spurdy Posted June 2, 2005 Report Posted June 2, 2005 Hey guys, I posted earlier about changing from 21cc to 19cc domes. Sounds like anything much over 150 psi compression warrants a race fuel mixture. If I remember right I was at 145 psi with the 21s. I have a Trinity head and I really don't want to give them any more money. Does anyone know where I can get a set of domes. I found a set of 18s on e-bay for $15 + s&h but I am not sure I want to go with that high of compression. How much compression will 1cc difference make? I also notcied a post about having the domes cut to improve performance. I have never seen this. Can someone fill me in. Trinity offers a "turbo cut" on there domes to improve "squish" but I think it is about as effective as the "boost bottle". What to do? SP Quote
ScrewMachine Posted June 2, 2005 Report Posted June 2, 2005 Someone with a Trinity head will have to confirm this, but I think they use the same domes as ProDesign, Noss, etc. Maybe try and PM dlnoss on this site, he makes the Noss Head and can prolly get ya setup. In my experience 1cc difference in head size will equal 8psi of compression. I'm at 5500 feet of elevation, so this equation may not be accurate at sea level. If someone at a lower elevation has any experience with this, I'd be extremely interested in the results. As far as squish is concerned, I dunno. I've heard varying opinions both ways. Too small a dome, not enough squish area. My experience has been the higher the compression the better and squish area be damned. Maybe some of the experts here can chime in. I need some clarification too. Quote
spurdy Posted June 2, 2005 Author Report Posted June 2, 2005 Someone with a Trinity head will have to confirm this, but I think they use the same domes as ProDesign, Noss, etc. Maybe try and PM dlnoss on this site, he makes the Noss Head and can prolly get ya setup. 376801[/snapback] Na, I checked and Noss and Pro Design heads use a round dome. Trinity has 5 lobes around their dome making it quite unique. I am afraid I am going to have to give them more money. I don't mind paying for them I just don't want to give any more of my money to them, they are bound to screw something even as simple as this up! Thanks for the rest of the info. If what you say is true about the 8 psi per cc and if I am still at 145 psi that would bump me to about 161 psi w/19s and 169 psi w/18s. Not sure what I want to do yet. SP Quote
rocketboy Posted June 2, 2005 Report Posted June 2, 2005 (edited) dude theres better ways to make power than turbo vains in the squish band , 1cc usually equals around 10 psi so 8 is close too. i had my stocker head cut for improved turbulence and cnc rechambered too, so i dont know what to tell you there on a coolhead somebody does it im sure but id just get a better port job or raise ignition timing or something before that , the gains would be minimal and going lower than 19cc starts effecting topend revability on hitting the high notes! Edited June 2, 2005 by rocketboy Quote
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