ESE's works engine tuner

[Moooools]

You are right, good point, and from the sound of the bike, it did seem to be way over rich there.

With it finaly swapping over injectors as planned, today felt like a great step foreword ......

Now I need to spend some time dialing it in.

Nice. Looking forward to further updates.

[TZ350]

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Avgas will kill any O2-sensor; pump fuel mixed with two-stroke oil will in theory do the same, but if you take care to heat the sensor to working temperature before starting the engine, and provided the sensor is not too close to the cylinder so it won't be hit by washed-through mixture, the sensor will last a long time.

I can hardly imagine that with the right injection timing you can avoid fuel entering the exhaust, certainly not over the entire rev range.
In order to make real power, the pipe needs to receive and subsequently push back about 40% of the cylinder capacity and I do not think you can separate air and fuel to such a degree that no fuel will enter the pipe. But in order to keep the sensor clean it will have to be fitted well away from the cylinder anyway.
At the end of the day it all depends on how the injection system is instructed to handle the various sensor signals.

http://www.vemssupport.com/forum/ind...opic,97.0.html

Before calibrating an engine, it is first useful to have some concept of what you are trying to control. The following is a fairly brief overview of the internal combustion engine, which will hopefully give you a basic understanding of some fundamental principles and terminology, so that when you change a number in a box on your laptop, you have some idea of the effect it is having on the engine.

""Fuelling Theory ... Lets start with the theory then. We are concerned with spark ignition gasoline engines here. I am only going to cover gasoline, since Diesel is for trucks and diggers, and alcohol is for drinking and drag racing.""

http://195.159.109.134/vemsuk/forum/...opic,97.0.html

Attachment 292539

There is good news and bad news.

The good news is, that after 40 liters of fuel and hours on the dyno the exhaust port dam and Belzona epoxy are still there and I am starting to get somewhere with setting up the EFI. The Beast idles at 3000 rpm and I can snap the throttle open to 100% and it will pull away very nicely.

Fiddled with the ignition and fueling but it it still detos around peak torque. The good/bad news is, my recent problems with the EFI look to have been pretty much self inflicted. I just checked the port timing and the exhaust and transfers are opening way to early and I am beginning to suspect that the compression is way to high for the fuel too, I will check that next.

Attachment 292558

OK its humble pie time, turns out I am responsible for most of my problems with getting the EFI going.



Not only has the port timing been way out with the Ex opening at 70 deg ATDC and Transfers 110, when they should have been Ex 80 and Trans 115.

Attachment 292559

I had to go and stuff up the compression ratio too, at 16:1 swept it was never going to work.

Attachment 292555

After changing the barrel this squashed plug was a clue about the compression ratio being to high.

Over compression and wrong port timing have been the biggest source of my problems all along and my only excuse is that the motor must have been rushed together after a few drinks on a Friday night in a fit of enthusiasm to start playing with the Ecotrons EFI kit.

I guess if I had of been working with something more familiar like an OKO carb I would have twigged that there was something fundamentally wrong with the motor much earlier.

Fitted a new barrel with exhaust at 72% wide and opening 80 deg ATDC, Transfers open 114 ATDC, Inlet Opens 145 BTDC Closes 70 ATDC and Std head.

Attachment 292556

Adjusting the fuel curve and ignition is real easy now, just requires time and a bit of patience. This is a really rough first cut but I expect to be able to polish it up nicely.

Attachment 292557

The blue line is after a couple of runs to improve the pickup.

I am starting to feel optimistic.

Tonight's effort. The Beast is starting to snarl and it will pull away in top gear on the dyno from 3500rpm and WOT, try that with your carburetor.

Attachment 292749

Red line is the best ever using a carb with this old cylinder and the Blue line is where I am at with fuel injection. In all fairness for a proper comparison it needs a proper head (the old head suited a dished piston) the original ignition map and chamber and a generator for the EFI. But I am pretty excited about the Ecotrons fuel injection system as its starting to be very easy to work with.

