Q&A Forum
I have found a Telma CC65 (4500 RPM / 479 ft lbs) that I plan to use to test air cooled VW motors. I expect to be under 7500 RPM and 250 ft lbs of torque at the flywheel, geared down to 4500 RPM at the retarder. This means the retarder will see 416 ft lbs. Would this retarder be big enough?
For an RPM sweep you will have no issues. For steady state, you could double check the max torque that the brake can take at the RPM your engine is at max torque. Do you have the torque curve for the brake?
I expect it will be fine, but of course it would be nice with a bit more margin.
I don't have the torque curve, just the max torque. I'm not expecting to do any steady state testing, but I also don't know enough about dyno tuning to really know for sure.
For a sweep RPM it will be fine for those VW engines. For steady state, it may take a bit longer to stabilize in those times where the RPM is higher than target RPM. The brake will then go to 100% and use a little time to slow down the engine to the target RPM. Also if you have turbo engines or any engine that abruptly changes power, you would want some margin because the RPM will not follow the target all the time.
In practice you should be completely fine for those VW engines!