Evo Ate

iTrader: (22)

I am buying after market cams preferably 264 HKS cams if I can find them, my question is will cam gears extract any more power from these cams or are the gears a waste of $225. I am trying to set up my car for quick spool up and midrange power at the expense of some top end. Thanks for any data.

sanfranevo

yes. changing the camshaft will definitely improve horsepower. Camshaft fools around with the value, and aftermarket cam increases the time these values are opened and closed. Why I don't know. They just do. I heard. somebody correct me if I am wrong. pls.

chuntington101

Cams increase power because they alter the LIFT and DURATION of the valve. They also have a different profile to the standard cams, more in a bit. With more lift the valve basically opens further. This means that the standard valve makes a larger “hole” and therefore more air and fuel can get in. more fuel and air, more power. With longer duration the valve stays open longer thus allowing more air and fuel in giving more power. Now, that is cool. You buy a cam with more lift and duration and you will get more power. But not the most power. To achieve this you need a more aggressive profile. This means the valves open and close faster meaning that in a given duration they spend more time open. People often say the duration at 50 thou lift (50 thou is when the air starts to flow I think). HKS 272 cams have 210 degrees of duration at 50 thou lift. This means that you are actually only getting good air flow for 210 degrees not 272. Some 264 degrees cams offer grater duration at 50 thou than the HKS units (I think Tomei and JUN cams do and I know that Piper cam do). Now there is no point in getting a set of new cams unless you (read engine builder) can set them up right, so you should get the pulleys as well. These will enable the tuner to alter the timing of the cams to get the best out of them. On turboed engines you want as little overlap as possible. This is when both the inlet and exhaust valves are open at the same time. This can lead to a situation when the inlet air “jumps” over the inlet valve and flows out the exhaust, thus not filling the cylinder. So if you dial out the overlap then when the inlet is open, all the air goes into the cylinder, thus making more power (and giving much better spool up). Sorry for any stupid spellings or **** grammar, but I have just wrote all this of my head (that’s why it f**ked up then!!).

Hope this helps, Chris.

sanfranevo

Great post. thanks for the help. I heard from people who changed their cam say that the car idle rough. Is there anyway to reduce the roughness.

chuntington101

i think its all in the set up. if your tuner is upto it then he will be able to get it to run good. A good standalone will help but i think you can get around it with less drastic solutions. an AFC and a remap with probaly do it, but im not sure. if you do a search then you will fined the answer.

glad to have helped, Chris.

mikesevo8

Yes, cam gears may allow you to extract a little more power depending on how close your
cam timing is to "perfect".
Due to cam belt wear and other factors, the timing relationship of the cams to the crank may be
a little off. The cam gears will help you to "index" the cam timing to get it back to optimum.
This will translate into more power.

For reference, the folks at Vishnu found that setting the gears at -3,-3 degrees worked the best.
Others found gains at -4 or -5.
I don't think anyone found better performance at + settings.

I have the 264 cams, but do not have gears.

Be careful ... putting parts on your car may get you some more power, but nothing beats
getting your car tuned to really take advantage of the mods.

Hope this helps.

nastea1

i have 272's, and my idle can be a little rough at times, but most of the time it sounds good...i posted a video clip of 272's at idle, it just lets you hear the sound.

its posted under my other name nastea

chuntington101

As mikesevo8 said, a lot of it is to do with the set up that your builder dose. I mean setting up of cams is a science of its own. I have read several articles on the subject and some of the guys in the UK that build engines for a living are amazing. They spend thousands of pounds on digital micrometers and then loads of time setting up jigs and holders for them on each engine! But the most important thing is experience. Some people will take your cam’d EVO that is running rough, move the cams a couple of degrees with their eyes alone and bingo, your engine is running fine!

Shahul X

iTrader: (3)

silver surfer is running 272, 272 cams (HKS) and -4, -1 setting with UR cam gears (i think) with more power and better than stock idle

-Shahul