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TRD Supercharger Kit




This dyno chart was scanned out of Today's SUV Magazine.  It shows the before and 
after supercharger dyno runs.  This chart shows an increase of 40 peak HP and a
max increase of near 60 HP.

There is no other performance modification that comes close to the fun that the TRD Supercharger can give you. Most other mods might give you some added performance in one area while decreasing it in another. The supercharger increases performance in all areas, low, midrange, and top end.

Most people and I report loosing only 1 MPG after installing the supercharger. That is a wonderful trade off for the added fun you will get from installing it, not to mention the cool factor. 

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 How a supercharger works and different types:

The engine draws into the cylinders when the pistons are moving downward in the cylinders.  This creates a pressure in the cylinders that is less then the air outside the engine.  The air outside the engine tries real hard to move into the area of negative pressure in the cylinder.  What this means is that air is not sucked into an engine but forced in by the higher air pressure outside the engine.

The amount of air the engine can consume, mix with fuel, and burn determines the how much power the engine can make.  Usually, engines of greater displacement can consume more air and fuel and make more power.

The down side to this is that engines of greater displacement have larger internal friction surfaces inside and that robs power. In cruise a car requires very little power to maintain speed on level ground.  Lets say a car needs 18 HP to maintain 60 MPH.  Now if you use a very small engine to make that 18 HP it will be more efficient due to less internal friction then a very large engine making 18 HP.  This is the biggest reason that smaller engines get better MPG then larger engines in cruise.  The problem is there are times that you need much more power like merging into traffic on the interstate.  This is where a bigger engine comes in handy, but you pay a fuel penalty when that larger engine is not needed.

There are advantages to making a smaller engine more powerful.  That way they can make the power needed, and still get better fuel economy.  One way to do this that is getting more popular is to force more air into the engine then it would normally draw in on its own.  This can be done with some kind of forced induction.  The most common ways to do this is with a turbocharger or supercharger.

A turbocharger has a turbine that is driven by spent exhaust gasses and that in turn spins a compressor wheel.  The compressor wheel causes more air to enter the engine then it would normally draw in on its own thereby increasing power.  The advantage to an exhaust driven turbo is that it is more efficient then an engine driven compressor AKA supercharger.  A piston engine is said at best to be only 33% efficient.  1/3 of the energy released from the burning gas is converted to heat that goes into the engine's cooling system.  1/3 of the energy powers the car.  1/3 of the energy goes out the exhaust pipe as heat.  The turbocharger harnesses some of that 1/3 wasted energy that goes out the exhaust to increase the power of the engine.

There are lots of other things that are really nice about turbochargers, but in an aftermarket bolt on application they can be very complex to install as it involves lots of plumbing changes in the exhaust, air induction system, oil system, and so on.  This is where the supercharger has some advantages.  It is an air pump that is driven by a belt from the crankshaft and no mods to the exhaust system are needed.  Overall the biggest advantage is it utter simplicity even if they are less efficient then a turbocharger.  Another advantage is the impellers are always turning at the ideal speed to provide full boost as soon as the throttle is opened.  In a turbo you have to wait for the turbo to speed or spool up to provide the boost.  That is called turbo lag.  That does not happen with the engine driven supercharger, you get boost as soon as you crack the throttle.

Centrifugal and Positive Displacement Superchargers

There are two basic types of superchargers, positive displacement and centrifugal.  

The centrifugal superchargers use the same type of compressor impeller as a turbocharger and the faster they spin the more boost they make and it is not linier.  If you double the speed of the compressor you quadruple the output.  The problem is that they only make peak boost at the engine's redline and tend to make very little boost at lower engine speeds where they are mostly operated.  These are the type used by the well known Paxton and Vortech brand.  In automotive use they really are not the best choice because of the very wide RPM ranges used in normal operation.  They are very well suited for aircraft use where the engines are operated in a very narrow RPM range the entire time the aircraft is in flight.  There are many auto manufactures that are using positive displacement superchargers on their cars, Mercedes, Jaguar, Ford, GM, Saab and many more.  Not a single one that I know of is using a centrifugal supercharger.  There must be a real good reason for that.

