -Now have a friend follow behind you in another car while you go for a test drive -Have him watch for smoke while you drive -Put it in 2nd gear, let the rpm drop to about 1500, and then stomp on it, and stay on it till redline, then let off the gas. Your friend should be watching for "gray/blue smoke". Just grey/black smoke is ok. -Smoke at cold start-up, leaving a stop-light, or throttle blipping from idle is valve stem seals. Smoke under boost, or after letting off of boost, or maybe when revving full throttle, is turbo seals. Smoking for no good reason, or if it doesn't stop pretty quickly is piston rings (may get better or worse when hot). -Your job while at full throttle in 2nd is making sure the turbos boost fine (smoothly), that you can feel full boost by 4000rpm or near it, and that you don't hear bad noises (slight turbo whistle/whine is ok, if it has an intake it will be noticeable) -Use all the gears in the transmission, and make sure it shifts fine (if it is a 6spd, it is going to feel and sound clunky too you, that’s normal. If the transmission makes "ball bearings in a can" sounds at idle or low speeds, that is 2-piece sprung flywheel and is normal) -While driving with the windows down, listen for clicking or popping noises coming from outside the car. (A POP when starting or stopping, or making a sharp low speed turn (maybe up a hill), is the drivers side engine mount. A clicking sound under initial mild acceleration or deceleration, that lasts for only a second or two then stops, and sounds exactly the same regardless of speed, is the rear upper control arm bushings. A clicking that changes with speed is wheel bearings) -Make sure the brakes work smoothly and reasonably quietly. When coming to a stop take your hand slightly off the wheel and make sure it stays straight. -Make sure the car tracks straight on flat roads. -A creaking noise from the hatch when turning up hill, means it needs rubber hatch bumpers. -Rattling from above you means the targa is loose (make sure the targa bolts loosen, and tighten back down smoothly) and make sure the targa wrench is there. -Make sure the rear hatch opens and closes fine, and that is stays up on it own. -Make sure all the doors open and close smoothly -If you can really smell the exhaust when coming to a stop, it has no cats -If when flooring it, the car pulls smoothly till ~4000rpm, and then rockets forward like getting hit with a semi, then it's BPU and not stock. If you can hardly feel a change over from the 1st turbo to both, then it's stock. -When checking under the car for leaks, don’t be alarmed by an oily sludge on the transmission and differential. That’s a greasy undercoating that Toyota applied. But check for fresh oil leaks, and check the rear CV joint boots for cracks. -If possible, look at the spot where the car normally parks. Check for fresh oil puddles or spots. If they say their other car caused the spot, don't believe them if it's a clean 1-2 year old car they are blaming it on. -Check the wheel rim, inside and out, for curb rash or bent rims. -Check for excessive or uneven wear on the tires -Check for cheap, or miss-matched tires -Look to see if all the little plastic panels and parts under the car all line-up, and are attached, and that paint is not where it shouldn't be (cracked under trays are not uncommon, don't be alarmed). Spend a fair amount of time on the ground, don't be afraid to get a little dirty. Also all the major body panels have the original VIN number visibly stuck on them, make sure they are all still there and are the right number. Look for missing, non-original, or out of place fasteners. All these things are possible signs off a collision. -Check for signs of rust in the wheel wells and inner fender -Check the condition of all the exposed rubber on the suspension joints -Make sure the power steering is smooth and quiet -Make sure the gaps in the body panels are all even. -Walk all around the car, and look at each panel at different angles. Looks for small dents and dings, and make sure the paint matches all around. -Look over the paint condition very closely -Check around all the glass to see if it has been replaced. Check the manufacturer information on the glass to see if they are all the same. -Make sure all the exterior lights work -Check the headlamps for cracks, moisture or fogging/yellowing (expect them too be fogged/yellowed if an earlier model) -Make sure to test every last switch in the car to make sure it works (power windows, locks, turn signals, light switch, dome lights, power seat, cruise control, everything). Use all the functions on the A/C and make sure they all work. Go from HOT to COLD A/C and make sure it's getting very hot, and very cold. If it has a factory alarm, make sure the key-fobs work. -Check the interior for excessive wear (cracked leather in the seat's side bolsters is pretty damn common). -Check all of the fluids, make sure the fluid isn't terrible. Open the oil fill cap, and look inside for sludge build-up (you shouldn't see any) -Find out what oil the use, and how often (don't trust their answer unless they have receipts) -Ask them if they have had any work done to it. If they have owned it for several years, and say they have done nothing to it, don't take that as being a completely good thing. -Ask if it has ever had modifications, and what. -Make sure it still has the spare tire, jack and wrenches, owners manual, and targa wrench. -Try to get the repair records -Do a Carfax.com check on the VIN # -Take it to a mechanic you trust AFTER you have done all this to get it checked out one last time before buying it. -If the owner refuses any of this, be suspicious. -Try to take a level-headed friend with you who you can trust. This may sound like a lot to do, but really it's not, most of these things take no more than a second to do. Make sure to always go look at a car on a bright sunny day, and make sure you and the seller will have plenty of time (don't rush anything) Any problems you find (and your likely to find a few) should not mean you shouldn't buy the car. But you need to know what you are getting into, and whether the price is reasonable. Always negotiate. People are almost always willing to come down some on their asking price. And be prepared to walk away as hard as it may be. Quote Link to comment Share on other sites More sharing options...
