Supercharger Performance and Engine Performance Parts

What modifications do I need when adding a supercharger to a truck? What modifications do you need when adding a supercharger to any car for that matter?

When adding a supercharger to your car there isn’t that much that changes with the basics of how the car works. The main difference between a supercharged car and a normal car is the elevated power output, which comes from literally cramming more air into the engine than what it would have breathing on its own under atmospheric pressure. There are a lot of myths out there about needing to upgrade EVERYTHING when supercharging or turbo charging or even using nitrous injection on a car. That’s simply not true, this is not a fire sale J.

What is true are four things:

1-      Head Gasket

A multi layer steel headgasket

Supercharging, turbo charging, nitrous injecting, or even increasing the compression ratio on the motor ultimately increases peak cylinder pressures inside the cylinder. By having more air and fuel in the cylinder we have more effective compression pressure inside the cylinder (whether this pressure is from a higher compression ratio, a hotter mixture, a compressed mixture, or a combination of these factors).

The typical scenario here is that a late teens early twenties takes his 13 year old car that has 160,000 miles on it and adds a basic supercharger or turbocharger kit without proper tuning. The car runs lean on its first couple of runs (and a lean mixture creates more combustion pressure than a rich mixture) and eventually the engine’s designed fail point gives way. In every engine there is a weak point that will give out first, and this weak point is typically the head gasket. On the first couple of days of boosting, the head gasket will probably blow, the engine will sound different, we’ll find oil floating in the coolant and coolant and oil floating out of the exhaust, the engine will lose its power and the person will say that the supercharger ‘blew up’ his motor. If you’ve previously overheated your car and driven it like that for a while (or a previous owner had overheated the car because of a coolant leak, a radiator failure, a stuck closed thermostat, a broken water pump or any of a multitude of very common cooling problems) then it is very likely that eventually the you will lose your head-gasket under normal operation. Thus it is even more understandable if it does so the first time the engine is supercharged.

4 to 6 hours of labor and a couple of hundred dollars later (mostly in labor) and the car is back on the road running perfectly.

So if you have an old car that you want to supercharger or turbocharger, make sure that your engine cylinder head is still torque down to manufacturer specifications giving you a good seal on your head gasket.

2-      Tuning:

An EGT pyrometer gauge is a good way to listen to the health of the combustion inside your cylinder

I kind of hinted at this earlier, the other aspect of supercharging or turbo charging a car is the tune. A lean tune or over-advanced timing will cause higher cylinder pressures and more heat. The car will make GREAT power because the combustion is leaning out and rather than being a controlled and safe combustion, it’s becoming more of an uncontrolled explosion that wants to melt pistons or break ring lands. Now the fuel system on a typical car is not that complex but the turbo kit that you buy as a complete package does not upgrade the entire system. One of the main fore sights is installing a turbo kit on a car with an old and clogged fuel filter or an old and weak fuel pump, all the while not having a fuel pressure gauge, a wideband air fuel ratio gauge or an exhaust gas temperature gauge to be able to track whether or not your install was successful. Tuning includes a number of things including air to fuel ratio tuning, camshaft timing adjustment and ignition timing adjustment, as well as the most ignored skill (yet the most useful) in any tuner which is diagnosis and troubleshooting. Anyone can tell you to theoretically put these parts together to make a ‘good’ kit, but only a true tuner will be able to take the car with all of its history and figure out why it isn’t making optimum power and bring it back to health.

The second supporting procedure you can do when you supercharge your car is to check your power on the dyno. If the power figures are low, or if the tune is too aggressive then a simple trip to the dyno and a hookup of an OBD scanner during the run can tell you within 10 minutes weather you are running safe, or whether you need to make some adjustments.

3-      Heat management:

An oil cooler will help keep your oil cooler and more viscous

As much as we like to talk about engine efficiency and mileage, the truth is that internal combustion engines are only about 30 to 40% efficient. That means that almost two thirds of the energy potentially contained in the air/fuel mixture is lost as ‘heat’ where only 30 to 40% is transferred down to the wheels as power or acceleration. So starting with a 100hp car (that releases 200hp worth of heat) and increasing its power level by 100% using a supercharger at 15psi for example, leaves us with a car that new puts down 200hp worth of power and emits 400hp worth of heat.

