ESE's works engine tuner

[JanBros]

No free lunch, any sort of activation device that changes the case vol is no different to a variable Ex port valve setup - not legal.
Same with the 24/7 reed concept, maybe they would allow a spring loaded open/close setup, but any form of servo that was rpm
driven, be it electrical or mechanical, is out.

I wasn't talking specificaly for stricly regulated kart engines, more generaly. for example in 125cc bike engines : the displacement of the piston is the limiting factor. having a device that controles the volume of the crankcase in the same way as an exhaust valve - so only working in different rev-ranges, like a controlable solenoid that makes the volume smaller or larger- should have been possible/permitted in GP125's ?

so at lower rev's a smaller crankcase volume that increases the crankcase preasure and lowers actual blowdown-time (as Frits says, there might be more blowdown than needed at low revs). anyone ever treid something like that ?

[peewee]

Are you using DC or AC?

there may be special tricks to weld alloys on DC but generally i think its welded on AC, thats what i was using anyways. use a inverter machine if you can, they have much more adjustability and arent much bigger than a home computer tower. for the exh port floor the balance was on 70% and HZ on 120. gas flow around 15cfh. about 5sec postflow. 50/50 AR/HE mix. started out with 3/32 2% ceriated tungsten but it fell out of the collet and burned up the collet so i went to 1/16 setup and it still seemed to work fine. originally i was using a gas cooled torch but it was a pain in the ass so i switched to watercooled torches

[TZ350]

page 1210 ........

Hi I have been reading all the info on this forum with interest for a few months now it really helps amateur engine and pipe builders like myself . I have an engine problem that I need help with , we race 3 kx 250 engines in the nz superkart series and for the past 6 months or so have been trying to diagnos an engine electrical miss at about 7000 rpm plus under acceleration . we did everything electrical you can think of and did most things more than once, finally not thinking that this would fix the problem we swapped the flywheel from another engine and the miss was gone . so then obviously needed another flywheel , ordered one on e-bay fitted to the engine that was now missing a flywheel [ie different engine from the one that had the original miss ] engine miss returns . flywheel has same partnumber , same dimensions and looks perfectly fine . ignition is ignitec , trigger coil and ignition coil wiring has all been separated . Can anyone offer an explaination I don't want to keep buying flywheels until I get one that works
cheers Richard

What is the diameter of the rotor and what is the trigger lobe length.
In reality the lobe length only needs to be as wide as the magnetic trigger pole.
If the lobe is too long the rising voltage waveform from the upward bump can decay to zero and give a false trigger signal
before the actual dropping edge has left the poles magnetic field.
Re electrical interference, of course you have resistor spark plugs and a resistor cap ( measure both to ensure the resistor element isnt fried ).
And the other trick is to tightly wind the two wires together from the trigger up to the ECU, by holding the ends in a battery drill and slowly winding it over.
This gives good common mode rejection of spurious noise.

I was using a similar setup i.e. KX125 rotor and pick up triggering an ignitech. We ground away the bulk of the lobe length, and closed up the gap between the pickup and lobe to as tight as could be achieved without causing interference. If the gap was opened up just slightly it would start to misfire at around 7k. Dump the original KX pickup (if that's what you are using) and buy one of the ignitech units.

Yep the lobe is too long - 1/2 its length and all will be fine.
I dont know if the KX trigger is shit, but I have never had any trouble with regular CR125/250 types.
The Ignitech one operates exactly the same as the Kokusan type Honda ones, nothing special at all.
There is an option under special setting called wide lobe, this is probably to suit exactly what you have, but I have never used it.

Strange. For the subject of kick-started engines I talked to Ignitech and they told me this:
"Hello,

You have make pulse lobe with lenght about 30 degrees. Surface, height and
width of pulse lobe must be homogenous.
We recommended to use pick-up IP6.

Regards.

Jiri Krejzl
IGNITECH"

My daily driver with ignitech has now exactly 30° of lobe lenght - and I am not able to adjust the idle where I want it to be. 3000RPM is as low as it gets.
On my RZ350 the lobe length seems to be shorter - and this engine has a nice idle.

So talking about the KX engine of karter4444: half of 30mm would be around 20° of lobe lenght. So would that be the general lenght you would recoment for a kickstarted engine?

And is there a base advance I should prefer?
cheers and thanks!
Tim

The length of the lobe makes no difference to the performance parameters of the Ignitech, except the issues we have seen
when it is too long.
Its the trailing edge position that triggers the spark event, but in some cases the leading edge is used to limit the total advance capability.
Below 300rpm the base timing is the default timing when the ecu first starts to supply a spark, above that the curve takes over.
You want enough base timing to enable ignition to occur early enough, but not so early that you can get "kick back " that can if bad enough
cause the engine to start backwards, or at the least break your leg.
I have found that 10 to 20* of base timing works fine in almost every case with a kickstarter.

