Comparative Feasibility Study of Engines Upgrades for a
1979 Volkswagen Scirocco
Final Report
This is a paper I wrote for my technical writing class, that compares
the following engine swaps for the ‘79 Scirocco
(or really, any car built on the A1 chassis):
· 3A: 2L 8V, aka “bubble block”
· ABA: 2L 8V, aka “tall block”
· PL: 1.8L 16V, aka “sucky stock 16V engine”
· 9A: 2L 16V, aka “good engine”
· AWP: 1.8T 20V, aka “5 valves per cylinder, baby!!” and “eat my dust”
This report is in no way meant to be a detailed account
of what needs to be done for these engine swaps. It is merely an overview of what you can expect if you choose to
do one of these engine swaps. Some of
the info relating to the AWP is not up to date...such as the availability of
parts. I will be editing this report to
reflect the changes when I have time to do so.
I have finished fulfilling the recommendation of this report:
I have swapped the stock 1.6L engine and 020 tranny in my ’79 with a
1.8T engine (AWP) and 02J tranny from a 2003 VW Jetta.
If you reached this page from a search engine and are wondering where
on earth the rest of my website is, click here www.funksoulkitty.org
There you will find: lots of Scirocco related material including pics,
literature, articles, ads, turn signals for the Mk 1 Scirocco in amber,
clear, smoked, and custom, as well as the details of the 1.8T engine
swap into my ’79 Scirocco and more!!
Prepared by Kirsten Jensen
June 11, 2002
TABLE OF CONTENTS
OVERVIEW OF ENGINE COMPONENTS AND OPERATION
OVERVIEW OF EVALUATIVE CRITERIA
Modifications that will need to be made
Modifications that will need to be made
Modifications that will need to be made
Modifications that will need to be made
Modifications that will need to be made
AUDI 1.8L TURBO 20V – ENGINE CODE AWP
Modifications that will need to be made
MODIFICATIONS THAT WILL NEED TO BE MADE
Parts That Will Need to be Installed
Parts That Will Need to be Replaced
Parts That Will Need to be Upgraded
Parts That Will Need to be Modified or Custom Made
LIST OF ILLUSTRATIONS
Figure 1: Engine Components ........................................................................................... 3
Figure 2: Comparison of Engine Horsepower .................................................................... 25
Figure 3: Comparison of Engine Torque ............................................................................ 26
Table 1: Comparison of Engine Displacement and Valves .................................................. 27
Table 2: Comparison of the Fuel Injection Systems ............................................................ 28
Table 3: Comparison of the Parts That Will Need to be Installed ........................................ 29
Table 4: Comparison of the Parts That Will Need to be Replaced ...................................... 30
Table 5: Comparison of the Parts That Will Need to be Upgraded ..................................... 31
Table 6: Comparison of the Parts That Will Need to be Modified or Custom Made ........... 32
Figure 4: Comparison of Engine Mileage ........................................................................... 33
Figure 5: Comparison of Cost of Engines ........................................................................... 34
Figure 6: Comparison of Price of Parts .............................................................................. 35
Table 7: Comparison of Advantages for Each Engine ......................................................... 37
Table 8: Comparison of Disadvantages for Each Engine ..................................................... 38
INTRODUCTION
Over the course of our last few conversations, you have told me that you would like to upgrade the stock engine in your 1979 Volkswagen Scirocco. Since purchasing the car several years ago, you have wanted to upgrade the engine for better performance. You know that there are several engines that can be used, but you are unsure of which ones. Additionally, you are unsure of what to consider when choosing an engine. You would like to know which engine will give you the most increase in performance and will require the least amount of modifications to be made.
You have stated that increasing the horsepower is important to you as well as having good low-end torque. You would also like to have the option of modifying the engine for increased performance in the future.
Since there are a number of advantages and disadvantages to each engine, thorough research should be done when choosing an engine. To help you determine which engine will be the best upgrade from your stock 1.6 Liter (L) 8 Valve (V) engine, I will research and compare the following alternatives:
· 2.0L 8V – Engine Code 3A
· 2.0L 8V – Engine Code ABA
· 2.0L 16V – Engine Code 9A
· 1.8L 16V – Engine Code PL
· 1.8L Turbo 20V – Audi Engine Code AWP
Based on your needs, I have chosen the following criteria to evaluate each alternative:
· Horsepower
· Torque
· Displacement
· Fuel injection system
· Modifications that will need to be made
· Mileage
· Cost
· Price of parts
· Advantages
· Disadvantages
The purpose of this report is to provide you with the data, analysis, conclusions, and recommendations regarding engine upgrades for a 1979 Scirocco.
I have organized this report into five sections. The first section includes an overview of the major components of an engine and how an engine operates, as well as an overview of the evaluative criteria used in this comparison. The second section consists of all the data, organized by each of the alternatives. The third section is an analysis of the data, which is organized by each of the evaluative criteria. The fourth section contains conclusions based on the analysis of the data. The last section of this report contains my personal recommendations for the best engine upgrade for your 1979 Scirocco.
OVERVIEW OF ENGINE COMPONENTS AND OPERATION
All of the major engine
components are shown in Figure 1.
