ESE's works engine tuner

[crbbt]

Quick question.

Will a single Det sensor pick up detonation on all cylinders in a multi cylinder engine?

I am planing on using a stud mounted sensor on the NX5.
I haven't found a two channel det sensor.
So I was going to mounted it to the cylinder which uses the leaner jet.

[41juergen]

Company April Sytems out of UK has a setup for 2 cylinder bikes...

[crbbt]

thank you!

[wobbly]

You can mount a det sensor on each head and run the signal wires to a 2 pole/2 position switch mounted on the bars or the dash.
The switch output then goes to det sensor input, means you can select what head to monitor.
Why are you running one cylinder leaner - it is alot better ( more power ) to change the ignition timing to end up with equal jetting, as the cause of the difference in the V Twin Yamaha engines is that
the case volumes are not the same , the intake lengths are different and the pipe shapes are also not the same.
In the 3YL/4DP it needs + 2* on the LH side.

[Tim Ey]

Why are you running one cylinder leaner - it is alot better ( more power ) to change the ignition timing to end up with equal jetting, as the cause of the difference in the V Twin Yamaha engines is that
the case volumes are not the same , the intake lengths are different and the pipe shapes are also not the same.
In the 3YL/4DP it needs + 2* on the LH side.

So which side has the longer intake and which side has the lower crankcase volume?

On the RGV250, the LH cylinder has the shorter inlet and the higher CR. Also 10 numbers higher mainjet.
So I assume you would increase ignition timing on the leaner side and adapt jetting?

[wobbly]

I dont think it matters what the cause of the jet split actually is - I decreased the timing by 1* on the RH side and it halved the EGT difference but power dropped.
So that direction wasnt optimum - I then reset the RH to zero and added 1* to the LH side , again that halved the split and power went up , and then with 2*added the EGT,s were around 10* different up to peak power
and they came together after PJ switching in the overev.
This need a small split of one size in PJ to get equal temps up the front side , and then equal EGT as before when they were switched off ( power on ) past peak.

[Grumph]

A guy I know spent hours equalising the case volumes on an '88 RS250.

Such is progress it's now possible to do effectively the same thing electronically.
And probably better.
thanks Wob.

[adegnes]

Wobbly, for peak power in a 50, how does reeds compare to RV with all clever reed-tricks applied?
I have a suspicion there's a point when going down in cc where friction cancels out the benefits of RV.
Wishful thinking maybe, it would be nice to not have the carb sticking out the side of the bike without having to resort to flappy belts or bevel gears.

Tried the 11yr Lagavulin Offerman? Not too bad! Then again it's hard to find a bad Lagavulin...

[crbbt]

I had never questioned why the jetting was different between the cylinders.

Looks like I'll be slotting one of the pick up!

or buying an expensive ignition

[koba]

I had never questioned why the jetting was different between the cylinders.

Looks like I'll be slotting one of the pick up!

or buying an expensive ignition

Buy a good ignition, in context this is very cheap.

[wobbly]

Two issues - in the case of reeds the crankcase volume is a " tuneable" element up to a point.
A bigger case ( and its associated Helmholtz frequency ) needs to be paired with a thinner petals higher 1st Mode frequency.
This works really well in that power rises , up to a point where the petals reduced stiffness in cantilevered bending causes loss of control at higher rpm
and then power drops - dramatically.

I tested this to death in the KZ , by making a small 1/2 moon cutouts in the petal sides up near the clamp, in 0.1 mm increments of depth.
With each subsequent increase in depth the now softer petal made more power everywhere - up to a depth of around 3mm/side.
At this point I had an extra 1.5 to 2 Hp up the front side and about 1 Hp at peak.
At 3.1mm depth suddenly the peak and overev power dropped hugely.
I now have a tape on gauge plate as a guide to the exactly correct depth to Dremmel.

