Darrell Taylor wrote:MattsDad wrote:Sorry I don't really use or own standard pipes but hopefully will be doing an expansion comparison next week.
Its new engine build and not standard. Not welded, 57 stroke, Vespatronic, reed, centred head, and TM carb.
Its got packing options to make into a touring tune also so will graph that too.
Here's the torque which shows efficient bmep peaks so happy will that and more than surprised the pipe revs through this far:
just noticed on this graph of the lambretta dyno put on by accident that the correction factor is missing/cropped off the picture ,i took a look at the old rapido 42bhp post and found the correction factor shown is sae 1.21 whereas the vespa graphs are 0.96 / 97 which is more or less what uk weather corrects to fluctuating from min 0.95 to 1.05max
this means the power figure shown is inflated by 0.25 which corrects to a real figure of 31.34bhp be worth asking the dyno guy for a new graph with the the appropriate correction applied
if the original 26.31 graph was 0.97 and the 1.21 applied you,d see 32.8
figures arent perfectly calculated ive applied 25% for the 0.25 which is close
id presume the old graph at 26.31 was around a 0.97 correction
and new graph with new tune 31.34 with 0.97 correction applied so a healthy 4bhp increase all the same
Ive checked through my previous dyno graphs and you are correct Darrel the correction is either 0.97/0.98 with a correction of 1.21 on the 42 bhp graph , your conclusion tallys with my dyno results by Dan that my engine is only producing 33 bhp and 22 lbs tq , this also corresponds with my sprinting times/speeds. I will now have to go and read up on how dynos are set up so i dont have the wool pulled over my eyes again.