ESE's works engine tuner

[adegnes]

Adegnes has:


https://m.youtube.com/user/TheAdegnes


https://m.youtube.com/results?q=2%20...0stuffing&sm=1

https://m.youtube.com/watch?v=MbfQpjWMQN0

Well, I have before but jumped straight to nitromethanol in my videos...

I experimented with e85 in an earlier version of the Spx. Slight powergain(might be placebo, no dyno back then), definitely cooler exhaust, shifted the powerband about 1500rpm down if I remember correctly.
Was a pain to get consistent results, as Fletner has pointed out fuel demand changes with heat.

I've had good results with methanol/nitromethane so far, 2hp increase over gasoline without touching anything but carburetion.

The bike will soon be up and running again, now with less conservative port timing.

[TZ350]

... moving the pin up increases the temperature the pin is subject to. After moving the pin up, I was able to repeatedly convert once silver colored piston pins to a nice blueish tan instead.

Before EFI and the piston slot I used to get blue piston pins, but not now.

I've always thought moving that amount of mixture under the piston is unproductive. Shorter crown to pin heights have proven beneficial every time so far.

A couple of advantages of the piston slot is expelling mixture from under the piston crown directly into the boost transfer with the added benefit of improved under piston cooling and pin lubrication.

[philou]

I have just seen that. produced by Di Carmine Technologies for vortex kart engine

[Neal]

I've had a look but yet to find a graph or spec sheet that shows what compression ratios unleaded pump fuels can handle , for example I understand avgas can handle 16:1 ,
What can 98 octane pump fuel handle ? Where can I read this info ?

Thanks , neal

[Frits Overmars]

I've had a look but yet to find a graph or spec sheet that shows what compression ratios unleaded pump fuels can handle , for example I understand avgas can handle 16:1 , What can 98 octane pump fuel handle ? Where can I read this info ?

That is an unanswerable question Neal. Any engine can handle 16:1 and a lot more, even on 95 octane pump fuel, when it's idling.
When it's starting to make power, things become more complicated. Has it got modest porting that will limit the attainable power anyway or is it state of the art?
Has the combustion chamber an effective squish band and a compact shape for fast burning or is the mixture playing hide and seek in nooks and crannies, inviting detonation?
Is the engine watercooled with a nikasil bore coating, or aircooled with a shrunk-in iron sleeve, hampering heat transfer so much that the piston is almost melting?
Is the carburation spot-on or so rich that the engine is practically fuel-cooled from the inside? Is the ignition timing safe or a tad too early?

Where can you read this info? I'd say: here. But you'll have a lot of reading ahead of you, enough to get you through the holidays.

Which brings me to my final point: best season's wishes for all.

[wobbly]

What you are up against is the definition of the engines two differing "compression's ".
The static com is easily measured and is simply the trapped volume at TDC.
But the big variable is the dynamic compression and this is tied directly to the bmep.
BMEP is tied to the Delivery Ratio, the Trapping Efficiency and the Scavenging Efficiency.
Thus the higher the above elements have been "tuned " by the builder, then the higher the effective volume ( and its composition ) is at TDC.
Put simply, the better the design,the static compression must be reduced to prevent detonation of the end gasses in the squish.
In a well designed race engine a very general, rule as you have read on here several times ,is that AvGas will handle 16:1 but a small bore will go well above that
and a bigger bore will not.
An example of 95/98 capability would be a KZ2 engine.
This has 11cc trapped,so 12.3 effective full stroke com.
But this engine has an extremely high bmep plus a debilitating straight line ignition, so is up against deto constantly - thus cannot handle high MSV at all.
If it had a proper retarding ignition curve, then my guess would be 14.5:1 would be fine on the 98 octane as used by the CIK in Europe,with a "real " squish .
But a full noise bigger bore engine on 95 pump gas would be lucky to survive that in a road race setup, maybe just ok in a sprint kart engine.
Very much swings and roundabouts - impossible to define as Frits said.

[Neal]

Thank you for the replies , I realise now my question had too little info really
I'll have another read through the various pages because it's highlighted how much I still don't understand .

Merry Christmas

[Greg85]

What you are up against is the definition of the engines two differing "compression's ".
The static com is easily measured and is simply the trapped volume at TDC.
But the big variable is the dynamic compression and this is tied directly to the bmep.
BMEP is tied to the Delivery Ratio, the Trapping Efficiency and the Scavenging Efficiency.
Thus the higher the above elements have been "tuned " by the builder, then the higher the effective volume ( and its composition ) is at TDC.
Put simply, the better the design,the static compression must be reduced to prevent detonation of the end gasses in the squish.
In a well designed race engine a very general, rule as you have read on here several times ,is that AvGas will handle 16:1 but a small bore will go well above that
and a bigger bore will not.
An example of 95/98 capability would be a KZ2 engine.
This has 11cc trapped,so 12.3 effective full stroke com.
But this engine has an extremely high bmep plus a debilitating straight line ignition, so is up against deto constantly - thus cannot handle high MSV at all.
If it had a proper retarding ignition curve, then my guess would be 14.5:1 would be fine on the 98 octane as used by the CIK in Europe,with a "real " squish .
But a full noise bigger bore engine on 95 pump gas would be lucky to survive that in a road race setup, maybe just ok in a sprint kart engine.
Very much swings and roundabouts - impossible to define as Frits said.

