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THUMP RRR RACING LLC was created by Peter Mitas after running into problems with  stock belt tensioners. He got in touch with his cousin also Peter Mitas, at High Precision Machine Shop in NJ, that is in business since 1987 with a fully equipped state of the art CNC and manual machines that he could very easily create a prototype part.

After designing, manufacturing and testing the prototype parts, we will go into production with the CNC machines.


After breaking a few stock tensioners and bending 2 arms of a certain billet tensioner I went down to New Jersey to visit my cousin who is a machinist with a goal of designing and building a better tensioner.

With Ron (94tbird) the broken tensioner king living 30 minutes away I invited him to come and provide his input in the design and build process. This also allowed us to test the tensioner for any fitments issues on a Kenne Bell equipped car.

The major difference with this tensioner over previous attempts is that it is designed exclusively for the S197 without the need for adapter plates and custom idlers.
The design uses a stock 8 rib idler pulley which gives you the flexibility to change idler diameters to fit your needs.

The tensioner uses the stock spring out of the factory S197 tensioner which will prevent overloading of the bearings of the various components of the system.

One of the improvements made on this tensioner is that the shaft has a 4340 hardened sleeve press fitted on the load bearing surface for the needle bearings to roll on.

After a marathon design and build session we had our first working prototype completed and tested on Sept. 23rd at island drag way on both Mine and Ron's cars.

After Ron split a Kenne Bell modified tensioner in 2 we installed the prototype on his car for some tough love.

Ron was able to power shift the car for the first time in a long time with no belt issues on his way to a new personal best.