Aerotop Dave Posted June 13, 2004 Author Share Posted June 13, 2004 I wish I'd had that when I bought mine! I think I did the worst inspection ever (not that I've found any major problems yet, touch wood) Thanks for that, very useful. Quote Link to comment Share on other sites More sharing options...
Sharpie Posted June 17, 2004 Share Posted June 17, 2004 What about the three/four slits in the dash by your left knee ? Quote Link to comment Share on other sites More sharing options...
SimonB Posted June 17, 2004 Share Posted June 17, 2004 Originally posted by Peter Sharp What about the three/four slits in the dash by your left knee ? Ah yes, good one. Cabin air temp sensor for the air con right? Quote Link to comment Share on other sites More sharing options...
400BHP Posted June 18, 2004 Share Posted June 18, 2004 Originally posted by SimonB Ah yes, good one. Cabin air temp sensor for the air con right? Correct! Hot wire air temperature sensor, works by passing a current through a wire to achieve a specified temperature, when the temperature changes, (by cooler air passing over it) the resistance changes, these resistance changes are mapped in the AC ECU and this adjusts the cooling/heating accordingly in compliance with the specified temperature on the controls. This is the same principle that the Airflow Meter on the induction system uses. Quote Link to comment Share on other sites More sharing options...
Matt Harwood Posted June 18, 2004 Share Posted June 18, 2004 Originally posted by 400BHP Correct! Hot wire air temperature sensor, works by passing a current through a wire to achieve a specified temperature, when the temperature changes, (by cooler air passing over it) the resistance changes, these resistance changes are mapped in the AC ECU and this adjusts the cooling/heating accordingly in compliance with the specified temperature on the controls. This is the same principle that the Airflow Meter on the induction system uses. I've taken apart counless Supra dashboards, and more often than not, these little sensors are caked in fluff. I assume this can't do them much good? Or at least, hinder their performance? Quote Link to comment Share on other sites More sharing options...
400BHP Posted June 19, 2004 Share Posted June 19, 2004 Thats right Matt, dust and fluff will affect its performance, on a service, toyota should gently suck the dust and dirt out of that aperture to maintain correct functioning. Quote Link to comment Share on other sites More sharing options...
Supragal Posted June 22, 2004 Share Posted June 22, 2004 nice one guys! this is all going brilliantly! Quote Link to comment Share on other sites More sharing options...
Dragonball Posted June 23, 2004 Share Posted June 23, 2004 I found this site highlighting all the specs on all the Jap models made Year by year etc http://english.auto.vl.ru/catalog/toyota/supra/ Quote Link to comment Share on other sites More sharing options...
Soonto_HAS_soop Posted June 29, 2004 Share Posted June 29, 2004 Front Windscreen Washer Pump Failure. Symptoms: Lack of water to wash window. Location: Pump located in washer fluid bottle under engine bay by battery. Replacement Time: Hours, as under wing cover has to come off. REAL REASON FOR NOT WORKING: Pulling stalk towards driver, rather than using the windscreen washer button on the end of the stalk. Ben.. Quote Link to comment Share on other sites More sharing options...
SimonB Posted July 5, 2004 Share Posted July 5, 2004 Right, I'm bored so I wrote an entry for BOVs:- Name: BOV Also known as: Blow Off Valve Dump Valve What is it? When you take your foot off the accelerator to change gear or whatever there is suddenly a lot of pressurised air from the turbos that has nowhere to go as the engine doesn't need it any more. A BOV is a valve that is triggered by the pressure difference in the manifold and gets rid of this excess air. If this didn't happen it would cause the turbos to suddenly stop spinning, which would not only knacker them in short order but mean they had to spin up from a standstill when you got back on the throttle again. There are two types of BOV, one vents the air to the atmosphere (atmospheric) and the other vents it back into the air intake (recirculating). The standard BOV (it's the black round thing to the left of the engine) is a recirculating job and is generally regarded to work fine up to around 18psi of boost. After this or when they get a bit old, they have been known to leak. The main reason for changing to an aftermarked one is to make a nice loud whoosh when you back off the throttle as nearly all of them are the atmospheric type . You can mount them in the same place as the stock one (kits are available to do this for most BOVs), or have a flange welded to a hard pipe somewhere (typically the one that goes into the throttle body). You can also keep the stock one and add an aftermarket one, or even two. Pros: Makes a cool whoosh noise when you back off the throttle . A well made one can hold more boost than the standard one without leaking. In theory recirculating the hot air back into the intake like the standard BOV could heat up the intake air whereas venting it does not but this is very unlikely to make any difference in practice. Looks 'bling' under the bonnet. Cons: If you have a UK car, an atmospheric BOV can confuse the ECU because they use a MAF airflow sensor which is ahead of the BOV. This sensor registers that a certain amount of air is flowing in, so the ECU reacts accordingly. But that air has been vented by the BOV! This can cause stalling. The jap spec cars have a MAP pressure sensor and don't suffer from this problem. Quote Link to comment Share on other sites More sharing options...
Aerotop Dave Posted July 5, 2004 Author Share Posted July 5, 2004 Excellent. I'll have to start cataloging this all now to see what we've got left. Quote Link to comment Share on other sites More sharing options...
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