ESE's works engine tuner

[katinas]

Rob, I found this video with Sr 50 DiTech max rpm, but maybe this is not a limit, because of cylinder/pipe/reed restrictions.
https://www.youtube.com/watch?v=1kj1rcnFDpo

If it is a limit for Ditech injection, so cylinder/pipe/reed must adapted for 6000 to 10000 rpm interval.

[jonny quest]

And then we have the pipe design aspect of a fuel injected engine where fuel is only above the piston.

Pipe will react the same on EO, but transfer opening... I think it would benefit from steep angles on header and diffuser.

What are your thoughts?

TZ350, the Ditech uses high fuel pressure, along with an air injector in head. They actually run really well when the multitude of harmonious fuel and air delivery system is working properly.

[Frits Overmars]

Frits, maybe this is of interest?
Attachment 346442

It is, thank you Neels

[jfn2]

Neels, what is the little curlique at the bottom of the ground electrode in the first diagram?

[Vannik]

Neels, what is the little curlique at the bottom of the ground electrode in the first diagram?

I have no idea, I assume it is a shadow as it does not show up anywhere else in the thesis.

[TZ350]

TZ350, the Ditech uses high fuel pressure, along with an air injector in head. They actually run really well when the multitude of harmonious fuel and air delivery system is working properly.

I don't doubt they run really well. I have seen Video of the Ditech and it looks very good. But real God's given "Time" is their enemy and limits their possible RPM compared to a carburetor engine.

I think there is no amount of mechanical or pipe design that can make any more real "Time" for direct injection to get things done. This "Time" limit is much less of a problem with B port injection and B port engines can more than compete with carburetor engines for outright performance and RPM.

https://youtu.be/wUleM_8LoP4

https://youtu.be/aIyDOmalP1U

A standard Ditech runs up to about 8,000 rpm and surprisingly, un restricted to about 10,000 which is good but I think about their limit. A single injector also limits things to 10,000 RPM or less. Simply because an injector small enough to allow good low speed tuning becomes to small to get things done in the limited "Time" available at higher RPM. A really well tuned B port injected or carburetor-ed 50 should run 15,000 RPM. 50% more RPM 50% more power possibility.

Currently my carburetor 50 only manages 12,000 RPM ( a better pipe might improve that). My B port EFI 110cc engine with the right fueling and ignition curve can run to 14,000 rpm which is a truly frightening experience. When I am standing beside it on the dyno at full noise I am acutely aware its con-rod comes from an old RD400.

[jfn2]

Thank you Neels:
Does this mean that a it is better to have a pin ground electrode rather then a ground electrode with a small hole drilled into its' center? Did the thesis say what the pin length should be?

[Wos]

Thank you Neels:
Does this mean that a it is better to have a pin ground electrode rather then a ground electrode with a small hole drilled into its' center? Did the thesis say what the pin length should be?

There are double iridium on the marked...with pin of iridium on the mass electrode ...or from beru ...with embedded iridium in the mass electrode. ..

Advantage should be higher livetime with more constant gap

[Vannik]

Thank you Neels:
Does this mean that a it is better to have a pin ground electrode rather then a ground electrode with a small hole drilled into its' center? Did the thesis say what the pin length should be?

I must still work my way through the thesis, its name is in the name of the picture, do a search and download it.

[katinas]

http://autosign.ps/brand-item/ngk-spark-plugs/ Interesting Cross slit type for rotary engine

[katinas]

I think it would benefit from steep angles on header and diffuser.

.

The easiest way would be to adapt two radically different existing race pipes from 50/65 cc, just correct header length for 6000- 10000 rpm. and see reactions.
As air is little easier to catch up to exhaust than mix, maybe more shallow angle is needed for front part of the pipe and steeper baffle. But maybe I am wrong.

With direct intake to transfers tests, simultaneously tried four different exhaust pipes.
Honda Rs copy (stainless 0.8 mm 121mm belly),
Aprilia Rsw simplifier copy (stainless 0.8 mm 128 mm belly),
Sugaya (specifically developed for this engine cylinder port dimensions, steel 0.8 mm 105 mm belly and longest)
BMB kart (steel 1mm 121 mm belly)
BMB kart modified (steel 1mm with baffle from stainless 1 mm 121 mm belly)

Honda and Aprilia both works in the good way, difference is just that Honda pipe always has sharper character from 10500 to 11500 rpm., but stops little earlier than Aprilia. Until 8000 rpm Aprilia pipe feels little stronger and fells more linear through rev range on this reed type engine.
But they both works very well and for this engine, after so many back to back tests still can't say which is more appropriate. Same was with RGV 250 engine, modified to 1 cylinder . Aprilia and Honda pipes was winners overall.

With BMB pipe engine revs highest, until 15000 rpm, but max power is lower than with Aprilia and Honda. Baffle is the same like on Honda, and whole pipe is more straight and accurate welded. Tried to extend header with 22 mm and 44 mm insert. With 22 mm engine stops at 13800 rpm, with 44 mm at 12500 rpm, but in both case max power was again lower than with 0,8 mm stainless Honda and Aprilia. is the barrier, the rise and fall time of the temperature is longer for BMB 1 mm steel , but maybe barrier is different oscillation amplitude of 0,8 mm sheet. On the second BMB pipe I will try to do baffle from 0.8 mm stainless.

[wobbly]

The kart pipes with the perforated reverse cone are specifically designed not to generate peak power , but rev like hell , with a very flat torque curve - as you discovered.
Lengthening the header will lower the peak rpm , but then the pipe proportions will be wrong , and anyway it still wont make any better peak power.
The only reason to use this design would be if you had a 4 speed gearbox , or no gears at all , like the karts the pipe design came from.

[katinas]

Thank you Wob.
I expected such a reaction from BMB pipe with a perforated part. So decide to cut rear perforated cone with outer cylindrical part and made usual rear cone from 1 mm stainless, with expectation to lose the bottom, but increase the top power.
Results, lower bottom and only just a little better top.
I have another, the same BMB pipe, so this time I will try to make thinner 0.8 mm rear cone see if there will be a difference.

Add dyno with exhaust pipes. BMB is modified, with usual rear cone.

[jonny quest]

Do you have the tuned lengths of the pipes Katrina's?

I enjoy reading your posts. Are you retired, and just enjoy playing with your toys? Or do you just not sleep?

[wobbly]

The best sparkplug for a racing 2T engine is the NGK R7376 - or the exact same plug with a short ceramic body designed for the RS125/250 from HRC - but you pay more for the cap than the plug itself.
Thats a R7282 ( A - being the longer thread version for use with a deto ring sensor ).
This was determined by a very detailed dyno session comparing many 10 range plugs all at one time.
The worst was a BR10EGV , next was the Denso version as was the later part number from Honda , then the best was R7376/R7282, same same.
All were resistor plugs , as my dyno goes spastic without them , as do the digital ECUs used on racebikes.

These NGK race plugs have a very small Irridium center electrode , and a fine wire Platinum ground ( mass , as I see others using ) electrode.
They are expensive due to the very small batch numbers , plus the special nose ceramic , special resistor element , and the fine wire mass electrode is laser welded.
Never , ever , had one fail .
The power difference best to worst , was 0.75 to 1.5 Hp - with the Denso almost exactly in the middle.

Frits , your Devil impersonation is well noted , but as NGK and Brisk plugs with huge sized ground electrodes are already confirmed as legal , having the nose flush with the chamber and then a small upstand
with the Platinum wire hanging off that , would be an easy argument to win in any Tech situation.

Machining the R7282A is easy to do with a rotating chuck 4th axis CNC , so I am having some done now.