Home History Legacy Spec B – A True Sleeper Or Not?

Legacy Spec B – A True Sleeper Or Not?

by Kelvin Yates

Have you been planning on getting yourself a Subaru Legacy? But not any Legacy, the real Legacy which is the Legacy Spec B? If this is the case, then you came to the right place because after we finish the article, you are going to be a Subaru Legacy expert and you will have all the data needed. In case, if you want to go onto the market and search for a Spec B car.

Having a car that looks normal but is packing a lot under the hood could be a fun experience. Why I’m saying this? I’m saying this because nobody will know what you are driving around and then when you put your foot on the throttle everyone gets surprised and amazed at the same time.

This is what is called a sleeper car. Sleeper cars are designed to look pretty normal and most people would not be able to differentiate them from any commuter car on the road. But under the hood, these cars are packing a lot of power and deliver quite a hefty performance. The engine is upgraded and the suspension as well compared to the base car and this makes a huge difference. So much that you will want one for yourself.

In this article, we are going to learn what the Subaru Legacy is. More precisely the Legacy Spec B. Then we will learn more about the specs and the engines that this car is packing. Also, the problems that this engine has. Then we will cover why the Spec B is popular in the modding community and also the alternatives on the market. So, let’s get started.

What Is The Legacy Spec B?

Before we go into the Spec B. Let’s first see what is the Subaru Legacy. The Legacy is a sedan made by Subaru. More precisely this version is code-named the BL/BP. This was the fourth generation of the Legacy that was introduced in 2003 and the production run lasted until 2009.

This car was offered in both 4 door sedan version and also in a 5-door station wagon for the people who wanted more space.

The Legacy was slightly bigger than the Impreza and offered considerably more space than the Impreza. Making it a perfect option for the ones that were in search of a family car. This generation of the Legacy also included modern styling that made it extra appealing a desired by the public allowing it to sell quite well during its six-year production run.

The Legacy was equipped with the standard boxer engines that Subaru makes. Which made it perfect for the people who wanted an engine that isn’t a regular straight 4 or straight 6. These engines also have a better balance and lower vibrations. They reduce the center of gravity because they are sitting so low. Making the Legacy a real menace on the road.

But that task wasn’t given to all of the Legacy models. But to the Legacy Spec B. The Spec B was the car to get back in the day. The Spec B was an extremely limited version of the Legacy that packed all of the goodies from the WRX which made the Legacy a real tire shredder.

Only 500 of these were made, that’s why they are in demand, and getting one could be quite tricky and expensive. But what were the Legacy Spec B specifications? Let’s find out.

Legacy Spec B Specifications

The Spec B was introduced in 2006 as a limited-run car with only 500 samples made for this production year. And the Legacy spec B sold extremely well which gave Subaru the ability to produce more of these cars and made the Spec B a standard model in the following years of production.

But what differentiated this model from the other Legacy models? Everything in the Spec B was beefed up and taken to a different level comparing the base model cars.

The new Spec B was equipped with a modern and racier suspension that allowed catching corners far quicker and allowed the Legacy to become a real sleeper on the road. They replaced the boring strut assembly with inverted Bilstein struts and springs on all of the wheels.

The Spec B was equipped with 18-inch alloys and included powerful Bridgestone Potenza tires that were extra sticky. These two upgrades improved the handling of the Legacy by a big margin. Making the Legacy drive like it’s on rails.

There were also exterior upgrades. They were subtle but a real Subaru fan could fairly easily distinguish a Legacy Spec B from a regular Legacy. The easiest way to tell if this was a Spec B was the exterior color and the 18-inch alloys. The exterior color on most of these Spec B cars was dark silver which was quite different compared to other Legacies.

The biggest difference was inside of the Legacy. The Spec B was equipped with red leather interior seats with red accents on the door panels. It also included satellite navigation and steering-mounted radio controls. But now let’s discuss more about the elephant in the room. And that is the powerful 2.5 engine that was included in the Spec B.