I think this EFI business is going to work out OK.

Me myself and i would like to see a bit more of the design process esp around the crankcases patterns

First I harvest the relevant information Yamaha left for me in their cases, shaft centers etc, X , Y and Z co-ordanence. Usually done in the manual milling machine.



Then imput data into the computer that runs the CNC.



Then apply cut paths and tools and do the job on the computer screen long before it gets to the CNC.



Glue suitable bits of board together



Press the button on the CNC, shut the door and wait.



Just like that, well it's not quite that simple but you get the picture. I program the computer to put taper on everything and also can tell it to account for shrinkage so the casting ends up the right size ( casting will end up smaller than the pattern ).

Rules:
Solo motorcycles shall have two engine capacity classes:
F4
2 stroke 55-100cc
2 stroke 55-125cc air cooled
4 stroke 55-150cc
F5
2 stroke 0-50cc
4 stroke 0-100cc air cooled

The maximum capacity for rebored engines shall be:
F4
2 stroke 55-100cc - 104cc
2 stroke 55-125cc air cooled - 130.5cc
4 stroke 55-150cc – 158.09cc
F5
2 stroke 0-50cc - 53cc
4 stroke 0-100cc - 104cc

In any badly tuned 2T you can easily get readings over 1300*F and survive,ONLY if the setup is not optimal. If the com is too low for the fuel, or if the timing is overly retarded, then the excess heat produced late in the combustion cycle is dumped into the pipe and thus alot less is soaked into the piston. But just the mere fact the engine did survive that insane abuse, points to the fact that the setup is nowhere near correct.

It still amazes me though that people have gauges on the bike, skid around the track, see death numbers on the screen then ride back to the pit and tell everyone about what just happened. Why is the gauge there ? To help tune the engine,but what if the com was perfect and the timing dialled in correctly on a dyno. The same rider would then do several laps - watching the temps scream past 1250, lock it up at the end of the straight - THEN come in and say " I saw 1300 and shit ive siezed it, bastard thing".

If a correctly setup engine cannot be held under 1200*F by the jetting, then it should be richened immediately so that it can be. THEN, go down one size at a time and approx 50* rise should occur for each change, shooting for a max on AvGas of 1250*F.

If the change produces less than 50* delta in egt then that indicates that you are approaching deto rather than making more power from the extra heat of combustion.

The opposite is true as well, if more than 50* is seen with 1 jet leaner, then you can be sure the setup is not correct for the fuel and a heap of unused heat is being dumped into the pipe.

But, using excess fuel to cool the combustion process will not make anywhere near the actual power available ,if the ignition and com was optimised.

This means as a general rule for a fast watercooled 125 cylinder on AvGas that the com is close to 16:1 and the peak power timing is close to 15* - any numbers alot less than that then you dont need AvGas,and or you do need to rethink the tuning.

If you were to convert an engine as described to unleaded pump fuel, ROZ 98, which numbers would you choose, regarding compression, ignition timing and max EGT?

Depends largely on the end use and the bmep capability of the engine.

The defining factor is the dynamic compression - this is created by the addition of the static com and that created by the combination of trapping efficiency and the delivery ratio.

The higher the trapping and delivery efficiencies are then the max static com that can be tolerated short of detonation ,is reduced.

But a good example is a conversion I did to a brand new TM KZ10 kart engine. This was designed to run in open class and has a 60mm piston giving 152cc.

The regulations only allow unleaded pump gas, and initially it was run with the standard straight line ignition.

I played with a few combinations of com and static advance with a det sensor bolted to a head stud. This engine would have state of the art trapping and delivery numbers , especially with a VF3 and 36mm carb in place of the 30mm regulated unit.

Thus a fairly low com was needed to get the right combination of peak power and overev capability when pushing up against the over advance created by the non retarding ignition.

It ended up with 13.2:1 full stroke and this setup was right back at the original numbers of 15* advance and 1180*F - the lower egt caused by the excessive advance.

