The main difference between the 13 and older cams and the 14 and newer HO cams is the amount of overlap. The newer cam has more which equates to more low end torque.
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Both of you are correct in that the newer cams have more overlap or duration than older versions, and that does make a difference.
However, it is the difference in lift that makes far more difference, and comparing a 255 cam with .556" lift to a stock cam is not logical. Also, I was commenting on differences between current 103 models, not on differences between older and current 103 models. |
Originally Posted by IdahoHacker
(Post 14867000)
Both of you are correct in that the newer cams have more overlap or duration than older versions, and that does make a difference.
However, it is the difference in lift that makes far more difference, and comparing a 255 cam with .556" lift to a stock cam is not logical. Also, I was commenting on differences between current 103 models, not on differences between older and current 103 models. Just included the pic so you can read the words, "closer to a SE255 etc etc". However, if you want to argue you win. |
Originally Posted by jt metal
(Post 14866895)
I have to ask.....is it worth it to do a cam swap on a newer bike? If the bike has a 255 or similar, and you upgrade to a 575. What are you really gaining?
Both bikes tuned and ready to go. Just a cam swap. 3ft lbs? Better curve? I think I spent around 200 bucks for each set of cams, I do my own work so hunting around for deals on parts is where I save money. Changing the cams was the most notable difference in the bike. I had gotten big torque gains from the 255s and more top end/scary fast from the Andrews. If you do you're own wrenching it maybe worth it. I could never see myself spending hundreds of dollars on labor or 1000k-1500k in performance upgrades for another 10-20hp |
Originally Posted by lp
(Post 14867010)
Disagree. It's not the lift, it's the lobe timing that made the difference here. Early closing like an 255 to increase torque.
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Originally Posted by IdahoHacker
(Post 14867015)
Actually, it's both. Always.
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I found this.
https://cimg4.ibsrv.net/gimg/www.hdf...32d01c94d7.jpg Edit, i see it's all ready been posted |
Originally Posted by lp
(Post 14867028)
You're not getting it. Since the new OEM cams did not increase lift, and there clearly is an increase in torque and HP, it's obviously the change in lobe timing. That's all I'm saying.
Perhaps my post was unintentionally confusing. The point I was trying to make is that none of the OEM cams are remotely close to the specs of an SE255. Going to a 255 cam in a stock motor, assuming a/c, exhaust, and tune are done, will make a huge difference in performance, far greater than the difference between '13 and '15, far greater than the difference between base 103, HO 103, and Twin-Cooled HO 103. |
Originally Posted by IdahoHacker
(Post 14867015)
Actually, it's both. Always.
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That's a great graphic, and I'm definitely saving a copy of it! But, that's NOT what the OP was asking about, at all. He's not asking about the difference between a '13 and older cam compared to a '14 and newer cam.
He asked this: "103 High output cams? The 2015 RGS special has the SE255 cams I do believe?" The answer to his question is: "No." And then, this being the internet and all, the thread went completely off the rails. :icon_teeth: |
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