Engine capacity and HP produced

The following is an update by WW on the CorvairListServe August 2011. It adds additional information to the development of the 2850cc and 3100cc engines he and the All Stars have developed. His text edited for length and topic focus. The original can be obtained from the List Serve archives. Edited WW text follows:

There are three categories of engine builds that people are currently working on:

• 2700cc group, which includes .020 over to .060" over bores. (Called 100HP engines.) This is the engine that 75% of builders are working on. If run up to 3500 rpm, this engine will produce slightly more than 100HP.
  
• 2850cc engines, called 110HP engines. These engines are built around a piston set I sell and which use the Clarks new HD cylinders bored .105" over. This is the largest displacement that can be run without boring out the case for larger cylinders. About 10% of new engines being built are 2850's.
• 3000cc engines, called 120HP engines. ( 3100cc engines are also in this power category). A 3000cc engine has a 92mm bore and uses a purpose built pistion that is sold by Mark Petz, Brother Roy, DanWeseman and myself. 3100cc engines were built around a modified VW 94mm piston and cylinder sets. They work well, but the 3000 is how we idealized the large displacement engine given a clean sheet of paper to work with after we got away from using a piston based on a VW design. A 3000cc engine has a much better basic compression ratio and does not require custom length pushrods and modification to the Corvair's connecting rods. There are many well known flying 3100 engines, Like Mark langfords KR2, Joe Hortons KR2, Dan Wesemans Cleanex, and Andy Elliot's 601XL. For the last two years, all the 120HP engines the 'Corvair all stars' have built are 3000's not 3100's. The 3000's have lower basic compression which should work better with 91 octane car fuel over 100LL, which is becoming more expensive. A 3000 cc engine in a Pietenpol run at 2900 rpm maximum, will probably yield slightly less than 120 hp.

Keywords

2850cc engine, 3100cc engine