Legacy Spec B 2.5 Engine

The B Spec Legacy also got a beefier engine with a slight bump in horsepower compared to the regular GT.

The engine used in the Spec B Legacy was the 2.5 liter flat 4 engine. This engine is a double overhead cam engine that guarantees that you will get the most out of it. This also means that this engine is incorporating 4 valves per cylinder which is 16 valves in total. It also included variable valve timing as most of the modern engines did back in the day when the Legacy was released.

The numbers for the Spec B were 243 hp at 6000 RPM and 241 lb. ft of torque at 3,600 RPM. This engine was paired with a 6-speed manual transmission and came with a 36,000 mile or 3-year warranty from Subaru.

This powerful 2.5 engine was able to propel the Spec B from 0 to 60 in less than 5.3 seconds and was able to achieve a maximum speed of 137 mph on the highway.

Legacy Spec B

But what MPG numbers did the Spec B get? Since this engine is a performance application it could not be regarded as a commuter car that focuses on fuel mileage rather than performance.

That’s why the Spec B only got 17 mpg in the city and 24 mpg on the highway with combined fuel mileage of 20 mpg. Although these are the official numbers, the real numbers are probably lower than these and the Legacy has a combined mileage of 17 to 19 mpg. Depending on how much you press your foot on the gas pedal.

But was this a perfect engine or did it suffer some of the problems that other Subaru engines have suffered? Let’s find out more in the next chapter.

Subaru EJ255 Flat Four Engine Problems

Although the Subaru engines are regarded for their excellent performance. There are still some of the Subaru engines that have some problems. And the EJ255 2.5-liter engine is one of them.

This engine was included in many of the Subaru high spec cars like the WRX, Legacy GT Spec B, The Baja Turbo, Forester XT, and Outback XT. This also meant that this engine was extremely versatile and a popular performance application for a Subaru.

Although popular, it still had some issues that need to be known in order for you to avoid some of these problems and learn them before making a purchase. Because knowing the problems will going to save you a ton of money in the long run. That’s why in this chapter, we are going to cover most of the problems tormenting the EJ255 engine by Subaru. So, let’s get into it.

EJ255 Turbo Failure

One of the prime problems of the EJ255 is the turbo failures which happens quite often. Most of these cars that are on the road suffer from turbo failures and most of the turbos have already been replaced in the past. That’s why it is key to learn more about these turbo failures and how to distinguish a car that had this turbo job done in the past. And also, how to tell if the turbo is failing when you go and see the car.

These turbo problems often happen because the oil filters that Subaru is using are extremely small. This means that they cannot filtrate enough oil and the oil is bypassing the filters. Leaving dirty oil inside of the engine that cannot pass through the mesh and the banjo bolt that is controlling the oil flow into the turbo. Leaving the turbo to starve from oil. Oil starvation will kill the turbo fairly quickly.


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The way around it is to replace the OEM oil filter of the EJ255 and replace it with a bigger one. Also, do your oil changes more often and make sure that there is no dirty oil inside of the engine. Doing oil changes every 5,000 miles would be perfect for the EJ255. Everything delayed could damage the turbo.

But which are the symptoms of a failing turbo? This is also good to know if you are on the market for a used Legacy Spec B car. Knowing this will save you a ton of money in the long run. That’s why here we cover the symptoms. Also, for more insights, check out our guide on why the check engine light comes on after an oil change.

Symptoms Of Turbo Failure

The first symptom that you will notice would be the black smoke that will come from the exhaust because of the failed turbo. This symptom can also point to other problems as well, that’s why it is better to see if there are any other symptoms.

The second symptom would probably be the turbo whine. When the turbo is bad and the shaft inside is broken. The turbine will lose its balance and will hit the wall of the turbo. This will result in an unpleasant sound when you accelerate.

Whining noise will be accompanied by a loss of power. The power loss will be more and more significant as the turbo nears the end of its lifetime. When it fails completely, you will only rely on the natural aspiration of the engine.

