TURBOCHARGE YOUR
GTI!
Nothing quite
gives you the acceleration of a turbocharged VW engine.
While kits for the A1 platform are no longer manufactured,
there are
still plenty of them floating around out there, just waiting to be
bought.
My proof of this fact is evidenced by my latest modification
- the
installation of a Legend Turbo System to my 1984 GTI. This
system is
based on a Warner-Ishi RHB-52 turbo that delivers 6lbs of boost.
First, let's determine if turbocharging is truly the way you want to go. If you plan on having someone do the conversion for you, well, BUTCH UP! If you're man enough to tackle such a job in your own garage, ask yourself the following:
If you answered a resounding YES! to all the questions above, then read on!
Here is the turbo before installation
GLOSSARY
OF TURBO PARTS &
TERMS
Stage I: In Callaway speak, this was the entry level system. There was no intercooler, no water injection, and fuel enrichment was managed by simple lamda enrichment through the temperature switch. Boost was about 6 psi. This is essentially how my car is presently configured.
Stage II: This system added additional boost, and was aided by the addition of an intercooler, a microfueler, and water injection.
Detonation: Detonation is a light pinging sound that can be faintly heard during hard acceleration, and is death to a turbocharged engine. Caused by combustion of gasoline during the compression stroke of the cylinder.
Fuel Enrichment Kit: Normally open pressure switches, when tied into the lambda temperature switch, provide a rich mixture to the engine under boost conditions.
Inlet Tube: Replaces the stock intake tube. Routes from the fuel distributor to the turbo inlet.
Outlet Tube: Intake tube that routes from the turbo outlet (compression side) to the throttle body in stage 1 systems, to the intercooler in stage II systems.
Intercooler: Basically a radiator for compressed air. This is connected in-line between the discharge of the turbo and the intake manifold, and cools the intake air for a denser charge. Required for boost levels over approximately 6 lbs. Mounting of the intercooler is much easier in non-air conditioned vehicles.
Lambda Temperature Switch: Part of the K-jetronic fuel injection system. Located on the driver's side of the car, and spliced inline with the heater core hoses, this switch tells the injection system to provide a rich mix to the engine when the coolant is cold. Can be used to provide a rich mixture under boost conditions.
Microfueler: A 5th injector mounted to the intake manifold that is actuated by a pressure switch and managed by a special "black box" controller. This provides additional fuel to the engine under boost conditions, and is typically used in stage II configurations.
Oil Drain Line: Tubing routed from the turbo bearing jacket to the block of the engine. This line drains oil from the turbo unit back into the crankcase. It is very important that this line be oriented so it does not point horizontally or upwards. To do so will prevent proper oil drainage.
Oil Supply Line: Tubing routed from the top of the oil filter base to the turbo bearing jacket. This line supplies pressurized oil to the turbo bearing for lubrication purposes.
Wastegate: A bypass valve tied into the exhaust manifold which opens at a pre-determined pressure. This regulates the boost level, and prevents damage to the engine from overboost. Wastegates can be either internal or external. Both internal and external Wastegates provide a means to bypass exhaust flow from the turbine wheel. Bypassing the exhaust flow reduces the power driving the turbine wheel to match the power required for a given boost level. Similar to the BOV, the Wastegates uses boost pressure and spring force to regulate the flow bypassing the turbine. Internal Wastegates are built into the turbine housing and consist of a “flapper” valve, crank arm, rod end, and pneumatic actuator. The turbo on my setup has an internal wastegate.
Blow-off Valve: The Blow-Off valve (BOV) is a pressure relief device on the intake tract to prevent the turbo’s compressor from going into surge. The BOV should be installed between the compressor discharge and the throttle body, preferably downstream of the intercooler (if equipped). When the throttle is closed rapidly, the airflow is quickly reduced, causing flow instability and pressure fluctuations. These rapidly cycling pressure fluctuations are the audible evidence of surge. Blow-Off valves use a combination of manifold pressure signal and spring force to detect when the throttle is closed. When the throttle is closed rapidly, the BOV vents boost in the intake tract to atmosphere to relieve the pressure. Many BOVs are fitted with various types of horns to make a "cool" noise when they are activated.
