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| Explanation of Two Unique T 850 Class Rules & Why https://hpbc.ca/viewtopic.php?f=24&t=4650 |
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| Author: | Hounddog [ November 6th, 2024, 2:19 pm ] |
| Post subject: | Explanation of Two Unique T 850 Class Rules & Why |
It was very difficult to come up with a simple engine spec sheet for T Class because there were so many different combinations of boats and motors run by people who were interested in racing. The engine maximum displacement spec was easy. Maximum displacement would be 60 cubic inches. That size covered ALL of the motors. I didn’t change the title of the class from T850 to T1000 because of the UIM World Wide recognition for that class. I needed to make engine spec rules that would equalize the different motors performance so all these combinations would be equal. That was a challenge! The “yardstick “ motor was a 100% legal Yamaha 70CES. That was the most common motor raced in UIM T850 world wide and it held all the speed records for the class. Fortunately the 70CES we had in our group performed almost exactly to the record book T850 class records. The problem motor was the 56 cubic inch OMC. The fishing version under performed and the SST 60 version over performed the 70CES in actual race and testing. Both the 49 OMC and the 60 cubic inch mercury were very competitive with the 70CES. I decided to try different volume cylinder heads on the 56 OMC motors to see if I could improve the fishing motors and reduce the SST 60 performance. I was also mindful that I didn’t want to change any spec for the 49 omc, 70CES or the mercury 60 cubic inch. I wanted to keep the class stock and simple. I lucked out....if you ran a cylinder head that produced 150 psi compression on either motor. Both motors were competitive. And oddly enough both the 49 omc and 70CES had 150 psi. I presented my suggestion to the group. I explained that for this to work the motors would need to be stock other than the cylinder head. Internal port changes would change the compression. The group decided they would follow the rule, but, wanted it to be 160 psi not 150 psi. So that is where the 160 psi rule as added. I wanted T class to expand and allow newer motors into the class. I also worried one combination would dominate the class and that would reduce the number of entries. So the last rule was: The fair competition rule......no boat was allowed to dominate the class. The racers liked the rule and we never had to enforce it. That rule was removed a few years ago. |
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| Author: | Hounddog [ November 6th, 2024, 7:01 pm ] |
| Post subject: | Re: Explanation of Two Unique T 850 Class Rules & Why |
Another unique feature of T Class is it races in the Stock Outboard Division of CBF.. Prior classes raced in OPC division of CBF. I needed a title for the that fit the other classes that raced in stock outboard. So the T classes race under VPR. V Production Runabout In 2024 we had 10 entries in T850 and their races were very competitive and great to watch. In the past when be had entries in both T750 and T850 the total number of entries was between 15 and 20 per event. The current T group are working well together in promoting the class. They are encouraging more people to come out and try racing. |
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