The two main sections of an engine are the engine block and cylinder head. The engine block contains all of the engine’s cylinders. Each of the cylinders has a piston and a connecting rod, which are attached to the crankshaft. As the crankshaft rotates clockwise, the connecting rods move the pistons up and down the cylinders. On the bottom of the engine block, there is an oil pan and sump.[1]
The cylinder head contains the intake and exhaust valves, which are attached to rocker arms and springs. The intake and exhaust valves are opened and closed by the camshaft as it rotates. On one side of the cylinder head there is an intake port which mates up with the intake manifold on the outside of the engine. On the other side of the cylinder head there is an exhaust port which mates up with the exhaust manifold on the outside of the engine. The cylinder head also contains the spark plugs.[2]
There are four stages to the combustion cycle of an engine. Each stage is referred to as a stroke. The first stage of the combustion cycle is the Intake Stroke. During this part of the cycle, the piston moves down to the bottom of the cylinder as the intake valve opens, filling the chamber with a mixture of fuel and air. This fuel air mixture comes from the intake manifold and fuel injection components. The next stage is the compression stroke. During this part of the cycle, the piston moves up to the top of the cylinder to compress the mixture of fuel and air.[3]
Once the piston has reached the top of the cylinder, the combustion stroke starts when the spark plug fires and ignites the fuel air mixture. The resulting explosion forces the piston back down to the bottom of the cylinder. Once the piston is at the bottom of the cylinder, the exhaust valve opens, and the piston moves back up the cylinder, forcing the exhaust out. The exhaust then goes through the exhaust manifold and the down pipe and finally exits out of the tail pipe.[4]
OVERVIEW OF EVALUATIVE CRITERIA
I will first give an overview of the technical details of horsepower, torque, displacement, and the fuel injection system. I will also discuss why each is relevant when comparing engines. For the remaining evaluative criteria, I will discuss what should be taken into consideration when comparing engines.
Horsepower (Hp) is a unit of measurement for power, where power is defined as work done in a set amount of time.[5] Work is calculated as force applied over a distance that is in the same direction as the force being applied.[6] During the combustion stroke of the combustion cycle, the piston is driven downwards when the fuel is combusted, thereby producing power.[7]
The horsepower of an engine is calculated after measuring the torque of an engine on a dynamometer. A dynamometer measures the amount of torque an engine can generate against different amounts of load. The measurements are then converted into horsepower using the following formula: Horsepower = Torque x rpm / 5,252. Peak horsepower is then determined by plotting the horsepower measurements and rpm values on a graph.[8]
Horsepower should be taken into consideration when comparing engines because the amount of horsepower an engine has, directly relates to how fast it can go.[9]
Torque is a twisting force used to rotate things. It is calculated by multiplying the amount of force applied, by the distance from the center of the thing being turned. A unit of torque is expressed as a foot-pound (ft-lb).[10]
As the piston moves downwards, during the combustion stroke of the combustion cycle, the connecting rod turns the crankshaft, producing torque. This torque is then mechanically applied to the wheels, causing the car to move forward.[11]
Torque should be taken into consideration when comparing engines because the amount of torque an engine can produce directly relates to how fast it can accelerate.[12]
Throughout the entire combustion cycle, the pistons move up and down the cylinders. Within each cylinder, the total distance the piston travels is multiplied by the diameter of the cylinder to determine displacement.[13] Displacement is expressed in units of cubic centimeters (cc), and 1,000 cubic centimeters is equal to one liter. To determine the displacement of an engine, you multiply the displacement of the cylinder by the number of cylinders the engine has.[14]
Displacement should be taken into consideration when comparing engines because the displacement of an engine directly relates to the amount of power it has.[15]
During the intake stroke of the combustion cycle, air is pulled into the cylinder from the intake manifold, as the piston moves down the cylinder chamber. Before entering the cylinder, the air passes by an air flow meter, which tells the system how much fuel is needed.[16] The required amount of fuel is then injected directly into the cylinder or into the air stream coming from the intake manifold.[17]
The fuel injectors, airflow sensor, and fuel distributor are some of the main components of the fuel injection system. All of the components function to provide the engine with precisely metered amounts of fuel. Most modern fuel injection systems also have some form of electronic control.[18]
The fuel injection system should be taken into consideration when comparing engines because each system has varying levels of electronic control, which affects the performance of the fuel injection system and the metering of the fuel to the engine.
There are three different fuel injection systems that are relevant to comparing these engines: CIS-E, CIS-E Motronic, and Motronic.
The Continuous Injection System – Electronic (CIS-E) fuel injection system uses a differential pressure regulator with the fuel distributor for more precise fuel mixture adjustment. The fuel mixture is controlled by a computer and is regulated according to the load and rpm of the engine.[19]
A coolant temperature sensor screws into the cylinder head and tells the computer what fuel mixture it needs, based on the temperature of the engine. This makes the fuel mixture more precise and provides better fuel mileage and more power.[20] The CIS-E system is easily tuned for increased performance.[21]
The CIS-E Motronic fuel injection system has different fuel injectors for increased flow, and dual knock sensors. A knock sensor ignition control system tells the computer if the engine is pinging and then retards the timing in 3-degree increments to eliminate the pinging. There is no thermo time switch or cold start valve because it is entirely controlled by a computer.[22]
The computer controls the fuel injection system and ignition system in one unit, which allows for more precise ignition firing for each individual cylinder. A coolant temperature sensor screws into the cylinder head and tells the computer the temperature of the engine. The computer then uses predetermined temperature maps to precisely meter the fuel.[23] The CIS-E Motronic system was designed for high performance tuning.[24] The computer chip can be upgraded for increased power, a better ignition advance curve, and different fuel injection mapping.[25]
The Motronic fuel injection system has entirely different fuel injection components than the other two systems have, as well as different spark plugs and spark plug wires. The computer controls the timing and fuel mixture, and can vary the amount of fuel being metered for each individual fuel injector as well as the spark to each individual cylinder.[26]
A coolant temperature sensor screws into the cylinder head and tells the computer the temperature of the engine. The computer then uses predetermined temperature maps to precisely meter the fuel. The Motronic fuel injection system provides better fuel mileage, more power, and better reliability. It is also designed for high performance tuning and the computer chip can be upgraded for increased power, a better ignition advance curve, and different fuel injection mapping.[27]
Modifications that will need to be made
Several things need to be taken into consideration when determining modifications that will need to be made. This includes modifications to allow the engine to function properly and fit into the chassis as well as modifications to other components that work directly with the engine. Additionally, any parts that would need to be upgraded to handle the increase in power or performance must be considered.
