ESE's works engine tuner

[TZ350]

Don't undervalue the engine so much, sometimes new technology promises but needs time to grow before it makes a worthy difference. example: graphene

Not under valuing the engine, just all the shit that those involved spouted.

That is right, not undervaluing the engine and the effort that has gone into it at all.

It is the smoke and mirrors and doubtful truths trying to promote it that has attracted all the derision. The reporting has not been transparent at all but more in the style of a sales promotion that has not stood up to even a cursory evaluation. We can see through bullshit and call it out for what it is, but a bit of truth about success and failures would get us all on side and cheering the Ryger team on.

We would all love the Ryger concept to be a success.

[guyhockley]

Not a bucket, but in the same spirit, I think...
https://www.facebook.com/groups/Suzu...9896881716202/

[TZ350]

Not a bucket, but in the same spirit, I think...

https://www.facebook.com/groups/Suzukiracing2strokes/permalink/1249896881716202/

Absolutely, great build.

[Nath88]

The exhaust pressure sensor I was using died by drowning in exhaust oil, so it motivated me to rig up the new exhaust pulse sensor for a test.



Green line is the exhaust pulse, rate of change of pressure. Red lines are the sample window (ECU takes the lowest value inside this window). White lines are the trigger wheel teeth as the crank rotates. There's 20 teeth on the wheel, first tooth is at 72°BTDC. Primary exhaust pulse hits the sensor at around tooth 11 (126°). On this trace we see 2 firing primary pulses followed by a misfire pulse, caused by a throttle blip at 2400rpm, however engine speed increases an unknown amount over the 3 rotations. Either way the pipe is way out of sync with the engine at these revs. I later tweaked the sample window from 30 to 45 degrees duration to properly catch the pulses.

I also took the bike to the dyno, it was running too rich, perhaps due to the dead sensor, maybe some other factors. Made 45hp on the dynojet, sounded rich all the way through but the curve was pretty consistent with carb 2 strokes, maybe a bit stronger coming onto the pipe. I'll scan the chart at some point and post it.

[peewee]

We run R7376-10 plug in everything and its been working great !

Nitro carrying a healthy dose of oxygen , makes the mix as much if not more rich tolerant . Setting the engine very rich also take care of a lot of temperature and atmospheric pressure fluctuation .

Regarding compression ratio , your application being far from my scope of expertise , I wont advise anything . The idea behind reducing the comp ratio is mostly because of the low octane rating of nitro . As stated earlier in this thread , at high rpm the octane needed lowers trendemously wich is probably another reason why we can get away with such high nitro percentage and comp .

im finding out that having the carb well on the rich side is the way to go. leaning it out like a petrol engine would be a huge mistake i think

whats the advantage to r7376 ? from what i understand , it has the electrode and ground strap inside the plug body and not protruding into the head chamber. is this the advantage over a standard plug ?

top fuel cars are around 7:1 com ratio from what ive read. i always thought the low ratio was because the huge volume of liquid in the cylinder but the low octane of 90% nitro makes sense

[wobbly]

The R7376 has a fine wire Iridium center electrode, and a very thin Platinum ground strap.
This combination dramatically reduces the voltage necessary to ionize the gap, and unshrouds this gap as well.
The Platinum electrode is laser welded to the body, and unlike plenty of " normal " race plugs I have never seen one drop off from deto damage.
Same with the ceramic insulator,never seen one crack, again seen plenty of cracked ones in things like ordinary cheap Iridium plugs.
You can learn plenty from the colour change position along the thin ground straps length.
This plug is exactly the same nose configuration as the original shorty plugs designed for the Honda RS125/250, but is less than 1/4 the price.
Plus it has a normal body shape and doesn't need the idiot priced special plug caps that cost more than the plug.
All race engines deserve this plug - nothing else comes close as far as reliability and power capability.
I have posted a dyno run on here previously showing the power advantage over everything else, including the Denso equivalent.

[koenich]

there you go: https://www.kiwibiker.co.nz/forums/s...highlight=7376 (scroll down a bit for the dyno graph)

After Wobblys post I bought a R7376 for my 50cc racer and they brought quite some improvements on the track. Driveability improved, midrange "bog" was eliminated, overrev behavior improved and they seem to last forever (I have one with 50+ hours on it and it's still working like a charm). Only issue in rain races when not revved hard all the time the R7376 tends to clock up faster than a BR10.

[Frits Overmars]

Sounds like we're in the same boat concerning nitro...

Here's hoping it doesn't dissolve duct tape .

[Frits Overmars]

Green line is the exhaust pulse, rate of change of pressure. Red lines are the sample window (ECU takes the lowest value inside this window). White lines are the trigger wheel teeth as the crank rotates. There's 20 teeth on the wheel, first tooth is at 72°BTDC. Primary exhaust pulse hits the sensor at around tooth 11 (126°). On this trace we see 2 firing primary pulses followed by a misfire pulse, caused by a throttle blip at 2400rpm

That looks very promising Nathan .

[Lbracing]

As promised , a couple pictures of what I do .

Pistons are machined out of 4032 . From 50cc to 140cc .

Cylinder with removable transfer port cover . Intake is controled by piston port . You cant really see it but the exhaust port floor is a nice convex shape . 5TH port is fed by a hole in piston , I am working on a better set up for my next engine .

Carburetor is based on walbro wb diaphragm for spacing reasons . Maximum venturi I can put in them with this design is 34mm . I use them on everything under 100cc .

Just a random toroidal shaped head in the works.

[nitro2tfx]

😂
That's interesting, I've experienced the same bogging. It goes away if I apply the choke, but the weird thing is with the choke on it acts leaner and idles high. Maybe the fuel part of the pwk choke circuit needs drilling too.

