Which Cams ?
04-20-2006, 03:46 PM
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Which Cams ?
Hi,
I will be building my engine and upping the boost on my ATI SC to 14psi.
I currently have JWT spec. cams (260 duration 10.9mm lift) but with the new heads I'm getting (valves 1mm over) I'm also receiving Tomei 268 Cams (268 duration, 10.5 lift)
Question, which cams will work better in my car/setup and why?
Danny
I will be building my engine and upping the boost on my ATI SC to 14psi.
I currently have JWT spec. cams (260 duration 10.9mm lift) but with the new heads I'm getting (valves 1mm over) I'm also receiving Tomei 268 Cams (268 duration, 10.5 lift)
Question, which cams will work better in my car/setup and why?
Danny
04-20-2006, 10:32 PM
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Rule of thumb: "Ten extra degrees of cam duration will raise the peak power point by 500 rpm."
So I would be making peak power like 400 rpms higher than I am now. Since my SC makes max power just before redline, I would need to shift at 7K with the Tomeis to take advantage of all power...
Danny
So I would be making peak power like 400 rpms higher than I am now. Since my SC makes max power just before redline, I would need to shift at 7K with the Tomeis to take advantage of all power...
Danny
04-21-2006, 12:01 PM
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Originally Posted by William@Altered
I wonder why you want the extra duration - your car is not reving very high - if it was and you were taking advatage of say9k rpms - then yes - but your shifting at or below 7k -
It's not that I really want the extra duration, the set of heads & vales I bough come with those cams. I now need to decide if I want to stay with my JWT spec cams or go with the Tomei 268s. That is actually the original question...
Thanks
Danny
04-21-2006, 12:05 PM
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Originally Posted by mdacko
off topic, but please let me know if you decide to sell your JWT cams 
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04-23-2006, 03:59 PM
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Originally Posted by G352NV
Where did you get this info?
04-23-2006, 04:41 PM
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Originally Posted by Sharif@Forged
Are you sure their duration is only 242?
Tomei Cam 256 /EX: 10.2 / IN: 10.2
Tomei Cam 264 /EX: 10.2 / IN: 10.2
Tomei Cam 268 /EX: 10.5 / IN: 10.5
JWT spec'ed ones are:
260 DEG DUR. / .428"(10.9MM) LIFT, INT. ADVANCED 2 DEGREES.
Nismo:
262 degree duration and .426" (10.8mm) lift. Cold lash is set at .010" to .013".
04-23-2006, 04:57 PM
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Originally Posted by bigbri
He has the same cams as I had...which are different than yours Steve....I think your duration is different right??
04-23-2006, 07:04 PM
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Everything I read about cams says "keep overlap as small as possible for FI". Does anyone happen to know how much overlap the JWT and/or the Tomei have ?
Thanks
Danny
Thanks
Danny
04-23-2006, 07:52 PM
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i got that number from the box.... and i i'm fairly sure my installer got that number from Ted also. these are true f/i cams. the other ones are n/a cams that work well with f/i cars. scotts performance kept the duration down, the overlap to a minimum.....here's your choice. i'm not sure if you have to shim the jwt's but i'm pretty sure you have to with the tomei 268's. scott's cams a hollow too!!! i'll let you guys know what kind of numbers i get with these cams after tuning.