Because the majority of engines being compared can only be purchased used, the engine mileage should be taken into consideration.
There are two things to consider in terms of cost: First, the cost of the engine itself and second, the cost of all the parts for any modifications that will need to be made.
Price of parts
Whenever you upgrade to a higher performance engine, the price of parts for the majority of mechanical components will increase. The biggest increase in price occurs when upgrading from an 8V engine to a 16V. This added expense should be taken into consideration.
There are certain advantages that are unique to each engine. Each of these advantages should be taken into consideration.
There are certain disadvantages that are unique to each engine. Each of these disadvantages should be taken into consideration.
The 3A engine has a peak horsepower of 115 Hp at 5,400 rpm.[28]
The peak torque is 122 ft-lb at 2,600 rpm.[29]
The displacement is 2000 (1984) cc.[30]
The fuel injection system is CIS – E Motronic.[31]
Modifications that will need to be made
Because the 3A engine was designed to fit into an Audi 80,[32] the cold start valve, which is connected to the intake manifold, will rub against the rain tray along the top of the firewall. You can either cut the rain tray to make it fit or use a different cylinder head with the stock intake manifold. If you keep the 3A head, you will need to replace the fuel injectors with CIS-E fuel injectors.[33]
The best cylinder head to use is the JH cylinder head ($150) which comes on the engines in the 83-87 Scirocco 8V and the 83-84 Jetta GLI. When you swap out a cylinder head, you must get a head gasket kit and bolts ($85).[34]
The 3A engine has a different location than the stock engine for the crankcase hose. To fix this problem, a block off plate ($65)[35] for the crankcase must be installed so the opening for the crankcase hose is sealed. The block off plate is also needed to provide a mounting surface for the warm up regulator. You will need to use the stock valve cover so that the stock crankcase hose will attach in the correct place.[36]
The following parts will need to be installed, replaced, or upgraded:
· The stock upper radiator hose will need to be replaced with an upper radiator hose from a 1984 Scirocco ($8).[37]
· The passenger side motor mount ($13.95)[38] will need to be upgraded to the larger of the two sizes available.[39]
· A knock sensor will need to be installed from a 16V Scirocco ($250).[40]
· The stock distributor will need to be replaced with a distributor from a 16V Scirocco ($150).[41]
· The stock 190 clutch will need to be upgraded to the 210 clutch ($200) so the car can handle the increase in horsepower.[42]
The 3A engine is only available used and typically has over 100,000 miles on it.[43]
The engine costs $550. The engine and all the necessary parts needed for modifications cost $800.[44]
The prices on parts for this engine are 30 to 40% more expensive than stock.[45]
The 3A engine block and cylinder head are designed for a CIS fuel injected car reducing the amount of modifications that need to be made. Additionally, the intake manifold is the correct orientation for A1 cars. The deck height is the same as the other 1.6L and 1.8L blocks so a new exhaust down pipe isn’t necessary.[46]
If the 3A cylinder head and intake manifold are used, the fuel injectors are located in the intake manifold for cooler operation and the intake runners on the manifold are larger than most stock A1 manifolds for increased low-end torque.[47]
The relationship between bore and stroke is not as proportionate as it is on the other engines, which results in less torque.[48]
The ABA engine has a peak horsepower of 115 Hp at 5,400 rpm.[49]
The peak torque is 122 ft-lb at 3,200 rpm.[50]
The displacement is 2000 (1984) cc.[51]
The fuel injection system is Motronic.[52]
Modifications that will need to be made
Because the ABA engine was designed to fit into a Golf or Jetta,[53] there isn’t enough clearance between the top of the engine and the hood of the car. You can either cut away some of metal in the interior of the hood, or use a different cylinder head with the stock intake manifold. The best cylinder head to use is the JH cylinder head ($150) which comes on the engines in the 83-87 Scirocco 8V and the 83-84 Jetta GLI. When you swap out a cylinder head, you must get a head gasket kit and bolts ($85).[54]
If you keep the ABA cylinder head, the stock fuel injection system will need to be converted to Motronic. The wiring and wiring harness will need to be modified and separate relay brackets will need to be installed by the fuse panel. The stock spark plugs and spark plug wire will need to be replaced with spark plugs and wires from a 93-99 Jetta or Golf. All of the stock CIS fuel injection components will need to be replaced with Motronic components, which can be obtained from a wrecking yard car ($400).[55]
The ABA engine has a different location than the stock engine for the crankcase hose. To fix this problem, a block off plate ($65)[56] for the crankcase must be installed so the opening for the crankcase hose is sealed. The block off plate is also needed to provide a mounting surface for the warm up regulator.[57] You will need to use the stock valve cover so that the stock crankcase hose will attach in the correct place.[58]
The following parts will need to be installed, replaced, or upgraded:
· The stock down pipe for the exhaust will need to be upgraded ($120).[59]