Got engmod, wohoo!!
first of all; a HUGE thank you to Neels for the superb service and great product, and to all of you guys especially wobbly and TZ350 for making me aware of the software and it's capabilities, and sharing all the info!

Everything is working great, no hickups...exept for that I'm experiencing problems when trying to run simulations in turbulent mode (probably user error though...)

heres my combustion data:
Attachment 312733

heres a simulation running prescribed
Attachment 312734

and heres what happens(and other variations of wierd output) when I try to run turbulent, no change to the combustion data, just ticked of "turbulent".
Attachment 312735


What am I doing wrong?

Occasionally the turbulent model is affected incorrectly by the combustion parameters being out of range ie the duration goes over 100* ( usually squish related ) and
it all goes wrong.
Send a pack to Neels and he will be able to see the issue and advise.

Re the blowdown question - with a single Ex port you are always fighting a lack of blowdown STA, and this is where the only way to balance the power capability's of the transfers
with the Ex is to run the numbers thru an analysis program.
In general it is usually possible to get alot more transfer STA by widening them all to the max, whilst keeping them low to help the blow numbers without jacking up the Ex timing excessively.
Ski engines generally aren't limited badly by close bore centers creating shit transfer ducts, so concentrating on the area can reap good results.

I've got today to play around with this, however, for a wide power band is this mixture not the best ?

Lean at the bottom, this means engine runs hotter, (less fuel cooling) exhaust is therefore hotter so pipe looks shorter and closer to optimal and by the same reasoning, richer at the top means more cooling and temperatures lower and so pipe seems longer ?

I may make more power with changes but a wide band is what I'm after or a 6 speed gearbox.

Cheers Wallace

Completely opposite logic is needed - unless im reading you wrongly?.
Rich at the bottom to cool the pipe, making it appear longer for drive of slow corners, then lean at the top to get it to spin
up with the higher egt making the pipe shorter.

You are correct, just as well I checked. Brain fade.

With todays technology the bar can now be raised to around 40 crank Hp without too much drama involved, and thus achieving around 35 RWHp.
Its just a matter of careful parts selection and very careful assembly.

The alloy inserts for the TZ350 was the customers choice - once its all proven, and we get a handle on what the engine likes, then I will do some bronze ones.

AvGas in NZ is all LL100, this is low lead 100 octain.But the rating is defined differently in avaition.Its approx equiv to 100 "pump" gas, but has a lean rating of 100 and a rich rating of 130.
MNZ Appendix E defines avgas as max 112 MON amd max 108 RON.

Avgas, or any leaded "race" fuel reacts completely differently to unleaded pump gas.
In general terms the unleaded hates compression, but loves timing.Avgas is the opposite in that it makes more power up to the knock limit with more com.
Unleaded makes better power when run rich,avgas makes more the leaner you go.
Tuning in the old days with RS and TZ engines meant using lean mains and small powerjets ( 35 ) as turning off a big jet over the top would mean being too lean in the overev.
Nowdays the unleaded fuel runs rich at peak power, then uses a big powerjet ( 55) to create some heat in the pipe over the top.

Got an update from Neels, now turbulent works fine.

Newb question:
When using the numbers I got from turbulent, can I play around with ignition timing in prescribed mode, or do I have to run turbulent again everytime I change timing for a rpm point?

No, once you have saved and imported the turbulent combustion model, you can use that with changed timing numbers, saving it as a new file each time.

After a bit of fiddling I made some improvement.

What about the peak and overev power - the main/corrector system can hves just as much effect there as in the mid.

Only a part of the rev range shown. The whole range including overrev will show the total effect of the changes.

Very nice.I'll put that on my todo list.

I need to get my O2 sensor working consistently to do the top end. I was basically just trying to get the bottom end better as the 5 speed MX gearbox is not the best for the track.



My EGT only shows 950 at max power on the track so I still have some work to do. I'm hope the EGT is correct ? Ashburton's dyno shows close to 12.5:1 fuel air so I'm not sure why the temp is so low.

Maybe I need to do a bench calibration of the sensor and GPX Pro box. .

Wobby, is their any part of the conventional 2 stroke engine cycle which would concern the terms "choked flow" or "positive choked flow"?

You need to understand the real meaning of the term " choked flow " in relation to the 2T cycle first.
So read the paper I have attached, as this is the best I have seen on the science involved.
In reality most people have a misunderstanding of the effect,in that once the local gas velocity is sonic, no increase in VELOCITY can occur.
But , the mass flow rate CAN increase, under the conditions stated..



