ESE's works engine tuner

[F5 Dave]

So you are saying that high horsepower might not win on the track. . . .Well yeah, but as long as it wins on the internet surely that racing stuff is just secondary to the real sport.

[TZ350]

So you are saying that high horsepower might not win on the track. . . .Well yeah, but as long as it wins on the internet surely that racing stuff is just secondary to the real sport.

Yes, yes your quite right, that racing stuff is so ho hum , ones opinion of what the "The Real Sport is", depends on what your good at I suppose.

Winning in the workshop and on the internet, now that is an inteligent and skilled sport ........ top me if you can.

And todays internet fast bike is tommorows track winner in the right (not mine) hands.

So I am pleased to have played my part in it and to have shared what we are doing to get there so that other stroker nuts can enjoy the fun too, as we all strive to unseat the dominant 4-strokes.

[F5 Dave]

and so we move to the next logical technological battlefield where the old guard are no longer king; the photoshop dynochart warriors.

Run for your wives

[quallman1234]

Attachment 233003

Av doing the data capture while Keith runs up her 09 Honda RS on the dyno.

http://www.youtube.com/watch?v=2fTE6AfPbUg

Do we get a Dyno Graph along with that one .

[jasonu]

and so we move to the next logical technological battlefield where the old guard are no longer king; the photoshop dynochart warriors.

Run for your wives

Bit harsh mate...

BTW I have overlayed the dyno graphs posted from all of the recent 'big hp' bikes, both 2 stroke and coal burners and my 12 year old 24.8hp KE still looks good. Now with 4 more HP on top with the same spread it might be dangerous.

On a side note, I was recently in a discussion about 'dyno technique'. One side (me and other animals) say small bore bike ie buckets dyno runs should be done in 3rd or 4th gear, no higher, assuming a 6 spd box. Any higher and the clutch will get hammered and possibly (probably after a few runs) slip. I seem to remember both Green and TZ talking about 'dyno sessions cut short due to clutch slippage'. I am curious to know what gear they do their runs in and am betting they both use higher or even top gears. Also, a top gear run might tend to make the curve look better than it really is as the bike is slower to gain revs which makes the curve look less peaky.

Does the gear the run is done in affect the actual result and/or figures? I think not as the motor doesn't know or care what gear the box is in and will make the same power regardless of gear sellected. Any knowegable comments on this one? Wobbly?

[F5 Dave]

I always run 4th for small bikes.

Taller gears will load slower & may produce different carburetion characteristics & posibly temp differences, but a 1 run won't have anywhere near as difference as an all gears run. Theoretically you should be able to overlay your (whatever gear) curve over an AG run & often this is true, but some bikes cough a bit between changes & load up (big inlet timed piston porters or rotary valves) & this can change how the next gear runs through. It will also show up fueling starvation in higher gears, or worsening heat build up in piston/pipe of advanced timing.

I would be interested (not that I have one, just for interest sake) in Waynes take on rotary valve tuning for consistent performance through the gears, though maybe this isn't an issue except for desperate tuning with crappy old tech carbs.

[jasonu]

I always run 4th for small bikes.

Taller gears will load slower & may produce different carburetion characteristics & posibly temp differences, but a 1 run won't have anywhere near as difference as an all gears run. Theoretically you should be able to overlay your (whatever gear) curve over an AG run & often this is true, but some bikes cough a bit between changes & load up (big inlet timed piston porters or rotary valves) & this can change how the next gear runs through. It will also show up fueling starvation in higher gears, or worsening heat build up in piston/pipe of advanced timing.

I would be interested (not that I have one, just for interest sake) in Waynes take on rotary valve tuning for consistent performance through the gears, though maybe this isn't an issue except for desperate tuning with crappy old tech carbs.

Mostly agreed especially heat build up on top gear runs. If you do an overlay of course you will 1st have to replot each resulting curve on a
new graph so the graduations on the x and y axis are the same, especially if the runs are done in different gears and on different dynos.

[TZ350]

I have overlayed the dyno graphs posted from all of the recent 'big hp' bikes, both 2 stroke and coal burners and my 12 year old 24.8hp KE still looks good. Now with 4 more HP on top with the same spread it might be dangerous.