· The stock upper radiator hose will need to be replaced with an upper radiator hose from a 1984 Scirocco ($8).[60]
· The passenger side motor mount ($13.95)[61] will need to be upgraded to the larger of the two sizes available.[62]
· A knock sensor will need to be installed from a 16V Scirocco ($250).[63]
· The stock distributor will need to be replaced with a distributor from a 16V Scirocco ($150).[64]
· The stock 190 clutch will need to be upgraded to the 210 clutch ($200) so the car can handle the increase in horsepower.[65]
The ABA engine is only available used and typically has between 25,000 and 100,000 miles on it.[66]
The engine costs $550. The engine and all the parts needed for modifications cost between $800 and $1,000.[67]
The prices on parts for this engine are 30 to 40% more than stock.[68]
The taller design of the ABA engine block allows for longer connecting rods, which minimizes engine vibration and reduces engine knock. For improved cooling, oil is sprayed directly under the pistons.[69] The crankshaft windage tray is metal instead of plastic and has an impregnated rubber gasket seal.[70]
The fuel injection system can easily be converted to full Motronic for better performance. The ABA cylinder head, if used, is a cross-flow head, which increases the flow of air for better performance.[71] The engine responds well to performance modifications.[72] The ABA engine can be bored to 2.2L to increase the displacement, which will produce more horsepower.[73]
The exhaust components could have problems with ground clearance due to the height of the engine block.[74] The engine is made in Mexico where cheaper parts are used resulting in diminished bearing life.[75]
The 9A engine has a peak horsepower of 134 Hp at 5,800 rpm.[76]
The peak torque is 133 ft-lb at 4,400 rpm.[77]
The displacement is 2000 (1984) cc.[78]
Fuelinjectionsystem
The fuel injection system is CIS-E Motronic.[79]
Modifications that will need to be made
The following parts will need to be installed, replaced, or upgraded:
· The stock intake manifold will need to be upgraded to the 40 mm intake manifold from a 16V Scirocco ($100).[80]
· The stock exhaust manifold will need to be upgraded to the exhaust manifold from a 16V Scirocco ($100).[81]
· The stock down pipe for the exhaust will need to be upgraded ($150).[82]
· The stock intake boot and elbow will need to be replaced with ones from a 16V Scirocco ($50).[83]
· The stock accelerator cable will need to be replaced with an accelerator cable from a 16V Scirocco ($15).[84]
· The stock fuel injectors will need to be upgraded to the fuel injectors for the 9A engine ($40).[85]
· The stock fuel injector lines will need to be upgraded to the fuel injector lines for the 9A engine ($50).[86]
· The stock upper radiator hose will need to be replaced with an upper radiator hose from a 1984 Scirocco ($8).[87]
· The stock passenger side motor mount ($13.95)[88] will need to be upgraded to the larger of the two sizes available.[89]
· A knock sensor will need to be installed from a 16V Scirocco ($250).[90]
· The stock distributor will need to be replaced with a distributor from a 16V Scirocco ($150).[91]
· The stock 190 clutch will need to be upgraded to the 210 clutch ($200) so the car can handle the increase in horsepower.[92]
The 9A engine is only available used and typically has over 100,000 miles.[93]
The engine costs $1,000. The engine and all the parts needed for modifications cost between $1,500 and $1,600.[94]
The prices on parts for this engine are 75% more expensive than stock.[95]
The 9A engine is easy to work on. The exhaust manifold is not covered by the intake manifold, which reduces the problems that typically arise when working on exhaust related components. The engine swap requires less time and has fewer potential problems.[96] The engine also responds well to performance upgrades.[97] The 9A engine can be bored to 2.1L to increase the displacement, which will produce more horsepower.[98]
It is expensive to do performance upgrades.[99] The 9A engine is hard to locate because it is not readily available.[100]
The PL engine has a peak horsepower of 123 Hp at 5,800 rpm.[101]
The peak torque is 120 ft-lb at 4,250 rpm.[102]
The displacement is 1800 (1781) cc.[103]
The fuel injection system is CIS – E.[104]
Modifications that will need to be made
The following parts will need to be installed, replaced, or upgraded:
· The stock intake manifold will need to be upgraded to the 40 mm intake manifold from a 16V Scirocco ($100).[105]
· The stock exhaust manifold will need to be upgraded to the exhaust manifold from a 16V Scirocco ($100).[106]
· The stock down pipe for the exhaust will need to be upgraded ($150).[107]
· The stock intake boot and elbow will need to be replaced with ones from a 16V Scirocco ($50).[108]
· The stock accelerator cable will need to be replaced with an accelerator cable from a 16V Scirocco ($15).[109]
· The stock fuel injectors will need to be upgraded to the fuel injectors for the 9A engine ($40).[110]
· The stock fuel injector lines will need to be upgraded to the fuel injector lines for the 9A engine ($50).[111]
· The stock upper radiator hose will need to be replaced with an upper radiator hose from a 1984 Scirocco ($8).[112]
· The stock passenger side motor mount ($13.95)[113] will need to be upgraded to the larger of the two sizes available.[114]
· A knock sensor will need to be installed from a 16V Scirocco ($250).[115]
· The stock distributor will need to be replaced with a distributor from a 16V Scirocco ($150).[116]
