Jorge_pg Posted July 30, 2015 Report Share Posted July 30, 2015 Hey guys, I've been wondering how exactly how domes for Coolhead or any head that use changeable domes work. Such as like what cc number domes do what, what octane should be ran with what domes and how to even add octane to pump gas from a station??? Ik I'm frecking noob but hey everyone start somewhere right? If possible detailed answers and examples please, thanks to all! Quote Link to comment Share on other sites More sharing options...
Bennett131 Posted July 30, 2015 Report Share Posted July 30, 2015 Different cc domes change compression, you don't add octane to fuel. Quote Link to comment Share on other sites More sharing options...
Jorge_pg Posted July 30, 2015 Author Report Share Posted July 30, 2015 Different cc domes change compression, you don't add octane to fuel. Why do people say you need different levels of octane for certain compression numbers? Quote Link to comment Share on other sites More sharing options...
Bennett131 Posted July 30, 2015 Report Share Posted July 30, 2015 They are talking about running race fuel exc. If you were referring to octane booster, it's a waste of time. Quote Link to comment Share on other sites More sharing options...
trickedcarbine Posted July 30, 2015 Report Share Posted July 30, 2015 Why do people say you need different levels of octane for certain compression numbers?Octane rating of a fuel is it's resistance light/burn/detonate, whichever school of terminology you wanna use. Adding compression to a motor makes it "explode harder". The issue is you need to remember that Compression can actually force lower octane fuel to light before the spark plug lights it. That is detonation. So if a motor has a substantial amount of compression and you mix regular 87 octane gas in it, the motor will pretty much continue to light it self under load and potentially break pistons or a crank. But if you have a low compression motor and way to high of octane fuel in it, the fuel will be hesitant to light. It will burn slower (think of lighting kerosene vs gas)and incompletely. Don't let your friends tell you adding high octane fuel makes performance..... Quote Link to comment Share on other sites More sharing options...
sheerider1026 Posted July 30, 2015 Report Share Posted July 30, 2015 ^^^ basically yes^^. Google detonation and also pre ignition Quote Link to comment Share on other sites More sharing options...
Jorge_pg Posted July 31, 2015 Author Report Share Posted July 31, 2015 Octane rating of a fuel is it's resistance light/burn/detonate, whichever school of terminology you wanna use. Adding compression to a motor makes it "explode harder". The issue is you need to remember that Compression can actually force lower octane fuel to light before the spark plug lights it. That is detonation. So if a motor has a substantial amount of compression and you mix regular 87 octane gas in it, the motor will pretty much continue to light it self under load and potentially break pistons or a crank. But if you have a low compression motor and way to high of octane fuel in it, the fuel will be hesitant to light. It will burn slower (think of lighting kerosene vs gas)and incompletely. Don't let your friends tell you adding high octane fuel makes performance..... And what dose the numer of domes (17cc,18cc,22cc, ect) mean or do? How do you know what dome is good for what and what octane should be used? Quote Link to comment Share on other sites More sharing options...
Jorge_pg Posted July 31, 2015 Author Report Share Posted July 31, 2015 I've tried looking for answers from the pages or company's that sell them and couldn't find any so I'm hoping you guys will know Quote Link to comment Share on other sites More sharing options...
twayne24365 Posted July 31, 2015 Report Share Posted July 31, 2015 The cc of the dome relates to its volume, the larger the cc or "cubic centimeters" the more volume the dome or "chamber" has. A smaller chamber will increase the compression ratio, and the higher the compression ratio means you need a higher octane fuel as described in trickedcarbine post. To check your compression get a decent compression tester and check your cylinders, I believe 93 octane fuel is fine up to about 140psi. Anything over that I would run some vp100 unleaded just to be safe. And don't think 93 octane with some octane boster is sufficient. Sent from my XT1254 using Tapatalk Quote Link to comment Share on other sites More sharing options...
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.