The positive displacement supercharger will move a fixed amount of air on each rotation and that is not dependant on impeller speed as it is on the centrifugal type.  When a positive displacement supercharger's size is properly matched to an engine and it turned at fixed ratio to engine speed it will produce a set amount of boost throughout almost the entire RPM band, from just off idle to full RPM.  There are great advantages to this over the centrifugal type superchargers and that is why they are the better choice.

Types of positive displacement superchargers-


This is the common piston in cylinder type.  These are mostly used as air compressors and not to many are used as superchargers as they are not any more efficient as the piston engine its self.


These use a central shaft with sliding vanes inside a housing of decreasing radius.  They have been used on older cars of the past.  The most current use of this type that I know of was the VW G-Lader.  This also very similar to most power steering pumps.


That's right the Wankle engine started out as a supercharger before someone got the idea to install spark plugs and shooting in gas and call it an engine. 


Lysholm superchargers are similar to the modified roots type, but the impellers are dissimilar.  One is a male rotor of three or four lobes and the other is a female rotor of five lobes.  The Lyshlom superchargers are used more in applications where the boost pressure is over 13 PSI.   The reason for this is that the supercharger compresses the air to a high degree inside the supercharger and it decompresses as it enters the plenum.  The advantage to this is that the air in the plenum will not back flow into the supercharger as the pressure in the supercharger is always more then in the plenum.  The side affect to this is higher heat and more parasitic drag then the modified roots type in non and low boost conditions.

Saab and Mercedes Benz uses the Lysholm superchargers, but Mercedes only uses them only in their high boost applications and the Eaton modified roots type in their low boost applications.  Currently Mercedes is using Japanese made Lysholm superchargers and has asked Eaton to supply them for their high boost applications.  Eaton has obtained the license from the patent holders to start producing Lysholm superchargers for Mercedes.  

There are some aftermarket companies that use the Lysholm supercharger in their kits.  Some of them are Stillen and Kenne Bell.  They are sometimes referred to as screw chargers.

Roots and Modified Roots Type-

The roots is the oldest type of positive displacement supercharger.  They started out life made of wood and were used to ventilate mines and as blowers in blast furnaces.  This is the type you see sitting on top of those big top fuel dragsters.  In these the air comes in one side and travels around toward the outside of the housing and as the impellers mesh the air is forced out the other side.  The most common use of this type supercharger or blower is on the Detroit two stroke diesel engines.  They are needed to force air into the intake ports on the two stroke diesel engines and they would not run without them.  This is the type of engine that is used in most of the fire trucks and buses.  It is not known as the most efficient type of supercharger.  The later Detroit two stroke engines had both a blower to make them run and a turbo for top end power. This was done in the Silver series until the Feds banned them for emission reasons.  You now will only find new ones in marine applications.

This is what the impellers look like inside the TRD Supercharger. Notice the twist of the impellers. 
That is modification that Eaton came up with to make them more efficient.

This is a picture from the intake end of the impellers.

 To make the Roots type more efficient, Eaton has modified the impellers by adding a twist to them and moving the intake port to the end.  This makes them more efficient and quieter.  This is called a "Modified Roots" type supercharger.  This is the type used in the TRD Supercharger kit.  The biggest difference between the modified roots type and the Lysholm supercharger is that the modified roots type has two impellers that are same, where the Lysholm uses two dissimilar ones, a male and a female rotor.

This is the supercharger housing. The intake port is the big hole on the bottom in the rear. 
Air is draw in there to fill the empty space between the impellers and then carried out toward the outside 
and toward the top.  When the impeller lobes intermesh at the top the air is forced out of the space 
between the lobes and out the discharge port on the top.  You can see the little holes on each side of the 
discharge port.  Those are placed there to increase the discharge efficiency and is called "S" porting.  That is 
fairly new thing. 

