ESE's works engine tuner

[Muhr]

If i had free hands to alter some small things.
This is from my mind only, no calculations at all. =)
Look carefully, there are a couple of changes.

Attachment 335217

The v twin that I'm testing for will inevitably have longer intake to cylinder A. I also do not want to challenge foaming at this moment.
But yes it may be batter with a sorter intake.

[Frits Overmars]

If i had free hands to alter some small things....

I like your version Patrick. But why did you alter the lower part of the inner transfer duct curvatures?

[wobbly]

Two quick changes I would go with.
Get rid of the steps in the spigot, and the exit should match the header entry = Effective area of Ex ports total.
Water cool inside the transfer inner walls.

[SwePatrick]

I must say your version looks better Patrick. But why did you change the lower part of the inner transfer duct radius?

This is by experiance from 4stroke tuning, as i stated before one should be careful with to much taper in runners.
And, i have actually made good experiance from a small radius at the beginning of runners that are sitting in a pressurised enviroment.
Look at the runners in an Pro-stock V8(dragracing)
HUGE runners, but small radiouses.
These engines are making HUGE power per litre and the inlet manifold has actually a small pressure inside when in powerband.(ram effect)

Edit: ahh,, now your originalpost made it into this one =)
These prostock engines spit out about 1500-1600hp and has 8liters of displacement, if cylinders only fired every rotation they would be really really cool
A taper of 7 degrees is about maximum from my experiance.

[Muhr]

Two quick changes I would go with.
Get rid of the steps in the spigot, and the exit should match the header entry = Effective area of Ex ports total.
Water cool inside the transfer inner walls.

Tanks for the comments

I didn't get exactly how you ment.

The first 3mm is four machining.

I will take a lock at the transfer cooling.

[Haufen]

Look at the runners in an Pro-stock V8(dragracing)
HUGE runners, but small radiouses.
These engines are making HUGE power per litre and the inlet manifold has actually a small pressure inside when in powerband.(ram effect)

These prostock engines spit out about 1500-1600hp and has 8liters of displacement

200 hp per liter is only half way to a decent two-stroke, Patrick

So these engines are n/a engines and part of their power is due to intake resonance tuning?

[SwePatrick]

200 hp per liter is only half way to a decent two-stroke, Patrick

So these engines are n/a engines and part of their power is due to intake resonance tuning?

Yes, they have a plenum that becoming pressurised a little bit due to 'rejecting air mass' (RAM)
This is so important in those engines that they have some really weird setup on the engines bottom end, rod/stroke ratio at 1.5-1, so the deckheight of the engineblock doesn´t get to high, if getting to high the heads come more apart and thereby destroys the tune in the inletsystem.
They rev these engines ~10000.

Think about all this development gone into an twostroke 8 litre V8 that revs the same.
Could we say about 3500hp?(less frictionlosses due to less moving parts)

[wobbly]

Muhr, remodel the back face of the spigot such that it matches the cylinder, no steps.
And the exit of the spigot should be the same diameter as the header entrance.

[Muhr]

Muhr, remodel the back face of the spigot such that it matches the cylinder, no steps.
And the exit of the spigot should be the same diameter as the header entrance.

Ok got it! like a k9c

I saw some pictures on the RSA cylinder that made me interested in testing.

[Haufen]

Yes, they have a plenum that becoming pressurised a little bit due to 'rejecting air mass' (RAM)
This is so important in those engines that they have some really weird setup on the engines bottom end, rod/stroke ratio at 1.5-1, so the deckheight of the engineblock doesn´t get to high, if getting to high the heads come more apart and thereby destroys the tune in the inletsystem.
They rev these engines ~10000.

Think about all this development gone into an twostroke 8 litre V8 that revs the same.
Could we say about 3500hp?(less frictionlosses due to less moving parts)

Then maybe they don't have a bigger radius because this would move the effective resonance point out of ideal tune. And getting ideal distance and big bellmouthes is not possible because of space / design limitations etc. (or maybe just because nobody has tried yet). There are several papers out there describing the ideal bellmouth shape. And a small radius is not what one would look out for in this occasion.

these are fully grown bellmouthes for example
n/a F1 engine on dyno

(they really should make such videos for two-stroke people, too)

I like your idea about the V8 2S engine, although you'd probably have to throw in a couple more cylinders without supercharging to achieve these 3500 hp.

I think Muhr could increase the radius from the entry to the bore face. Seems to be quite small at the moment - if there is one. And as he is designing the cases by himself, he might be able to place the discvalve accordingly to allow for an ideal inlet tract length.

[katinas]

will be very interesting if this engine, you must give it a name..., does the same under load. im still not quite sure how the set up is even with pictures. is the crankcase still isolated from the cylinder barrel?

Under load.....I don't know, but like practice show, static tests like this, does not mean anything. For me, it was interesting to see, if that type scheme can work.
Now quickly pictured sketch on paper, maybe would be more simple to explain.

Yesterday video made with 1 scheme and Spec piston. Transfers ducts, from reed to A and B windows, is isolated from crankcase. C is isolated from reed and work like std transfer. So fresh mix flow to trans windows not from crankcase, but directly from carb. When piston moves up, A, B opens under piston, suction signal goes to carb and fresh mix flow in duct and some part fall in crankcase. What happening when piston moves down, actually is not clear, but maybe hotter fresh mix, return through A and B to trans duct, mix with cooler fresh gas mix from carb and when piston close A B on down stroke, this isolated space became like pressure chamber. When A B opens this pressure help to scavenge and C work in normal way. This is only considerations.