I went thru this exercise a while ago in relation to determining if sonic conditions occurred when using a nozzle in the Ex duct, or in the tailpipe.
Short answer is that if a normal sized venturi or duct/pipe restriction are used, the local velocity does not exceed Mach 1.
I found that in the sim ( where determining the local gas velocity at any point is trivial ) as soon as you approached sonic conditions, power went down dramatically.
From this I concluded that the energy required to create sonic flow is very high, and this appears to detract very quickly from the energy being used in the pipe for expansion,compression
and stuffing. My logic may be faulty, but the end result of sonic conditions for sure are not.

And one small point in relation to blowdown.
Port stagger, front to rear, uses the remnant blowdown pressure ratio at the transfer opening point, to affect the scavenging regime.
Remember, no flow can occur until the pressure ratio at the port face goes negative, thus until the pressure in the duct exceeds the cylinder pressure, flow will stall, or in a worst case
it will be reversed back down the transfer that opens first.
This short moment in crankshaft rotation, is enough to affect the distance traveled by each transfer stream in turn,and is why a KZ2 engine needs the A port opening first - as with no PV
it needs the " natural " effect of that regime to widen the powerband.
An Aprilia on the other hand uses reverse stagger, with the B/C ports opening first, that has the effect of boosting peak and overev power by its change in the scavenging pattern, along with the bigger STA
available from the wide B port being high as well.

You are on to it, knurling old pistons to take up the slack was the standard procedure back in the day. A knurled piston only needed half the clearance of an ordinary piston.

Attachment 312899 and Attachment 312903
Pretty sure TeeZee has already showin you can successfully glue the inside of a piston .....

Attachment 312902 Page 231

At Orbital, we used to centre pop new design pistons on a grid pattern, each centre pop creating a small mound of aluminium around the pop. Then it was run in an engine for a little bit at max power. Taken out, put on a Talyrond roundness measuring machine and the height of the mounds, relative to the surrounding surface was measured. Then, if the mounds were high, then a new profile was developed based on the profile of the heights. This was fed into a Takisawa camless piston turning CNC lathe and a new shape was produced. The goal was to be able to minimise the clearances for performance, durability and NVH reasons. Not completely perfect, but not too bad.

Re doing the piston shape - we finally got the shape right on the BSL by getting the pistons skirts HPC coated to give zero bore clearance.
Then ran them long enough for the hot piston shape to rub hard enough to wear away the coating.
This was then measured the same way as Ken did it with the results going back to Vertex to reprofile the next batch.
It took 3 goes before the shape of the new ( 59.6mm ) piston was perfect, as proven by the fact we could then warm up a new set with
one heat cycle in the pits - and then go race immediately - no running in at all.

[peewee]

got the exh hole and some of the roof filled up today. anybody know a easy way to tell if the manifold is regular or stainless steel ? its cr500 manifold im using and its highly magnetic. will probly expose it to water and see if rust forms.

[husaberg]

anybody know a easy way to tell if the manifold is regular or stainless steel ? its cr500 manifold im using and its highly magnetic. will probly expose it to water and see if rust forms.

http://www.google.co.nz/url?sa=t&rct...rZ4RvL2UGtSUeA

Spark testing......... is one way, note some high Chromium steels are still magnetic.

[Flettner]

I know how it's done, with a rocker arm ( Ryger ). As Frits said simple, piston and rod are one as we decided before but forget that complicated crank within a crank idea. Round conrod comes down through the "sealed off from oil" guide bush under the piston then terminates at a rocker arm. This arm is anckored at the area where the case reed used to be, there is a solid looking plate covering that hole that looks like it could be more than just a crank case seal, I think something is attached to it. The crankshaft could be connected to this rocker arm further down the fulcrum so the crankshaft stroke is less than 54mm. The problems with bigends are not so much combustion load but load from centripital force so less stroke, less centripital force at higher rpm, no problem with increaseing the combustion load ( leaverage from the arm ). The attachment to the case ( plate ) would need a small secondary linkege to allow for the fact that the lever arm pivots. This attachment linkage could be adjustable to make the piston move higher or lower in the cylinder ie low rpm or high rpm also having a useful effect on the compression and port timing, on the fly. Tell me I'm right!
And I still think they are using combustion pressure to " excite " the crankcase pressure at higher rpm where there is not enough blow down time and higher transfer pressure is needed, probably through a fine wire mesh to take out some of the combustion heat.

And done right you could have a fast / slow piston movement, like an old shaper, fast one way slower the other. Perhaps help with blowdown time?

To be fair, Ken Seeber was the one who noticed the thick alloy cover over the bottom reed housing.

