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PowerPages: 1991 Toyota MR2 Turbo

Text By Richard Fong

Owner: Nevin Oca
Dynamometer Model: Dynojet 248C

Dyno 1: Baseline

The MR2 Turbo is one of Toyota's retired sport compact cars of the '90s. It has a mid-engine, rear-wheel drive layout that you usually only find on expensive sports cars. Also, it shares the Celica All-Trac Turbo's potent powerplant, the 3S-GTE motor. With a claimed 200 hp at the flywheel, it was without a doubt a potent player in the sport compact arena. Not to mention it's arguably the best looking in its pedigree.

During its model run from 1991 to 1995, it saw progressively declining sales due to a high sticker price, higher insurance rates and super-competitive sport compacts from the Honda, Mitsubishi and Nissan camps. Its numbers are few, but its fan base is solid and faithful. Unfortunately, the number of aftermarket manufacturers with parts for it is limited.

This particular MR2 Turbo has well over 130k on its odometer, so its baseline is a few horsepower short of where we're used to starting. It has all original equipment and should benefit from the tweeks we will be giving it. Let's see how many ponies this mid-engine machine can give.

Air temperature @ 72.2 degrees Fahrenheit

Horsepower: 148.9
Torque: 158.6

Dyno: Tune up

It never hurts to tune older cars more often than required by the manufacturer. Newer components will generally outperform older ones. Ignition is critical in turbo cars, and the cap, rotor, wires and plugs are all essential for a hot spark with each cycle. Clean lubricants are always welcome. We were able to gain 3.5 hp and 3.1 lb-ft of torque.

How can you go wrong when you teach an old dog new tricks?

The MR2 is surprisingly easy to perform regular maintenance on. The oil pan is easily accessible, as is the filler cap and filter. The ignition components are also accessed with little difficulty.

Ratchet, 5/8-inch spark plug socket, 3/8-inch extension, 10- and 14mm socket, oil drain pan

Spark plugs, wires, cap, rotor, oil and filter

Installation time
45 min

Air temperature @ 72.8 degrees Fahrenheit
Temperature difference from previous run: +1.3 degrees Fahrenheit

2000 to 3500 HP range: 1 to 5
3500 to 5500 HP range: 0 to 7
5500 to redline HP range: 0 to 10

2000 to 3500 TQ range: 0 to 6
3500 to 5500 TQ range: 0 to 9
5500 to redline TQ range: 0 to 10

Peak HP: 152.4
Peak TQ: 161.7

Dyno 3: A'PEXi Power Intake

The A'PEXi engineers crafted a functional and clean-looking heat shield, and perfectly shaped brackets. The intake adapter mounts up neatly to the stock MAF with four nuts. Fitment is excellent. Removing the stock airbox makes the side vent very functional and brings cool air straight to the filter. The turbo is more efficient if it breathes without restriction. This intake proves it: We made 7 hp and 5.8 lb-ft of torque--and we didn't even change the intake hose.

This intake utilizes A'PEXi's proprietary air filter, which is not reusable. Some people may want a cleanable filter, and this isn't. The A'PEXi adapter attaches to the filter with four bolts, so it cannot be adapted for use with any other filter system.

All instructions are in Japanese, but the illustrations will get you to where you want to go. The intake fits like a charm and gives you a healthy dose of horsepower throughout the power band, especially on the mid to high end.

Filter, intake adapter, gasket, heat shield, brackets, instructions and hardware

10- and 12mm sockets, extension, ratchet, 10- and 12mm wrenches, Phillips screwdriver

Installation time
40 min

Air temperature @ 73.5 degrees Fahrenheit
Temperature difference from previous run: +0.7 degree Fahrenheit

2000 to 3500 HP range: 0 to 4
3500 to 5500 HP range: 1 to 10
5500 to redline HP range: 0 to 10

2000 to 3500 TQ range: 0 to 5
3500 to 5500 TQ range: 2 to 10
5500 to redline TQ range: 0 to 9

Peak HP: 159.4
Peak TQ: 167.5

Dyno 4: RS*R Ex Mag GTII Exhaust

This exhaust system is among the nicest available for the MR2 Turbo. It also reduces a lot of weight, since the factory muffler spans the width of the car compared to just one side. The stainless canister is clean and the tone is smooth and deep. Fitment is exemplary, and finish is top notch. And it breathes: We gained 16 hp and 13.7 lb-ft of torque at the peak and up to 28 hp in the mid to high rpm range. The turbo spooled more freely resulting in improved output and smoother power delivery.

To say the least, Toyota engineers didn't want this exhaust to come off easily. We spent the majority of the time trying to remove the B-pipe with the catalytic converter and hardly any time installing the aftermarket exhaust. Also, the RS*R exhaust doesn't have a catalytic converter (there are two on the MR2), so it may not pass smog. Keep your old pipes for registration time.

The exhaust flows so freely that we noticed the boost was peaking a little higher than with the stock exhaust. The reduced backpressure really helped the turbo ramp up quicker, and this resulted in greater output. Don't forget, this exhaust system includes a silencer which restricts some of the flow, but keeps the decibels down. You'll probably want to leave the silencer installed when you're in areas populated by your city's finest. It's a pretty loud exhaust. Lastly, remember to WD-40 the hangers and bolts to make the disassembly process easier.

Stainless-steel muffler, B-pipe, silencer, gaskets and bolts

17mm combination wrench, 14mm socket, ratchet and WD-40

Installation time
75 to 85 min

2000 to 3500 HP range: 0 to 7
3500 to 5500 HP range: 6 to 20
5500 to redline HP range: 11 to 28

2000 to 3500 TQ range: 2 to 10
3500 to 5500 TQ range: 6 to 20
5500 to redline TQ range: 10 to 18

Peak HP: 175.4
Peak TQ: 181.2

With two performance items and a tune-up, we netted a total of 26.5 hp and 22.6 lb-ft of torque. Pretty impressive numbers for a 15-year-old car. The turbo seems to be holding up well considering its age, which is in part a testament to its owner. With heavy use and neglect, the turbo can go bad and require a rebuild or replacement. This car still has room to grow. With a larger intercooler, boost control and fuel programming, solid 200 plus-hp figures aren't too far away.

 HP Level HP+TQ Level TQ+
Baseline148.9 158.6 
Tune up152.43.5161.73.1
A'PEXi Power intake159.47.0167.55.8
RS*R Ex Mag II exhaust 175.416.0181.213.7
Tune up$100.00
A'PEXi Power intake$159.00
RS*R Ex Mag II exhaust$669.00
MSRP Total$928.00
A'pexi RS*R
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By Richard Fong
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