Sunday, February 27, 2011
2/25-3/2 reengineering, updating dyno drive system. The big dyno starter drive is mounted to the high speed dyno drive shaft used by 99.99% of the engines we tune. From experience I know that the "blower" (Gates PowerGrip toothed) belt drive we to reduce absorber speed 33% is on the edge at 500+ HP (remember how we noticed it literally smoking hot after each of Justin Durand's Vmax 4 turbo dyno runs). So, we must on occasion remove the belt reduction and drive the dyno absorber at engine output shaft speed. But in doing so we lose the function of our electric starter.
Don Emery and Tommy McConkey are planning to come back with Tommy's big four cylinder radar run sled (they made the first 500+ HP dyno run here with n2o and have run 192mph with n2o). This time, they have made the engine bigger and stronger, and engaged turbo madman Gus Bohne to create a turbo system for this engine with hopes of even more power.
Since this huge engine has only pull-start, and will have to be run with the absorber at crank speed, I'm creating a high speed electric starter drive for the main drive shaft. This requires making some custom parts, and chasing around for a high speed automotive starter with the largest possible drive gear, hence the extended down time.
3/4 Andy Caffaro PS1000 Polaris
3/7 Ken Pielechowski PS800 SkiDoo
3/10 DNE, Tommy McConkey and Gus Bohne tuning Tommy's monster two stoke quad with huge turbo sysem, hoping for enough HP to add 10 mph to his 190mph radar run sled
3/11 Barry Britton & son, tuning two hilldrag sleds
3/13 (rescheduled) Polaris ProR 800 tested with Aaen, BMP, DynoPort, and SLP pipes (and PCV maps created where necessary). Then if we find good power improvement, Casey Mulkins will install the cylinder shim/ revised head again. finally great success with pipes/ shim kit! results posted!
3/15 Sean Dingman/ Todd Hogan SkiDoo 800 twin hilldragger
3/24 Dan Cerio tuning a Cat 1000 hilldragger
Thursday, February 03, 2011
DTR members have the greatest interest in HP upgrades for the ProR800 and Etec800! Where is the long awaited data?
We're still waiting for pipes to test on the ProR800--SLP is doing their flatland field testing this week before shipping, and BMP and DynoPort should be shipping their production stuff soon. As soon as we can get pipes from them, Casey Mulkis is ready to test a stocker, and one more time with the shim kit.
Billy Howard was scheduled to test stuff he's acquired for the Etec800 but his field testing on his long plowed snow strip has shown strange issues--one 1/4 mile blast with good acceleration, followed by another short blast with poor acceleration, underrevving. So we've put that session on hold until we figure out what is causing the grief. My pal Rusty from Rapid City SD is experiencing the same problem with his bone stock Etec800 at 6000 ft altitude. We're thinking now that it is exhaust temp creating this strange loss in power after some reasonable time at WOT. The probe in the muffler may be getting up to some temperature, and then the ECU drops the power level and causes underrevving. What causes the drop the power? Retarding the timing would only increase the ex temp, making the pipe even hotter. Adding fuel would even help Billy's sled, which is boarderline lean with the exhausts he's testing. So could they be lowering the exhaust valves slightly to choke off airflow? At any rate, Billy has eliminated the power dropoff by advancing his ignition timing with his buds computer. Rusty is planning to do the same with his stocker, and test it this weekend. Now, advancing the timing reduces exhaust temp (the fire stays inside the combustion chamber instead of blowing out the exhaust ports, hopefully making more cylinder pressure and torque), and maybe Billy advanced his enough to heep the muffler temp below the threshold temp. We'll know more about this phenomenon next week, and hope we can reschedule the Etec800 test session.