At the same time as I was testing the petals I played with case volume by machining 5 mm off the reed block mount face on the case.
Running the now smaller case volume it lost power everywhere , and I only gained back 1/2 the loss by going 0.12mm thicker with the petals.
Then I went bigger in volume by adding a 10mm spacer plate - this lost power as well , so I started first with softer petals , then the side cutouts.
But it very soon hit the wall with reed flutter and I could never get back the power seen with a stock case volume.
That volume gave a ratio of exactly 1.3 - and so it seems that for a wide range of engine displacements that ratio is the baseline to start experimenting with.

The second issue is the superiority factor or Rotary Vs Reeds. Again I have tested this in a 125cc engine that was available in both configurations and had identical cylinder stud fixing.
After optimizing the Rotary with a carbon valve and using HPC friction coatings and CNC cut indentation cutouts on both the cover and case face , it ended up making around 3.5 Hp more than
the reed version after that to was optimized using the modified petals at 1.3 case volume.
The rotary ended up down at 1.22 case volume , and I went bigger by machining the case around the outsides of the flywheels to achieve 1.2 ratio but it then lost a bunch of front side
no matter what valve closing was used , so I had to machine a ring and weld it back into the case to get back to 1.22 ratio.
The rotary made just on 46 Hp at the time so it was about 7.5% better than I could achieve with the reed using the same cylinder and pipe.
I do wonder now if , using EngMod , I could optimize both and maybe get a closer result , but although I have developed better reed stuffers , and of course way better pipes, I think the newer elements
of pipe design would still put the rotary ahead by a desirable margin.

Thus in answer to the idea about ignoring different case volumes in a twin and reducing jet splits with timing changes - I believe that there will be an optimum case volume in each scenario
and using that will make more power than the compromise of changing the EGT by splitting the timing.
Other elements such as intake length and pipe configuration differences can be ameliorated way more easily by ignition fiddling.

Plus in a 50cc you are going to have to be reving it to at least 16,000 to gain maximum benefit of sonic tuning , and as usual I would bet the friction goes up as the square of rotational velocity.

[adegnes]

Thank you! What would the world be without you doing the 0.1mm reed cutting work.

I ran my (too)experimental engine with a timing belt primary to a jackshaft in place of the crank in an am6 engine on my inertia dyno.
2:1 primary gave 13.3hp, 1:1 gave about 6.
I did the runs in different gears to have the same acceleration of the roller.
Where did half the power go?
My guess is friction.
There's so little torque produced.
Peak power was at about 17k rpm.
26hp without the dual primaries? 😁

[Wos]

Alex Denges?

Which Material pairing do you have in your rotary valve?

There are so many diffrent coatings available today which reduce friction to 1/2

For example hard coatings that are filled with ptfe, graphite or MoS2 for steel or aluminium.

And many spray coatings for diffrent special use.

Finding optimum pairing and you can drop friction further more 😉

Good luck!! 😀

Grüße Wolfgang

[adegnes]

Alex Denges?

Which Material pairing do you have in your rotary valve?

There are so many diffrent coatings available today which reduce friction to 1/10

For example hard coatings that are filled with ptfe, graphite or MoS2 for steel or aluminium.

And many spray coatings for diffrent special use.

Finding optimum pairing and you can drop friction further more 😉

Good luck!! 😀

Grüße Wolfgang

Yep, that's me👍

I've mostly used carbon fiber in aluminium housing. With methanol/nitro I'll use steel valves from now on. Methanol leaches into the resin and softens it, happens pretty fast.

I'll do some coating research, thanks!

[Wos]

Alex,

Corrected my Statement down to a half, because lubricated conditions.

Ptfe to steel pairing is hard to beat with 0.04... dont know if dlc ( diamond like carbon) coated steel rv will bring further big advatages, cause the load is small, there are no abrassive conditions... i hope no sands or salt is involved!! 😉 😀
Are there signs of wear alex?

Surely carbon fibre is not best pairing to aluminium...fibres can be abrassive...frits and jan did a special coating of the case..

But maybe its better to coat rv and case...or searching for carbonfibre that is filled or coated with petfe...
Or do a complete insert of pure ptfe to the case...

Highly complex and interesting thing 😉

Grüße Wolfgang