General Supra Twin Turbo "Frequently Asked Questions":


What does the term SUP-Dawg mean?
It is a commonly used nickname for the 4th generation (MKIV) Toyota Supra. First coined by Dave Mashour.

What does MKIV stand for?
That stands for MARK 4, meaning the 4th generation of the Toyota Supra. Which was sold in the U.S. from 1993.5-to-1998.

I am 16 and I love Turbo Supras, should I get one now?
The truth is that at 16, regardless of how cautious you are you are not going to have had a lot of practice driving. A high-powered car, such as a Supra, requires some driving experience, and a lot of self-control! My advice, would be to start out with something a little more basic, start saving your money, and get some experience behind you. Then in a few years you'll be ready. I know how hard it is when you want something bad, but trust me, the time will fly by, and when you do get it, you will be able to appreciate it even more.

What does 2JZ-GTE mean?
It's the code for the Supra Turbo's engine. "2" stands for the iteration of that block, "JZ" stands for engine's family, "G" means dual over head cams and high performance cylinder head, "T" means turbo, and the "E" means electronic fuel injection. So you have the 2nd iteration of the JZ engine family, with a dohc high flow head, a turbo, and electronic fuel injection. The engine in the non-turbo Supra is designated as 2JZ-GE.

What does JZA80 stand for?
That is the model number of the 4th generation Supra.

What does BPU™stand for? (BPU is a registered trademark of SupraStore.com)
Basic Performance Upgrade. These modifications are: A full length three inch down-pipe (with or with-out a high flow catalytic converter), 3" (75mm) or bigger cat-back exhaust system, raised boost (18psi), and the required boost cut eliminator (GReddy BCC) needed to achieve that boost without activating the factory fuel cut-off at 14-15psi. These are the modifications that have proven to provide the best initial HP-to-$$$ ratio. BPU™ is the registered trademark of SupraStore.com (www.suprastore.com)

What does the + mean when someone says BPU™+? And what is APU?
That stands for any additional power producing modifications other than the basic BPU™ modifications. One "+" refers to Adj. Cam Gears and under-drive pulleys, the second "+" refers to a Fuel controller, ECU upgrade, etc. For instance, a Supra with the BPU™ modifications, plus a front-mount intercooler, would be called BPU™+. If you added cam gears to that, it would be BPU™++, and so on. The "BPU™" term is used until you have an upgraded turbo(s). Then it is referred to as APU, advanced performance upgrades. This designation pretty much covers every modification that can be performed.

Why do Supra Twin Turbo owners refer to their cars as a Supra TT, isn't that an Audi?
TT is just an abbreviation of Twin Turbo, used for convenience. People were calling it that long before the Audi TT was introduced.

I want to have a fast 4th gen Supra, for as cheap as possible. Can I just buy a high mileage Non-Turbo model and convert it to a Turbo?
To convert an "NA" Supra to a full Twin Turbo spec Supra would require a lot of money, a lot of time, and a lot of headache. The Twin Turbo is more than a NA Supra with two turbos bolted to the cylinder head. The entire drivetrain is different, as well as the brakes, electronics, wiring harness, etc. This would be an unwise route to go.

The other option is installing a Turbo Kit specifically designed for the NA on a non-turbo Supra (kits for twin turbos will not bolt on an NA). This is an easier route, but it can still get expensive, and the NA is not capable of NEARLY as much power.

The wisest thing you could do would be to save your money for a Twin Turbo model, it will cost much less in the end, and your resale will be higher.

I can only find Automatic equiped Supras for sale, can I buy an auto and convert it to manual?
This is not a bolt-in swap. To do this swap you would need the Transmission, Shifter, Clutch Master Cylinder and accesories, flywheel, pressure plate, clutch, ECU, Pedal Assembly, Driveshaft, Rear Differential, Wiring Harness, Rear Axles, and the transmission tunnel requires modification. Most shops charge around $7,000 to do this swap with USED parts. Use of new parts pushes this up MUCH higher. Keep in mind the Getrag transmission costs $5,000-$6,000 new. This is only a logical swap if you already have an Automatic Supra with a significant investment in it.

What does RWHP stand for?
Rear Wheel Horse Power. That refers to the actual horsepower at the drive wheels, so this horsepower figure is noticeably less than more commonly used horsepower figures that are measured at the flywheel (crank) because significant power, along the lines of 13-15%, can be lost through the mass and friction of the driveline of the Supra. Horsepower is measured at the wheels with a chassis dyno, with the most common brand being DynoJet. Wheel horsepower is a more accurate and relevant figure, since it tells you how much power is actually being used to accelerate the car, as well as being more convenient to measure and confirm.

What is the Getrag transmission?
Getrag is the German manufacturer of the Supra Twin Turbo's 6-Speed manual transmission.

What does RSP stand for?
Royal Sapphire Pearl. It's an Exterior Color. It is one of the more rare, and sought after colors available on the MKIV Supra during 1997 and 1998.

What is MSB?
It stands for "Monkey Sh*t Brown". Referring to the color Anthracite, which was available on Supra Twin Turbos till 1995. Once again first coined by Dave Mashour.

