ESP G340 vs OBR G340 reed

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Sean

The way I try to explain it to customers is you need to look at overall picture of a graph. These will be just made up numbers as an example. You look at a dyno graph and it making 12 hp. You see another one only making 10 hp. Now keep in mind a graph that looks like an upside down "V" is useless because power band is so narrow. We had a pipe we built once. Made the most power BUT the powerband was only like about 1000 rpm either way. So this means you fall off the powerband either side it takes forever to get backup to power again. Now if you have a power band that is more flatter looking. Yes it may not have the peak big number but you can have a more forgiving setup. Same thing with using a engine designed for topend only and you doing short course track racing. Yes. IF you have a long enough straight you can outpower the other guy. But. If it is a tight course or a lot of turns? More of a mid lowend engine may be better suited because of the flatter torque on pulling out of the corners. Think of your saws. Probably around maybe 8500 rpm or so is the norm with a powerband that you can bog on in heavy cuts. Now take same cutting but a motor designed for top end only. Unless you going to say keep it above 12500 rpm or so with light cuts. The first time you push it hard it will fall off pipe or muffler and be a dog. Than you have the pipe itself that comes into play. Topend pipe on torque engine or vice versa is not good. Has to be a package to work together optimumly. There of course is more on this kinda stuff but should be at least a rough idea. Using a dyno is fine. As long as the dyno is calibrated correctly. They will all read either same or really close. We had two other people who dynoed the same engine we sent to someone. Both were in totally different areas and elevations. One guy read 1 tenth higher and the other guy read 1 tenth lower than ours. They setup their way on calibrating the dynos. We had someone who ran an inertia dyno tell us how it made more power when you lightened the flywheel. He was on an inertia dyno where you spin the weight up and so much time will make so much power etc. When we asked if he recalibrated for the lightening of the flywheel? He got quiet when we told him it will of course show a power increase because it is spinning less weight quicker. BUT is still set for the heavier weight it had before. The other thing is rpm and where power is made. Let say 12 hp at 12,000 rpm and once you get into the over rev area you have 4 hp at 19,000 rpm. Now take an engine that makes 10hp but now has torque through whole powerband and had 8 hp at 19,000 rpm. It will be faster because you have more power available on topend and if you are never at the 12,000rpm area? Than the power there is useless to give up where you need it higher up. Keep in mind though that we make our engines and the cylinders also. So we can have the optimum in port layout compared to an industrial style engine. People ask me why I don't talk bad about the zen engines like they do about ours. That is fine but we do not knock them. They are built for something else and than modified and run really good. Where ours is purpose built. Plus if a customer asks me a question and I do not know the answer. I will just flat out tell them. I would rather someone think that guy doesn't know the answer. Than to BS the person and than them find out I had no clue. Better to say you don't know than to bs and than it is worse than just not knowing.
 
Last edited:
TODD said:
Sean

The way I try to explain it to customers is you need to look at overall picture of a graph. These will be just made up numbers as an example. You look at a dyno graph and it making 12 hp. You see another one only making 10 hp. Now keep in mind a graph that looks like an upside down "V" is useless because power band is so narrow. We had a pipe we built once. Made the most power BUT the powerband was only like about 1000 rpm either way. So this means you fall off the powerband either side it takes forever to get backup to power again. Now if you have a power band that is more flatter looking. Yes it may not have the peak big number but you can have a more forgiving setup. Same thing with using a engine designed for topend only and you doing short course track racing. Yes. IF you have a long enough straight you can outpower the other guy. But. If it is a tight course or a lot of turns? More of a mid lowend engine may be better suited because of the flatter torque on pulling out of the corners. Think of your saws. Probably around maybe 8500 rpm or so is the norm with a powerband that you can bog on in heavy cuts. Now take same cutting but a motor designed for top end only. Unless you going to say keep it above 12500 rpm or so with light cuts. The first time you push it hard it will fall off pipe or muffler and be a dog. Than you have the pipe itself that comes into play. Topend pipe on torque engine or vice versa is not good. Has to be a package to work together optimumly. There of course is more on this kinda stuff but should be at least a rough idea. Using a dyno is fine. As long as the dyno is calibrated correctly. They will all read either same or really close. We had two other people who dynoed the same engine we sent to someone. Both were in totally different areas and elevations. One guy read 1 tenth higher and the other guy read 1 tenth lower than ours. They setup their way on calibrating the dynos. We had someone who ran an inertia dyno tell us how it made more power when you lightened the flywheel. He was on an inertia dyno where you spin the weight up and so much time will make so much power etc. When we asked if he recalibrated for the lightening of the flywheel? He got quiet when we told him it will of course show a power increase because it is spinning less weight quicker. BUT is still set for the heavier weight it had before. The other thing is rpm and where power is made. Let say 12 hp at 12,000 rpm and once you get into the over rev area you have 4 hp at 19,000 rpm. Now take an engine that makes 10hp but now has torque through whole powerband and had 8 hp at 19,000 rpm. It will be faster because you have more power available on topend and if you are never at the 12,000rpm area? Than the power there is useless to give up where you need it higher up. Keep in mind though that we make our engines and the cylinders also. So we can have the optimum in port layout compared to an industrial style engine. People ask me why I don't talk bad about the zen engines like they do about ours. That is fine but we do not knock them. They are built for something else and than modified and run really good. Where ours is purpose built. Plus if a customer asks me a question and I do not know the answer. I will just flat out tell them. I would rather someone think that guy doesn't know the answer. Than to BS the person and than them find out I had no clue. Better to say you don't know than to bs and than it is worse than just not knowing.
Click to expand...
Right mate ??. Peaky engines suck. We build saws much the same way, shoot for long torque curve and the hp numbers kinda are what they are, of course the rpm range is quite a but different between a 40cc and 80cc but same principal applies. Thanks for the response mate, I think that cleared up a few things for me at least.
 
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