[breezy]

I know how it's done, with a rocker arm ( Ryger ). As Frits said simple, piston and rod are one as we decided before but forget that complicated crank within a crank idea. Round conrod comes down through the "sealed off from oil" guide bush under the piston then terminates at a rocker arm. This arm is anckored at the area where the case reed used to be, there is a solid looking plate covering that hole that looks like it could be more than just a crank case seal, I think something is attached to it. The crankshaft could be connected to this rocker arm further down the fulcrum so the crankshaft stroke is less than 54mm. The problems with bigends are not so much combustion load but load from centripital force so less stroke, less centripital force at higher rpm, no problem with increaseing the combustion load ( leaverage from the arm ). The attachment to the case ( plate ) would need a small secondary linkege to allow for the fact that the lever arm pivots. This attachment linkage could be adjustable to make the piston move higher or lower in the cylinder ie low rpm or high rpm also having a useful effect on the compression and port timing, on the fly. Tell me I'm right!
And I still think they are using combustion pressure to " excite " the crankcase pressure at higher rpm where there is not enough blow down time and higher transfer pressure is needed, probably through a fine wire mesh to take out some of the combustion heat.

can you draw a picture of how you think the rocker turns crank wheels/ shafts.. sounds like the set up could look like a 4 stroke valve or desmodronic , with the valve face being the piston...

[breezy]

All credit for the Ryger engine should go to Harry Ryger, and Harry alone. I'd post a picture of the engine's spiritual father, but Harry prefers to stay in the background. Finding his photo on the world wide web may prove to be as difficult as finding the Ryger patents .

maybe RYGER is just the tradename?..."spiritual father"... is the original ideas man still with us? maybe ill get its eventually...

[Yow Ling]

I know how it's done, with a rocker arm ( Ryger ). As Frits said simple, piston and rod are one as we decided before but forget that complicated crank within a crank idea. Round conrod comes down through the "sealed off from oil" guide bush under the piston then terminates at a rocker arm. This arm is anckored at the area where the case reed used to be, there is a solid looking plate covering that hole that looks like it could be more than just a crank case seal, I think something is attached to it. The crankshaft could be connected to this rocker arm further down the fulcrum so the crankshaft stroke is less than 54mm. The problems with bigends are not so much combustion load but load from centripital force so less stroke, less centripital force at higher rpm, no problem with increaseing the combustion load ( leaverage from the arm ). The attachment to the case ( plate ) would need a small secondary linkege to allow for the fact that the lever arm pivots. This attachment linkage could be adjustable to make the piston move higher or lower in the cylinder ie low rpm or high rpm also having a useful effect on the compression and port timing, on the fly. Tell me I'm right!
And I still think they are using combustion pressure to " excite " the crankcase pressure at higher rpm where there is not enough blow down time and higher transfer pressure is needed, probably through a fine wire mesh to take out some of the combustion heat.

Frits has gone quiet, you must be close

[Larry Wiechman]

I envision a Watts linkage in place of a simple rocker; for true straight line motion.

[breezy]

Frits has gone quiet, you must be close

Frits is probably getting stuck into a big barrel of rum and raisen icecream laughing his ***ts off

[wobbly]

Peewee, you are of course going to be tig welding the inside of the steel spigot to grind and match it to the duct exit shape,
by making an oval to round transition - yes.

[TZ350]

Btw TZ any progress made with RGV cylinder?

No not a lot, pulled the old GP EFI motor out of the Beast to recondition it with the view of re fitting it to the new NSR chassis so as to continue the EFI development.



But the whole EFI project is taking to long, so instead of proving everything one step at a time I think I will just take a leap of faith and say the EFI will work and finish the RGV motor complete with the EFI and Plenum system.



Also been helping Chambers a little bit with his RG50 project.



Here is his RG50 cylinder with the 86% exhaust port after we ran it for 20-30 pulls or so on the dyno, looks good, we are aiming for 16-17 rwhp, near 14 is our best so from an RG50.

[sonic_v]

I know how it's done, with a rocker arm ( Ryger ). As Frits said simple, piston and rod are one as we decided before but forget that complicated crank within a crank idea. Round conrod comes down through the "sealed off from oil" guide bush under the piston then terminates at a rocker arm.

This would be even simpler.



http://www.marinediesels.info/Basics...ad_labeled.gif

[peewee]

Peewee, you are of course going to be tig welding the inside of the steel spigot to grind and match it to the duct exit shape,
by making an oval to round transition - yes.

weld the red areas was my plan. is the roof and floor of the manifold supposed to flat like the cylinder exit ? i was just going by how the rsa looked. from what i understand, stainless needs a different welding rod than regular steel. ive got some water on the manifold to see if any rust forms. worst case i may have to get a few different rods and see which one works