What colors were available on the Supra Twin Turbo during which years?
040 Super White 1993.5/94/95/96/97/98
1A1 Anthracite Metallic 1993.5/94/95
199 Alpine Silver 1993.5/94/95/96/97
1B9 Quick Silver 1998
202 Black 1993.5/94/95/96/97/98
3L2 Renaissance Red 1993.5/94/95/96/97/98
6P3 Deep Jewel Green Pearl 1996/97
6Q7 Imperial Jade Mica 1998
752 Baltic Blue 1993.5/94/95/96
8L5 Royal Sapphire Pearl 1997/98

What's the longest a Supra can last?
You could make any car last as long as you want, as long as you are willing to properly maintain it, and repair anything that fails. Now there may eventually be a point where it's just not economical anymore, and it's time to move on to something else, but that's a personal choice. I've seen ford mustangs with more than 500,000 miles. Sure, they went through 2-3 engines, 4 transmission, and a ton of smaller parts, but as long as you are willing to keep a car going, and parts are available for it, you can make it last as long as you want. I have not yet seen a Supra "put-down" because it has too many miles, and there are numerous Supras with over 200,000 miles.

How much horsepower, measured at the wheels does the Supra put out completely stock?
285-305 RWHP. This proves that the Supra with it advertised 320-flywheel hp, was underrated. Stock Supras actually put out in the neighborhood of 330-350 crank (engine) hp.

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 don't 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 limit's 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. The 4spd Automatic is not nearly as strong stock. It holds up well enough with BPU mods. But anything past that and it will need to be upgraded, as well as the torque converter. I hear good things about the Sound Performance upgraded trans.

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.

What is the better transmission in the Supra Twin Turbo? The 4spd Automatic, or the 6spd Manual?
Automatic's Advantages:
-Will be faster in the 1/4 if you have "average joe" driving abilities (tried to put that as politely as possible )
-More consistent for drag racing (no missed shifts)
-Easier to launch while drag racing
-More pleasant to drive in heavy traffic
-Allows you to be a more absent minded moron with a Cell-Phone glued to your head (OK, that wasn't so polite )
-Wonderful if your left leg is broken
-No fumbling for the right gear when you get taken off-guard
-Usually easier to find, and a little cheaper to buy


Manual's Advantages:
-SO much more fun and engaging to drive
-Better for any racing that involves using the steering wheel
-Faster in the 1/4 if you are a good driver
-Handles much more horsepower stock
-Less parasitic driveline loss (more wheel HP)
-50% more gear ratios to choose from
-Better gas mileage (who cares!)
-If you have a high effort clutch, your wife (g/f, or whatever) will never ask to borrow the car!
-Better re-sale value


Is the G-Tech/Pro Accurate?
The "times" as in 0-60, and 1/4mile E.T.s are usually about dead on, maybe off by as much as 2/10th of a second in the 1/4. But the 1/4 mile trap speeds can be off by as much as 5-7mph, usually on the optimistic side. However, the G-Tech is extremely consistent, and therefore can be useful for tuning (when a dyno is not available). My favorite function on the G-Tech is the "Instant Gs" function, which shows how many G's your car is pulling in acceleration or braking in real time. This is very useful in seeing if there are changes in your power output at any given time, because the G's directly correlate with power output. And if turned sideways, it can be used to measure lateral G's for skid pad handling.

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 long should the car idle before shutting it off?
Anything over 3 minutes for daily driving is just excessive. I recommend 1-1/2 minutes for normal (i.e., calm) driving, and 3 minutes for "enthusiastic" driving, and after a race, it is recommended that you drive the car for a few minutes to let air flow through the radiator and cool things down before parking. Then I would follow that up with a 4-5 minute cool down. Here is what the Toyota manual recommends:

Normal city driving: Idling time- not necessary

High-speed driving, About 80 km/h (50mph): Idling time- About 20 seconds

High-speed driving, About 100 km/h (63mph): Idling time- About 1 minute

Steep mountain slopes or continued driving above 100 km/h (63mph): Idling time- About 2 minutes


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 mild 50-60deg temperatures, and 90deg plus temperatures

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, 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 driver's 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 180mph 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 equal's 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.

How come the Supra TT was never on Car & Drivers Top Ten list, but the RX7 and 300ZX were?
Car and Driver has a price limit for the Top Ten list. And when the Supra TT was introduced in 1993 it was over that limit, but the 300ZX TT and RX7 TT were not. Even though the Supra TT received a HUGE pricing drop (about a $10,000 drop) in 1996, it could not be put on the list. That is because the only cars that can be nominated to the list, are ones that have been significantly updated or redesigned, or that were winners from the previous year. The Supra TT was not significantly redesigned that year, nor was it a previous year's winner, so it could not be nominated. So the Supra never made it to the Ten Best list, even though it beat the 300ZX TT and RX7 TT in every major magazine comparison test.