· The stock 190 clutch will need to be upgraded to the 210 clutch ($200) so the car can handle the increase in horsepower.[117]
The PL engine is only available used and typically has over 120,000 miles on it.[118]
The engine costs $400. The engine and all the parts needed for modifications cost between $1,000 and $1,100.[119]
The prices on parts for this engine are 75% more expensive than stock.[120]
The PL engine is easy to work on. The exhaust manifold is not covered by the intake manifold, which reduces the problems that typically arise when working on exhaust related components. The PL engine is easy to locate because it is readily available.[121]
The PL engine has poor low-end torque and shows no increase in torque until around 4,500 Rpm. The engine does not respond well to performance upgrades.[122]
AUDI 1.8L TURBO 20V – ENGINE CODE AWP
The AWP engine has a peak horsepower of 180 Hp at 5,500 rpm.[123]
The peak torque is 173 ft-lb at 1,950 to 4,700 rpm.[124]
The displacement is 1800 (1781) cc.[125]
The fuel injection system is Motronic.[126]
Modifications that will need to be made
The stock CIS fuel injection system will need to be converted to Motronic. The wiring and wiring harness will need to be modified and separate relay brackets will need to be installed by the fuse panel. All of the stock CIS fuel injection components will need to be replaced with Motronic components, which can be obtained from a wrecking yard car ($400).[127]
This is not a complete listing since this report is meant to be more of an overview. Since I chose to use the AWP in my engine upgrade, you can find more exhaustive details in my engine swap pages:
The following parts will need to be custom made or upgraded:
· A down pipe will need to be custom made ($250 - $300).[128]
· The intercooler piping will need to be custom made ($300 - $400).[129]
· An aftermarket intercooler ($300) for the turbo will need to be installed.[131]
· The stock upper and lower radiator hoses will need to be replaced and vary depending on which radiator you use.
· The passenger side motor mount bracket will need to be modified. If the 02J tranny is used, the driver’s side and rear mount brackets will need to be custom made.
· The stock 190 clutch will need to be upgraded to a racing clutch ($250 - $300) so the car can handle the increase in horsepower.[133]
The AWP engine is available new with no miles on it.[134]
The engine costs $4,500. The engine and all the parts needed for modifications cost $5,800.[135]
The prices on parts for this engine are 90% more expensive than stock.[136]
The AWP engine has five valves per cylinder, which enables rapid and efficient combustion. It also has good torque throughout a wide range of Rpm.[137] By upgrading the turbo, intercooler, and computer chip, you can bring your horsepower to over 350 +.[138]
Parts for the engine are not widely available because the engine has only been on the market for four years.[139]
The AWP has the highest amount of horsepower by a substantial amount. This engine produces 180 horsepower at 5,500 rpm.
The 9A has the second to highest amount of horsepower. This engine produces 134 horsepower at 5,800 rpm.
The PL has the second to lowest amount of horsepower. This engine produces 123 horsepower at 5,800 rpm.
The 3A and ABA have the lowest amount of horsepower. Both engines produce 115 horsepower at 5,400 rpm.
Figure 2 below, is a comparison of the horsepower for each engine.
Figure 1: Comparison of Engine Horsepower
The AWP has the highest amount of torque by a substantial amount. This engine produces 173 ft-lb of torque. It can sustain 173 ft-lb of torque throughout the range of 1,950 to 4,700 rpm.
The 9A has the second to highest amount of torque. This engine produces 133 ft-lb of torque at 4,400 rpm.
The 3A and ABA have the second to lowest amount of torque, at 122 ft-lbs. The 3A achieves this at 2,600 rpm and the ABA at 3,200 rpm.
The PL has the lowest amount of torque. This engine produces only 120 ft-lb of torque at 4,250 rpm.
Figure 3 below, is a comparison of the torque for each engine.
Figure 2: Comparison of Engine Torque
When comparing the displacement of these engines, it should be noted that the chosen alternatives are all either 1.8L or 2.0L engines. Because of this, there are only two different displacement specifications. When discussing the performance of an engine’s displacement, the amount of valves is typically taken into consideration as well.
The 3A, ABA, and 9A have the larger of the two displacement specifications with 1,984 cc or 2.0 liters. The 3A and ABA are 8-valve engines and the 9A is a 16-valve engine.
The PL and AWP have the smaller of the two displacement specifications with 1,781 cc or 1.8 liters. The PL is a 16-valve engine and the AWP is a 20-valve engine.
Table 1 below, is a comparison of the displacement and amount of valves for each engine.
Table 1: Comparison of Engine Displacement and Valves
|
|
3A |
ABA |
9A |
PL |
AWP |
|
Displacement
|
2000 (1984) cc |
2000 (1984) cc |
2000 (1984) cc |
1800 (1781) cc |
1800 (1781) cc |
|
Valves |
8 |
8 |
16 |
16 |
20 |
The AWP and ABA engines both have Motronic fuel injections systems. Motronic is superior to the other types of fuel injection because it utilizes complete electronic control of the fuel injection and ignition systems.
The 3A and 9A engines both have CIS-E Motronic fuel injection systems. CIS-E Motronic partially utilizes the superior characteristics of the full Motronic system.
The PL engine has CIS-E fuel injection. CIS-E is inferior to the other types of fuel injection systems because it does utilize full electronic control.