The modified roots type is the best type of supercharger to use until the boost pressure exceeds 13 PSI.  At that point the pressure in the manifold starts to exceed the pressure in the supercharger housing and it starts to backflow into the supercharger and decreases its output and the heat generated really goes up.  Above 13 PSI the better supercharger would be the Lysholm type.  It is said that the compression of the air occurs in the plenum after it leaves the supercharger in the modified roots type supercharger unlike the Lysholm where the air is compressed inside the blower and then decompresses as it leaves the blower and enters the plenum.  The advantage with the modified roots type is that it has less parasitic drag on the engine when boost is not needed.  The Eaton superchargers also use a bypass valve that equalizes the pressure on both sides of the impellers when the engine is operating in vacuum.  This takes more load off the engine and reduces the heat generated in non-boost conditions.  The Lysholm is still compressing air internally even during non-boost conditions and this generates heat and has more parasitic drag on the engine during non-boost even with a bypass valve.  Mercedes Benz does use some Lysholm superchargers on their super cars and they employ a clutch to disengage the supercharger from the crank shaft during non-boost conditions to counter the negatives of the Lysholm superchargers.

Overall the modified roots type supercharger is the much better choice if you are staying under 13 PSI of boost.  This is why most of the OEM producers choose the Eaton modified roots type superchargers for their production cars.

The Eaton modified roots type supercharger is the one that is best suited for the Toyota 3.4 supercharger kit given its low boost, low parasitic loss during non-boost conditions, and instant full boost throughout most of the RPM band.

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The TRD Supercharger kit:

The kit is produced by Magnuson Products for TRD.  They also make kits for other companies like Jackson Racing and Neuspeed, and help develop supercharger applications for many of the OE manufacturers, like GM. The original supercharger kit which is the one that I have uses an Eaton M-62 3rd Generation supercharger.  It has a 62 cubic inch displacement.  The first design kits had a separate plenum that the supercharger was bolted to.  The plenum is the part that carries air to the engine that is higher then atmospheric pressure also know as boost pressure.  It also doubles as the mounting for the supercharger.

The newer or current supercharger kit uses a single casting for the supercharger housing and plenum.  It is based on the newer 4th generation Eaton supercharger.  It differs from the 3rd generation mostly in respect to the bypass valve.  In the 4th generation the supercharger body has the bypass valve cast into the supercharger body where on the 3rd generation it was a separate part that had to be plumbed into the works some how.  This saves space and allows a more compact installation so it can be fitted to more applications.  Magnuson has taken this to the extreme and made the supercharger body, bypass valve, and plenum all one casting to make for a very compact installation.  Some people get confused thinking that the new supercharger is a totally different supercharger.  It really is not.  It is still an Eaton M-62, 62 cubic inch supercharger.  Magnuson has really done a fantastic job on the second version.  The layout and casting is very well thought out and still uses all the factory connections and cables.  The newer one is easier to install saving on installation time and confusion.

You can download a compressed file containing several pictures of the 2nd Generation TRD Supercharger Kit by clicking here.  You can see how Magnuson cast the housing, plenum, and bypass valve all as one compact unit.  It is very nicely done.

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The supercharger replaces the upper and lower intake connectors and bolts to the manifold.  The upper intake connectors are the long aluminum tube looking things that are between the throttle body and the intake manifold.  The kit retains the stock throttle body and all the vacuum hose connections.  If you have an EGR system on your truck there is a provision for this, but you will have to purchase an EGR adaptor kit at extra cost.

The installation is fairly simple and requires unbolting and removing the intake connectors, installing a longer alternator belt that will now also power the supercharger and reconnecting all the vacuum hoses.  The hardest part of all is removing the A/C compressor and power steering belt to get to the alternator belt.  This is not hard to do, but is tedious.  If you can replace your belts then you can install your own supercharger, it is that easy, really.

You can go the the TRD website and download the installation instructions and read them over to see what you are getting yourself into.  I suggest if you can, install the supercharger yourself.  That way you will be more familiar with the supercharger, hose connections and other parts of the engine that can help you trouble shoot problems in the future.  From the countless emails I get, I would have to say that most of the problems come out of installation errors from dealer installations.  There is also a good chance that the guy at the dealer that is installing your supercharger is installing his first one.  If you do go that route try to find a dealer and a mechanic at the dealer that has installed a few before yours and can demonstrate to you that he knows what he is doing.

