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Re: TS1 Sprint/race engine, pics of porting in progress.....
Posted: Mon Jan 02, 2012 1:50 am
by Darrell Taylor
Muppet wrote:Darrell Taylor wrote:Muppet wrote:transfer ports would normally taper down the length of the tract so I would have thought to feed the transfers the cross sectional area of the feeds in the case should be slightly greater or at least equal to the combined initial cross section of the feeds
muppet,
so a venturi exists,is that beneficial?
Now mr Darrel that's very unfair; I know I finished my post with a question mark but it's gone in your reply/quote, did you work for the News of the World?
I would guess that YES a slight Venturi effect would be beneficial to help give momentum to the gas stream; but it's a guess as I don't design two stroke engines for a living; just read a few books and looked at many two stroke barrels,
muppet
a venturi can be beneficial in some engines with good transfer duct and port window design
another question the eureka moment is getting closer
if the transfer duct cross section at base is 30mm x 20mm = sqmm
if the transfer window area is 20mm x 10mm = sqmm
Re: TS1 Sprint/race engine, pics of porting in progress.....
Posted: Mon Jan 02, 2012 1:52 am
by sean brady scooters
oh come on Darrell ..you can do this ...ha ha
Re: TS1 Sprint/race engine, pics of porting in progress.....
Posted: Mon Jan 02, 2012 1:56 am
by Darrell Taylor
600sq mm base
200 sqmm window
think my calc is right but just go with it
are 600 and 200 dimensions that stay constant ?
Re: TS1 Sprint/race engine, pics of porting in progress.....
Posted: Mon Jan 02, 2012 2:03 am
by Darrell Taylor
600 to 200
3 - 1 ratio
200 is a 20mm x10mm port window or is it all of the time
Re: TS1 Sprint/race engine, pics of porting in progress.....
Posted: Mon Jan 02, 2012 2:05 am
by sean brady scooters
but whatever the time/ area of a transfer port in a barrell ...my point is that as the japs have found out ..they will need MASSIVE ports in the barrel /crankcase to accomodate
Re: TS1 Sprint/race engine, pics of porting in progress.....
Posted: Mon Jan 02, 2012 2:13 am
by Darrell Taylor
Darrell Taylor wrote:600 to 200
3 - 1 ratio
200 is a 20mm x10mm port window or is it all of the time
upon initial opening of the port by the piston a large % flow occurs unless you have insufficient blowdown which will always be the case
1mm uncovered the port is 20mmx1mm 20sqmm
2mm uncovered the port is 20mm x 2mm 40sqmm
the entry is still 600mm
the port is massive
Re: TS1 Sprint/race engine, pics of porting in progress.....
Posted: Mon Jan 02, 2012 2:13 am
by Muppet
I'm still doing the maths; this is getting to be like an episode of countdown; I'll have three from the top two from the middle and one from the bottom,
muppet,
Re: TS1 Sprint/race engine, pics of porting in progress.....
Posted: Mon Jan 02, 2012 2:15 am
by sean brady scooters
ok yes ,but bigger crankcase barell trans would always be better yes ?
Re: TS1 Sprint/race engine, pics of porting in progress.....
Posted: Mon Jan 02, 2012 2:22 am
by Darrell Taylor
the point here is that we look at the cylinder and forget about the pistons interaction with it
we presume the transfer duct/entry is small cos we look at the window as been permanently open
the clue transfer is that all we are trying to do is transfer from a to b and in the case of a lamby do so in a controlled manner to assist the schnurle loop
Re: TS1 Sprint/race engine, pics of porting in progress.....
Posted: Mon Jan 02, 2012 2:25 am
by sean brady scooters
you are talking in riddles again darrell lol