Table 2 below, is a comparison of the fuel injection systems for each engine.
Table 2: Comparison of the Fuel Injection Systems
|
|
3A |
ABA |
9A |
PL |
AWP |
|
Fuel Injection |
CIS - E Motronic |
Motronic |
CIS-E Motronic |
CIS - E |
Motronic |
MODIFICATIONS THAT WILL NEED TO BE MADE
There are four different categories of modifications that will need to be made. They include parts that will need to be installed, replaced, upgraded, and modified or custom made. The modifications that will need to be made for each engine vary in both amount and difficulty of task.
Parts That Will Need to be Installed
Parts that will need to be installed refers to the mechanical components that are not currently in the car and that will need to be put in.
The 9A and PL engines have only one part that will need to be installed. Both engines will need to have a knock sensor put in. Installing a knock sensor is a moderately difficult task.
The 3A and ABA engines have two parts that will need to be installed. The first part is a knock sensor and the second part is a block off plate. Installing a block off plate is an easy task. Additionally, if the ABA head is used, relay brackets will need to be installed by the fuse panel. This is a moderately difficult task and has the potential for damaging the fuse panel.
The AWP engine has two parts that will need to be installed. The first part is an intercooler for the turbo and the second part is relay brackets by the fuse panel. Installing the intercooler is a difficult task and has the potential for many problems.
Table 3 below, is a comparison of the parts that will need to be installed for each engine.
Table 3: Comparison of Parts That Will Need to be Installed
|
|
3A |
ABA |
9A |
PL |
AWP |
|
Installed |
Knock sensor |
Knock sensor |
Knock sensor |
Knock sensor |
Intercooler |
|
Block off plate |
Block off plate |
|
|
Relay brackets |
|
|
|
Relay brackets if ABA head is used
|
|
Parts That Will Need to be Replaced
Parts that will need to be replaced refers to the mechanical components that are currently in your car and that will need to be replaced with the same type of part from another car.
The 3A and ABA engines have two parts that will need to be replaced. The first part is the upper radiator hose and the second part is the distributor. Replacing the radiator hose is an easy task and replacing the distributor is a moderately difficult task. Additionally, if the 3A head is used, the fuel injectors will need to be replaced, which is a moderately difficult task. If the ABA head is used, the spark plugs and wires will need to be replaced, which is an easy task.
The AWP engine has two parts that will need to be replaced. The upper and lower radiator hoses and all of the fuel injection components will need to be replaced. Replacing the fuel injection components is a very difficult task. There is the potential for many problems and working with fuel injection components can be somewhat dangerous.
The 9A and PL engines have four parts that will need to be replaced. The upper radiator hose and distributor will need to be replaced as well as the accelerator cable and intake boot and elbow. Replacing the accelerator cable and intake boot and elbow are both easy tasks.
Table 4 below, is a comparison of the parts that will need to be replaced for each engine.
Table 4: Comparison of Parts That Will Need to be Replaced
|
|
3A |
ABA |
9A |
PL |
AWP |
|
Replaced |
Radiator hose |
Radiator hose |
Radiator hose |
Radiator hose |
Radiator hoses |
|
Distributor |
Distributor |
Distributor |
Distributor |
Fuel injection components |
|
|
Fuel Injectors if 3A head is used |
Spark plugs and wires if ABA head is used |
Intake boot/elbow |
Intake boot/elbow |
|
|
|
Accelerator cable |
Accelerator cable |
Parts That Will Need to be Upgraded
Parts that will need to be upgraded refers to the mechanical components that are currently in your car and will need to be upgraded from stock.
The 3A engine has two parts that will need to be upgraded. The first part is the passenger side motor mount and the second part is the clutch. Upgrading the motor mount is a moderately difficult task. Upgrading the clutch is an extremely difficult and time-consuming task, which typically requires more than one person to complete.
The ABA engine has three parts that will need to be upgraded. The passenger side motor mount, clutch, and down pipe will all need to be upgraded. Upgrading the down pipe is a moderately difficult task.
The 9A and PL engines have seven parts that will need to be upgraded. The motor mount, clutch, and down pipe will all need to be upgraded as well as the intake and exhaust manifolds. The fuel injectors and fuel lines will also need to be upgraded. Upgrading the intake manifold, exhaust manifold, and fuel injectors is a moderately difficult task. Upgrading the fuel lines is a difficult task and has the potential for many problems.
The AWP engine has one part that will need to be upgraded: the clutch.
Table 5 below, is a comparison of the parts that will need to be upgraded for each engine.
Table 5: Comparison of Parts That Will Need to be Upgraded
|
|
3A |
ABA |
9A |
PL |
AWP |
|
Upgraded |
Motor mount |
Motor mount |
Motor mount |
Motor mount |
|
|
Clutch |
Clutch |
Clutch |
Clutch |
Clutch |
|
|
|
Down pipe |
Down pipe |
Down pipe |
|
|
|
|
Intake manifold |
Intake manifold |
|
||
|
Exhaust manifold |
Exhaust manifold |
|
|||
|
Fuel injectors |
Fuel injectors |
||||
|
Fuel lines |
Fuel lines |
Parts That Will Need to be Modified or Custom Made
Parts that will need to be modified or custom made refers to the mechanical components that will need to be modified in some way to make the new engine fit into the chassis. It also refers to parts that will need to be fabricated because they are not available.
The 9A and PL engines have no parts that will need to be modified or custom made.
