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<head><meta http-equiv="Content-Type" content="text/html; charset=iso-8859-1" > <meta content="http://www.deskshare.com/st.aspx" name="Site Translator"></head> FAQ en la modificación del Toyota supra por: Estuardo B ¿Para qué BPU está parado? (BPU es una marca registrada de SupraStore.com) Mejoras Básicas Del Funcionamiento. Estas modificaciones son: Una longitud completa abajo-pipa de tres pulgadas (con o sin los gatos altos del flujo), 3 (75m m) o un dispositivo de escape más grande del gato-detra's, el alza levantada (18psi), y el alza requerida cortar el eliminador (GReddy BCC) necesitó alcanzar esa alza sin activar el atajo del combustible de la fábrica en 14-15psi. Éstas son las modificaciones que han demostrado proporcionar el mejor cociente de HP-to-. ¿Qué + medio cuando alguien dice BPU+? ¿Y cuál es APU? Ese soportes para cualquier energía adicional produciendo modificaciones con excepción de las modificaciones básicas de BPU. Uno "+" refiere al ajuste. Los engranajes de la leva y debajo-conducen las poleas, el segundo "+" refieren a un regulador del combustible, a mejora del ECU, al etc. Por ejemplo, un supra con las modificaciones de BPU, más delantero-monta el intercooler, sería llamada BPU+. Si usted agregara los engranajes de la leva a ése, sería BPU++, etcétera. Se utiliza el término de "BPU" hasta que usted tiene un turbo(s) aumentado. Entonces se refiere como APU, mejoras avanzadas del funcionamiento. This designation pretty much covers every modification that can be performed. What are the first engine modifications I should perform? I recommend starting with raising the boost of the stock turbos to roughly 18psi. This will require a quality boost gauge and a boost cut eliminator (GReddy BCC). You will achieve 15 or so PSI with the stock Down Pipe in place. This will provide an addition of approximately 30rwhp. After those modifications are completed, it would be a logical next step to install the Down Pipe and Cat-Back Exhaust at the same time. You will now be at full BPU. What do all the various "Free Mods" do? Hay muchos diversos "mods libres" para el TT supra. Cubriré apenas a algunos de ellos aquí. Los cubriré caída en tres categorías, control del alza, EGR que inhabilita, y TTC o verdad la conversión gemela. Tres de los mods del control del alza son: MOD del Sangrador-T, MOD de la abrazadera, y la MOD de puente de VSV. Cada uno de estos niveles del alza del aumento de las modificaciones sin el uso de un regulador del alza. Pero usted tiene que observar de cerca su galga del alza, y se cerciora de no están permitiendo que los turbos alzaran demasiado arriba (18psi es un nivel seguro). Los mods siguientes, son los mods gemelos verdaderos de la conversión (o TTC). Esta modificación inhabilita la operación gemela secuencial de turbo, y hace los turbos funcionar constantemente en el paralelo (ambos encendido en el mismo tiempo). Esto se supone para permitir una energía levemente mejor del alcance medio (antes de que vendría el turbo secundario normalmente en línea) y tiene en cuenta una venda más lisa de la energía, sin el aumento precipitado del alza causado por la transición de primario a la operación secundaria. Sin embargo, esto perceptiblemente disminuye energía del bajo-extremo, y aumenta los niveles de ruidos del extractor, y por lo tanto puede no ser deseable en la calle. Dos tipos de la MOD de TTC son, la MOD tradicional de TTC que incluye 2 métodos, atando con alambre los actuadores, o instalando una válvula unidireccional, y la MOD electrónica de TTC (ETTC). La MOD pasada que discutiré es la MOD de EGR. Esto inhabilita el sistema de la recirculación del gas de escape, que se significa para las emisiones, y por lo tanto, esta modificación está para el uso del apagado-camino solamente. Esta MOD se supone para prevenir la calefacción estupenda de los cilindros del número 5 y 6, que pueden causar las válvulas quemadas. ¿Cuánto energía mi coche hará en BPU? Varía del coche-a-coche, y de las condiciones así como templar. La mayoría del BPU-only Turbos gemelo supra, dyno entre 370 y 410 caballos de fuerza en las ruedas posteriores. Esto se alcanza generalmente con las temperaturas moderadas, un reajuste el ECU (borrar cualquier cosa malo el ECU pudo haber aprendido), y a menudo un poco del combustible un-leaded high-octane de la raza. En la calle, la energía será reducida, especialmente en pobres resiste, pero por lo menos de 90 por ciento una energía debe ser conservada. ¿Qué clase