cam spec opinions

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robinsongtir

Guest
I have a contact who can get me some high lift and long duration cams the spec of them are inlet 272degree 11.6mm lift and 278degree 11.6mm lift.
Just want to know if they would suit my car with a stroker kit and big turbo
 
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memski

Guest
More lift, more lift! Do you know what your rev limit will be with the stroker Pete? If it were me I would try and get a 12.5mm lift cam with 272 duration (I know you will be drag racing your car).
 
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Anonymous

Guest
robinsongtir said:
I have a contact who can get me some high lift and long duration cams the spec of them are inlet 272degree 11.6mm lift and 278degree 11.6mm lift.
Just want to know if they would suit my car with a stroker kit and big turbo
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yes they will but you can go for a little bit more lift [12mm]
 
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skiddusmarkus

Active Member
Yep as your stroker will rev to 8500rpm I think you said :?: .You could probably go higher(280) with your spec.The big parts manufacturers reccomend new valve springs after about 10.8-11m lift though(though grumpy git :wink: above hasn't).I was looking at a site I found randomly on google and it said the standard duration&lift is only 240degrees&8mm(IIRC),so there's a massive difference.
 
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Hkondakci

Member
Standard spec for RNN14 cams are:

IN/EX 248 degree duration, 10.00mm lift IN/EX, center angle IN=110 degree and center angle EX=120 degree

Would certainly go for a 280 duration cams (lift IN/EX 11.5mm) with massive drag-spec turbo and stroker kit. Also would prefer JUN, since they are more meant for top-end power and very aggressive high rpm characteristics, than good for torque Tomei bump-sticks. But who siad torque was bad :wink: :p

rgds
habib
 
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robinsongtir

Guest
so the highest lift and duration the better? something like 12mmlift and 280duration on ex and in sides would be upgrading the springs and retainers possibly valves also
any sites list these kind of spec JUN or Tomei
 
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Anonymous

Guest
robinsongtir said:
so the highest lift and duration the better?
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for power production,yes.be careful about going for a lot of duration and lift if it`s to be used as a road car as well.a lot of lift and duration can give driveability problems,especially in the lower half of the rev range and you have to go for a higher idling speed.
 
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Anonymous

Guest
robinsongtir said:
whats the spec of yours what does it idle at?
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i`ve got 270 and 12mm{iirc}.if the idle is set at any lower than 1500rpm it tends to get a bit "lumpy" and can cut out every now and again.sam thinks he might be able to map it lower but not to expect miracles.i think he`ll do well to get it down to 1200rpm which considering the difference in profiles is quite good.
 
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caz

Guest
Do most R's not have a high idle speed anyway. I know minp sits at 1500 most of the time! What benefits would a young chap have in fitting cams to mildly modded R, zorst, filter, raised boost etc. Could a set of cams be added straight to a set up like that :?:
 
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AZ STE

Guest
robinsongtir wrote:
so the highest lift and duration the better?

There is an optimum/max setting beyond which things go bad.If you imagine the pistons going up and down and the valves opening and closing the tighter you get all this happening the more difficult it is to get the 4 stroke cycle to behave its self.If its going to be a road car as well as track car I wouldnt go all out on the cams
 
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robinsongtir

Guest
Bruce,

have you got adjustable vernier pulleys fitted as well do these not make a difference to the idle speed at all?
 
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Anonymous

Guest
robinsongtir said:
Bruce,

have you got adjustable vernier pulleys fitted as well do these not make a difference to the idle speed at all?
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i don`t have them fitted but with their more accurate/finite adjustment i`d suggest that they would help in getting the idle speed down.
 
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Anonymous

Guest
caz said:
Do most R's not have a high idle speed anyway. I know minp sits at 1500 most of the time! What benefits would a young chap have in fitting cams to mildly modded R, zorst, filter, raised boost etc. Could a set of cams be added straight to a set up like that :?:
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no they don`t unless they have a problem.cause they are getting old,like me :cry: ,some bits and pieces don`t work as well as they should,like the aac thingy :D .
a s-afc will control the idle speed at 950rpm all day even if you have other issues with idle speed control side.

even with a mildly modded r,such as you suggest above,will gain from fitting cams as the mods you`ve listed all help with the engine breathing.
 
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