The 3A engine has one modification that will need to be made to allow enough clearance for the cold start valve. Either the rain tray can be cut or the cylinder head can be swapped out with a different one. Cutting the rain tray is an easy task; however swapping out the cylinder head is a moderately difficult task.
The ABA engine has one modification that will need to be made to allow enough clearance for the top of the engine. Either the underside of the hood can be cut or the cylinder head can be swapped out with a different one. Both of these tasks are moderately difficult. Additionally, if the ABA head is used, the stock wiring harness and wiring will need to be modified for the Motronic fuel injection system. This is a difficult task and has the potential for numerous problems.
The AWP engine has two parts that will need to be modified and two parts that will need to be custom made. The stock wiring harness and wiring will need to be modified for the Motronic fuel injection system as well as the passenger side motor mount. The intercooler piping and downpipe will both need to be custom made. This is a job for an automotive machine shop so it is more expensive than difficult. As an alternative, you can do the fabrication yourself if you have the proper tools and knowledge.
Table 6 below, is a comparison of the parts that will need to be modified or custom made for each engine.
Table 6: Comparison of Parts That Will Need to be Modified or Custom Made
|
|
3A |
ABA |
9A |
PL |
AWP |
|
Modified or Custom Made |
Cold start valve clearance |
Top of engine clearance |
|
|
Wiring and Wiring harness |
|
|
Wiring if ABA head is used |
Passenger Side Motor Mount |
|||
|
Wiring harness if ABA head is used |
Intercooler Piping |
||||
|
Downpipe |
The mileage for each engine varies according to the age of the car the engine comes from. Each engine’s mileage is just an average and what you would typically find going to a wrecking yard.
The AWP has the lowest engine mileage. This engine is used in the 2000 through 2002 Audi TTs, and is only available new.
The ABA has the second to lowest engine mileage with an average of 25,000 to 100,000 miles. This engine has lower mileage because it was used in Golfs and Jettas from 1994 through 1997. Because these cars are relatively new, the engines will typically have lower mileage.
The 3A and 9A have the second to highest engine mileage with an average of 100,000 miles. The 3A was used in Audi 80s in 1988 and 1989 and the 9A was used in Jettas, Golfs, and Passats from 1989 through 1994. Because these cars are relatively old, the engines will typically have higher mileage.
The PL has the highest mileage with an average of 120,000 miles. The PL was used in Golfs, Jettas, and Scirocco 16Vs from 1986 through 1989. Because these cars are old, the engines will typically have higher mileage.
Figure 4 below, is a comparison of the mileage for each engine.
Figure 3: Comparison of Engine Mileage
The PL is the least expensive engine costing only $400. Although this is a 16-valve, the price is low because of the age and typical mileage on the engine. For the engine and necessary parts however, the PL is the third most expensive, costing between $1,000 and $1,100. The difference between the two prices reflects the cost of parts for 16-valve engines.
The 3A and ABA engines are both the second to least expensive, costing $550. The cost is relatively low because they are both 8-valve engines and typically have higher mileage due to their age. For the engine and necessary parts, the 3A is the least expensive costing $800, followed closely by the ABA costing between $800 and $1,000.
The 9A is the second to most expensive engine costing $1,000. This price is high because it typically has lower mileage and because it is a 16-valve. The cost of the engine and necessary parts is also second most expensive, costing between $1,500 and $1,600.
The AWP is the most expensive engine costing $4,500. This drastic increase in cost is because the engine must be bought new and the design is significantly superior to the other engines. The cost of the engine and necessary parts is also the most expensive, costing $5,800.
Figure 5 below, is a comparison of the cost of each engine and the necessary parts.
Figure 4: Comparison of Cost of Engines
PRICE OF PARTS
The prices of parts for each engine were compared to the cost of parts for the stock engine and then a percentage of increase was determined.
The 3A and ABA have the smallest increase in cost for parts, with a 30-40% increase in price. The price of parts is lower because both are 8-valve engines.
The 9A and PL have the second to largest increase in cost for parts, with a 75% increase in price. The price of parts is much higher because both are 16-valve engines.
The AWP engine has the largest increase in cost for parts, with a 90% increase in price. The price of parts is much higher because it is a 20-valve engine and has a turbo system.
Figure 6 below, is a comparison of the increase in price of parts for each engine.
Figure 5: Comparison of Price of Parts
The types of advantages for each engine vary making it difficult to directly compare them. The advantages for each engine vary in type, amount, and relevance.
The ABA engine has six advantages. There are three structural advantages and three performance advantages. Two of the structural advantages and two of the performance advantages are very relevant. The remaining two advantages have minimal relevance. Additionally, there is a fourth performance advantage if the ABA head is used. This advantage is very relevant.
The 9A engine has five advantages. There are two performance advantages and three simplicity advantages. Both of the performance advantages are very relevant and one of the simplicity advantages is moderately relevant. The remaining two advantages have minimal relevance.
The AWP engine has three advantages. All three are performance advantages and all three are very relevant.
The PL engine has three advantages. All three are simplicity advantages with only one being moderately relevant. The remaining two advantages have minimal relevance.
The 3A engine has three advantages. All three are design compatibility advantages, and the relevance of each is minimal. Additionally, there are two performance advantages if the 3A head and intake manifold are used. Both of these advantages are very relevant.
The table on the following page is a comparison of the advantages for each engine.