Loss of power means also little or no boost buildup. The car will struggle to run properly and build up speed as it used to before. That’s why if you test drive a Legacy, make sure that it builds up the boost nicely and doesn’t have any big lags until the car comes to boost. Which usually occurs at 3600 RPM for this engine.

Cost To Replace The Turbo

The cost to replace the turbo isn’t cheap. You can expect to pay between $1,000 for a turbo rebuild or $1,500 for a brand-new turbo in order to replace the failed one.

But this problem can also give you ideas that will make your Legacy a real menace on the street. With only an aftermarket turbo you could bump this engine up to 400 hp pretty easily.

This is the case because the engine is extremely tunable and allows more power to be created without sacrificing much of the internals. This makes this engine a perfect tuner car and a really desirable platform for doing performance upgrades. And that is something that we are going to cover a bit later after we finish the problems with the EJ255 engine.

Valve Cover Gasket Failure

Subaru gaskets are not that famous for their durability. The valve cover gaskets are one of these examples. They are prone to premature failure.

Unlike other gaskets, they are made out of poor-quality materials that tend to degrade over the years of long use. More precisely somewhere at 100,000 miles, you will experience the first symptoms of this gasket failing.

When the valve gasket fails, there are visible leaks of oil on the side of the engine. This leak is not a big deal because the problem can wait before you get a proper fix for it.

Legacy Spec B

The symptoms that you are going to experience are the smoke coming from the engine bay caused by the oil burning when it comes in touch with the hot exhaust manifolds. Then there are the visible leaks on the side of the engine and the overall smell of oil inside of the engine bay when you open up the hood. This smell can also be very notable inside of the cabin if there is a lot of oil that is leaking. But the Legacy Spec B gasket problems do not end here.

Head Gasket Failure

Head gaskets also tend to fail on Subaru engines, specifically on this engine as well. Similarly, to the valve cover gasket. These gasket failures are caused by the low-grade material of the gasket which simply starts to degrade and basically is dissolving little by little.

Then when the gasket gets damaged. The oil and coolant start to mix or the coolant starts to leak from the side of the engine or enters into the combustion chamber. That’s why it is a good thing to replace these gaskets simply as prevention when the car is nearing 10 years of age or 100,000 miles.

This problem can be a big headache if you delay the repairs. Most notably because the engine will start to overheat and engine damage could occur. In the best case, you will have to replace the engine head. In the worst case, you will have to replace the whole engine if the problem is not treated properly.

For the engine head replacement, you can expect to pay somewhere between $700 to $1,500 and for a new engine, you could even pay more than $3,000. That’s why when you get a Legacy Spec B make sure that all of the gasket issues are sorted properly by the previous owner and no permanent engine damage is on the engine.

Piston Rings Problem

Another problem with the Legacy Spec B engine is the problem with the piston rings. The EJ255 packs 3 piston rings, upper and lower compression ring along the oil ring that is found in the middle.

The space between the rings is called a ringland area. These pistons are notorious to develop cracks in this area. The cracks can be so big that they could basically crack a chunk of the piston.


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If this happens to your EJ255, the consequences would be big. This chunk if it falls off it could create huge damage on the engine head as well as on the cylinder walls. Your engine would be all scarred and mangled.

If you notice problems on your EJ255 like engine knocking, poser loss, loss of compression, and also smoke coming out of the exhaust. Then you probably are experiencing something similar and the engine has to be opened a checked. Checking will give you a good input of what is happening inside of your Legacy Spec B.

Rod Bearings Problem

Rod bearings are also notorious to go off on an EJ255 engine. The rod bearings are the bearings that are between the rod and the crankshaft which means that they are exposed to the hard work of the engine and make sure that the engine always gets the right turning momentum without any friction.

Unfortunately, the bearings on the Legacy Spec B tend to fail and develop rod knock sound. When the engine starts knocking then you know that it is due to a rebuild. When this happens, you will also lose power and the engine will not behave as it did before.

