The original TR-01 v1.0, v2.0 and v2.0 Baro from TwistedRotors set the standard for hand-held, digital, rotary engine compression testers. And now you can build your own!For 2017, in honor of the 50th Anniversary of Mazdas Rotary Engine and 20th year of SevenStock, I am releasing a DIY version of th... By: TwistedRotors