Any lower on the com and the peak dropped ( 58Hp crank @ 12800 ) but any higher and the peak remained constant but it detoed in the overev at 14400 +.
This deto could be suppressed by going richer, but then the power suffered everywhere.

With a proper ignition I would guess at 13.8 :1 and an egt up at 1280 as unleaded burns alot faster than AvGas and added to the extra retard able to be dialled in with a digital.

[2T Institute]

From a different forum, A kit NSR500V cylinder

Remarkable by how ordinary it is, same scavenging pattern as CR, NSR(125, 250, 500) RS 125/250 and CR 500. Only departure from the script is water cooled cases on the 500V

[F5 Dave]

If they weren't such evil fekers and spent some r&d on emissions, imagine what a stonking basis that layout would have made for a road bike. They sound like 2 CR250s and then some.

[TZ350]

Ok finally got the O2 and exhaust temperature sensors installed.

Ecotrons has been pushing me to do this, they need the Lambda info so they can better help me develop a good Alpha-N map.

No idea if they are in the optimum place but they will do for a start.

Had to change to un-leaded fuel but still have to drop the compression a touch to suit the 96.



The air fuel meter and Lambda controller/transmitter.



Using the cursors, with Cursor-1 I can see that at N_b 7206 rpm LamWO2 is rich at 0.85 and Cursor-2 lean at 1,247 Lam at 9120 rpm.



Now that it all seems to be working I am really looking forward to getting a bit of time on the dyno to play with this thing.

[Dodgy]

Has anyone else been playing about with EGT probes and had weird readings?

I installed a dual Koso with Stinger probes on my MC28 (almost a bucket). These are 110mm from the piston face. Ozzy jetted it up on his dyno and we were getting 1250deg peak and running nicely.

Fast forward to a session at Manfield and they peaked at 1440deg. It didn't feel lean at all, but slowed down and came off WFO as the revs came up and managed to keep temp down to 1250 again. After speaking with one dude with an Aprilia/Wobbly 400, he kinda put the fear of god into me about the readings. Well, the bike sat in the garage for a while as I was distracted with the new GSXR100 and a wedding. Pulled off the heads and exhaust, expecting to see some sign of damage, but nothing.

I am wondering if the probe is installed too far into the gas stream? The installation notes specify halfway in, but I am not even that far in. I didn't do a plug chop, but as you can see, there is no sign of damage on the piston crown, and no ring smear, etc either...

[Frits Overmars]

Ok finally got the O2 and exhaust temperature sensors installed. No idea if they are in the optimum place

Both are looking good, but do not move them any closer to the cylinder. And remember to heat the lambda sensor before starting the engine; otherwise oil will soon choke it.

with Cursor-1 I can see that at N_b 7206 rpm LamWO2 is rich at 0.85 and Cursor-2 lean at 1,247 Lam at 9120 rpm.

1,247 is definitely too lean but 0,85 is about optimal for best power. That goes for both two- and four-strokes.

[TZ350]

Both are looking good, but do not move them any closer to the cylinder. And remember to heat the lambda sensor before starting the engine; otherwise oil will soon choke it.

1,247 is definitely too lean but 0,85 is about optimal for best power. That goes for both two- and four-strokes.

Great, thanks for that. I am flying a bit blind here, so I am greatfull for the input.

[TZ350]

The combination of port and pipe is firmly set at 12,000 so this is what I would use as a baseline.



Its initial drop off is to get it to idle well from the big static, plenty of mid advance for throttle response and then enough for a good peak ( assuming correct com cc ) but falling further to help revon.

Ok I have nearly finished fitting the Aprilia TPS and now its time to think about ignition curves again. I got into trouble at Taupo and Kaitoke by having a to aggresive ignition curve which was great for WOT but over advanced for reduced throttle settings.



This is Wobblys suggestion for my engine on wide open throttle WOT but will need to be retarded around the peak torqe point when the throttle is partly closed.