Is the Supra TT practical as a daily driver?
DEFINITELY! My Supra is my only form of transportation, and it makes a great daily driver. It has PLENTY of room for 2 people, as well as sufficient storage room. It has a decently smooth ride. The interior is very Lexus like, all the amenities, very comfortable; everything placed logically, and good fit and finish. Interior noise levels are very low, even with most aftermarket exhausts. The motor is very smooth, and has great low-end torque. In typical Toyota fashion, it is very reliable and dependable. You have good visibility, even with that big wing. And the Supra doesn't draw TOO much attention. My only complaint, gas mileage in the low teens if driven aggressively.

I am over 6 feet tall, is the Supra TT roomy enough for me?
Definitely, I am 6 foot 4 inches. I have no problem at all with room in the Supra. I actually keep the seat about 1" ahead of it's rear-most travel. There is also plenty of headroom, unless I am wearing a racing helmet, then it gets tight.

Is the back seat roomy enough for passengers?
Small children yes. Anybody else, and it will be VERY tight. But you can actually fit 4 (smallish) adults in the Supra, if they are VERY good friends and it is a short trip.

The Supra has no stink'n cup holder, what can I do 'bout it?
You can remove the ashtray, and use the remaining hole, that seems to work pretty well. The space between the right side of the seat back and the belt buckle is also a good place.

Do some Twin Turbo models not have a "Turbo" badge on the hatch?
Correct, not all Twin Turbos came with a Turbo badge. It appears to be a dealer-installed feature, and there is more that one style of Turbo badge.

Do all Twin Turbo models have the rear wing?
No, the rear wing was an option on earlier models. Most Twin Turbos had the rear wing though. Also, not all Supras with wings are turbos. Many naturally aspirated Supras came with them as an option, and it became standard in the later years.

Does the Supra TT's rear wing actually provide a purpose, or is it just supposed to look pretty?
Unlike most spoilers, the Supra's rear wing actually provides down force. It provides 66lbs. of down force at 90mph.

Are all Twin Turbo models equipped with Sport Roofs (Targa Tops)?
No, the Sport Roof was an option on earlier models. Most Twin Turbos that were sold were Sport Roofs though. But the hard tops may be more desirable because of their rarity, added chassis strength and reduced weight. The Sport Roof became standard on later models.

Were any Twin Turbo models more powerful than the rest?
No, even though performance test results varied slightly, the stand out being the TT featured in the 1993 Car and Driver, there were no changes in power output between the years, and there were no special high-output models.

What are the sizes of the factory stereo's speakers?
The dash-mounted tweeters are 1" in diameter. The door speakers are 4" and are mounted in ported enclosures. The rear speakers are over-sized 6.5". And the Subwoofer is a 5x7".

What is the box under the passenger seat?
That is the factory stereo's amplifier.

Do all Supra TTs have key-less entry?
No, it was an option.

Are the Super White bulbs worth getting (Headlamp bulbs)?
They look nice, I am not certain if they are actually brighter than the stock ones.

How does Bar translate to P.S.I., and is kg/cm2 the same thing as Bar?
Atmospheres, Bars, and kg/cm2, are always assumed to be the same value, but each of them is slightly different.
1 Atmosphere Equals 14.69psi
1 Bar Equals 14.50psi
1 kg/cm2 Equals 14.22psi

You more than likely only need to worry yourself with "kg/cm2". That is the common metric measurement for pressure and what is used on almost all of our automotive "metric" gauges and meters. Below is a chart that converts kg/cm2 to psi.

Kg/cm2 value = equivalent in psi
0.50 kg/cm2 = 7.11psi
0.55 kg/cm2 = 7.82psi
0.60 kg/cm2 = 8.53psi
0.65 kg/cm2 = 9.25psi
0.70 kg/cm2 = 9.96psi
0.75 kg/cm2 = 10.67psi
0.80 kg/cm2 = 11.38psi
0.85 kg/cm2 = 12.09psi
0.90 kg/cm2 = 12.80psi
0.95 kg/cm2 = 13.51psi
1.00 kg/cm2 = 14.22psi
1.05 kg/cm2 = 14.93psi
1.10 kg/cm2 = 15.65psi
1.15 kg/cm2 = 16.36psi
1.20 kg/cm2 = 17.07psi
1.25 kg/cm2 = 17.78psi
1.30 kg/cm2 = 18.49psi
1.35 kg/cm2 = 19.20psi
1.40 kg/cm2 = 19.91psi
1.45 kg/cm2 = 20.62psi
1.50 kg/cm2 = 21.33psi
1.55 kg/cm2 = 22.05psi
1.60 kg/cm2 = 22.76psi
1.65 kg/cm2 = 23.47psi
1.70 kg/cm2 = 24.18psi
1.75 kg/cm2 = 24.89psi
1.80 kg/cm2 = 25.60psi
1.85 kg/cm2 = 26.31psi
1.90 kg/cm2 = 27.02psi
1.95 kg/cm2 = 27.74psi
2.00 kg/cm2 = 28.45psi

How come when they opened the hood of the Supra, in that "movie", they were surprised to find a "2-J-Z" (Non-Turbo at that)?
Because they are all retards!

Information and Content Accumulated by Mike T

Mike T
94 Supra TT 6spd

[This message was edited by Mike T on August 29, 2002 at 02:24 PM.]

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