Subaru

My wife and I have owned several Subarus over the recent years. They include:

These cars all tend towards being very reliable and quite safe if you believe the NHTSA crash test data. The biggest concern is the gas mileage which is not that great - although this may be more the driver's fault... The Subaru I particularly like is the STi which is identical to the Impreza WRX EXCEPT for the engine, transmission, suspension, interior, and some exterior bits.

History of the US-spec STi from Wikipedia

Rev. D (2004)

In 2004, Subaru of America announced it will sell the WRX STi. Subaru Tecnica International's president said in an interview with Road & Track magazine that he wishes to beat the Mitsubishi Lancer Evolution in the US. Thus, each iteration of the US-spec WRX STi was essentially the same as the respective J-spec STi Spec C. All the part numbers match up, including the part-numbers for the glass windows and dampeners. However, instead of the EJ207, the USA receives the first EJ257, a 2.5 liter version of the EJ207. Unlike the EJ207, it features hypereutectic cast pistons as opposed to the forged pistons in the EJ207. The steering rack is the standard STi's 15.2:1 instead of the Spec C's 13:1, which many find too slow.

Rev. E (2005)

As with the Japanese-spec C models, US-spec STis received additional rear fender flaring in order to allow an increase in wheel size. The wheel size went from 17" x 7.5" to 17" x 8". In accordance with the increased wheel width, steering lock-to-lock turns have been reduced. Wheel hub strength was improved. The P.C.D. was changed from 5 x 100 to 5 x 114.3. The Suretrac L.S.D. in the 04 model was replaced with the Helical limited slip differential. In the interior, the Stereo became standard. The badging has been revised and different look was given to the steering wheel, shift knob, HVAC controls, and center console.

Rev. F (2006)

The US-spec STIs receive the same facelift as the Japanese-spec STIs. Mechanically speaking, the DCCD and the engine mounts have been changed. Like the Japanese-spec STIs engine mounts were changed from metal to liquid-filled plastic mounts to reduce vibrations into the car's cabin. On the largest Impreza forum, North American Subaru Impreza Owners Club NASIOC, 2006MY owners have had issues with these plastic engine mounts. The manufacturer will replace them, under warranty, if broken, with the 2005MY rubber and metal mounts. Later 2006MY vehicles were equipped from the factory with 2005MY mounts. The center differential is updated with the addition of a mechanical limited slip mechanism to supplement the electromagnetic DCCD. The torque split is changed to 41/59. The 2006MY STI weighs approximately 3,350 lb (1,520 kg).

Rev. G (2007)

2007 US-spec Subaru Impreza WRX STi Limited. Only 800 were produced.

In 2007, quite a number of changes were made to the US-spec model. Due to Subaru's decision to reduce costs by cutting the amount of aluminum used, the US-spec STI no longer receives the J-spec Spec C control arms. The control arms are now the aluminum ones used on the Japan-spec revision A and B non-Spec C STis. The high caster angle has been reduced, which in turn reduces the wheelbase from 100" to 99.4". The rear sway bar has decreased in size from 20 mm (0.8 in) to 19 mm (0.7 in). The gear ratios of second, third and fourth gears have been made longer (higher ratio) in order to improve fuel economy and driveability, which inadvertently reduces 1/4 mile drag racing times due to the ability to trap 114 mph (183 km/h) in 4th gear, without the shift to 5th. The EJ257's cylinder heads have been redesigned to improve cooling, and the sodium-filled exhaust valves have been deleted. Pistons are the same as previous years also came with the new valves and cylinder heads. The alternator is changed from a 90A rating to 110 amps. The rear Limited Slip Differential is now a Torsen unit, considered an upgrade over the previous model's helical unit. The turbo has also been changed to the VF43, which has a different wastegate actuator than the VF39. The side cowl braces are stiffer than the 2006MY. The engine mounts are once again the hard rubber mounts used prior to 2006. On the interior, there is an audio jack that replaces the ashtray, a rear center armrest with trunk pass-through and a 120 W audio system.

The ECU was completely re-engineered in order to meet US LEV2 emissions requirements, which has caused throttle and timing issues. A secondary air pump was also added to help meet LEV2. Top Feed injectors replaced the Side Feed from the previous models.

The WRX STI Limited is introduced. It is similar to the Japan-spec STI A-line, except the mechanicals of the car are based on the 2007MY US-spec WRX STI.

The differences between the 2004-2006 STi and the 2007 STi are significant and many; making these two vehicles very difficult to compare to each other. The 07 STI with a proper tune will make massive power, more then previous years of STI's do to the unique cylinder heads for that year only.

Technical information

If you have bought the STi and plan on tracking this car, there is a lot to think about. When I say 'track', I mean more than 10 track excursions a year and less than transforming the car into an all out race car. Either extreme requires a very different approach. I tend to do about 20 track days a year and drive the car on occasion during the summer. In the winter, the car is up on jack stands, and being freshened up and fixed. The first suggestion I would make is that if you are going to track it significantly - say 20 plus or minus days a year, you should be able to write off the car and have another form of transportation, because you will either hit something or break something both of which can be a problem.

Problem areas

Areas to improve

Go-fast bits