joo eli olis kysymys: meneekö m20b25 venttiilit suoraan m20b20 kanteen?
kiitos vastauksista jo etukäteen!
ja mistä sais kyseiseen kanteen jyrkemmän nokan?
Finally, I'm showing flow coefficient relation to the Inner seat diameter.
This figure ignores how well a port can feed a cylinder and purely focuses on just how good that port is when considering the ISD size. Both the '731' and '885' ports are very accomplished and compare favourably even with a modern LS1 cylinder head. It also outlines the inferiority in this company of the '200' early 3 series port, and should hopefully bring home the folley in people who continue to pedal these cylinder heads for high performance/high capacity M20 conversions. Forget it. The '885' head casting is the undisputed best. Just to keep an eye on port velocities however at 6000 rpm peak powerspeed and taking into account the cylinder capacity, I calculate the following for the '200', '731' and '885' respectively:93m/s, 76m/s and 77 m/s the last two are lower than I had expected. I usually design ports for a velocity in the 'trouser leg' of over 90 m/s. You can move the compromise towards flow perhaps (making them bigger), if the design of the port won't deliver. The worst aspect of the M20 is the low roof of the port close to the valve seat.
And for all those who are used to CFM, I've converted my figures to CFM- using 25 inches of water as a reference:
Posted Image, might have been reduced in size. Click Image to view fullscreen.
Kuvaliite ei näköjään suostunut yhteistyöhön.
Testit tehty virtauspenkissä. Ei perustu arvauksiin. Jos lontoo taipuu niin tuossa oleellinen.
Jos jollain parempaa tietoa niin otetaan kyllä vastaan.
Poimittu ylläolevasta tekstistä. Kertoo oleellisen.
reggid wrote:
Do you think the 731 with 42mm intake valve and some reshaping of the port can be made to flow better than the 885?
I'm sure I could make the 731 flow better than a standard 885, yes, but the same modifications applied to an 885 would make it potentially unreachable.
731 virtaa paremmin modattuna 6mm nostoon asti paremmin jonka jälkeen 885 menee menojaan.
Eli suomeksi. 731 kannesta et saa niin virtaavaa kuin 885.
Poimittu ylläolevasta tekstistä. Kertoo oleellisen.
reggid wrote:
Do you think the 731 with 42mm intake valve and some reshaping of the port can be made to flow better than the 885?
I'm sure I could make the 731 flow better than a standard 885, yes, but the same modifications applied to an 885 would make it potentially unreachable.
731 virtaa paremmin modattuna 6mm nostoon asti paremmin jonka jälkeen 885 menee menojaan.
Eli suomeksi. 731 kannesta et saa niin virtaavaa kuin 885.
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