Portings effects on compression?
#11
08-14-2006, 12:41 AM
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Portings effects on compression?
Okay stupid question time.So if i want to run straight 110 and i am not burning it efficiently with my compression can i compensate somewhat with a different heat range of plug?Since i am going to run Nitrous i would prefer to run as high an octane number as i can to get good all motor performance and great Nitrous performance.Excuse my ignorance on this if i am way off on my suggestion of plug heat range. I am using NGK JR10B plugs now.
#12
08-14-2006, 01:43 AM
#13
08-14-2006, 02:12 AM
Portings effects on compression?
Originally posted by: TheStir
Just an FYI.
Static compression ratio is set and can be calculated by the CCs about the piston at TDC and the bore and stroke. And like Viper said, if you had a VE of 100% this would match you dynamic ratio.
Dynamic compression ratio is what you get in real life, and is affected by all the variables in an engine.
Scott
Just an FYI.
Static compression ratio is set and can be calculated by the CCs about the piston at TDC and the bore and stroke. And like Viper said, if you had a VE of 100% this would match you dynamic ratio.
Dynamic compression ratio is what you get in real life, and is affected by all the variables in an engine.
Scott
Static compression does not change. Dynamic compression (cylinder pressure) is effected by all of these factors.
You can effect static compression by changing your piston, increasing stroke and you will effect how much piston dome you can get away with when you change bore so even bore indirectly will effect static compression in some cases.
Dynamic is a product of what porting, cams and valve size can do with VE as stated on top of the base line static compression.
Yep, That about does it![img]i/expressions/face-icon-small-wink.gif[/img]
LMAO! Can you guys imagine this conversation on the Yami forum? lol. There would only be crickets chirping after a few of these posts by Bom guys[img]i/expressions/face-icon-small-wink.gif[/img][img]i/expressions/face-icon-small-happy.gif[/img]
#14
08-14-2006, 02:29 AM
Portings effects on compression?
Originally posted by: rcoop
You will need a colder plug for nitrous so if your trying to get the best of both worlds it wont help you there. You could have one of your vortex curves very aggresive for on the motor and retard for on nitrous.
You will need a colder plug for nitrous so if your trying to get the best of both worlds it wont help you there. You could have one of your vortex curves very aggresive for on the motor and retard for on nitrous.
Cover yourself because detonation ain't pretty but for maximizing power, you do not want to run more octane than you have to. Slowing the burn rate down will do nothing to make you faster unless you are using it to avoid detonation.
#15
08-14-2006, 02:32 AM
Portings effects on compression?
Originally posted by: rcoop
This is the same conversation Cape and I had last week. Static compression, cams , and porting all have a hand in creating cylinder pressure. This is why Hpr 3 cams and 12-1 will create better torque then 14-1 and 109's all else being the same. I'm not trying to say one is better then the other just your whole package needs to work together for the intended purpose of the engine. Trying to make up for poor cam selection by jacking up compression, you still won't get the full potential of your engine.
This is the same conversation Cape and I had last week. Static compression, cams , and porting all have a hand in creating cylinder pressure. This is why Hpr 3 cams and 12-1 will create better torque then 14-1 and 109's all else being the same. I'm not trying to say one is better then the other just your whole package needs to work together for the intended purpose of the engine. Trying to make up for poor cam selection by jacking up compression, you still won't get the full potential of your engine.
#17
08-14-2006, 02:46 AM
Portings effects on compression?
Originally posted by: rcoop
Just because we are not friends doesnt mean i haven't spent the money and dyno time seeing what makes these Rotax engines run.
Just because we are not friends doesnt mean i haven't spent the money and dyno time seeing what makes these Rotax engines run.
If you want to be friends, say so and we will be friends. If you don't, say that and we won't. Either way, can we stick to the subject?
Please PM me with any relationship crap from now on. Sorry........I am not used to discussing whether I am friends or not with other men[img]i/expressions/face-icon-small-wink.gif[/img] Usually we know where we stand and don't have to talk about it..............If you want to be friends, I am happy to be friends[img]i/expressions/face-icon-small-smile.gif[/img]
I really did like your logic, btw................regarding the topic[img]i/expressions/face-icon-small-smile.gif[/img]
#19
08-14-2006, 02:52 AM
Portings effects on compression?
Originally posted by: ERBEDS650
[img]i/expressions/face-icon-small-smile.gif[/img] ERBE sings why cant we be friends, why cant we be friends!
[img]i/expressions/face-icon-small-smile.gif[/img] ERBE sings why cant we be friends, why cant we be friends!
Dammit!......Who am I?....... Dr. Phil?[img]i/expressions/face-icon-small-happy.gif[/img]
lol
#20
08-14-2006, 03:00 AM
Portings effects on compression?
Well thanks Ron. This is a good topic though because i don't think it is understood by the average atv owner looking to get a little bit extra out of his bike. For example Flux who is struggling with 14-1 and Hpr 3 cams. If he can get it to run where he rides at it will be a torque monster. It is just building a lot of cylinder pressure for a dune bike that runs into different quality fuels and different riding conditions. I'm not picking on you Flux just the first bike I could think of for an example. I wish you luck with your bike and hope it performs to your expectations. Those type of combos usually work better with alky which is more forgiving on jetting and has a cooling effect on the engine.