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12-06-2008
Let's say i have a .600/.600 lift cam with 1.66 (wich is stock) rockers.
Well if i upgrade to 1.8 lets say roller rockers, Will the lift now be around .800/.800?
I'm just wondering how to calculate the lift if you put higher then stock rockers on.Just trying to get the most out of my future setup
12-06-2008
i dont think a higher ratio is going to be worth you buying. for the expense youd get maybe another 5 hp out of it. and with most aftermarket cams youd only be able to run 1.7s possibly only on either the intake or exhaust side.
12-06-2008
Let me ask you something. Or anyone that reads this. When i wan into mustangs when you switched from a non-roller rocker to a roller rocker there have been proven gains of about 25 hp. just in it being a roller rocker.
You don't hear about that in the gp world. And i'm not so sure the case would be any different with us.
It may be comparing apples to oranges.But it was just a question i have had for some time.
The MAIN reason i will be using a roller rocker is for valve train stability. I'll likely be shifting no less than 7000 possibly 7500 at wot depending on wich cam i go with.
It was just something i thought i could benefit from since i'm already getting them. And maybe i'd settle for something other than the is4 if i could come close to the lift that i could make with having a higher ratio than stock rocker arm.
Thanks for you're help
12-06-2008
You take the lift of the cam and multiply it by the rocker ratio. With stock rockers you should be getting .996 of lift at the valve. With 1.8s you'd be seeing 1.08. Though, these numbers seem off (high) so I'm not sure you've given me the cam lift and instead gave the lift at the valve to start with.Originally Posted by TDCRacing
12-06-2008
Please explain this in a different way so i'll understand.I guess that's why i asked the first question i did about how a 1.xx rocker will change the total lift.
As long as i dont go above the lift that i'm set up for on my valve train i should be ok...Right? and that would mean i could run the roller rocker on both intake and exhaust.
12-06-2008
Thanks,
Let me give you full info.Let's use this for an example. And if you could explain you're self again with the numbers i provided you with.
CAM-803 - INTENSE™ Stage 3 Nitrous/Blower Cam, duration @ .050": 220Ý/232Ý, lobe lifts: .337"/.351", valve lifts with 1.60:1 rocker arms: .539"/.562", lobe separation angle: 116Ý, intake centerline: 112Ý
12-06-2008
as long as you dont go above the lift of the valve train as a whole you should be just fine, but i would turn over the engine while youre down there just to make sure anyway. if it stops or you hear funny sounds, then something is wrong.
i do not know how the ratios come into play in all seriousness, but in the case of you wanting xpz-esque lift you could just put some 1.7s on with your xp. in the case of the intense nitrous blower youd just multiply the lift of the actual cam by a different ratio.
1.6 x .337 = .5392" total lift intake, 1.6 x .351 = .5616" total lift exhaust
1.7 x .337 = .5729" total lift intake, 1.7 x .351 = .5967" total lift exhaust
in theory, it should work, but i dont know if i would cut it that close. in that case, you could run 1.7s on the intake side and 1.6s on the exhaust side if you wanted more lift but i dont see why you would since youd want the extra exhaust bias for the spray.
with a high lift cam, i would just stick with the 1.6 RRs. its up to you though, i guess.
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