The most common installation errors are miss routing vacuum lines, specifically the power steering idle up line and the 4x4 vacuum supply line so pay specific attention to those.  The next most common error is not properly installing the throttle body gasket.  Putting it in backwards will cause a check engine light in a short period of time showing a lean code.  Make sure you use the gasket that comes in the kit and make sure it is in the right way.  Lastly, it seems that many dealers forget to install the check valve in the air assist line.  This prevents boost pressure from back flowing through the air passages in the fuel injector tip and back out toward the throttle body.  This can take needed fuel with it preventing it from being injected into the engine under boost.  Make real sure that the check valve is installed in the air assist line and in the proper direction. 

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Many people seem to get confused about the warranty.  Here is my impression of the warranty, it is simple really.  If you install the supercharger it will be covered by a 12 month unlimited mileage warranty.  If you decide to pay the dealer to install it, the supercharger is rolled into the remainder of the drive-train warranty.  If it is installed on a new truck by the dealer it will be covered for 5 years or 60,000 miles.  I know that sounds good, but most of the problems with installation seem to be from dealer installations, go figure.  

My truck had 44,000 miles on it when I bought my supercharger and was putting about 30,000 miles on it at the time.  It seemed that if I paid the dealer to install it I would be out of warranty in about six months.  Of course I installed it myself in less then four hours with a lunch break.

The warranty on the truck itself is not affected at all no matter who installs the supercharger so do not worry about that.

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Where is the boost port?:

This seems to stump a great many people including the pros at the dealer.  The boost port is the connection for things you may want to install with the supercharger that need to have access to positive boost pressure from the supercharger.  These things may include a boost gauge and other gadgets that need a boost pressure signal.

In the picture above, the hose labeled as boost line 1 is connected to the boost port on this 1st Generation TRD Supercharger.  This is the fitting that you want to connect thing like the boost gauge to so that they will have access to boost pressure.  The port labeled as Boost Port 2 is also a port that will provide access to boost pressure, but it is normally connected to the bypass valve actuator and should be left alone.

This is a picture of the rear side of the 2nd Generation TRD Supercharger.  This side normally faces the firewall.  As you can see the boost port comes plugged and is the ONLY port on the supercharger that you can get a boost signal from.  You will have to remove this plug and screw in a nipple that you can attach a vacuum line to.  Many people opt to have the TRD boost gauge installed when they supercharger is installed by the dealer and it seems that many of them only read vacuum on the gauge.  The reason for this is that it is not connected to the boost port.  The gauge will not read properly if it is not connected to this port.  The port on the right labeled as vacuum port is the best place to connect the 4x4 vacuum supply line to, another typical error in the installation of the supercharger.

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Problems with the supercharger its self:

Overall the superchargers have proven to be very reliable and problems with the supercharger itself have been very few.  There have been some installation errors, but that is expected to some degree.

I have heard of a few diaphragms blowing out in the bypass valve actuators.  On the later version the vacuum line is connected to a vacuum source only to help reduce this problem.  I have installed a couple 2nd generation superchargers and found that the bypass valve travel stop set screws were not properly set by TRD and that caused the valves to over travel and stick.  You may want to check the adjustment on yours.

There have been some superchargers with bad input shaft seals.  This allowed the oil in the nose drive to leak out around the pulley.  The ones under warranty had the entire supercharger replaced by TRD.  If this happens to you out of warranty you can just replace the nose drive.  You can get an exchange unit from Magnuson.  This problem seemed to affect a small batch of superchargers and other then that has not been a big problem on units outside this one batch.  

If you are having oil leaking out of your nose drive do not let TRD tell you it is normal or it is just the break in lube. That seems to be their standard response, the fact is it is NOT normal and needs to be address right away.  There are only four ounces of oil in the nose drive and it can run dry very fast.