The solution for this would be an engine rebuild. The sooner you rebuild the engine, the better and the less expensive will be. If you notice the knock before it does damage on the crankshaft, then you will be safe with only the rod bearings replaced. If you wait, the whole engine will seize and stop working. Then the only solution would be to get a new engine for your Legacy Spec B.

Subaru Legacy Spec B Modifications

A popular choice among gear heads. The Legacy Spec B is extremely popular in the JDM community where it enjoys a lot of praise. Mostly because of its powerful engine that is an extremely good platform for mods.

The parts for this engine are plentiful. And with simple upgrades, you could pack 400 hp under the hood. And that is not a small amount of power. The things you can modify are plenty. Start by installing a cold air intake that will drive a lot of cool air into the engine.

Then you can upgrade the camshafts and add some aftermarket alternatives that will make a huge difference. The cams along with aftermarket ported heads will do the trick. With these upgrades even with a stock turbo, you would gain 100 to 150 horsepower.

Nevertheless, if you also add a bigger turbo with a beefier intercooler on top of this, you could easily make 600 hp with no problem. That’s why the EJ255 is a good platform. It’s a more reliable engine for modding than using it as a commuter.

Alternatives To The Legacy Spec B?

Knowing all these problems that the EJ255 has, maybe looking for an alternative would be your best bet. Since there are more than a few cars that could fit the bill and sometimes even deliver more than the Legacy Spec B. But which are these cars?

The first car that would probably come to mind is the BMW E46 328i or 330i. These two cars would be more than a good replacement for the Legacy with the EJ255 engine. They have straight-six engines that deliver a lot for the money.

Then another good option would be the Mitsubishi Lancer X that was released in 2007. If you are into the JDM world, this would probably be interesting for you as well. There are also other options like the Honda Civic and the Subaru WRX if you still want to get a Subaru anyway.

Facts about the 2006 Subaru Legacy 2.5GT spec.B

  1. The Subaru Legacy is a powerful sedan, with 250 horsepower, a balanced chassis, a sharp-looking interior and exterior, and a five-speed manual.
  2. However, its suspension isn’t firm enough, which results in a noticeable roll while cornering and excessive squat under acceleration, and needs improvements.
  3. The Legacy spec.B, a limited edition (only 500 made), has a revised suspension that addresses the GT’s dynamic faults.
  4. The spec.B swapped the front-strut setup with the WRX STI’s inverted struts, stiffened the shocks and springs, and added 18-inch wheels with wider Bridgestone Potenza RE050A summer tires.
  5. The spec.B looks essentially the same as lesser models, with slight exterior differences, but with red-leather seats, a touch-screen navigation system, and steering-wheel-mounted radio controls.
  6. The spec.B’s skidpad grip is up 0.06 g to 0.87, and its stopping distance from 70 mph is 177 feet, better by 19 compared to the base 2.5GT.
  7. The car can go from 0 to 60 in 5.3 seconds and the quarter-mile in 14.0 seconds, with a top speed of 137 mph and fuel economy of 20 mpg.
  8. Although the spec.B suspension better controls body motions, it still has some shortcomings such as a brake pedal with too much squish and a shifter with slightly too much resistance to gear changes.
  9. The price of the spec.B is $34,620, 18% higher than the 2.5GT manual, and inhaling the rarefied air of the Audi A4, BMW 3-series, Lexus IS, and Mercedes C-class.
  10. In the first couple of months, Subaru sold 160 copies of the spec.B, so waiting to find a slightly used example may be a wise financial move.


In this article, we covered a lot when it comes to the Subaru Legacy. We learned what the Legacy is and what are the specs of this car. Then we learned what is the Legacy Spec B and how it differentiates from the ordinary legacy.

Then we have covered the engine that the Spec B is using. We learned the numbers that it produces and also the problems that this engine has. This engine would a perfect option if you want to get a car that you want to modify, but if you want a simple commuter then you should consider other options since the engine isn’t that reliable after all.

Lastly, we have covered some alternatives that are worth considering if you are on the market for a similar car.

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