Table 7: Comparison of Advantages for Each Engine
|
|
3A |
ABA |
9A |
PL |
AWP |
|
Advantages |
Designed for CIS fuel injected car |
Longer connecting rods |
Easy to work on |
Easy to work on |
5 valves per cylinder |
|
Intake manifold is correct orientation |
Oil sprayed directly under pistons |
Exhaust manifold not covered by intake manifold |
Exhaust manifold not covered by intake manifold |
Good torque through wide range of rpm |
|
|
Deck height is the same as stock |
Metal windage tray |
Engine swap takes less time with fewer problems |
Easy to locate |
Can be upgraded to 350+ hp |
|
|
Fuel injectors in Intake Manifold if 3A head and intake are used |
Fuel injection can be converted to Motronic |
Responds well to modifications |
|
|
|
|
Larger intake manifold runners if 3A head and intake are used |
Cylinder head has better air flow if ABA head is used |
Can be bored to 2.1L |
|||
|
|
Responds well to modifications |
|
|||
|
Can be bored to 2.2L
|
The types of disadvantages for each engine vary making it difficult to directly compare them. The disadvantages for each engine vary in type, amount, and relevance.
The PL engine has three disadvantages. All three are performance disadvantages and all three are very relevant.
The ABA engine has two disadvantages. One is a design compatibility disadvantage and the other is a structural disadvantage. Both disadvantages are moderately relevant.
The 9A engine also has two disadvantages. One is a cost disadvantage and the other is a simplicity disadvantage. The cost disadvantage is moderately relevant.
The 3A engine has one disadvantage. The disadvantage is structural and is moderately relevant.
The AWP engine also has one disadvantage. It is a simplicity disadvantage and is moderately relevant.
Table 8: Comparison of Disadvantages for Each Engine
|
|
3A |
ABA |
9A |
PL |
AWP |
|
Disadvantages |
Bore and Stroke aren’t as proportionate |
Exhaust component ground clearance |
Expensive to do performance upgrades |
Poor low-end torque |
Parts are not widely available |
|
|
Made with cheaper parts |
Hard to locate |
Requires high rpm to increase torque |
|
|
|
|
|
Does not respond well to performance upgrades
|
CONCLUSIONS
The 3A engine has the larger of the two displacement specifications, and the fuel injection system is the second to best type. It is one of two engines that are the second to least expensive, and has the lowest cost for the engine and necessary parts. The 3A is one of two engines having the smallest increase in cost for parts. It also has the least number of modifications needing to be made. The 3A is one of three engines with the least number of disadvantages with relevance.
The 3A is one of two engines having the least number of valves. It is also one of two engines having the lowest amount of horsepower and the second to lowest amount of torque. The 3A has the least number of advantages with relevance. It is one of two engines having the second to highest engine mileage.
The ABA engine has the larger of the two displacement specifications, and the fuel injection system is the best type. It is one of two engines that are the second to least expensive, and it has the second to lowest cost for the engine and necessary parts. The ABA is one of two engines having the smallest increase in cost for parts. It also has the second to least number of modifications needing to be made. The ABA has the most number of advantages with relevance. The engine mileage is the second to lowest.
The ABA is one of two engines having the least number of valves. It is also one of two engines having the lowest amount of horsepower and the second to lowest amount of torque. The ABA has the second to most number of disadvantages with relevance.
The 9A engine has the larger of the two displacement specifications, and the fuel injection system is the second to best type. It has the second to highest amount of horsepower and torque. It is one of two engines having the second to most number of valves. The 9A is one of three engines having the least number of disadvantages with relevance, and one of two engines having the second to most number of advantages with relevance.
The 9A is the second to most expensive engine, and has the second to highest cost for the engine and necessary parts. It is one of two engines having the second to largest increase in cost for parts. It is one of three engines having the most number of modifications needing to be made. The engine mileage is second to highest.
The PL is one of two engines having the second to most number of valves. It is also the least expensive engine.
The PL has the second to lowest amount of horsepower and the lowest amount of torque.
It has the smaller of the two displacement specifications and the fuel injection system is the worst type. It has the third to highest cost for the engine and necessary parts, and is one of two engines having the second to largest increase in cost for parts. It is also one of three engines having the most number of modifications needing to be made. The PL engine has the second to least number of advantages with relevance, and the most number of disadvantages with relevance. The engine mileage is the highest.
The AWP engine has the highest amount of horsepower and torque. It also has the most number of valves and the best type of fuel injection system. The AWP is one of two engines having the second to most number of advantages with relevance, and is one of three engines with the least number of disadvantages with relevance. The engine mileage is the lowest.
The AWP has the smaller of the two displacement specifications and is one of three engines having the most number of modifications needing to be made. The engine is the most expensive and it has the highest cost for the engine and necessary parts. It also has the largest increase in cost for parts.
Based on the conclusions in this report, the AWP engine is the best choice for an engine upgrade for your 1979 Scirocco. Even though the AWP is the most expensive, it offers the most increase in performance, in both horsepower and torque. It will also provide phenomenal low-end torque because of the wide range of rpm in which the peak torque is achieved. You also have the option of modifying it to increase the performance substantially. Because of the lightweight of the chassis in your Scirocco, the AWP will provide you with all the horsepower and torque you could ever need.
As a second, less expensive option, I would recommend the 9A. The 9A provides the second to most increase in performance, in both horsepower and torque.
For details on swapping the AWP engine into the A1 chassis, check out my engine swap pages.
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