My point exactly, to be dangerous you don't have to have the most hp you need to have the right sort of hp (power spread).

On a side note, I was recently in a discussion about 'dyno technique'. One side (me and other animals) say small bore bike ie buckets dyno runs should be done in 3rd or 4th gear, no higher, assuming a 6 spd box.

Does the gear the run is done in affect the actual result and/or figures?

We realy don't know.

The GP has a 5 speed box, we have been doing our dyno runs in 4th as that is closest to 1:1 through the box and 5th is overdrive at 0.8:1.

I think the Dynojet we use was basically made for people who load a bike, push a few buttons rev it up and get a graph without knowing to much about the science of it.

Which is pretty much us at the moment, but we would like to know more about the pitfalls to look out for and good dyno techniques so we can make better dyno measurements, any positive input based on experiance is welcome.



My two engine setups compaired to Speedpros engine (green line). (red line runs were cut short as the vibration became excessive)

Another possible problem is that when you compair different bikes you also have to choose which one of the overall gear ratios to graph things with, I am not sure if this distorts things or not, but its possible.

[bucketracer]

..... just secondary to the real sport.

I am sure your right, there is only one true religion........ yours.

[wobbly]

Several points to consider.
The dyno load ( gear ratio) should be selected to simulate the end use.
ie do you want the thru the gears performance as seen at Mt Welly or pulling 6th gear for several seconds at Taupo, where you have a huge wind drag factor to push against.
Around a sprint track you can use way more timing and not see deto due to the short "power on" period.
But either way the heat soak in the pipe and case should be similar to what would be seen on the track.

The only reason that the clutch slips in the taller gears is because its a crap clutch pack and needs more plates or more spring to take the applied torque.

Re the rotary valve timing.The problem here is that every engine is different, with the case vol interacting with the timing and the carb length/size.
Basically when you exceed 140/88 you get finicky jetting and questionable power increases at the expense of drive down low.
Only way to define what is best is to leave the closing at say 88 and go from 135 up to 145 in 2* increments.
Stop or go back if no useable power is seen.
Then see if top end is lost by going back to 86/84 on the closing.

Graphing power Vs rpm takes the load out of the equation,but it is unrealistic to back to back a cold engine in 3rd, against a stinking hot all gear run up to 6th.
Not apples for apples.

[F5 Dave]

Thanks for the response. What do you think about high rpm coughs between gear changes? sometimes they appear on bikes with tame, well, not radical inlet durations (piston port & rotary).

[wobbly]

See this all the time in kart racing - reeds as well,usually its the needle/tube combo going lean as you pass thru 3/4 throttle, when backing off for the change.
Get an Ignitech on there and do full throttle shifts - easy.

[F5 Dave]

hmm, sounds plausible.
yeah I used to see it on my RG, 1/2 piston port, 1/2 case reed. I used to shift full throttle using the clutch, (had a 12deg baffle so it wouldn't go past 12,500), but sometimes it coughed like buggery. Sometimes, usually at the wrong time.

My next engine with same mx ignition, a substantially different pipe, similar inlet port, lower exhaust & higher transfers doesn't do it.

I've theorised but couldn't hand on heart say I've nailed why.

[wobbly]

Also happens when an engine is reved too far past peak power before a gear change.
The airflow drops in the overev, the carb goes lean and it will backfire as the change is made ( even using a speedshifter).
RS125 engines in karts do it with steep baffles, as soon as you rev them too hard.

[F5 Dave]

Now this makes more sense, my baffle taper is now 2 stage & less steep than previous setup. The engine used to brick wall so clearly the airflow was well out of sync at past power revs. Thinking more about it I'd developed this changing routine on the dyno with an all gears run as it appeared to give the least drop off on a peaky engine. And it worked most of the time, but I guess if borderline lean & a slow change & more revs than normal that it would occasionally cough. Often late in the race when everything was pretty hot.

I'd assumed in the ex side & thinking about it I can see how this may well stop the airflow, however the scavenging should continue. . . .hmm, been a busy day at werk so I may have to reflect on this later. But if the suction drops right off suddenly then for combustion to continue it still needs the correct mixture ratio, so what you say makes perfect sense. Thanks for the brain food. I'll have to digest.