camatv Posted December 17, 2014 Report Share Posted December 17, 2014 simple. the more exhaust pressure is bled off the faster the transfer charge can enter the cylinder.. the port height to an extent can dictate where in the rpm range the most power will be made. also shape can help "shape" the power output. either long an broad or short and pipey. of course on a fixed port there is pretty much "it goes this way and thats it" kinda things going on in there. the ole square port was sapposed to bleed off lots of exhaust pressure ( making power) faster and can produce big numbers on a dyno compared to an oval port in the same setup. BUT they can shred rings due to the excessive amount of hang the ring experiences . AND usually bog like mad men due to the pretty much nonexistant time of the flame front to exert pressure on the piston making power. most square port crap was in the 200-209* range that i had seen. way to high for pretty much any motor except super light rider on extra light frame running alky/nitro mix.. the more rounded the port is the less chance or ring snagging, and longer lifespan the motor can have. cylinder bore and port shape also dictate how wide the port can be. but of course this is only one very small thing to consider in the overall plan of the cylinders port layout. triple exhaust and powervalves can make all kinds of wonderfull things happen in the cylinder. Quote Link to comment Share on other sites More sharing options...
registered user Posted December 17, 2014 Author Report Share Posted December 17, 2014 camatv you think the down south hillbillies are just now catching up to what everyone else was doing in the '90s ? seems that way by all the homeboy port jobs on ebay Quote Link to comment Share on other sites More sharing options...
Deadbeat Posted December 21, 2014 Report Share Posted December 21, 2014 camatv you think the down south hillbillies are just now catching up to what everyone else was doing in the '90s ? seems that way by all the homeboy port jobs on ebay the quality of work def seems to be regional somewhat, competition encourages better builders to keep pushing Quote Link to comment Share on other sites More sharing options...
tfaith08 Posted December 26, 2014 Report Share Posted December 26, 2014 It's regional because there's nowhere to ride down here. The market is nonexistent. Halls motorsports has had the same 450R for over 2 years on the floor. Nobody races or rides fast, only jacked up and LED covered with speakers on back. On a slightly unrelate topic, the fastest 3ci hot saw builder in the world lives in Jackson Alabama. 6 consecutive Stihl Timbersports championships. He knows how to build a 2-stroke. Quote Link to comment Share on other sites More sharing options...
trickedcarbine Posted December 27, 2014 Report Share Posted December 27, 2014 It's regional because there's nowhere to ride down here. The market is nonexistent. Halls motorsports has had the same 450R for over 2 years on the floor. Nobody races or rides fast, only jacked up and LED covered with speakers on back. On a slightly unrelate topic, the fastest 3ci hot saw builder in the world lives in Jackson Alabama. 6 consecutive Stihl Timbersports championships. He knows how to build a 2-stroke. Stihl..... Pshh. Should see what I can do to a bag of cotton with this monster! Sent from my iPhone using Tapatalk Quote Link to comment Share on other sites More sharing options...
registered user Posted December 27, 2014 Author Report Share Posted December 27, 2014 simple. the more exhaust pressure is bled off the faster the transfer charge can enter the cylinder.. you ever notice the tripples usually open couple degrees after the main. maybe it better for the windows to open more gradual rather than all 3 at once ? Quote Link to comment Share on other sites More sharing options...
registered user Posted December 30, 2014 Author Report Share Posted December 30, 2014 traditional triangled divider. dont understand why people keep doing it. cant think of a worse shape to use. i bet even zillafuk would have more sense than that Quote Link to comment Share on other sites More sharing options...
n2otoofast4u Posted December 30, 2014 Report Share Posted December 30, 2014 ^ Skeeter porting Quote Link to comment Share on other sites More sharing options...
do-work-son Posted December 30, 2014 Report Share Posted December 30, 2014 Why is a triangle divider such a bad desing? Quote Link to comment Share on other sites More sharing options...
trickedcarbine Posted December 30, 2014 Report Share Posted December 30, 2014 It does not provide the velocity people think, plus a lot of folks think it's great to make it real slim. Big no no if you expect it to not break Quote Link to comment Share on other sites More sharing options...
Dixie normus Posted December 30, 2014 Report Share Posted December 30, 2014 (edited) things need to be smooth. A lot like the shape of an airplane wing. Edited December 30, 2014 by Dixie normus Quote Link to comment Share on other sites More sharing options...
registered user Posted December 31, 2014 Author Report Share Posted December 31, 2014 i have my own thoughts how wide it can be without any problem but enough about that. im certain the V shape acts like a snowplow and forces the air somewhat toward the outside walls. thus decreasing the affective area of the window. thats another reason im not a fan of the steeply slanted roof to the window. on the rounder shape air can pass over it without being forced outward Quote Link to comment Share on other sites More sharing options...
registered user Posted December 31, 2014 Author Report Share Posted December 31, 2014 these seem to be your common cylinders that youll typically see. snowplow style bride and fairly steep roof Quote Link to comment Share on other sites More sharing options...
sprinklerman Posted December 31, 2014 Report Share Posted December 31, 2014 No HP difference seen in my experience . Vee shaped or not. Lots of guys put too much emphasis on the intake bridge shape imho. I bet there isn't enough hp difference to accurately measure between any of those intake shapes. ..assuming the rest of the cyl work is the same Quote Link to comment Share on other sites More sharing options...
registered user Posted December 31, 2014 Author Report Share Posted December 31, 2014 do you have any pics of you test cylinders ? im not arguing there would be a huge difference either way but if you go to the trouble of grinding the whole cylinder then it doesnt make sense in my mind to put a V on the divider, unless the porting shop is just following everybody else because he doesnt know any better. its no secret how air flows over objects so theres plenty of evidence which way is better. theoretically it should give more power. i have no plans to test the V shape because i already know its not the better way. and like i said the cross sectional area of the window when it enters the bore is decreased with steep angles leading into the window. we see the same thing with the boost port and its steep angle. often times its as large as the side transfers but because of its angle the cross sectional area is not as great Quote Link to comment Share on other sites More sharing options...
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