Water Injection: The main function of these systems is to suppress detonation caused by high temperature and pressure developed within the combustion chamber when the effective compression ratio has been taken beyond the auto-ignition point by either a turbo or a supercharger. Many of these systems use alcohol to cool the combustion chamber temperatures and decrease the chance of detonation.
Turbo Timer: When a turbocharged car idles, the temperature of the hottest part of the turbocharger begins to stabilize to a temperature that is not typically damaging to the bearings. At that point, the engine can safely be turned off. If the car is immediately turned off after experiencing a load, the heat from the exhaust manifold can cook the oil on the bearings. Once restarted, the bearings may not not roll properly. A Turbo Timer is an electronic timer that calculates the amount of time necessary for the car's engine to remain running so that the turbocharger can cool properly. Once you remove the key from the ignition, the turbo timer will keep the engine running until it determines that it is safe to shut it off.
TURBO
BASICS
What type of performance do you want? Sure, you want to go faster, but do you still want the car to pass emissions tests and visual inspections? If you drive your car on public roads, keeping the emissions system in place should be one of your primary concerns. The diatribe below will relate to how the turbo kit fits a car with CIS w/lambda fuel injection. This is not intended to provide detailed installation instructions, but is a basic primer so you'll know what parts are needed to make the conversion.
SYSTEM TYPES
Turbo kits come in two basic forms. Stage I is 6 lbs of boost, with no intercooler or microfueler. Expect about 150 hp from a stage I kit. Stage II includes an intercooler and fuel system enrichment, and can provide about 10 lbs of boost and up to 180 hp. Stage I is the easiest to install, while stage II provides the most entertainment.
Click HERE to view a diagram of the Stage 1 Callaway system.
Here are scans of an original Callaway advertisement COVER, PAGE 1, PAGE 2, PAGE 3, PAGE 4, PAGE 5
Click HERE to view a short article about an old Spearco turbo system
Click HERE to view a diagram of an old Arkay turbo system
Stage II Callaway system with intercooler piping shown
There's the turbo hiding back there
1.8 liter VW engines can easily handle 10 lbs of boost without detonation given than compression ratios are dropped to the 7.5:1 area and an appropriate intercooler and microfueler/enrichment kit is installed (stage II). If you want to keep the stock compression ratio, and don't want to mess with intercooler piping, you will be limited to about 6 lbs of boost, but this is plenty for most people (it has been for me anyway - so far).
SYSTEM CONFIGURATION BASICS FOR STAGE I SYSTEMS
To summarize the basics of the system, the turbo is mounted to a special exhaust manifold, with the exhaust gas passing through an appropriate downpipe into your stock or aftermarket exhaust. Some kits will have provisions for the OXS sensor on the exhaust side of the turbo, which is preferred. The existing intake plumbing on your car is thrown out and a new tube is installed between the fuel distributor and the turbo intake. In stage I form, the compression side of the turbo is routed into the intake manifold through an aluminum casting that ties into your existing throttle body. In stage II form, the compression side of the turbo is routed through the intercooler and then into the throttle body. The intercooler itself is generally mounted under the car in the area of the battery.
The turbo is lubricated by routing an oil line from the oil filter base (by removing the oil temperature gauge sender on a GTI, or by tapping a hole otherwise) to the bearing housing of the turbo. This drains out through another line that is routed to the back of the engine block. In order to install this line, you must tap holes in either the oil pan or block of your engine. If you choose to install the drain line by welding a fitting onto the oil pan, keep in mind that during cornering it is likely the opening will be covered by oil sloshing in the pan, which will limit lubrication of the turbo bearings and cause premature failure. The Callaway kits had the oil drain line attached to the back of the block, which is where I have my line attached.
Boost is regulated by the wastegate. In the Legend system, the wastegate is integrated with the turbo itself. In the Callaway system, the wastegate is external to the turbo, and is attached to the exhaust manifold. The benefit of the Callaway configuration is the boost is easily adjustable, where in the Legend system, it is not. To change the boost level in an internally wastegated turbo, the turbo must be removed and the actuator swapped. External wastegates open the possibility of fitting adjustable devices that let you dial in the amount of fun you want to have for that particular day, or at a minimum easily change the unit out for additional or reduced boost.