Here is an Aprilia RS250 curve sent to me by Kel and you can see that above 8,000rpm when its starting to get on the pipe the WOT curve is the most advanced and the curves retard as the throttle opening is reduced.

Posted because I was asked about my old Ignitec curve .....

[Neal]

[/QUOTE]

That's not a 250 cylinder ! I thought that the probe had to protrude to half way in the pipe but I could be wrong . Mine is 110mm from the piston if I remember correctly from earlier discussions .
My readings would go over 1250 but I would just roll off and reject until it remained at 1200 ish on avgas .
Is it possible that the colour is not a true reflection of a wide open 30 second plug chop ?

[TZ350]

From PitLane:- http://www.pit-lane.biz/t4072p20-gp1...vermars-part-3

If the crankcase would behave like a pump, you would be right. But when the engine is running in the power band, it is no longer a pump; it is a resonator.

I thought that it is a pump exactly until that point, where the transfers open.

That is right. But it is a very ineffective pump: its volume ratio is only between inlet closing and transfer opening.

I thought, that the crankcase pressure was lower right before transfer opening with a larger crankcase. Maybe I forget the influences of the previous cycle

Yes, that may be the case.

All in all: You still think, the bigger, the better, Frits?

A large crankcase volume is good but with a very large case the flow velocity inside the case will become so low that fuel and air separate.

If we had direct fuel injection, I would definitely say 'the bigger the better'.

In practice this means opening the crankcase to the atmosphere as soon as the pressure inside the case allows it.

With a good engine running at rpm of maximum torque that would be about 15° after BDC.

In theory that is also valid for an engine with a carburetter but in practice the pulse signal to the carburetter jets would be so weak that it would be difficult to achieve good carburation.

Direct fuel injection ... really big crankcase volumes.



Himmmmm .... now how could I get a huge amount more crankcase volume??? nope nothing obvious there.

[wobbly]

In any badly tuned 2T you can easily get readings over 1300*F and survive,ONLY if the setup is not optimal.
If the com is too low for the fuel, or if the timing is overly retarded, then the excess heat produced late in the combustion cycle is dumped into the pipe
and thus alot less is soaked into the piston.
But just the mere fact the engine did survive that insane abuse, points to the fact that the setup is nowhere near correct.
It still amazes me though that people have gauges on the bike, skid around the track, see death numbers on the screen then ride back to the pit and tell everyone about what just happened.
Why is the gauge there ? To help tune the engine,but what if the com was perfect and the timing dialled in correctly on a dyno.
The same rider would then do several laps - watching the temps scream past 1250, lock it up at the end of the straight - THEN come in and say " I saw 1300 and shit ive siezed it, bastard thing".
If a correctly setup engine cannot be held under 1200*F by the jetting, then it should be richened immediately so that it can be.
THEN, go down one size at a time and approx 50* rise should occur for each change, shooting for a max on AvGas of 1250*F.
If the change produces less than 50* delta in egt then that indicates that you are approaching deto rather than making more power from the extra heat of combustion.
The opposite is true as well, if more than 50* is seen with 1 jet leaner, then you can be sure the setup is not correct for the fuel and a heap of unused heat is being dumped into the pipe.
But, using excess fuel to cool the combustion process will not make anywhere near the actual power available ,if the ignition and com was optimised.
This means as a general rule for a fast watercooled 125 cylinder on AvGas that the com is close to 16:1 and the peak power timing is close to 15* - any numbers alot less than that
then you dont need AvGas,and or you do need to rethink the tuning.

[fbear40]

No idea if they are in the optimum place but they will do for a start.

Had to change to un-leaded fuel but still have to drop the compression a touch to suit the 96.

Move to unleaded might benefit the thermally challenged as well as a drop in comp

[TZ350]

Heres some pics from today. Its been a warm day and no rain.

Looks like another great weekends racing at Taumaranui.

[F5 Dave]

2 stroke new lap record there too. Just thought I'd say today. Just in case someone beats it tomorrow. Actually I think Kel and Rick are 2nd and third fastest on smokers.