de 1/4 milla ETs y de trampa apresuro debo funcionar en BPU-only? Varía EXTENSAMENTE dependiendo de habilidad del conductor. Así como condiciones de la pista, la elevación sobre nivel del mar, temperaturas ambiente, humedad, y la preparación de la pre-raza. Pero la mayoría de la caída entre los ets 12.3 a 12.9 con 112 a la trampa 119mph apresura en los neumáticos de la calle. Los tiempos pueden caer bien en el 11s con las partes radiales de la fricción, un buen conductor, y las buenas condiciones, así como la preparación apropiada de la pre-raza. ¿Cuál es velocidad superior de BPU'd un TT supra? Las velocidades en la gama mediados de-alta 180mph deben ser realizables. Una vez que el velocidad-limitador sea lisiado, tirando del fusible de "TRAC" por supuesto. ¿La vida de mi motor y Drivetrain será afectada al contrario con los mods de BPU? Sí, pero no por una cantidad significativa. Si el coche se mantiene correctamente, y el coche se trata con un cierto respecto por los componentes, usted debe mantener mucha de la vida de los trenes de energía. Qué consideración del hecho que el supra es en gran medida uno del más confiable y artículo se divierte los coches, durará más de largo los coches COMUNES que lo más mejor posible mantenidos de los deportes. Los únicos componentes de Drivetrain que considerarán una vida perceptiblemente acortada serán el embrague común. más que probablemente no por último mucho más de largo que las millas 8-10k una vez en BPU. Esto especialmente es verdad si el coche está haciendo funcionamientos de alta velocidad repetidos usando el 5to y 6to engranaje en la válvula reguladora de par en par abierta. Si su embrague común tiene alto kilometraje en él, o está comenzando ya a deslizarse, usted necesitará planear en un embrague de alto rendimiento nuevo. También los turbos comunes estarán conforme a una vida algo acortada (cómo la voluntad corta depende de cómo usted conduce y mantiene el coche, así como cuánto alza usted funcionará) ¿Cuál es la confiabilidad de un 600hp Turbo supra? Los componentes del chasis, eléctricos, y de la suspensión deben considerar poco efecto sobre confiabilidad en Supras conducido calle. El motor de la acción 2JZ-GTE debe soportar bonito bien a este nivel de la energía. Apenas cuánto tiempo depende de mantenimiento, y cómo usted lo conduce difícilmente, y cómo a menudo. Pero Supras puede ir típicamente por años en este nivel de la energía. La confiabilidad de la transmisión dependerá encendido si es una automática o manual. Un automático común no llevará a cabo esta mucha energía, una transmisión construida será requerida, y es confiabilidad dependerá de él es diseño y construcción. El manual 6spd debe soportar la multa justa, así como el diferencial y los árboles posteriores. Las únicas preocupaciones verdaderas de la confiabilidad en estos niveles bajos de la energía rodearían las modificaciones reales que usted se realiza. Excepto defectos de la instalación, los componentes utilizados, incluso calidad muy alta unas, pueden faltar la confiabilidad componente de la fábrica, como construida en los compromisos que existen en todo, se inclinarían más hacia el lado del último funcionamiento, que de la última confiabilidad (tenga presente que estamos hablando de un Toyota aquí, que estándares reliabilty son excepcionalmente altos) éste puede incluir componentes del sistema de carburante, los componentes de turbo, y wizardry especialy electrónico. Una disposición que está MUY bien concieved básicamente, o utiliza componentes de OE tanto como sea posible, fuera el excedente que los cargaba, confiabilidad de la acción del near* del * de los posses. And tuning of the components, and component selection, and matching, would play a HUGE role in this. What are the power limits of the various factory components (Differential, Transmission, Motor, etc.)