Turbos run very hot, so some type of heat shielding is required on the firewall of your engine compartment to prevent heat transfer into the passenger compartment. This also prevents overheating the brake and electrical lines that run on the firewall behind the engine.
ADDITIONAL REQUIREMENTS FOR STAGE II SYSTEMS
Obviously, Stage I systems are the cheapest and easiest systems to install, but your level of boost is limited to about 6 lbs. Fortunately, VW engines are built very well, and have internal conponents that make most other manufacturer's engine parts look like Tonka toys, so your engine can stand a withering amount of boost. The primary concern is avoiding detonation by keeping the intake charge as cool as possible. Additionally, and externally wastegated turbo system is preferred for ease of tuning.
The first thing you must do is install and intercooler, which will safely get you to about 10 lbs of boost. The outlet of the turbocharger is routed to the intercooler, and then back to the throttle body. There are multiple areas that an intercooler can be installed in a non-air conditioned vehicle. The Callaway system had it mounted on the passenger side of the engine compartment adjacent to the radiator. Others elect to install the intercooler below the radiator and create an opening in the front of the vehicle for airflow. For air conditioned cars, the intercooler was located underneath the battery and attached to the front crossmember with special brackets. Mounting an intercooler in a car with A/C presents a challenge, since there is no location around the radiator (and therefore the front of the car) that has sufficient room for installation. Some creativity is in order, such as relocating the battery to the rear of the car to clear room on the driver's side (with the benefit of moving the battery's weight to the back of the vehicle!). The location is limited only by your fabrication skills and budget. The limiting factor may be finding a suitable fitting to attach to the throttle body.
Another slick way to reduce combustion chamber temperatures is to fit a "water" injection system. Most don't really use water, but rather some form of alcohol. The old Callaway systems could use windshield washer fluid. These devices simply squirt fluid into the intake when certain rpm and boost parameters are met. Some of the newer systems have intelligent controllers on them that will adjust the amount of fluid introduced to the intake, which helps to reduce the amount of water/alcohol introduced to your lubrication system. The downside of these systems is - depending on the size of the tank and the weight or your right foot - you have to refill the tanks often.
Additional fueling will also be necessary, along with some sort of ignition control. Both are addressed below and will aid operation of any system you install on your vehicle.
CONVENIENCE ITEMS
To increase longevity, the ideal setup will have a water-cooled turbocharger, although this will dramatically increase the thermal load on your cooling system. A radiator upgrade will probably be necessary if this type of turbo is used.
One of the most annoying things about non-water cooled turbos is the necessity of waiting while the car idles for a minute or so before you shut it down. This is to allow the turbo to spin down, and to keep the turbo from "heat soaking," which will burn engine oil inside the turbo bearings and greatly reduce the useful life of your engine. The addition of a "turbo timer" will allow you to shut off your ignition while the engine runs for a predetermined amount of time. You can remove the key, lock the doors, and walk away from the car while it idles on its own.
INSTALLATION BASICS
For starters, your engine should be in EXCELLENT shape. It should not use oil, and a compression and leak-down test should be performed to determine if your engine still is within factory specifications. Failure to check these two things could lead to CATASTROPHIC ENGINE FAILURE. A complete tune-up should be performed before operating the engine under boost - this means adjusting your valves, replacing fuel and air filters, replacing the OXS sensor, and adjusting the CO%.
To keep the emissions and lambda system in place, the following steps are necessary:
Do yourself a favor and replace the head gasket with one from a Corrado G60. This gasket doesn't reduce your compression ratio, but it is a stouter gasket with steel lined fire rings. If you really want your head bolted down tight, use Raceware head studs to secure the head on the block. This is an extra amount of insurance that will prevent problems with head gasket leakage.
I you still have the stock exhaust system on your vehicle, consider upgrading it to at least a 2" system. A 2" or 2.5" system will enable the turbo to spin up to speed quicker, reducing lag and improving overall performance.
A note about oil temperature: Once your kit is installed, you may be shocked to see how high your oil temperature will rise. At a minimum, a baffled aluminum oil pan or an oil cooler should be installed. I have the aluminum pan, and so far have had no problems.
