ESE's works engine tuner

[wobbly]

Just love it when you finally get the right gear to do a job properly , and it does.
Rule says no part of the BODY to protrude into the chamber .
Now , dyno time , to test this and the cylinder water jacket cooling .
Watch this space.

[husaberg]

Just love it when you finally get the right gear to do a job properly , and it does.
Rule says no part of the BODY to protrude into the chamber .
Now , dyno time , to test this and the cylinder water jacket cooling .
Watch this space.

Shit that's an extreme. i thought that's going to be hard on the heatrange
but of course the colder longer the internal inside path the shorter the outside path...........

how much cc is inside a plug? 1-1.5?

[wobbly]

The race plug I use is a 10.5 heat range , and as you can see the insulator is super short.
All I have done is move the spark gap , 3mm closer to the middle of the combustion space - but kept the body flush to the roof as per the rules.
Same deal as using a toroidal chamber roof - but the tech rules for measuring the chamber volume wont allow a toroid as it traps air.
The difference in actual trapped chamber cc will be tiny - but a normal 10.5 race plug has 0.15cc of added volume between the body inner and the insulator.

[husaberg]

The difference in actual trapped chamber cc will be tiny - but a normal 10.5 race plug has 0.15cc of added volume between the body inner and the insulator.

Shit here was me already making a pig of myself only to be told there is no free lunch.
my eye-ometer was thinking a cc of volume not being fully utilised there.
Have you milled that in situ?

[koenich]

Thanks!

Reg the availability of 35cc/50cc engines with close to optimal power output - likely just no one had a real go at it. At least for 50cc I'm pretty certain that even Bidalot was surprised how many cylinders they can sell.

[dutchpower]

Dutch - purely by my eye dyno the cylinder Exhaust duct exit looks very big. And if its a T port , it should be oval like a Honda, and if a 3 port it should have Aux eye ducts down the side, like an Aprilia.


Wobb

This are the cil. Nico made in the beginning 4 jears ago some are compleet scaled copies of the aprilia all give 10 hp
Duct exit now is 21.15
His last cil. had nice inner cirkle of the transfers resulting in 2 hp lost !!!!!!

[lodgernz]

Well, there are numbers given by Frits as to how much time-area is needed in any application, I think the blow-down is 8,72mm2 x cc x rpm to be rsa equivalent (I or someone else has the correct furmulas if needed) Just looking, 192*, even for 50cc isn't much, and possibly 500* is a too high estimaton.

Thanks Andreas, I do use that formula from Frits, and I know how crap my setup is. I think you are right about my EGT estimate being too low, so I will make a new pipe.

Thanks also to Dave and others who have helped. I'll be checking all your suggestions.

[wobbly]

Lodger - couple of things.
If I put in 13,000 / 84* / bulk temp av =580* ( very average to lower guess ) into EngMod then Lt = 725.
But then you say the ignition is 14* at 11,000.
It should be 15* at 13000 ( your calculation peak ) if everything else is correct.
What egt in the header were you seeing , something basic is not right .

[dutchpower]

According to Thiel/Frits 54*(25/125)**.6666= 18.5shp that shal be reduced with something between 36 and 0% due to extra friction and thermic losses.
Let me asume 20% for a 25ccm cylinder and we can reasonably realistic expext ca 15shp from a Thiel/Frits equal 25ccm cylinder.


Did you ever measure that we did com not even close

[wobbly]

Dutch - no is the answer but if you look at the Quickdraw website they say the "best " gas ( petrol I assume ) engine is the Pioneer 30.5 " stroker " engine , that has a dyno sheet making 8. 75 Hp @ 16250 with power out past 20,000 -
but considerably less.
As I keep saying that level of bmep ( the baseline measure for outright engine efficiency in any displacement ) and piston speed , to my way of thinking is a technical joke in 2T tuning terms.
Unless what Im underestimating hugely is the disparity in friction losses as the rpm goes stratospheric , or something else completely.
I really am in the dark here , as im trying to make a full effort , cost no object race engine of 35cc on unleaded race gas , but as far as I can ascertain no one is even remotely close to the numbers
given by " normal " bmep and piston speeds already fully proven elsewhere.
WHY.

[Niels Abildgaard]

According to Thiel/Frits 54*(25/125)**.6666= 18.5shp that shal be reduced with something between 36 and 0% due to extra friction and thermic losses.
Let me asume 20% for a 25ccm cylinder and we can reasonably realistic expext ca 15shp from a Thiel/Frits equal 25ccm cylinder.


Did you ever measure that we did com not even close

It indicates that Aprilia/Thiel/Frits have not been in that country yet.
Enjoy the journey.

[lodgernz]

Lodger - couple of things.
If I put in 13,000 / 84* / bulk temp av =580* ( very average to lower guess ) into EngMod then Lt = 725.
But then you say the ignition is 14* at 11,000.
It should be 15* at 13000 ( your calculation peak ) if everything else is correct.
What egt in the header were you seeing , something basic is not right .

Thanks for your input Wobbly. I don't have an EGT sensor, so I don't know the EGT.
Here are the two curves for the HPI ignition. As you can see, I misquoted the numbers.

[Brett S]

Just love it when you finally get the right gear to do a job properly , and it does.
Rule says no part of the BODY to protrude into the chamber .
Now , dyno time , to test this and the cylinder water jacket cooling .
Watch this space.

Most karting rules have a minimum length of spark plug thread to stop people doing things like this.

[wobbly]

The spark plug and the head insert thread length are identical to the stock parts.
In what way is this plug ground electrode any different to the huge thing hanging off a B10 EGV or EIX.

[dutchpower]

It indicates that Aprilia/Thiel/Frits have not been in that country yet.
Enjoy the journey.

I wonder why is that 54 without friction and thermic losses !!!!!!!