ESE's works engine tuner

[wobbly]

Well if you melted an engine when using egt , all that says is you were not using them correctly at all.
But the answer about the deto system is that it is adjustable to a preset amount of sensitivity , that will light up several led's to show deto onset , that then has a huge red light the instant
real deto starts.
So plenty of time to back out of it , before damage.
But in the case where you get deto onset , the egt has already flatlined or started to suddenly drop , so why do you need another gauge to ignore.

[husaberg]

Well if you melted an engine when using egt , all that says is were not using them correctly at all.

But in the case where you get deto onset , the egt has already flatlined or started to suddenly drop , so why do you need another gauge to ignore.

What would be the appropriate corect temps for AC and LC engines.

[wobbly]

How long is a piece of string.
You have Yamaha KT100 on 91 petrol that run at 650*C all day.
Then you have a Banshee that will melt @ 600*C on 110 race gas.
No such thing as any guideline as to what an engine will make max power at , nor what egt it will detonate at.

But a real simple guide is that when starting rich , the egt will rise at a near constant rate per jet size , say 20*C per jet.
As you lean down , suddenly the egt may only rise 5* or not at all , that is onset deto , so back out real quick and go back to safety.
On the dyno its very easy to watch the egt during the run , and you quickly recognize the telltale sign of the egt rise , slowing down , and power will stop rising as well.

All this assumes you are using exposed tip egt probes that are on the header centerline - running enclosed short things only 10mm into the header is a complete waste of time.

[F5 Dave]

Works great bolted to watercooled stuff. Air-cooled may be harder to achieve. And its already 'ringing'. That may cause issues.

[aljaxon]

to be fair these were too cheap to expect to be accurate, the needles were all over the place. i did insert the probes into the centre of the header and 150mm from cylinder exit. but i soon stopped watching them as they were a waste of time. i was told to watch out for a drop in temp as the early warning. but every time i opened the throttle the temp dropped. fresh charge in the pipes?
only left them fitted on the bike for show raised eyebrows at cafes etc.

i do have decent spark plug washer sensor fed temp gauges and they let me know when im getting hottish and i keep my eye on those. have them fitted to a few of my 2 strokes.

but i would love a deto sensor. only thing is i reckon i would need to initiate deto first, eg advancing the ignition etc to calibrate them? so as to have a reference point?

and F5 Dave i didnt quite understand the already ringing = Air-cooled may be harder to achieve. And its already 'ringing'. That may cause issues.
you mean the noise on a worn aircooled motor? i rebore once ive got piston slap so might not be an issue for me.

[F5 Dave]

The fins themselves vibrate. It is measuring a piezo sensor for knock shock. Can it ignore the fin vibration? Especially as - where do you mount it?

[wobbly]

Gauges with needles are useless on a 2T , they sample so slowly and react even slower that as you say the thing has seized before the sensor had realized what's happening and told the world.
Aircooled is irrelevant , the background " noise " of an engine is nothing even remotely like the frequency and amplitude signal of deto events.
You initially calibrate the gauge ( with the sensor under a head stud , or I have even clamped one to the frame fitting boss on the back of a CR125 head ) and rev/blip the shit out of the thing.
When set overly sensitive the background mechanical clatter will light up a couple of the lower 5 indicator lights , turn it down a bit and its done.
You know its set right when under full throttle load against the brakes or up a hill , the lowest indicators flicker.
Then the instant deto starts a couple more lights come up , then actual deto "shock " causes the big red warning LED to flash - REAL bright.

Here is a Bosch sensor fitted to a TM on my dyno

[Rudex]

Hi Wobbly,

Can you share tips to measure correctly one pipe built?. Normally I measure the short and lenght inside and outside of each pie cuts. But later the angles doesnt fit perfectly and it is difficult to draw in cad.

For example, in kart pipes, in FIA papers you can check the measures but How do you draw in cad the values to fit correclty?.

Regards.

[wobbly]

Thats easy to draw out from the CIK papers. Each line with inside and outside dimensions , plus the cut length , represents a straight cone that has been cut at an angle.
Thus if you draw that angled cut in CAD and extend the shorter length past that cut , then draw a new line thru the mid point of the cut perpendicular
to the cone centerline , that will give you the straight cone dimensions and the cone angle.
The only thing to be aware of is that often the first few cuts are not shown as inside and outside dimensions correctly , as the pipe is bent upwards , not around the corner.
Also all CIK dimensions are outside.
EDIT - sorry I forgot to add the straight line length to the sketch .

[Pagi]

Just for info I discovered Avejas is advertising his deto knock sensor box again on Ebay - havnt seen it for ages.
Ive used dozens of the things for over 10 years , they work perfectly.
You can order the 0-5V output for data logging - as well as add an ouput that shorts to ground when deto is happening.
This is great with an Ignitech input that retards a setable amount when its grounded.
The Bosch sensor with an 8mm hole can be got for nothing from wreakers or new on Ebay as well.


https://www.ebay.com/itm/18573910441...3Avlp_homepage

Wobbly,

do you mean this BOSCH sensor : https://www.ebay.com/itm/31495361952...DC9ZG9NE21KJER

[Rudex]

Thats easy to draw out from the CIK papers. Each line with inside and outside dimensions , plus the cut length , represents a straight cone that has been cut at an angle.
Thus if you draw that angled cut in CAD and extend the shorter length past that cut , then draw a new line thru the mid point of the cut perpendicular
to the cone centerline , that will give you the straight cone dimensions and the cone angle.
The only thing to be aware of is that often the first few cuts are not shown as inside and outside dimensions correctly , as the pipe is bent upwards , not around the corner.
Also all CIK dimensions are outside.
EDIT - sorry I forgot to add the straight line length to the sketch .

Thanks Wobbly!.

If i understood well, You first draw the vertical line = 47.48mm , perpendicular line to this line (axis), the 65mm and 57.47mm inside and outside dimensions and the outside diameter. Maintain the program without restriction only symmetry between each side dimensions to maintain the same angle of both, and then you get the angle of cone. If I would want the straight cone get perpendicular line from center point. Like i did in example. The pie cue is 6.7º cut and 14.8º of input output angle.

This is easy in program like Fusion 360 or solidwork, in Autocad is a bit difficult.

If the pie cut is angled in the input and output I suppose it would be similar. Am I right?.

Yes, I know CIK diameters are outside, I get only the data like example. With a real pipe with several pie cuts (in header harder) is no easy to get the real dimensions. that's why I ask for tips.

[ken seeber]

None of this big 50 cc or huge 125 cc stuff, just 35 cc, in this case for RC gas racing.
Not my project at all, but got the ok to post a couple of pics. Cast using 3D printed sand moulds.
Features pretty much "state of the art" transfers and exhaust ports and passages. It did get help from you know who, but no C port as it is piston ported.
This engine features a detonation free piston material.

[lohring]

I love it. Where can I get one? By the way, I drew a piston ported engine with a C port. Is t better? I have no idea.

Lohring Miller

[Frits Overmars]

I drew a piston ported engine with a C port. Is t better? I have no idea.

It looks nice. But won't it require rather long piston skirt sides that may get in the way of the transfer duct entries?

[lohring]

The skirt gets cut away except in the intake area. The bottom of the intake port is above the transfer entry. See the cylinder below that has a lot milder port setup. I'll do a drawing to check.

Lohring Miller