I just read a bunch of threads about camshafts and none of them said anything about whats the diffrents between 272/272 from 280's , if 280's are more powerful , why do more of the evo owners use 272's????and will someone please take the time and explain to me how is it that it can be 272/280 or 262/272 what i mean by that is how can the camshaft of the intake be smaller then the exhaust?



Thank you

 

280's are more for drag racing applications. As to where the 272's are more for like autox cause of the lobe size.

 

do more research,advertised duration is not what makes or breaks a cam
some 272s make more power than 280s....i have 262s that make more power than some 280s....keep reading bro,check out the AMS cam test thread
Negative...

 

That's a loaded question, those duration numbers seem to be subjective based on the lift and ramp rate of the cam, its best to look at dyno charts of cars with like mods to yours to get the idea of what to expect, or ask a tuners advice on the best cam for what you want. In theory, a cam with less duration will give you more low end power over high rpm power, but that does not always seem to be the case with the dyno results and tuner opnions on here.

To answer your other question, when someone says 280/280, they are refering to first the intake cam duration, then the exhaust cam duration... therefore if someone says they're running 272/280, that means they have a cam with an adveritised duration of 272 on the intake side, while the exhaust cam is one with a 280 duration. Basically they've mixed and matched a set.

 

280,272,264, etc. is the cam duration. Thats not always what you look at on a cam. But normally higher the duration the higher the lift on the cam will be, more or less higher the lift the cam has the more you will see that cam on a car with a bigger turbo or a built block.

like for example, Cosworth M3 cams for the evo IX are 280/272 duration cams. Meaning the intake cam has a duration of 280 and the exhaust having a duration of 272. With a lift of 11.6mm on the intake and a 11mm on the exhaust.

alot of guys will run 272/272 cams because its more of a street cam for turbos like the stock evo turbo, 18g, 20g, FP Green, FP White, and sometimes maybe a red.

Anthing like a FP Red, 3076, 3582, etc, you will see more 280/280 set-ups or even the 280/272 to still gain power.

Reason for the 280/272 is the more then likly had 272s on there stock turbo and when they went bigger they just switched out the intake cam to a larger duration of 280.

Or you can always buy them like that

Cosworth M3 is 280/272
Kelford 280/272
etc

 

so they both have the same sizes right?

 

People mix and match sets so they can compromise, like I have 264 intake cam and 272 exhaust cam in my DSM so as to maintain some streetability of a straight 264/264 setup and the peak power of a 272/272 combo. 272/264 used to be a combo people played with a lot on Evos. If you don't mind the lope/rough idle, don't compromise.

280/280 tends to require upgrade springs and retainers and work better on bigger turbo upgrades, while 272/272 can work with a stock head and works well with stock or stock frame (green, tomei) turbos on Evos.

 

so they have diffrent sizes...so wouldnt that like mess up the car or cause back fire?

 

What do you have on your car?i like the kelfort 272 , well ams said it was nice

 

No. You only use "sizes" adjacent to each other. 264,272,280.

So 280/272 or 272/264

but not 280/264.

Cams control when and how long the valves open and close.

 

correct me if im wrong but i understood that the intake valves stay longer open then the exhaust valves if installed lets say 272/264 and if installed 272/272 they open and close for the same amout of time...

 

That's roughly how it works, but duration is only part of the story. There's lift also and how the lobes are shaped.

 

the higher the duration the higher in the power band they work

264 - auto-x/street
272 - street/autox/drag/etc
280 - mostly drag

 

I have BC 272/272 and I my reason for the 272 cam was simple. I really didn't want to to get in to the valve springs and guides. That is alot of work, and I just don't have time. Most 280 or better duration cams will require some better valve springs than the stockers.

 

try to go with an overall cam , acam that can satisfy ur present and future needs
example gsc s2 , kelford 272