VW Beetle Engines and performance parts - A guide for beginners

How do you start a beetle performance engine build

There are generally two approaches to the Beetle or Bug depending on what part of the world you are in. Apart from the granny down the road who bought her bug new and has maintained the stock standard 30 horsepower engine and has most or all of the original beetle trimming and brightwork, you now the one because you may have tried to buy it from her, there are either street and drag version of the beetle bug or there are concourse versions.

The concourse bug owner will generally not be satisfied if there is even a spec of dirt on the undercarriage and will spend the morning diapering the interior exterior and underside of his beetle for all to admire. There are usually a mixture of standard motors and some hot cal look engines around at the same VW day display.

The beetle owners who has mostly strip/street gear on his beetle is part of an endless quest to have the fastest quarter mile E.T in their respsective class form a variety of performance engine configurations. I have even seen some buses that scream off the starting line and ending up going like the clappers as they cross the quarter mile or eighth mile.

So which category do you fall into?

So, if there are so many different categories for the beetle engine to fall into, then how does one approach the build of a hot cal look beetle or how do you produce enough brake horse power to be competitive in a beetle.

The Beetle class at Santa Pod Raceway, consistently pushes the 8, 9 and 10 second boundaries. Can you imagine if Paul Walker handed Vin Diesel the keys to a 10 second beetle in the fast and the furious movie. Vins character would be in hysterics. However any beetle fan knows that a correctly built and tuned high performance beetle engine can draw some serious times and can comfortably beat a few supercars in the sprint to the quarter mile. These performance engines can push out any thing in the region of 100 to 300 brake horsepower.

So let us look at a few engine components that can be modified

There are 3 types of beetle engines that you can consider building

  1. The big bore high performance beetle engine.
  2. The Turbo Driven Beetle engine
  3. and The Nitrous Driven Beetle engine

All three of the above beetle engines can be built using a variety of custom components to end up with a completely different configuration to the beetle engine lined up next to it.

In all of the above types of beetle engines, the basic engine components will be the same save for the manufacturer and choice of specs used in the engine build.

Let us look at these components to get a better idea.

Please note that everything you find here can be read about and learned in more detail in the cheap How to handbooks below. Just clcik to view in more detail.

Keith Seume is a popular attendee at many beetle or bug race functions and calls UK his home. He has recntly returned form a trip to Southern California with his beloved cal look beetle called Bluey. As a writer for Ultra VW magazine and having been involved in beetle performance for close to 50 years, his books on performance engines are second to none.

Performance beetle engines

Beetle performance engines
Beetle performance engines

The Beetle Engine

The Beetle Engine, if you understand the basic working of the petrol engine, is a simple flat four engine with two sets of barrels and pistons on alternate sides of the crankcase.

Onto these barrels is a cylinder head on each side of the crank case holding the cam lifters and tappets with the ignition spark plugs. The inlet and exhaust ports enter and exit the cylinder head via the headers and intake maniflolds which hold the pump gas carburretors.

The crank case holds the assembly for the alternator and ignition system as well as oil cooling stack and air circulation sheet metal.

So, in essence if we want to deliver more horsepower from such a simple beetle engine that has no water cooling system and cools itself with oil and air circulation only, then we need to look at modifications to the crank case, heads, electrical and ignition system as well as assiting the gases to move more quickly in their processes.

So where do we start?

The Crankcase and crankshaft

The standard beetle 1600 crankcase was not designed for free flow oil cooling and circulation and as such, a hole would need to be machined to make provision for an oil flow pipe to be connected. The same would then apply to the sump whereby an extra deep sump and oil pickup kit can be installed.

Companies like Berg (of Gene Berg fame) produce a deep sump for a few extra quarts of oil which enables better cooling and lubrication.

Standard crankcases can handle a limited amount of machining to the sides depending on how big the increase in crank size will be as machining will need to take place to the webbing in the mold thereby weakening the strength and integrity of the crankcase walls. Autolinea provide a stronger crankcase for those looking for a pre engineeried crankcase for bigger performance engine components.

The crankcase will also house the camshaft in the upper section of the casing and there are many custom camshafts for beetle performance out there with Scat performance and Berg cams being the most popular. The camshaft will determine the open and closing times of the valves the allow fuel into the combustion chambers and the exhaust valves allowing the gases to exit after the mini explosion above the piston. This means that by adjusting the angles of the lobes will delay the valves and in turn allow custom methods of this explosion to take place depending on where one wants the telemetry of the pistons to be when forced back down for their next revolution (revs).

The Pistons, Rings, Bigend bearings and Rods

With the above in mind for your performance beetle engine, you will need to decide as to the type of piston kits to choose.

Mahle barrels and piston sets seem to be the most favoured as they produce a larger barrel than the standard set which enables machining to a wider bore for the barrels and limits heat exchange during running of the engine. Bigger barrels and pistons mean more surface area for these gases top explode in the combustion chamber which means more horse power. You get the picture.

There are a variety of pistons that one can choose from depending on the cylinder heads chosen and the barrels used. The rings will vary according to how much oil is need to coat the barrels and pistons, but is much of a muchnesses and has no real bearing if you are using performance pistons as they will come with a set of custom rings.

The big end bearings will need to be fitted to the crankshaft and as such some machining may be necessary to enable this depending on the piston rods used.They could be I -Rods or H-shaped Rods depending on clearance needed of the crankcase walls.

Building a performance beetle engine usually commands psitons sets in the 90 - 94 mm range for better compression.

Beetle Cylinder heads

 The most popular beetle heads used for performance engines are the CB performance 044 cylinder heads. In conjunction with the porting and polishing practices carried out by many performance engine builders, the valves and seats in the head will play an important role as this seal is the crux of the compression system. Using 37.5mm inlet and 42 mm exhaust valves is in my opinion the best configuration for performance cylinder heads on a beetle engine.

The compression is determined by the volume of fuel in the space between the piston and the valve deck area of the cylinder head, when the piston is at its top most position before returning towards the crankshaft end of the barrel whilst exhasut gases are omitted. Simultaneously, the other head will experience the next piston in the firing order approach its compression maximum. Some folks like to use Chevy valve springs for better valve movement.

Beetle turbos and electronic ignition sytems

Turbos are a regular feature on performance engines, but are complex in nature to install as you are forcing fuel mixtures into the firing chamber with added air intake via the turbine of the turbo. Wastegates and dump valves need to be consider as well as complex ECU installation programs and the electronic fuel injection systems incorporated into the mainfolds.

So in order to build a performance street or strip beetle

you will need to decide on a few simple options, then set about collecting up your components and slowly put it together in your spare time.

Below are a few other items of interest to add to your performance handbook. It covers all specifications and helpful hints to follow in the setup process before you stick the new performance motor on the dyno and test the new horsepower.

A word to the wise, put some serious thought to upgrading your drum brakes to a willwood or similar disc set on a beetle. You will apreciate the added stopping power.

How to modify a VW Bug,Beetle or Bus Engine for added performance

Comments 1 comment

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