DRIVING A TURBOCHARGED VW
Detonation is lethal to the engine of your car. It is a light pinging sound that is usually heard during hard acceleration. If detonation is heard, immediately back off the throttle and start looking for the problem! Exposing an engine to sustained detonation will cause internal failure of engine components, i.e. melted pistons, busted connecting rods, etc.
Do not subject the engine to boost when it is not up to full operating temperature. Failure to heed this warning will result in a shot head gasket over time.
Turbochargers run at extreme heat. Before shutting off the car at the end of a hard day's driving, allow the car to idle for about one minute before shutting it off. Failure to do so will leave the turbo spinning in the housing and starved for oil, resulting in premature bearing failure. In addition to this problem, what oil is left in the bearing housing will become overheated and "coke" the bearings.
Always use the highest octane gas available. I use 89 or 91 octane (RON+MON)/2 unleaded in my car. Use of 87 octane gas could result in detonation.
All these things are at most a minor inconvenience - well worth the extra power you get from a turbocharged engine!
OPTIONS
TO INCREASE FUEL
DELIVERY
CIS-lambda fuel injection should suffice for stage I turbo systems if rudimentary measures are taken - like engaging the lambda temperature sensor or WOT circuit. Stage II and greater will require additional fueling options. The easiest solution is to add the warm-up regulator from an Audi 5000 with a vacuum port. This item is designed to increase fuel delivery under boost. Additionally, a fuel distributor from a Volvo 240 can be installed that can handle the fuel requirements to 200hp and beyond. These items can often be found on eBay for a reasonable price. Purchasing these items new can be quite expensive - the WUR alone retails for over $400.
There are also other options, like fitting Digifant or Megasquirt fuel injecton that go well beyond the scope of this site. Research through VW Vortex for further information.
OPTIONS
TO ELIMINATE
KNOCK
To eliminate knock, you must do one or more of the following:
Installing a knock-sensing ignition is probably the cheapest and easiest way to increase power output while reducing the possibility of detonation.
WHERE
TO LOOK FOR TURBO
KITS
These kits are no longer made because the appropriate turbos are almost impossible to find. As I mentioned earlier, I lucked onto an unused system, but I paid a great deal of money for it, and I figure there are not too many "new" kits left out there. Most of what you will find are Callaway "Stage II" kits, which include the microfueler and intercooler. Other manufacturers are Spearco, BAE, and Legend. Don't buy a kit that doesn't contain at least all the parts listed earlier - if you don't have the part, you'll most likely never find it elsewhere.
Start by looking in the classifieds section of VW Vortex. In the old days you could search the watercooled VW news group as well. Every so often you will see someone wanting to sell a complete kit or a car or engine with a turbo already installed. Don't hold your breath, and look often.
ATP Turbo has many of the hoses, fittings, and other bits necessary for installation of a turbo system.
An excellent source for turbos and turbo rebuilding is Turbonetics.
And last but not least, eBay is always a good source if you keep your eyes out for the parts you need and have the patience to wait. Unfortunately, many of the folks listing "kits" on eBay tend to think their item is worth much more than it really is, or their item is missing critical components. Buyer beware.
WHAT TO LOOK FOR IN A USED KIT
The kit you locate should contain at least the following major parts. If it doesn't, don't buy it or have a good source for the missing components!
There are, of course, a multitude of bolts, hose clamps, and gaskets that will be required, but most can be picked up at a local hardware store, and are not critical when determining if a particular kit will work on your car.
When looking at the turbo, check the shaft rotates easily in the housing, and that there is minimal or no wobble in the shaft. If the blades contact the side of the housing, or you can see marks in the housing where the blades have rubbed, do not purchase the kit, since the turbo is shot and cannot be rebuilt. Minor free-play in the shaft is okay, but the unit will require a rebuild.
The other item to check closely is the manifold itself. Make sure it isn't cracked and no studs are broken off inside it. These are expensive defects to repair, and failure of the manifold will only be a matter of time.
CLICK HERE FOR INSTALLATION INSTRUCTIONS!
