ESE's works engine tuner

[TZ350]

It's getting closer to something, it's just the hard one left! To make the beast.

Very interested. I can see that a lot of good work has gone into the design and drawing. I am looking forward to watching progress as it turns into metal.

[Muhr]

Very interested. I can see that a lot of good work has gone into the design and drawing. I am looking forward to watching progress as it turns into metal.

Thank you Tz
It's a few hours to wait before I get to hear the little one

[JanBros]

in the Bimotion Head program, the squish isn't parallel to the piston, but in some "tangetial line" to keep a constant velocity of the gases within the squish (see page 8 : https://dokumen.tips/documents/bimot...manualpdf.html)

are there circumstances where this type of squish band is better than parallel to the piston ?

[Buckets4Me]

.

Ex-Ferrari Engineers Are Building a Carbon Fiber Two-Stroke Superbike

The Vins Duecinquanta is a carbon-fiber monocoque bike packing a 249cc V-twin two-stroke with electronic fuel injection. With an eye on extreme lightness, the street bike promises a curb weight of less than 210 lbs. No power figure is given, but with such a featherweight bike, it's almost guaranteed to be quick.

http://www.roadandtrack.com/car-culture/a14763497/ex-ferrari-engineers-are-building-a-carbon-fiber-two-stroke-superbike/

Time for a come back

[Grumph]

Weren't there ex Ferrari engineers supposed to have been involved with the Bimota V-Due ?

I hope that they aren't the same ones - or at least that something was learned from that....

What's the engineering staff turnover like at Ferrari ? You never seem to hear of ex Honda engineers starting something up.

[Jannem]

Pictures, drawings and dimensions might help, Jannem.

Ok, here we go:

44mm bore
39mm stroke
11krpm targetmax. torq.
Durations:
ex 192,5 with radiused upper edge, radius included in the duration
blowdown 33
ABC 122,6

Roof angles:
ex 15
A 22
B 10
C 51

Shapes:
ex elliptical @70% with small bulges in port within blowdown area, floor stuffer planned.
A Rectangular
B Rectangular
C Rectangular

Angle corrected chordal areas:
Blowdown 305mm^2
A 143 mm^2
B 162mm^2
C 91mm^2, maxed out c-port would be 153mm^2
Transfer total 701mm^2, with maxed out c-port 764mm^2

Port directios:
A-port: ex. port side wall "extension line" crosses exhaust centerline at cyl center
A-port: B-port side wall "extension line" crosses exhaust centerline at midpoint between cyl center and c-port wall

B-port: A-port side wall "extension line" crosses exhaust centerline at 2mm from cyl center towards c-Port
B-Port: C-port side wall "extension line" crosses exhaust centerline at midpoint between cyl center and c-port wall

C-port: wall "extension lines" cross exhaust centerline at cyl center

Thoughts:
If my calculations are reasonably ok, existing transfer and blowdown areas should be reasonably balanced, although somewhat limited from ideal. However, transfer flow coefficients in this case will be relatively worse due to shapes, so thinking adding 10% area might not be a bad idea.

[Twopints]

carb is a Mikuni VM
Look for kawasaki ke125/ks125 carbs on ebay.
actually is that a clip on version? so maybe early 90cc suzuki ie rv90 or a100 would be the easiest cheaply obtainable option
if you were attempting to build a repo unit or restore an old engine mock up the measurements of the origional and work from there.
If you give the the measurements of what you want i can sift through a few sites i know to give you some modern options.
The conrod is likely to be arround 100mm as it was the style of the time to run stroke times 2 for rod length.

Thanks that would be great, scaling from the drawings i have the centre line of the crank to head gasket line is 158mm so from the information i have gathered from you guys 25mm from the throw of the crank ( half the stroke) plus 100mm rod and a piston with 30mm compression height gives me 155 mm or with a 103mm rod 158mm

as i only have the crankcase ,all this scaling is done from grainy photos, so there is a margin of error

with the assistance i have got here this is much clearer to me, i am starting to lay out the ports to the timing figures i have

I am keeping my eye out for a Suzuki GP 125 crank ,rod and piston to mock things up

and i have worked out how to attach photos

[Muhr]

Ok, here we go:

44mm bore
39mm stroke
11krpm targetmax. torq.
Durations:
ex 192,5 with radiused upper edge, radius included in the duration
blowdown 33
ABC 122,6

Roof angles:
ex 15
A 22
B 10
C 51

Shapes:
ex elliptical @70% with small bulges in port within blowdown area, floor stuffer planned.
A Rectangular
B Rectangular
C Rectangular

Angle corrected chordal areas:
Blowdown 305mm^2
A 143 mm^2
B 162mm^2
C 91mm^2, maxed out c-port would be 153mm^2
Transfer total 701mm^2, with maxed out c-port 764mm^2