Even yesterday I was thinking that C placed in this way can help to start, bottom and mid. But last night I did not sleep, thinking about C.

Today change to 2 scheme. But first try Std piston. And was again very surprised. Revs to aprox 13500 rpm. with such short suction time.
https://www.youtube.com/watch?v=Qp_cDp3WQI8
When Std piston is at TDC, A and B opens just just ( attach image). And all suction is coming in a very short time, through the such small area. Maybe exhaust doing job but..... with Std piston, succeeded to start engine without reeds. Revs to 12000 rpm, but in a very very lazy way, not like on normal scavenge engine at hi revs without reeds. Strange why exhaust not help. Maybe reeds very important to this scheme.
With 2 scheme at BDC all gas under piston is pressurized and no way to go out. Its like spring under piston and maybe that helps much more than C in 1 scheme.

Tomorrow will try 2 scheme with Spec piston

[Muhr]

I think Muhr could increase the radius from the entry to the bore face. Seems to be quite small at the moment - if there is one. And as he is designing the cases by himself, he might be able to place the discvalve accordingly to allow for an ideal inlet tract length.

You are right there is no radios at the moment (was a bitch to lay something with the geometry the program can't work out)
Do you have any thoughts on ideal inlet tract length? (the problem with the V-twin engine is the cylinder offset of 21mm)

[jonny quest]

Attachment 335180Attachment 335176Attachment 335177Attachment 335178Attachment 335179Attachment 335181

If you want to beat NX4 with a NF4 try a 2004 cr125 cylinder with a PV. If you get out of the corners quicker you will beat them around the track.
Jerry Burgess and Doohan then Rossi did this for years.
Pray on the weak points of a NX4 rather tha try to replicate one.
Get yourself a decent carb
if moneys tight.A Keihin PWK38S (short body w/Power Jet)

of a KX250 the electric solenoid and tps arround 2001.

throw in a decent pipe and a VF3 Reed valve and a short intake
Spend the rest of some decent suspension.

https://www.tapatalk.com/groups/nsr2...rels-t414.html

Ask Wobbly about the rest he has given out the details on how to mod the mx carb.

Curious on what mods are done to the MX carb please

[Vannik]

Look at the runners in an Pro-stock V8(dragracing)
HUGE runners, but small radiouses.
These engines are making HUGE power per litre and the inlet manifold has actually a small pressure inside when in powerband.(ram effect)

The flow conditions are not the same - on the V8 inter-cylinder air stealing is a major issue and one of the reasons for the small radius.

[husaberg]

Curious on what mods are done to the MX carb please

Get rid of the air strikers reprofile it add a bell mouth to mimic the RS125 NX4 SPJ carb
Bend the PJ dohicky up to nearer the top. this is the dohicky in the bell mouth side.

I have the quote onfile from Wob somewhere on a word doc I will dig it up the describes the another mod.

When using a simple powerjet nozzle the tip position matters in that no flow will occur until the slide is well past the exit hole, and there is sufficient airflow

to drag fuel up the feed tube above the bowl level.
With the aftermarket add ons and the ones as used by Lectron you can shorten the dump tube so that the flow will only occur at high slide openings,as well as high air flow.
These also have a built in "lag "control in that it takes time for the fuel to rise up the tube and dump out the exit into the air stream.
With a solenoid controlled setup all this is pretty much irrelevant as the flow can only occur when the solenoid is not powered up, and this
is TPS as well as rpm dependant inside the ECU program..
The carbs as used on the MX bikes has the dump tube very low in the bore as they added and subtracted fuel at low slide positions in those bikes.
For a race engine I bend the tube up to around 1/2 bore, as this is where the exit is on the Kehin SPJ carb for RS125/RS250 Honda.
And the general setting is the solenoid is powered up ie no flow below 4000 and 60% TPS and is powered up again at around 12400 to lean off the mixture and increase revon.
This causes a problem with Ignitechs that are used with only a capacitor, as at startup the solenoid is powered up, dragging all the voltage out of the ECU, so I convert the ECU output
to a 3 step truth table, and have the setting such that below 1500rpm the solenoid isnt powered.

It might pay to bore out the 38mm carb a bit at that stage as well.
I am pretty sure the slide cutaway will need preprofiling for a 125 but the 2001 KX125 one should fit.
I haven't measured the body on the 36mm one. but it might just be the same body as the 38mm.
but someone would have to check. if it is the case it might be better starting with one of those.
I have a 38mm body here I am happy to measure. If someone has the 36mm version.

Here is the bowl of the Solenoid PJ carb, with brass tube added to keep the PJ siphon point underwater at the front.

The carbs of the MX bikes with the Powerjet and TPS all have the air guides in the bellmouth in front of the slide.

This kills a heap of flow compared to an SPJ, but does give good response down low ( worth a couple of Hp on a RS125 in the top end for example ).
The flow thing isnt really an issue for a bucket motor as they are only made in 36 and 38mm - so plenty big enough to get the flow back with area.
The SPJ will handle more downdraft due to the Powerjet fuel pickup point in the bowl.
The MX ones have an issue with this as the suction point is right at the back of the bowl and would not be under water if tipped up too far.
I posted a pic of the fix a while ago.

I have no idea why its splitting up wobs quotes but it will not edit it out.