The bogging is because the crankcase is loading up with fuel. When you open the throttle after a period of idling the engine goes super rich as it picks up a bunch of fuel from the crankcase as well as from the carb. Rev it up and blip the throttle to clear it out, first. Could take a few seconds or more.

Applying the choke makes the engine go lean because the choke circuit is only rich enough for gas. It is a leaning circuit on a methanol/nitro mix and an excellent way to get a runaway engine, especially at startup when you are in neutral.

[nitro2tfx]

top fuel cars are around 7:1 com ratio from what ive read. i always thought the low ratio was because the huge volume of liquid in the cylinder but the low octane of 90% nitro makes sense

Top fuel cars are highly supercharged and actually run lower compression ratios than that.

Naturally aspirated nitro engines, running straight nitro from the can (no methanol), run compression ratios of 11 to 12:1 and do not experience any detonation, despite the very large displacement and low revs, compared to the engines being discussed in this thread.

[SwePatrick]

The bogging is because the crankcase is loading up with fuel. When you open the throttle after a period of idling the engine goes super rich as it picks up a bunch of fuel from the crankcase as well as from the carb. Rev it up and blip the throttle to clear it out, first. Could take a few seconds or more.

Applying the choke makes the engine go lean because the choke circuit is only rich enough for gas. It is a leaning circuit on a methanol/nitro mix and an excellent way to get a runaway engine, especially at startup when you are in neutral.

Correct!

Already with methanol only you get same effect with having choke pulled to long.
But one can use it for faster warmup, let it 'sniff' on the runaway for a while.
Then engine is more responsive quicker due to heat has started to build faster inside cylinder.
I noticed if starting engine with no choke it spits unburnt fuel through the tailpipe for a long time.
Using choke shorten this a lot.

I also noticed that the mixture it gave as much power as possible on, is way to rich on a cold engine.
Somewhat 'other way around' then a petrol engine =)

Start without choke, pull up the choke, let it touch the runaway, press down choke again.
I gained a lot of time doing this, also saved fuel

A Methanol and/or Nitro could do really well with a termoregulated radiator also.
As it need heat to burn everything properly.
If not having heat, the mixture it produces max power with is actually keeping it from getting warm fast.
Can be really frustrating with dragracing, the engine must produce power quickly.

I did actually a experiment on my dyno.
I pulled through the gears, started on 1st with cold engine.
On 1st it gave only ~46hp
And for every gear the power raised.
On 5th gear i had 68Hp, that´s actually 22hp loss at the most important place in dragracing,, the start.

Pipetemp does also play a part in this, but it is much much more noticable with methanol.

Another experiment i did was to reduce powerjet to get it to warm up faster.
I did nine 5th gear pulls in a row.
And when i saw the exhausttemp raise i turned out the powerjet again.
And yes,. it gained power.

I dunno actually if it was vaporization or fuel actually releases it´s oxygen when engine is in desired working temp.
But it needs more fuel when it´s hot =)

[adegnes]

As promised , a couple pictures of what I do .

Pistons are machined out of 4032 . From 50cc to 140cc .

Cylinder with removable transfer port cover . Intake is controled by piston port . You cant really see it but the exhaust port floor is a nice convex shape . 5TH port is fed by a hole in piston , I am working on a better set up for my next engine .

Carburetor is based on walbro wb diaphragm for spacing reasons . Maximum venturi I can put in them with this design is 34mm . I use them on everything under 100cc .

Just a random toroidal shaped head in the works.

Nice work!

The bogging is because the crankcase is loading up with fuel. When you open the throttle after a period of idling the engine goes super rich as it picks up a bunch of fuel from the crankcase as well as from the carb. Rev it up and blip the throttle to clear it out, first. Could take a few seconds or more.

Applying the choke makes the engine go lean because the choke circuit is only rich enough for gas. It is a leaning circuit on a methanol/nitro mix and an excellent way to get a runaway engine, especially at startup when you are in neutral.

Correct!

Already with methanol only you get same effect with having choke pulled to long.
But one can use it for faster warmup, let it 'sniff' on the runaway for a while.
Then engine is more responsive quicker due to heat has started to build faster inside cylinder.
I noticed if starting engine with no choke it spits unburnt fuel through the tailpipe for a long time.
Using choke shorten this a lot.

I also noticed that the mixture it gave as much power as possible on, is way to rich on a cold engine.
Somewhat 'other way around' then a petrol engine =)

Start without choke, pull up the choke, let it touch the runaway, press down choke again.
I gained a lot of time doing this, also saved fuel

Thanks! Makes sense.

[jbiplane]

Thank you for the interesting information. I earlier got some assistance to make a series of simulations to better understand the airflow paths through a "RSW type" engine (cause I find in general somewhat difficult to fully understand the (dynamical) flow through a two stroke). I would have liked to make them dynamical with a full piston movement, but the circumstances at the time did not allow this. I have a quite new contact with a Ph.D. in CFD calculations. I will discuss this topic with him to see if I there is a possibility to continue somehow. It also depends on the time he is willing to give me on this, because to buy in these kind of simulations is very expensive, you will hardly get a calculation start up under 5000EUR. I cannot give any time schedule on this. However, if and when, I find out something that could be to some use for anyone here, I will share. At the moment I do not know any better source than you presented Valery, I'm afraid.

Thank Norman, Frits and others. I found here many interesting ideas. We are small company which works like "engine atelier" for small aircrafts, UAV and other applicarion where weight and fuel economy are vital. To the moment numerous codes like ~bimotion ~mota ~Ricardo Wave ~Lotus concept
gives irreal results on boxer 2-strokes engines I produce. So one of my present objectives is to make parametric CAD model linked with CFD simulation of 2-stroke engine complete from intake to exhaust. I believe will sucseed in ~4+ month by myself and understand what have to be changed.