Cam question? Intake lift higher then exhaust lift?
06-26-2005, 11:31 AM
#1
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Cam question? Intake lift higher then exhaust lift? I been in the search for a cam for a long time now. I have this cam here i am looking at, that is pretty much a custom grind. It was recommended from a guy over on EFA, that is most likely on here as well. He knows his Sh*t. But ive never seen any cams have a higher lift on the intake side then the exhaust side. 230/236 .578/.560. Anyone ever run a cam like this. Its an N/A setup. Longtubes, OFY. stock heads, stock bottom ebd. Valvetrain will all be done as well as timing chain. Has 4:11 gears most of the bolt-ons. Let me know your opinions on this cam.
06-26-2005, 11:49 AM
#2
Originally Posted by RUNanLt1
I been in the search for a cam for a long time now. I have this cam here i am looking at, that is pretty much a custom grind. It was recommended from a guy over on EFA, that is most likely on here as well. He knows his Sh*t. But ive never seen any cams have a higher lift on the intake side then the exhaust side. 230/236 .578/.560. Anyone ever run a cam like this. Its an N/A setup. Longtubes, OFY. stock heads, stock bottom ebd. Valvetrain will all be done as well as timing chain. Has 4:11 gears most of the bolt-ons. Let me know your opinions on this cam.
Not sure what else you have been looking at, but that is pretty normal for a race cam. Higher ratio rockers on the intake side is also the norm. If that is the one I think it is (Comp?), it is a very good cam. Use it.
Good luck, Ed
06-26-2005, 04:33 PM
#3
Exhaust get blown out and as such duration means more than lift.
I think the reason we all get so accustomed to seeing more lift on the exhaust side is most cams are meant to work with often restrictive exhaust systems and stock heads are comparatively weak on the exhaust side. With the smaller valve and more duration it is easy to get more lift without have a need for different springs than the intake side or overly aggressive ramps on the lobes to get the lift.
I think the reason we all get so accustomed to seeing more lift on the exhaust side is most cams are meant to work with often restrictive exhaust systems and stock heads are comparatively weak on the exhaust side. With the smaller valve and more duration it is easy to get more lift without have a need for different springs than the intake side or overly aggressive ramps on the lobes to get the lift.
06-26-2005, 04:54 PM
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Im not too sure, but maybe i havent been looking at race cams 
But just about every cam off the shelf has a higher exhaust lift then intake lift. Thanks for the calrification and explanation of why i am seeing cams like this. The plan is to throw this cam in there on 1.6 RR's and see what kinda numbers i am getting as well as how it lopes. If we feel like we need a little more hp and torque at lower rpm's(stock bottom end, stock heads) then we are going to throw on 1.5 RR's on the exhaust side. See how everything works out. 
But just about every cam off the shelf has a higher exhaust lift then intake lift. Thanks for the calrification and explanation of why i am seeing cams like this. The plan is to throw this cam in there on 1.6 RR's and see what kinda numbers i am getting as well as how it lopes. If we feel like we need a little more hp and torque at lower rpm's(stock bottom end, stock heads) then we are going to throw on 1.5 RR's on the exhaust side. See how everything works out.
06-26-2005, 07:05 PM
#5
I don't think it worthwhile to use 1.6 with that cam unless you know your heads will flow well at those lifts which not a lot of LT1 heads will even ported. Going past peak flow is OK but you don't want to go way past. Ideally you want the valve to spend a lot of time at max flow lift best way to do that would be to have the peak lift be just beyond so that the slow parts of the lobe on either side of peak keep it at that lift as long as possible.
06-27-2005, 08:12 AM
#7
Originally Posted by 96capricemgr
I don't think it worthwhile to use 1.6 with that cam unless you know your heads will flow well at those lifts which not a lot of LT1 heads will even ported. Going past peak flow is OK but you don't want to go way past. Ideally you want the valve to spend a lot of time at max flow lift best way to do that would be to have the peak lift be just beyond so that the slow parts of the lobe on either side of peak keep it at that lift as long as possible.
Otherwise you would not see the NHRA Super Stock guys running .800" or so lift at the valve. Very high ratio rockers is very common with those guys. A lot like putting faster ramps on the cam, except that it won't cause the lifters to loft off the nose of the cam.
Take care, Ed
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06-27-2005, 12:32 PM
#8
Originally Posted by RUNanLt1
Im not too sure, but maybe i havent been looking at race cams But just about every cam off the shelf has a higher exhaust lift then intake lift. Thanks for the calrification and explanation of why i am seeing cams like this. The plan is to throw this cam in there on 1.6 RR's and see what kinda numbers i am getting as well as how it lopes. If we feel like we need a little more hp and torque at lower rpm's(stock bottom end, stock heads) then we are going to throw on 1.5 RR's on the exhaust side. See how everything works out.
But just about every cam off the shelf has a higher exhaust lift then intake lift. Thanks for the calrification and explanation of why i am seeing cams like this. The plan is to throw this cam in there on 1.6 RR's and see what kinda numbers i am getting as well as how it lopes. If we feel like we need a little more hp and torque at lower rpm's(stock bottom end, stock heads) then we are going to throw on 1.5 RR's on the exhaust side. See how everything works out. Ed
06-27-2005, 12:37 PM
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Originally Posted by 96capricemgr
I don't think it worthwhile to use 1.6 with that cam unless you know your heads will flow well at those lifts which not a lot of LT1 heads will even ported. Going past peak flow is OK but you don't want to go way past. Ideally you want the valve to spend a lot of time at max flow lift best way to do that would be to have the peak lift be just beyond so that the slow parts of the lobe on either side of peak keep it at that lift as long as possible.
06-28-2005, 07:11 PM
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Originally Posted by Formula94
With stock, untouched heads I am spinning the car to 6550rpm shift points with the cc306 and I think my car is making decent numbers and running a decent time.
