WuddupDoc Posted March 19, 2007 Report Share Posted March 19, 2007 is the modquad alumin impeller a good buy Quote Link to comment Share on other sites More sharing options...
blowit Posted March 19, 2007 Report Share Posted March 19, 2007 When I was screwing around monitoring a Banshee ening cooling circuit on a dyno I had thermocouples on the head at the coolant inlet and outlet, one over each cylinder, the water pump, under each cyclinder on the engine case, and at the base of each cooling jacket. Since I was on an engine dyno, I was running the house cooling system and not a Banshee radiator. Even with the house cooling system, engine still ran hot and had a very uneven heat rejection plume across the cylinders (the dyno cells also have heat sensitive IR cameras in them). As eluded to by Blowit, a spark ignited, gasoline fueled, engine performs at it's best on the verge of detonation and thermal run away. In other words, the engine is at it's best right before it blows up. The most intersting thing that I have learned with regard to heat management of two stroke engines is that with in reason it doesn't matter what the cooling system of the engine is doing as long as it keeps the engine from auto igniting, seizing, or similair. What does make a huge difference in power out put is the temperature at which you keep the crank chamber. As a general rule, the cooler the crank chamber is kept with the rest of the engine at normal operating temperature, the more power you will make. :geek: One thing we really push here is thermal coatings because it causes heat reflection and reduces convection of heat into the head so the heat is reflected back into the charge where it is better used and the overall engine temp is reduce drastically. We use coatings on much more than just the head though. By doing this we ensure that the dome is not super hot when the charge enters the chamber because the heat is carried away with with exhaust and not absorbed by the head. This allows for more compression without detonation. Flame head, that reminds me, have you played with nitro yet or what????? I used to play with it but at a rate of about 3oz per gallon. I know it pops fast and I did kill a motor with it but that was before some good testing equipment too. I can't help but love the stuff. Brandon Quote Link to comment Share on other sites More sharing options...
FireHead Posted March 19, 2007 Report Share Posted March 19, 2007 One thing we really push here is thermal coatings because it causes heat reflection and reduces convection of heat into the head so the heat is reflected back into the charge where it is better used and the overall engine temp is reduce drastically. We use coatings on much more than just the head though. By doing this we ensure that the dome is not super hot when the charge enters the chamber because the heat is carried away with with exhaust and not absorbed by the head. This allows for more compression without detonation. Flame head, that reminds me, have you played with nitro yet or what????? I used to play with it but at a rate of about 3oz per gallon. I know it pops fast and I did kill a motor with it but that was before some good testing equipment too. I can't help but love the stuff. Brandon Thermal barrier coatings can be very helpful. We use a variety of them depending on whats allowed in a given race series and/or where there is a noticeable performance benefit. The most common areas that we coat are the under side of the piston, the inside of exhaust components/turbos, and oil control compnents. I haven't run nitromethane in any oy Banshee engines yet for the same reasons that I am not running alcohol at the moment (it takes too much effort). We have had to run it at work for a few different projects. It's quite a different animal. Nitro reacts veyr differnetly than any other fuel to changes in combustion pressures among other things. If you are developing an engine to run on nitro you need to make sure that you have alot of extra rotating assemblies on hand. Quote Link to comment Share on other sites More sharing options...
blowit Posted March 19, 2007 Report Share Posted March 19, 2007 Thermal barrier coatings can be very helpful. We use a variety of them depending on whats allowed in a given race series and/or where there is a noticeable performance benefit. The most common areas that we coat are the under side of the piston, the inside of exhaust components/turbos, and oil control compnents. I haven't run nitromethane in any oy Banshee engines yet for the same reasons that I am not running alcohol at the moment (it takes too much effort). We have had to run it at work for a few different projects. It's quite a different animal. Nitro reacts veyr differnetly than any other fuel to changes in combustion pressures among other things. If you are developing an engine to run on nitro you need to make sure that you have alot of extra rotating assemblies on hand. Mine was not a crank killer, but a piston killer. Detonation and nasty. Now, I was also pushing the timing at the time so that did not help. I never did any numbers at the time but I know it needs ROOM because it pops very fast and can get down right forceful on parts. Maybe that is why I went through a wrist pin every few hours. I was making nice power but nothing NOS would not out-do. However, getting the right amount and not having to mess with a bottle would be nice. We have never probed out combustion pressured but I know that will be a must to tune for that stuff. I will have to look into that again. Brandon Quote Link to comment Share on other sites More sharing options...
FireHead Posted March 19, 2007 Report Share Posted March 19, 2007 Mine was not a crank killer, but a piston killer. Detonation and nasty. Now, I was also pushing the timing at the time so that did not help. I never did any numbers at the time but I know it needs ROOM because it pops very fast and can get down right forceful on parts. Maybe that is why I went through a wrist pin every few hours. I was making nice power but nothing NOS would not out-do. However, getting the right amount and not having to mess with a bottle would be nice. We have never probed out combustion pressured but I know that will be a must to tune for that stuff. I will have to look into that again. Brandon We lost everything from pistons to rods to crankshafts. All of our nitromethane work has been in support of teams in a couple of NHRA race classes. Nitromethane will auto ignite if you have even the smallest hot spot in the path of the intake charge. You also wind up some interesting exhaust fires after you lose a cylinder. We haven't done any work with NO that I have ever heard about, but then again I havonly been at my current job for three years. I am not sure how NO would perform versus nitromethane in a large format engine like we were working on. :geek: Quote Link to comment Share on other sites More sharing options...
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