? There have really not been enough failures to really pin point a limit for the various power-train components. The motor could fail at factory power levels if it was running dangerously lean. But when well tuned, the motors internals (Pistons, Rods, Crank, Head Gasket etc) are reliable to 700rwhp. But of course at these power levels, if the engine is not set-up and tuned properly, it is literally a bomb waiting to go off, however this would be just as true with a built motor. . Some owners have pushed their stock internals to the limit and have well exceeded 800rwhp, and even approached 900rwhp. . I still dont understand how such an over built motor made it past the bean counters at Toyota Corporate. . The 6-speed Getrag is ridiculously strong for an OE transmission. . Its limits will be affected greatly by driving technique, such as launching, and whether or not power shifting is used. . Even driven hard, the Getrag should hold up reasonably well with 700RWHP. . If you treat it with some respect, it should be able to handle around 800RWHP or more, although great care and respect will need to be practiced at those levels. . Differential, axle, CV Joint, and drive shaft failures are a VERY rare occurrence. . So I don't have much info on their failure limits. . On street tires, it would be almost impossible to break any of these components at ANY power level. . The tires would spin before they would put the driveline under that kind of strain. . The tires act sort of like a circuit breaker. . If you run drag slicks, this does not hold true of course, yet they have proven themselves to be 10 and even 9 second capable. . Will drivability, interior noise levels, and low-end power be adversely affected with the BPU mods? . Drivability is not adversely affected. . Interior noise level depends on the exhaust system you choose. . Some will make it far louder; some will actually make it quieter. . But most are just a little bit louder than stock. . But the added dBs are also combined with a MUCH sweeter exhaust note, so it's definitely worth it. . And the interior of the Supra is pretty quiet anyway, so on the highway, it will be VERY livable. . As far as low-end power goes, the down-pipe will greatly decrease Turbo Lag. . So low-end power and response is much improved over stock. . Will emissions be adversely affected by the BPU mods? . As long as a high-flow cat is used, emissions should not be effected, and you should still pass visual inspection. . If you run without catalytic converters, you are doing so at your own risk, and you would not pass visual or emissions testing. . Will fuel mileage be adversely affected by the BPU mods? . If driven calmly, as in light throttle, mileage should not be significantly affected. . Mileage will greatly decrease during however, if you drive vigorously, more power equals more burned fuel I am afraid. . Should I install an "Intake" (Open Element Filter)? . This is a bit of a yes and no answer. . The stock filter assembly is a flow restriction, and an open element intake would increase potential flow. . However, it will also draw in more heated engine compartment air, which can hurt performance. . My advice is to either modify the stock filter box, or install a cool air induction box, like the Max Air. . An added bonus of the open element filters, is that they allow you to easily hear the primary turbo and by-pass valve. . What about the stock intercooler? . The stock intercooler does a decent job up till about 17psi on the stock turbos, after that you would probably notice a significant gain, especially in warmer temperatures, with a nice front mount intercooler. . However, keep in mind it will block some of the airflow to the radiator, as well as decreasing response slightly. . Should I replace the factory rubber Intercooler hoses with aftermarket metal hoses? . It wouldn't hurt. . But it wont help a lot either. . At the most you may slightly increase throttle response, but at least it will look nicer. . What about the fuel system, are the stock injectors and fuel pump large enough for BPU? . Yes, the stock fuel system is very safe and reliable to 450RWHP, although I would recommend a fuel pulsation damper bypass. . Anything over that, and I would highly recommend having the car dynod, and using a wide-band O2 sensor (not a cheap A/F gauge connected to the stock O2) to check the fuel ratio at your high boost setting. . 11.5:1 would be a safe fuel ratio. . What are the stock injectors rated at? . 540cc/min . Would the Supra benefit from a fuel controller? . BPU'd Supras run a little on the rich side as far as fuel ratios go. . This hurts power. . What it does do is provide a safety margin that makes engine damage through detonation unlikely. . If you get a fuel controller, and tune it properly (on a dyno, with an accurate EGT gauge, and a high band O2 (The Stock O2 sensors are not accurate), then you should be able to gain a noticeable amount of power. . One of the most popular electronic fuel controllers is the APEXi S-AFC. . The Fields SFC is good too. . What should I use to increase my boost level, an Electronic Boost Controller, or a Manual BC? . Using an EBC is the safest way to raise