hello wobbly you talk about kz2 engine compression so more engine has trapping efficiency (better cylinder) need to decrease static compression for more power? I did a test recently on a kz2 engine outgoing a good power but I had 12.70cc of volume chambers, when I put the right volume so 13cc I had lost 1.4hp .. so in theory I ' have reduced my static compression by putting more volume chambers, does this mean that my cylinder has more enough trapping effiency to get to the power I had before putting the volume right? is it my relationship between up and down which is better or just the cylinder that needs to be improved?

Thanks

[TZ350]

...

Kicked the beast into life tonight.

...

And was able to see an ignition trigger pulse (the spiky trace) and the (fatter) pressure sensor trace. The pressure sensor is a 16 bar unit, 4-20mA output dropped across a 450 Ohm resistor so the Voltage is reading about twice as high as it should, I needed to do that to get some resolution.

So the concept works, definitely can see if the engine fired or not. Now to refine the idea and get it to do something useful.

[peewee]

Has the combustion chamber an effective squish band and a compact shape for fast burning or is the mixture playing hide and seek in nooks and crannies, inviting detonation?

hi frits can you tell me about the nook and cranies your talking about ? ive welded and machined a new head for my nitromethanol engine in order to lower the comp ratio way down. at the inner edge of the band it goes pretty much straight in to the bowl and then makes a radius toward the spark plug if that makes sense. ive made a arrow to show the straight in angle im talking about. the band width is 52% bore area so I could recut it to 50% which would decrease band width by about 1mm (green line) and make that angle into the bowl less straight in but im not sure if it would make a world of difference. do you think I should just try the head as is and recut it later if I gives any problem or just cut the 1mm now ? unless this straight in angle isn't a nook crannie that your talking about ?

[Frits Overmars]

hi frits can you tell me about the nook and cranies your talking about ? ive welded and machined a new head for my nitromethanol engine in order to lower the comp ratio way down. at the inner edge of the band it goes pretty much straight in to the bowl and then makes a radius toward the spark plug if that makes sense. ive made a arrow to show the straight in angle im talking about. the band width is 52% bore area so I could recut it to 50% which would decrease band width by about 1mm (green line) and make that angle into the bowl less straight in but im not sure if it would make a world of difference. do you think I should just try the head as is and recut it later if I gives any problem or just cut the 1mm now ? unless this straight in angle isn't a nook crannie that your talking about ?

Straight in is OK Peewee. But don't continue the straight; use the biggest radius that you can fit in. You might take a look at the Aprilia head below to see what I mean.
If you have a head that will fit, try it before modifying it, or you'd be throwing away a chance to learn something.
The nooks and crannies I was talking about are too much squish clearance, a squish gap that does not follow the contour of the piston but radially opens to the outside of the bore, head gaskets with a bigger bore than the cylinder, a piston top land with too much radial clearance, etc.

[Bert]

...

Kicked the beast into life tonight.

...

And was able to see an ignition trigger pulse (the spiky trace) and the (fatter) pressure sensor trace. The pressure sensor is a 16 bar unit, 4-20mA output dropped across a 450 Ohm resistor so the Voltage is reading about twice as high as it should, I needed to do that to get some resolution.

So the concept works, definitely can see if the engine fired or not. Now to refine the idea and get it to do something useful.

It would be interesting to see how much the pressure increases with the failed ignition- could be useful to enable a slightly advanced spark to ensure a complete combustion process over the next few cycles.
This method could also be interesting if you have one mounted in the crankcase.

[wobbly]

The KZ engine running ( illegal ) 12.7cc would have no overev power past 14,000, end of story.
The peak power generated would be used for such a short period as to be of little advantage during a lap.
Franco's factory engines all run 13.6cc to enable plenty of overev and much leaner jetting.
Running 12.7 I guarantee you would deto badly on track, and would need very rich jetting.
Using fuel to cool the squishband and not make power, is always doomed to failure.
Modifying the reeds, the exhaust manifold, the stinger , the porting and the head shape are easily capable of getting back the lost power from lowering the com.

Re the KTM 250 kart engine - this is still sitting on the workshop floor unfinished due to lack of payment.
Im happy to give you the EngMod file for it.

[Michael Moore]

wobbly, would you mind sending that EngMod file to Jeff Henise? I've got a 2015 250SX engine that Jeff will be helping me with.

thanks,
Michael

[jfn2]

wobbly;
I also would like to see the EngMod file for that KTM 250. I am also working on a similar motor. Thank you.
Jeff Neilan
jneilan46@gmail.com