Port directios:
A-port: ex. port side wall "extension line" crosses exhaust centerline at cyl center
A-port: B-port side wall "extension line" crosses exhaust centerline at midpoint between cyl center and c-port wall

B-port: A-port side wall "extension line" crosses exhaust centerline at 2mm from cyl center towards c-Port
B-Port: C-port side wall "extension line" crosses exhaust centerline at midpoint between cyl center and c-port wall

C-port: wall "extension lines" cross exhaust centerline at cyl center

Thoughts:
If my calculations are reasonably ok, existing transfer and blowdown areas should be reasonably balanced, although somewhat limited from ideal. However, transfer flow coefficients in this case will be relatively worse due to shapes, so thinking adding 10% area might not be a bad idea.

Is it looking something like this?


To me it seems like you have more than enough tans area for 11krpm targetmax. torq. 14m/s and peak hp at 16-17m/s.

I would focus on exhaust

[Jannem]

Is it looking something like this?


To me it seems like you have more than enough tans area for 11krpm targetmax. torq. 14m/s and peak hp at 16-17m/s.

I would focus on exhaust

Seems I have probably goofed up my calculations entirely... If those areas are uncorrected, It would seem I have even more than that.

Do you mean 14Krpm & 16-17Krpm? Or am I missing something? Piston travel/s? Wouldn't that equal max.torq @10700 max hp @ 12300?

Exhaust height is purposefully conservative at this point and easier to tune afterwards, once I see if it falls on it's face after the peak. Just would like to get the transfers into ballpark with one royal pain with this iron cylinder, aged eyesight and less than professional tools...

How did you evaluate the required area / rpm in general?

[Muhr]

Seems I have probably goofed up my calculations entirely... If those areas are uncorrected, It would seem I have even more than that.

Do you mean 14Krpm & 16-17Krpm? Or am I missing something? Piston travel/s? Wouldn't that equal max.torq @10700 max hp @ 12300?

Exhaust height is purposefully conservative at this point and easier to tune afterwards, once I see if it falls on it's face after the peak. Just would like to get the transfers into ballpark with one royal pain with this iron cylinder, aged eyesight and less than professional tools...

How did you evaluate the required area / rpm in general?

yes i was referring to piston speed.

I have not done any calculations just went on feeling

or maybe i misunderstood.

[TZ350]

My pressure sensor has turned up. I think it is a pizeo resistive type. It is 5Volt in and 0.5 to 4.5 analog Volt out. Perfect for the Arduino. Hopefully have it all wired in, in a couple of nights ready for the big test. I am unsure what the pressure range should be but figure that the cylinder pressure at exhaust port opening is about 10% of maximum combustion pressure, so maybe about 150 to 200 psi. The sensor is rated for 3 times over pressure so should be good.

[Jannem]

Speaking of sensors, found this cable operated TPS, which could be useful for others too. Haven't figured out the connector type yet. These are Citroen/Peugeot/Suzuki 2.0HDI sensors, some Fiat's as well.

[TZ350]

Great, thanks, I have been looking for TPS like that.

[peewee]

hey guys I need some help from the masters. I have a common cr500 steel exh spigot (not the exact one in the photo but similar) and I need to narrow it down closer to 75% or so. I have to first say that theres no reasonably easy method (or even reasonably hard method) I can water cool it, without a huge undertaking and I don't have time for that now, so ill make do with what I can at the moment. maybe you fellers have even a better solution

my amateur ideas are simply to get some flat steel plate which I already have in the garage and weld it in the spigot, creating the roof and floor ( like in the pics), and of course weld caps over the ends at the exit so its sealed from the pipe side , the other end may not need a cap since its mated against the cylinder. but this method leaves a hollow void below the floor and above the roof (arrows in pics)

my other Idea is to get a chuck of 6061 or 7075 (assuming it can be fairly easily machined as I have no experience with 7075). then have a local shop machine the outside spigot dimensions then ill hand grind the inside of the passage. t6-7075 would be more appealing since I think it would have a higher wear resistance between the spigot and pipe, as this engine vibrates quit alot

heres were im stumped, im thinking the steel method is the better of the two situations. wouldn't the steel spigot idea heat up slower and put less radiant heat back into the washed through mixture ? and the hollow cavities might even help this alittle ? aluminum seems like it soaks up heat so fast and would radiate it back into the mixture a lot

[Jannem]

yes i was referring to piston speed.

I have not done any calculations just went on feeling

or maybe i misunderstood.

I think you caught up an error in my spreadsheet regarding the t-port heights. I need to dig up my old mm-paper portmaps and take a look at it. Thanks.

The ex. port in your pic matches pretty well, although the width you show is what I have as chordal width. The rod length I have is 85mm.