boost, it will prevent spiking and over-boosting. . But it really comes down to your budget. . If you can afford an EBC, get one. . If you can't, go with a MBC. . And always keep an eye on that boost gauge. . And whatever you are using to control boost, remember to not get carried away, I don't recommend going regularly over 18psi. . What is the best Electronic Boost Controller? . There really is no BEST. . Although the APEXi AVC-R is a nice unit, it provides much more control over boost than other EBCs, but it is also more complex to install, and tune. . The new Blitz unit is also nice. . Most of the large manufacturers make decent units. . Just avoid fuzzy-logic equipped models if you still have the sequential stock turbos, they will become "confused" by the unnatural behavior of the sequential system. . When installing my EBC, do I connect it to both of the Turbo's Wastegates? . The Primary Turbo is the only one with a wastegate. . When in full twin turbo mode, the boost of both Turbos is regulated by the primary turbo's wastegate. . So, only connect it to the Primary's. . Some people say I need to replace my ECU with a reprogrammed one, instead of just using a boost controller. . Do I? . Reprogrammed ECUs for the Supra TT are VERY $$$. . They are in the $1200 range. . And they have not been proven to provide a significant increase in performance or safety on BPU level cars. . Their merit shows itself on cars with upgraded Turbo(s). . Just be sure you buy your ECU, or have it reprogrammed by a reputable shop that knows what they are doing. . And have it tailored to your particular car (Driving habits, and Mods). . And I would also recommend taking a look at the AEM Programmable system. . What is a safe boost level to run at BPU? . The general consensus is 17-18psi. . Some people have taken it higher, but I don't recommend it if you dont have the money for a turbo replacement/upgrade. . Which Down-Pipe is recommended? . The RMM (or Rod Millen Motorsports) Cat-less Downpipe is the most commonly used. . However many other brands exist. . Some down-pipes, such as the Random Technology DP, feature an emissions legal high-flow catalytic converter. . Will a high-flow cat hurt performance? . It will have some effect on power output, but not a lot. . Its exact effect on HP is not clear, but it probably costs a few hp at the most, maybe 5-15hp at BPU power levels. . What is a Down-Pipe? . It is the section of the exhaust system that connects the outlet of the Turbocharger's Turbine section to the "Cat-Back" exhaust system. . The Downpipe is also where the two catalytic converters are located, as well as the O2 sensor (or sensors in OBD-II cars). . I have an OBD2 car. . Can I still install a Down-Pipe? . Yes. . But unless the DP has a Catalyst and a second location for an O2 sensor, you will trip your check engine light, unless you get one of those O2 black boxes. . Which Exhausts are the loudest? . The Tanabe Racing Medallion, and HKS Hiper Titanium seem to be the two loudest systems. . Which Exhausts are the quietest? . The Tanabe Hyper Medallion, the discontinued Tanabe G-Power Medallion and the GReddy (SP) Street Performance seem to be the quietest. . At anything less than full throttle, they are no louder than stock. . But at full throttle they seem to wake up a bit. . What are some recommended exhaust systems? . It depends on your personal preferences. . Below I will break down some of my recommendations based on certain combinations of preferences. . Subtle Styling / Very Low Cost: . -Random Technology (75mm, full stainless steel) . Subtle Styling / Low Sound Level / Moderate Cost: . -GReddy Street Performance (80mm) . -Tanabe Super Hyper Medallion (80mm, full stainless steel, 50-state legal) . Subtle Styling / Moderate Sound Level / Moderate Cost: . -ATR (75mm, full stainless steel) . Tasteful Styling / Low-Moderate Sound Level / Low Cost: . -HKS Dragger II (85mm) . Tasteful Styling / Low-Moderate Sound Level / Moderate Cost: . -GReddy Power Extreme (80-94mm) . -HKS Super Dragger (95mm) . Tasteful Appearance / Moderate Sound Level / High Cost / Super Light: . -Veilside Tear Drop Titanium (90mm, full titanium) . Tasteful-Wild Styling / Low Sound Level / Moderate Cost: . -TRD 2nd gen. . Wild Styling / Moderate Sound Level / Low Cost: . -APEXi N1 . -HKS Hiper (75mm) . Wild Styling / Moderate Sound Level / Moderate Cost: . -APEXi GT Spec (95mm, full stainless steel) . -Blitz NUR Spec (80mm, full stainless steel) . -HKS Hiper Carbon/Titanium (75mm, CF wrapped