The supercharger does make noise, it is supposed to.  Under boost it will make a wonderful whine sound that most find very pleasant.  At idle it will make a rattling like sound.  That is from gear slack in the nose drive.  The supercharger uses straight cut gears in the nose drive and at idle there is no load on the gears that they tend to rattle back and forth a bit and that presents as a rattling sound.  It should go away if the engine is rev-ed up just above idle.  This is all very normal.  As the supercharger ages the rattle sound at idle may get louder.  I replaced my nose drive at 65,000 miles and the rattling sound was greatly reduced.

You can jump over to my supercharger maintenance page for information on how to keep your supercharger in top condition.

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Short comings with the TRD Supercharger kit:

Although the Magnuson did a fantastic job developing the supercharger for TRD, I feel there are some short comings in the kit.  The hardware part is beautifully done, but there are some issues that have not been properly address in my opinion.  They are:

You can click on the links above to find out why I think they are problems and what I have done to fix the problems.  Many of the other aftermarket supercharger kits are complete kits and include different ways to address issues with the ignition system, fuel system, and some even include transmission upgrades to prevent damage from the added power.  Some of the folks that make a complete kit are Kenne Bell, Stillen, Safari from Australia, and Alpine from South Africa.   TRD simply tells you that additional upgrades are not needed.  I disagree with that, but I guess because you can bolt on the supercharger and it will run without any other upgrades then I guess they are not lying, but I can tell you things can be so much better with a few other add-ons.  

Alpine from South Africa makes a real nice supercharger kit for the Toyota 2.4 and 2.7 truck engines.  The kit comes complete with extra fuel injectors and a piggy back engine computer to retune the engine for the supercharger.  TRD recently struck a deal with Alpine to produce a stripped down kit for TRD to market as their own kit.  It uses a smaller supercharger and does not have the extra injectors or piggy back computer and costs a lot more, but does have the pretty TRD label on it.  I think you would be better served by getting the original Alpine supercharger kit that is available in sever versions and boost levels.  Because of the import agreement between TRD and Alpine, TRD now has the exclusive import rights to the 2.4 and 2.7 supercharger kits in the US.  There is a small loop hole that you may want to take advantage of.  It was several members or Tacoma Territory that initiated the importation of the supercharger kit to the US that later led to TRD marketing it.  If you are a member of Tacoma Territory you can still import the original complete kit direct from Alpine.  Look up the New England chapter site of Tacoma Territory for more info on the 2.4 and 2.7 supercharger kit if you want.

There is a good reason why TRD does not include fuel and ignition upgrades with their supercharger kit.  I was told by the folks at TRD the reason they do not do so is that they are being restricted by Toyota.  TRD is part of Toyota in North America and because they are an arm of the manufacturer they would have to submit the entire kit with upgrades for EPA approval just like it was a new complete car.  There simply is not enough profit in the supercharger kits to cover the cost of getting something like this through the EPA approval process, so can not include ignition and fuel system upgrades and the engine will run without them, but I can tell you for certain, it will run so much better with some additional tweaking in the fuel and ignition system.  That is my understanding of what I was told by the folks at TRD.

When I was told that story by a guy at TRD, I recommended a way for them to get around all of those restrictions.  My idea was to start another company separate from TRD and Toyota, or have another company provide the fuel and ignition upgrades for them.  Then market the superchargers at a much lower boost level where the stock engine control system can handle things just fine and call that a stage I kit with full warranty even if it needs to be 2-3 PSI.  Then tell people that want more that they can get the stage II kit from the other partner company complete with a higher boost pulley and fuel system enhancements with a disclaimer that they can not warranty the upgraded kit.  That will give every one what they really want.  Shortly after that conversation the Kazuma off shoot of TRD was announced.  When the Camry supercharger was announced on the TRD web site they said that it came with a low boost pulley, but would sell you a smaller higher boost pulley that would need fuel system mods.  They would not sell it, but could refer you to a company that will sell you fuel system upgrades. Interesting, don't you think?

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