Portings effects on compression?
#31
08-14-2006, 02:48 PM
Portings effects on compression?
Originally posted by: ERBEDS650
BSnut don't be so pedantic - get over it and move on.
BSnut don't be so pedantic - get over it and move on.
Your response is yet more proof that you were lying when you made your apology for the thread going off course[img]i/expressions/face-icon-small-wink.gif[/img]
Btw, just to make sure everyone knows what pedantic means, I googled it[img]i/expressions/face-icon-small-happy.gif[/img]
pe·dan·tic (p-dntk) KEY
ADJECTIVE:
Characterized by a narrow, often ostentatious concern for book learning and formal rules: a pedantic attention to details.
Are you ready to go back to porting and compression ratios yet?
#32
08-14-2006, 03:00 PM
#33
08-14-2006, 03:08 PM
#34
08-14-2006, 03:22 PM
Portings effects on compression?
Im not sure i agree with you there. Two of the better running stock bores out there Choose and Mike don't have high compression. They are obviously building cylinder pressure or they would be turds. The engine does need to accelerate as quickly as possible especially under a load. Which is why the 450 are so quick with even a little spray. they accelerate fast and the nitrous makes the torque that they lack. Airforceone's bike is a great example and he uses a nitrous controller to keep it on the edge of tire spin so it pulls the whole track.
#35
08-14-2006, 04:15 PM
Portings effects on compression?
Scott is a little different scenario. He is mostly chassis and NOS. His cams and porting are stock as well as his piston.............for a little longer anyway........so I don't think his motor really applies. He would be an excellent example if we were discussing how to put power to the ground.
Mike is a good example since he is at 11.5:1 compression. The question would be, given his current setup would he rev faster and make more power if he increased his compression only or would he not see benefit?
Mike is a good example since he is at 11.5:1 compression. The question would be, given his current setup would he rev faster and make more power if he increased his compression only or would he not see benefit?
#36
08-14-2006, 04:24 PM
Portings effects on compression?
Chooses bike is fast because one, it weighs 300lbs. And two, he knows how to setup, and get the parts working together that he has. Its a stock motor, nothing fancy in there.
I run 12-1 comp. I also run a very aggressive cam. It builds alot more pressure than a 3 cam per say. But it requires it to rev alot higher. The place my bike lacks, is in the low to mid rpms. Where if I were to raise the compression, I could get goo pressure at the low and mid that I lack.
So take Duneits bike for example. If his cams build the best pressure at say 7500, and then he goes and adds more compression. The gain he will see will more than likely be below that 7500. The lower end will be the biggest difference. He will probably suffer a little from it on the top. Compression is great for acceleration, but can hurt the top end. After all, it takes more power to compress the higher comp.
I run 12-1 comp. I also run a very aggressive cam. It builds alot more pressure than a 3 cam per say. But it requires it to rev alot higher. The place my bike lacks, is in the low to mid rpms. Where if I were to raise the compression, I could get goo pressure at the low and mid that I lack.
So take Duneits bike for example. If his cams build the best pressure at say 7500, and then he goes and adds more compression. The gain he will see will more than likely be below that 7500. The lower end will be the biggest difference. He will probably suffer a little from it on the top. Compression is great for acceleration, but can hurt the top end. After all, it takes more power to compress the higher comp.
#37
08-14-2006, 04:26 PM
Portings effects on compression?
Mike would obviously see some benefit but not an incredible amount. He would be able to make a greater improvement with more aggresive timing and dual carbs. While still having the option of going back to stock timing to spray on. Why have 14-1 and spray 15 horse jets when you can have 11.5-1 and spray 25 horse jets. The nitrous will always make greater torque gains then static compression. So then you would have the best of all worlds.
#38
08-14-2006, 04:28 PM
Portings effects on compression?
Originally posted by: rcoop
Mike would obviously see some benefit but not an incredible amount. He would be able to make a greater improvement with more aggresive timing and dual carbs. While still having the option of going back to stock timing to spray on. Why have 14-1 and spray 15 horse jets when you can have 11.5-1 and spray 25 horse jets. The nitrous will always make greater torque gains then static compression. So then you would have the best of all worlds.
Mike would obviously see some benefit but not an incredible amount. He would be able to make a greater improvement with more aggresive timing and dual carbs. While still having the option of going back to stock timing to spray on. Why have 14-1 and spray 15 horse jets when you can have 11.5-1 and spray 25 horse jets. The nitrous will always make greater torque gains then static compression. So then you would have the best of all worlds.
#39
08-14-2006, 04:31 PM
#40
08-14-2006, 04:41 PM
Portings effects on compression?
Im talking a dune hill combo here. At 11.5-1 he has less problems worrying about good fuel, hot weather, poor air his bike will run all day in it. When he hits the hill he hits the bottle and its not like its a slug on the motor either. With how the Hpr 3 work so well at building cylinder pressure that motor should jump on the spray. It will be one of those motors that makes more power then the nitrous jets claim. Where the cams that bleed of pressure struggle to make even the claim on the jets for horsepower.