This heat has to be properly managed… one of the things that we do for in cylinder heating is use colder spark plugs to prevent the spark plug from becoming a hot ignition point inside the cylinder even when there is no spark. Other things we might need are a larger capacity radiator or an added/larger engine oil cooler. If the coolant temperature rises and the oil temperature eventually rises, then the oil will start to lose its thickness and viscosity. Now, fully synthetic oil is designed to be more resilient to higher oil temperatures, but eventually if you continue to cook your oil by heating it over its desired operating temperatures then it will no longer become useful as a lubricant, engine wear and friction will increase, and ultimately you will lose power from the added friction.

The thing to note here is that cars make a variable amount of power depending on what rpm, boost pressure, throttle opening, and load conditions you drive it. If you drive your car very sparingly and then do the occasional drag race then the engine has plenty of time to settle down and cool down. If on the other hand you are always asking your engine to produce its maximum amount of power then that heat will start to accumulate in the under-rated factory radiator and oil cooler (that were not designed for an extra 200hp worth of heat) and eventually you may run into problems.

To sum things up, if you’re an aggressive drive and you’re looking to significantly boost the performance of your vehicle or plan to use it in severe conditions such as high load towing conditions, then it is advisable that you upgrade your radiator to a higher capacity better flowing radiator as well as install or upgrade your engine oil cooler. Other things you might see people do might include cooler thermostats and high pressure radiator caps and high flow water pumps. These are all geared towards helping the stock cooling system cope with an increased heat demand. For most of the rest of us that go on the occasional spirited drive, these modifications may not be necessary.

4-      Transmission:

Clutches are rated based on their torque holding capacity, the more torque you produce, the better the clutch you need.

When you are trying to put down all this increased power that you made with the addition of the supercharger on of the most common after problems realized is either clutch slip for manual transmissions or transmission slip for automatic transmissions.

If you have a manual transmission then typically an upgraded clutch and pressure plate combo may be necessary for supporting modifications. It may be a good idea to use synthetic fluid for your transmission oil as well as most manual transmissions don’t have any cooler associated with them.

If you have an automatic transmission, then you must know this: The ability of the automatic transmission to hold power is highly related to the viscosity of the transmission fluid, and the case of excessive heating of this fluid, then naturally the transmission will start to slip. To deal with this problem the typical first line of defense is switching to synthetic fluids that are better capable of dealing with the heat, as well as installing a transmission cooler to help cool down the fluid so that the transmission doesn’t slip.

The extent that these modifications are or are not required for your car will have a lot to do with the history of the car (is it well maintained or is it about time for something bad to happen such as an abused head gasket or a failing fuel injector). It also has a lot to do with whether the manufacturer is known for over-building their cars (such as companies like Mercedes or Toyota that typically design their cars with 15 years of service in mind) and whether or not some parts on your car (such as your motor, your fuel pump, your radiator and your transmission are shared with another car or platform that produces more horsepower than your car). It also has to do with the driving habits and ambient environment that you live in as we explained earlier. So these may or may not be required depending.

One good practical example of this ‘theory’ applied is the Underdog Racing and Development supercharger package for the 2005 to 2008 Toyota XRunner and Tacoma.

The V6 supercharger kit includes what you would expect in a well thought out supercharger system including:

§  Upgraded fuel injectors and a brand new fuel pump.

§  Customized ECU calibration software including air/ratio remapping and optimized ignition timing.

§  An adjustable cam gear for camshaft adjustment for optimum power delivery.

§  Cooler than stock iridium spark plugs

§  A cooler temperature thermostat that opens at 170*C

Furthermore, for their higher staged kits, that can be making over 400+ RWHP at 10PSI of boost, URD recommends:

Recommended vehicle upgrades for the increased power level:

• Install OEM Toyota engine oil cooler. This engine oil cooler is stock on some Tacomas with Toyota’s tow package. If your truck does not have an engine oil cooler, we recommend installing it to stabilize engine oil temperatures, especially in hot environments. Toyota part numbers are included in URD’s MKII installation manual.
• If your truck has an automatic transmission, URD recommends upgrading the transmission’s valve body so it will better withstand the additional power levels. Contact Import Performance Transmission for information regarding their auto transmission valve body upgrade.
• Grill Craft MX Series grill to improve airflow over the front mount intercooler.

Now considering that this is a truck supercharger application, then URD has operated under the assumption that the truck will be used for the purpose which it was designed, and that includes heavy lifting, towing, and rough terrain with adverse conditions, and so it makes sense that they have designed their kit to cover all the supporting modifications that I’ve mentioned above sans for the upgraded head gasket (which usually is not a problem that will appear on younger vehicle that has been well maintained).

For more information please visit:

Underdog Racing & Development (URD)

Technorati Tags: Intercooler, Rotrex, supercharger performance, supercharger tuning, URD, V6 Supercharger

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