can someone give me an explanation of what cam gears do without making fun of me for not knowing or telling me i should have bought an evo cause my car will never be fast? i've spent a good portion of the afternoon reading howstuffworks but couldn't find any mention of them. i comprehend camshafts, just not how cam gears fit into the picture.

 

http://auto.howstuffworks.com/camshaft1.htm does that help?

Fox

 

Most aftermarket cam gears happen to be lighter that OEM; plus they are mostly adjustable. Able to advance or retard the timing can help "tune" the car better. Plus, they look nice (look at the one here I got a while back[but haven't installed]...https://www.evolutionm.net/forums/sh...d.php?t=136109).

 

i read the camshaft stuff. that makes perfect sense to me. i don't understand how the gears fit into the process, i guess is what i'm missing. what controls those and how exactly is a gear adjustable?

*eats some more humble pie*

 

the gear is adjusting the cam in relation to the crank. so and adjustable cam gear lets you move the crank slightly. On our car the important part is the cam angle sensor on the diver's side end of the cam. The CAS tells the ECU that the cam is at a certain position, and that the pistons should be at their positions and it's time to fire the injectors- this is all defined by the programming done to the ECU. Following? now, if the piston is at 5deg BTDC when the CAS would tell the ECU that the cam is at a certain angle (has certain valves open and others closed) and you move the cam gear back 1 degree (counter clock wise) you're advancing the timing (you've effectively moved the crank back one degree, which on our car advances the timing- try to picture both wheels strapped together and moving one of them- you move the other the same direction in a proportionate amount). Now the cam will spin and do its thing the same as before. What's different is the piston is slightly lower than it was originally. So when the injector fires, you get one more degree of compression out of the piston. In general advancing gives more power because more pressure can be built up with the fuel charge in the cylinder. To a point. If you go TOO far, you make too much pressure and the fuel charge just explodes inside the cylinder, instead of making the pretty flame front that pushes the cylinder back down. Explosions are bad. We generally call this knock.

I hope that helps- I'm out of break time at work

 

so when you start playing with cam gears and start deviating from the expected AF mixture, that's when you need to start busting out the electronics and monitoring what you're doing, correct? so is there any noticable benefit to installing an adjustable cam gear on a stock camshaft? i'm assuming my minimal mods here, instake/header/test pipe/exhaust.

i get the most enjoyment out of learning about what i'm about to do and then either doing it myself or helping someone do it. i don't have any interest in dumping my car off at a shop and coming back a week later with it performing better. i figure if i've been on here for 3 years i might as well start learning something before i become "evolved". lol

oh yeah, thanks for the info so far guys, you might make a non-idiot out of me sooner than i expected!

 

I actually turn the crank by hand (with the timing belt off of the cam). I don't know if there's a gear available that has degree markations on it or not.... maybe a Fidanza gear? AEM? Soemthing from the Evo might fit...

you can advance until you hear knock, then back off 3 degrees (or a little more). That's what I've heard, btu I haven't had any knock yet The fancy electronics don't really tell you when you have knock- you'll hear it. It sounds like a car that's about to backfire or a big diesel truck.

 

Slow down there, Hoss.

Evo cam gears -

AEM -

Fidanza -

I believe Fidanza is the only company to make Lancer cam gears. And yes, I believe they do have the timing marks.

 

ergo the roll is slow, playa

 

Yo Alchy, check out the red Fidanza cam gear I got here... ( https://www.evolutionm.net/forums/sh...d.php?t=136109 ).

 

So how is retarding/advancing the timing related to hp?

Which way to turn for the best results? What to look for?

 

Retarding your timing is good for turbo and supercharger (forced induction) applications because it allows you to allow more boost per pound of boost of manifold vacuum - meaning it helps prevent detonation. It also allows more horsepower at top speed.

As far as cams are concerned...this is from my Power and Performance book from school - "The piston moves rapidly and reaches maximum speed 73 degrees to 83 degrees after Top Dead Center after Exhaust Valve Close." Meaning - you buy a cam that has longer exhaust and intake duration, you can have more air in the cylinder and move it out faster, also good for boost applications.

This is why when you are thinking of super- or turbocharging your car, replacing not only the cam but redoing the fuel/ignition system, the FULL intake (intake, port-matched throttle body and matching intake manifold) and FULL exhaust system benefit you GREATLY. Your stock fuel system can't handle the amount of fuel needed, your stock injectors just won't cut it. Your intake system lets in way more air, an upgraded fuel pump can push more fuel into a port-matched manifold to mix with the increased air flow. Thus, you create a denser mixture, and the increase in valve opening on the new cam will create more power, and the full exhaust system will allow better cylinder scavenging to pull the exhaust gasses out and exit the car, and let the turbo (if that's what you choose) compress the rest of the gasses to return to the intake...starting the cycle over again.

I know I explained WAY TOO MUCH, but this will help you build a faster, more efficient car. Make sure you dyno it and get the best air/fuel ratio so that your car isn't running too lean or too rich. A 13:1 ratio is good for racing, 14.7:1 is good for street use and economy.

Hope this helps!

 

so what effect would only a cam gear have on a stock cam? seems like it would just screw things up since the intake/exhaust timeframe would be the same. intake would open earlier but exhaust woudl open earlier too.

 

Right...that's why if you put in a cam gear you should match the same cam, too, so that the intake opens earlier and the exhaust opens later...and your piggy back ECU or reflashed ECU should retard the timing accordingly...in THEORY.

 

damn, i think i just learned something.