To Cam or Not To Cam?

[Guest]

Allright, before I am bombarded with "use the search feature", I have and all I got where post with degrees and all sorts of stuff that made me feel like I was reading a physics book. I need like a brief "Camshafts for Dummies" or something. After hearing all these cool soundclips, I want that chop in my exhaust. Where can I buy one? When I searched it looked like everyone has different specs. Are they custom? I am not clueless when it comes to my car, just Camshafts are a new area for me. What can they do for me (my bad sounding exhaust) and what is the range of gains to expect (from a mild Cam to a Semi-Agressive)?

[staticpike]

my recommendation for you my friend would be to got to How Things Work and get a general synopses of what a cam-haft does and how it works. After that, you can look at the camshaft owners spec page (it's in engine tech) and see the different cams that are being run here on the board and see what's extreme and whats not. The final step would be to do a search here in advanced, get some idea's and then throw up some questions.

At least that's how I did it, and everyone was more than helpful.

Some vendors for you are:
ZZP
Intense Racing
Super Six

I would also highly recommend the site sponsors since I know some of them also sell cams of different variety's.

I hope this helps! [img]smile.gif[/img]

[Butters]

Cams regulate the opening and closing of the intake and exhaust valves in the cylinders. When you buy an aftermarket cam, the longer duration and tighter lobe seperation angle as compared to the stock cam allow the engine to flow more air, and thus make more power. You will see duration marked as degrees at .050" lift. The bigger the duration the more power, but at the same time to big of a duration is not streetable. Generally a good range for a streetable cam would be 200-220 degrees lift at .050". The LSA is related to how much lift the cam makes, and the smaller the number, the more aggresive. This is the factor that gives you that choppy sound. Well.... i guess you would call this a breif explantion. I am by no means an expert so if I messed somethin up feel free to tell me.

[hawgs]

2KThunder... What part of Houston are you in? You should meet up with us sometime, check and post in the Sick-Sixx forum at the bottom for events and gatherings. We have installed many many cams and can help you out. :D

[Guest]

So the LSA gives the choppy sound? And the lower the more aggressive?

I see a Comp Cams VS:
206/216 at .050"
Intake Lift: .512"
Exhaust Lift: .507"
LSA: 115

And a Comp Cams GT2:
216°/216° at .050"
Intake Lift .507"
Exhaust Lift .507"
LSA: 111

They both cost the same, what would their pros/cons be,or are they both to aggressive?

[ December 22, 2003: Message edited by: 2KThunder ]</p>

[Arctc Wolf]

The camshaft determines how much the valves open and for how long, as well as when they open and when they close to get the maximum ammount of air into each cylinder as possible. These specs all depend on how each part of the engine works. It depends on how bing the engine is, how much air can flow through the head, how high of a redline the engine has, what the powerband is that ur looking for, and whether it's a NA engine, FI engine, or Nitrous engine.

Camshaft lift should be based on how well the heads flow on a flowbench. you don't want to use a cam/rocker combination that opens the valves higher than the heads is good at flowing. For example, having heads that flow best below .450" and having a cam that opens the valves up to .525" won't make as much power. Matching the lift to maximize the heads flow will get you best power gains in this area.

Camshaft duration should be based on how big each cylinder is. if it's a big cylinder, and the valve doesn't open up for a long enough time, it won't get enough air into it. if the valve is open for too long, air won't go into it fast enough and it won't make enough power. matching the duration to the size of the cylinders will get you bestpower gains here as well.

Not all motors and heads are the same. sometimes the motor will be huge and the heads won't allow much lift, so to make up for the lost lift, you could add a little duration to get some more air into the cylinders. The opposite is true as well. of the heads flow great, but the engine is small, then having lots of lift and only a little duration will help make more power.

The 2 things that make power is the ammount of air and the speed that it's going into the cylinders. more air means more power, but if it's going in slow, it won't fill up the cylinder to it's maximum capacity. same is true if the air is going in fast, but not enough is getting in. Think of it as, when u run, u open ur mouth more to get more air into ur lungs, but when ur walking, u can breathe thru ur nose, which is much smaller. being able to do this allows us to "make power everywhere" so to speak. This is why Vtec on honda's is popular. Camshafts have a specific area that it can work in, usually maximizing gains in one area and killing power in another.

Lobe separation and lobe duration determine where the car's powerband will be. these both contribute to valve overlap, or the time when the intake and exhaust valves are both open. having them open for a short time or not at all helps low rpm power, and having them open longer will help higher rpm power. finding the right balance for your car is key. once u have the lift and duration set for ur motor, u can use lobe separation to basically tune ur powerband to where u want it. more lobe separation for more low-end torque, less lobe separation for high end torque.

the last thing that will affect power is the camshaft's timing. this is when the the valves open in relation to the piston's location. adjusting timing one way will make the powerband flatter, and adjusting it the other way will make it more peaky. this is why people get adjustable cam gears, so that on the dyno, u can chance when the cam opens up, to make max peak power or a more broad, streetable powerband.

hope this helped, I know I've written it about 4 times in the last few years on this board.

[FireFighter]

you wont lose with the vs you will just gain more na with the gt cam, i have the vs cam in my car.

[Arctc Wolf]

The VS will have the same manners as the stock cam has, but will make a little more power everywhere. The GT cam will probably make more top-end power than the VS, but won't gain anything or might even lose some low-end, but I'm not sure about that since our motors are fairly restricted from the factory.

[Guest]

It would have the same manners....meaning??? My idle would be like it was stock? And no nice exhaust tone. And since this is more for sounds, and I would actually like more lower end power than top end (I dont plan on ever taking it to the track). I know I read the VS wont throw codes and the GT would. But what are the ~gains? like 10 HP? 20? Thanks, your all being very helpful. Especially the base info. I just need to pick one out now.

[Timbo1969]

The VS cam is really a forced induction cam. The GT cam is an NA cam. The GT cam you described is the GT2 cam.. Both the GT and GT2 cam's are fine for stock heads. If you want some manners and more N/A punch go with the GT cam specs I believe 210/210 .507/.507 112 lsa 108 ic. That should get you what you want. The 216/ 216 cam will push your powerband significantly over 5K and would be best with the P300 code deleted from your PCM as well as raised shift points, and of course rev limit. An aftermarket torque converter would be good too if you have an A4. I don't know much at all about the VS cam, there is a guy on here who has it. SSMS or something like that. He should be able to help you with how the VS cam acts