muffler, titanium tip) . Wild Styling / High Sound Level / Moderate Cost: . -Tanabe Racing Medallion (80mm, 50 state legal) . Wild Styling / High Sound Level / High Cost / High Flow: . -HKS Hiper Titanium (104mm, titanium muffler) . What is the cheapest route to replacing the DP and Cat-Back? . Have a custom performance exhaust shop fabricate a complete 3" exhaust system (Turbo-to-Tip). . It should cost well less that $400. . And then you can use the muffler and exhaust tip of your choice. . Which Fuel Cut Eliminator is recommended? . The GReddy BCC (Boost Cut Controller) is highly recommended. . What does the Fuel Cut Eliminator do? . The factory ECU is programmed to activate a fuel cut if the manifold pressure exceeds 14-15psi. . It does this as a safety measure to prevent what the ECU sees as over boosting. . The Fuel Cut Eliminator effectively eliminates, or at least raises the cut to a higher pressure. . A reprogrammed ECU can also eliminate this function. . Which boost gauge is recommended? . Any high quality boost gauge will work well. . Accuracy is the important feature to look for. . Autometer gauges are a good value. . The Japanese gauges, APEXi, GReddy, HKS, etc., have more features, but at a much higher price. . Where can the boost gauge be installed in the interior? . If you want to mount it in the dash, the two most popular places are the Clock location (which holds a 52mm gauge), and the Air Vent beside it (which holds a 60mm gauge). . You can also use an A-Pillar gauge pod. . What is the stock boost pressure? . 11-12psi . Are Cam Gears a good modification for the Supra TT? . Yes, they have been shown to provide a 5-15rwhp gain on a BPU'd car. . But to extract their potential, you must have them tuned, by a knowledgeable tuner, on a dyno. . And most of the power gains will be seen on the exhaust side. . I also recommend buying cam gears which feature 5-bolts. . Are Under Drive Pulley(s) a good modification for the Supra TT? . Most of the crank-shaft under-drive pulleys require the removal of the factory torsional damper. . This is from MKIV.com :"this is NOT an external (harmonic) balancer, as the crankshaft is fully balanced, rather it dampens both the axial twisting couples produced by the firing pulses, and the radial bending moment from the accessory drive belt." . Basically this device provides crutial isolation between the engine driven accessories, and the crankshaft. . However, removal of this can provide a 10-15rwhp gain, but at a cost for long term use. . Do I need to upgrade the ignition when upgrading to BPU? . The stock ignition system is VERY capable of supplying enough fire for a BPU'd car. . The stock ignition system uses 6 large coils, one for each cylinder. . So the system is capable of supporting VERY impressive HP levels. . You may need to change to a colder range plug with a tighter gap (see below). . What about the spark plugs, which are recommended at BPU or higher level? . Basically you want similar plugs as stock, but a cooler heat range and a smaller gap. . The stock plugs are NGK BKR6EP-11 (2978) and are platinum tipped and have a .044 (1.1mm) gap. . The ideal NGK replacement for a modified Supra would be the BKR7E (6097). . It is one range cooler (the '7'), is non-platinum tipped (the lack of the 'p') and has a smaller .0315 gap (lack of the '-11'). . This plug is also called the NGK 6097 and they are fairly inexpensive. . Platinum tipped plugs are not desired for high power applications, Iridium plugs are more prefered. . Unfortunately their doesn't seem to be a BKR8E which might be better for high-HP Supras. . Another good plug to try is the Denso Iridium IK22 or IK24. . These plugs may last longer than the above mentioned NGKs, but are also 6 times as expensive. . The stock replacement plug would be the IK20, the IK22 is one step cooler, and the IK24 is two steps cooler than stock. . The IK22 would be good for ~400rwhp to ~600rwhp. . The IK24 would probably be a good choice above that. . Two other plugs commonly used are the NGK 3330 (BCPR7ES) which differ much more from the specifications of the stock plugs than NGK 6097. . Also the Rapid Fire #5 used to be very popular, but are more expensive, don't last as long, and have fallin out of favor. . Both of those plugs have been known to cause slight stumbling at idle. . Plugs on Supras do not live long, usually around 5,000-10,000 miles. . So I recommend replacing them with every other oil change. . What is the HKS VPC and GCC? . It is an electronic device, which