RS Honda power graph

This power graph is of three pipes tested during one session on the dyno, and there were no engine adjustments made and the spec was just as it finished its last race. We were very aware that the engine was running rich but was left as is. There are three graphs in all, the last one which I don`t have, shows the power after some adjustments to jetting then to ign settings to the “Abcon” made pipe!
The poorest performing pipe is the original Honda item, as can be seen it gives good power up to around 11,750rpm and 40.84 hp then falters badly.
The second best performer is the pipe that was in regular use and gave 41.59 hp at around 12,600rpm and is a Frank Wrathall made pipe. This is pretty good as it maintains its power reasonably from 12,000 to 12,700rpm.
The best performer is the one we provided the drawing for and Andy Bacon made for us. With over 40hp from 11,900 to 13,100 and a peak of 42.5hp it performs strongly.
The last session opened up a gap where the blue and red lines merge at 12,600 and pushed peak up by just .3 hp. This was achieved by taking some of the richness from the top end of the jetting range and a small adjustment to the ignition timing.
I posted this graph to show how important the correct pipe can be, and it`s not often that three pipes are shown on one print out.
The diffuser on the home conceived pipe is 34% of the T/L!
We now have direct correlation between all of the physical pipe dimensions of the three pipes and their respective power delivery characteristics. Set against this are the engine data and specifications. The way ahead now is a lot clearer, and for a very standard spec engine, although meticulously prepared by Steve, it is pretty damn good!

Trevor

I looked at these this am but, as usual, got sidetracked. However, the questions remained so I`m back again.
Why did Honda, with every possible facility and vast experience, manage to knock the power off in such a decisive way ? To prevent it breaking ? To enable a predictable maintenance regime ? To keep everything together in such a way as to make it reliable and rideable ? Or is it just out of date ?
I clicked on the title of the piece and up came a site of US serious go-faster goodies. Are any of these used in the chart ?
Is this device ridden in anger (competition) ? How does it do ?
I thought, as I grew older, this obsession with asking questions would fade. Still, they say that scepticism is the chastity of the intellect. Well, that`s my excuse. Terry.

Or, as Confucius said, "Chastity is but a bubble in the stream of life - one pr!ck and it's gone."

Isn`t philosophy wonderfully descriptive. Well. the way you use it. Terry

It's the way I tell 'em!

Thank you for the explanation which I can see. You`ll gather that most of my interest in almost any analyses is to find support or repudiation of my assumptions. I take the point about `Fast- anywhere`, hence my preoccupation with a specification that will enable the rider to be quick. Terry. p.s. Yes, I remember coming out of the hairpin on the Cadwell Club circuit now you mention three gears.

Great to see you are enjoying the Bantam forum, I bet you never imagined this would be happening in your septuagenarian years, Nothing like a bit of grey-cell stimulus to keep one fit and active.
We are all enjoying you contributions keep it up!

Trevor

Maybe sticking my neck out here but I´d suggest the torque curve -- not shown -- would tell another story relative which of the curves suited the rider....

Whoops!
I just saw the BMEP curve which is the same shape (as the torque courve) and does nicely for the point I´d like to make. Although that top curve -- Pipe A3 -- drops off drastically at the higher speeds   it is for the increasing speeds -- as one is accelertaing -- putting more tractive effort at the rear wheel than the others. Suitably geared the bike´s acceleration would make it the winner. The other two pipe curves might suit a race track with a very long straight -- like the old Snetterton´s Norwich straight -- where max speed for a major part of the lap nullifies the advantage of better acceleration.


I await brickbats or whatever they are....