Some Facts about Type 1 Air Cooled Engine?
As you might know by now, there are a lot of myths, miss information and outdated information about the VW air cooled power plant. You will find there is allot information available on the VW air cooled power plant, with hardly any data to back there findings.
We have taking the time, to give the customer some insight. This information was written, on behalf of the daily customer questions we answer. Please use this information as guidance towards building your air cooled type 1 engine, based on naturally aspirated conditions.The Air cooled engine is what we at DRD have studied for over 30+ years, with real world testing, and development.
This article has been broken down into a few sections, and not wanting to get into allot technical terms and data, that the reader will have a hard time understanding.
What is your power plant going to be used for?
There becomes a line were engine life and power meet. The more power the engine makes, the more the engine will wear parts out. Heat also plays a big part on engine life. We at DRD look at a few basic states of tune on an engine.
A: Daily driver, low state of tune, dependable, good power output. 60-130hp.
B: Performance Street engine, Medium state of tune, good power output, up to 160HP.
C: Weekend Warrior, part time driver, High state of tune, 200hp+. It is not uncommon to have 200+hp pump gas engines running around on the streets today.
D: On all vw aircooled engines, the cylinder heads will need to service around every 20-30 kmiles of service. Due to the design of the engine, the cylinder heads take some abuse. thermal expansion will cause parts to move around.
With the three states of tune, you can see were you fit in with your engine project. In todays time, 99% of our customer base, are using there vehicle as a weekend hobby vehicle.
Basically what dictates the power in the engine, is the cylinder heads, carbs, and camshaft. All Engines are air pumps, and the more air the engine can pump, the more fuel they burn, in turn making torque. Notice we have mention torque, torque is what pulls mass, and hp is derived off torque. Also to note, there are limitations with pump gas, and safe compression ratios, depending were you are located in the world, the quality of fuel varies. The fuel quality currently available at the gas station, is a far cry from what the gas was 10 years ago,
We at DRD have broken our engine program down to 2 engines.
1914cc, 69mm stroke X 94mm bore, and the 2276cc, 82mm stroke X 94mm bore. We feel these 2 engine sizes give the best bang for the dollar hands down. These engines also are the same width as a stock engine, so sheet metal and parts fit correctly. Early sedans have very narrow engine bays, and these engines will fit with out cutting the engine bay up.
The 1914 engine can be tailored to make 130hp, 130 lb tq, with the right combination of parts. Dual carbs are a must, along with a good set of heads and the proper cam. For the person on a limited budget, this is the way to go for sure. Compression ratios around 8.0 to 9.0 around work very well on these engines, and they will have an excellent power band if built correctly.
The 2276 engine can be tailored to make 140hp on up 200hp, 180 lb tq, with the right combination. Dual carbs are a must, along with a good set of heads and the proper cam. Compression and cam play a huge role in extracting the power from these large engines. Compression ratios around 8.0 to 9.0 work very well on these engines,with power levels up to 180hp with an excellent power band if built correctly. Add more compression and cam, and now you can produce more power, say 9.5 to 10.00 compression, will bring the power up to 200hp, these engines will produce more heat, in turn reducing the life of engine parts.
We strongly don’t recommend stroker cranks of 74-76-78mm. These cranks will require cylinder shims under the cylinders to obtain correct deck height, and leave the piston not properly supported at bottom dead center of rotation. Also to note, these types of engines will get wider, and sheet metal fitment will be a problem, along with fitting a wider engine in early sedans.
We say that there is no substitute for displacement.
There are many combinations of bore and stroke, but we like to say, build it as big as you can.
Also remember, the power is in a good set of heads, and high flowing cfm numbers from heads are not always the best solution for providing torque. A well balanced set of heads, with CFM and air velocity make excellent torque, and make a very efficient running engine. Also the key to making an engine live is, proper oil temperatures, along with proper head temperatures, without controlling these temperatures, the engine will degrade, and will burn itself up very fast.
Has modern technology improved the air cooled cooled engine?
We as world, have access to modern design and development technology. The tools available today, make engine performance development a game changer for sure. What was current practice 10 to 30 years ago, is history now. The VW type 1 engine platform today, is 100% dominated by new aftermarket parts.
New oem vw engine parts are not available anymore. Over the past 5-10 years, almost all of the oem vw engine parts, crankshafts, heads and cases ect, we inspected, have been worn to there life service limits. These oem parts have not been made for some 40+ years, and have been in operation most of the years. With aftermarket parts available today, most new parts meet or exceed oem specs. We at DRD strongly recommend using new parts. Why use a rebuilt part , not knowing it’s past history or failure? Oem German parts are thing of the past.
When sourcing out your engine build, you best bet is to purchase parts from a company that has the tools and machines in house to provide you with parts and technical info. Anyone can sell you a part, but companies that machine parts in house, have dyno’s and flow benches and measurement equipment, can prove there work, and are separated from the rest of the bolt together engine companies. As we say, you have engine assemblers, and engine builders. Anyone can bolt parts together, shops that have tools and machines, have fully control on there product, know what works, and how to make it work.
We highly support , customers to build there own engine, there is nothing like saying you built your engine yourself !