electronically and physically removes the highly restrictive mass airflow sensor from the intake tract. . VPC stands for Vein Pressure Converter. . The HKS GCC is a device that allows further fine-tuning of the VPC. . Do I need an after-market Blow off Valve? . It is not absolutely required, but it is a good idea. . The factory by-pass valve is prone to failure, and an aftermarket BOV is probably a wise investment for preventing turbo damaging compressor surge. . And it sounds cool too. . However, it must be noted that if you still have the factory mass-air flow sensor, a blow-off valve, which is vented to the atmosphere, may cause stumbling between shifts. . Can I run Nitrous Oxide on the Supra TT, even if I am already at BPU power levels? . Yes. . Most people run 50-75 shot wet manifold systems. . If you want to run a higher shot than this, you might want to consider a well-designed direct port system. . I have seen as much as a 200-shot used on one of these systems, and an upgraded fuel system would be a must. . 450hp just isn't enough, what can I do? . Ah the possibilities Basically you are only limited by your imagination, and your wallet. . You know what they say, speed costs money, how fast do you want to go? . The real power lies in Single and Twin turbo upgrades, and the options are limitless. . You can either build a mild motor that puts out 450 RWHP all day long with instant boost response, or a 1000+ RWHP monster. . Unfortunately, things start getting more difficult after simple BPU modifications. . Modification becomes more than "bolt on Downpipe, gain 50hp". . Things like tuning, parts selection, and matching combinations of parts become much more important. . However, this is the case with ANY high HP car. . Actually, even at exceptionally high power levels, the Supra TT is still easier to extract power from than almost any other performance car. . But it should be kept in mind, that it wouldnt be as simple as the BPU bolt-ons. . If you just want something that will toast that pesky Viper GTS. . Then focus on a mild single turbo upgrade (T04S04, T60-1, SP57-SP61). . Along with this, you should install a front mount intercooler, a fuel controller, fuel pulsation damper bypass and EGT gauge. . This is assuming you have done all the BPU mods, plus BOV, EBC, Cam Gears. . With tuning, and a few odds and ends, you should be able to pull 450-500 RWHP (490-580 crank HP) numbers while on a stock fuel system (assuming it is in great condition). . This would be a total investment of approximately $6,700-$11,500 in engine/electronic components (also includes the proper gauges). . If you already have the BPU mods or FMIC, etc., you will spend less than this. . The difference in prices reflects the cost of higher end parts and addition of a HKS VPC to replace the restrictive stock MAF. . The next level would require a completely upgraded fuel system, and performance cams would be recommended, as well as further electronics (programmable engine management such as the AEM, or VPC/GCC/ECU combo, etc.). . This would allow you to run much larger turbos and injectors. . You can make it past the 700RWHP range without needing to replace the internals of the motor with stronger components, even at these power levels, if properly tuned and maintained you should retain a fair amount of reliability while still on the stock internals, as some people have eclipsed the 800RWHP level while still running stock bottom ends in their Supras. . If you choose to go ahead and build up the bottom end, then the skies are the limit as far as power goes. . Just make sure to have part selection, installation, and tuning done by competent and experienced persons. . Although this should hold true at ANY level of modification. . Should I install a Turbo Timer? . Absolutely. . Unless you don't mind sitting in your car while it idles down every single time you need to turn the car off. . A Turbo timer keeps the engine running for a preset time once you turn off the ignition. . So you can remove your keys, and lock up the car and not have to worry about it, it will shut off on it's own. . This is important for the life of the turbos. . If the turbos are not given time to cool down, it can overheat the oil and cause coking which will block oil flow to the turbos and damage bearings and cook seals. . How much is the Supra's power output affected by changes in ambient temperatures? . Very noticeably, just as with most turbo cars, the Supra Twin Turbo can be very temperature sensitive. . Especially with the stock turbos and intercooler. . On a BPU car, I would not be surprised to see a 10 percent reduction between 50-60deg temperatures, and 90deg plus temperatures . Will the stock clutch hold the power levels of a BPU car? . It depends on the condition and wear on the stock clutch. . If it is in good condition, yes, it will hold the power, pretty well in fact, although you may experience clutch slip while at full boost in high gears such as 5th and 6th. . If you drive vigorously, meaning you run at high boost frequently, then the life of the stocker will be GREATLY shortened. . Be surprised if you see an extra 10,000 miles after BPU. . Can I resurface my flywheel when replacing the clutch? . It is not recommended. . Buy a new Toyota Flywheel. . Can I install a lightweight flywheel? . Yes, but be aware that they can create a lot of noise at idle, and can transmit more vibrations and shock to the expensive Getrag transmission. . Why is pulling the TRAC fuse beneficial over just turning it off with the switch on the center console? . Just pushing the "Trac Off" button only partially disables the Trac system. . It disables the Trac throttle body and TRAC funtion through the ABS System (on 93.5-96 only), but not the Trac system's ignition timing retard function. . Unplugging the Trac fuse eliminates both functions, as well as the 155mph speed limiter, which works through the trac system. . The fuse can be found in the main fuse box on the drivers side of the engine compartment. . It must be noted that removing the fuse will cause the TRAC light to stay on, but you'll get used to it. . Will the TRAC system improve the cars performance? . No. . The Trac system was calibrated to improve traction in slippery conditions. . It was not calibrated with performance in mind. . When the Trac system senses a loss of traction, it comes on hard, cutting power drastically; this will do nothing but hurt performance. . I also would not rely on the Trac system for providing stability at high speeds, if you were to loose control, it would be too slow and clumsy, and would more than likely hamper your efforts to regain control. . How can I remove the factory 155mph speed limiter? . Remove the fuse for the Trac system. . The speed limiter works through the Trac throttle body. . What is the Supra TT's top speed with the Trac fuse removed? . There is some debate on this subject. . There are rumors that 180 can be achieved. . But by going with the numbers, 168-172mph in stock form seems possible. . What is the Supra TT's maximum theoretical top speed? . Can it exceed 200mph with enough power? . Lets find out. . The Supra TT with the 6-speed has a stock engine redline of 6800rpm, and a 6th gear ratio of .79:1, with a rear axle ratio of 3.13:1. . Now we multiply our 6th gear ratio times our rear axle ratio, and we find out our final gear ratio is 2.472:1. . Now we divide 6800rpm by our total gear reduction of 2.472:1 and we find out our rear axles, and therefore wheels are spinning at 2751rpm at 6800 engine rpms. . Now we need to calculate our tire circumference. . The rear tires section width it 255mm, and the sidewall's aspect ratio is .40, so our sidewalls are 102mm. . Now, to convert this to inches, we divide this by 25.4, which equals 4.015 inches. . Now multiply this by two, since we have two sidewalls making up the total diameter, and add the wheel diameter of 17", and we see a total diameter of 25.031 inches. . Now to find out our circumference, we multiply that number times pi (3.14), and we find out the circumference is 78.59 inches, now divide that by 12 to convert to feet. . And we get 6.549 feet total circumference. . Now multiply our tire's revolving speed, by the tire's outside circumference, and we find that the tire is covering 18,016 feet per minute, divide that by the 5280 feet in a mile, and we find we are covering 3.412 miles per minute, now multiply that by the 60 minutes in an hour, and we find we are traveling 204.7miles per hour @ 6800rpm in 6th gear. . If the engines redline is increased to 7500rpm, which it often is, because of a higher flowing turbo. . Then our maximum speed would be 225.8mph, given enough power of course. . For more go to <a href="Http://www.ausdriftcar.cjb.net" target=new> . Http://www.ausdriftcar.cjb.net </a> <table width=100% cellpadding=8 cellspacing=0 border=0 bgcolor=#dddddd><tr><td> Sobre El Autor . Stuart B <a href="Http://www.ausdriftcar.cjb.net" target=new> . Http://www.ausdriftcar.cjb.net </a> </td></tr></table>