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This article assumes that you have a clear understanding of what cam gears are and that you have at least one of them installed. Keep in mind that your modifications (turbo, fuel setup, etc.) might yield different results for your application. Use the explanation below to experiment with your cam gear settings but we HIGHLY advise not exceeding 5 degrees in either direction, advance or retard. As with all of our tech tips and how tos, You should have a certified mechanic working on your car, or if you wish to do yourself, Pro Street Industries is not responsible for the modifications you perform on your own vehicle.

On the 4g63 DOHC engine you can dial-in intake and exhaust timing independently of each other to regulate overlap. As you'll start to see as you make changes, combined with the use of a chassis dyno (highly recommended) you can fine-tune your cam's entire operation by advancing or retarding its action, squeezing as much horsepower and torque from your state-of-tune as possible.

It's important to note that adjustable cam gears have no direct effect on the duration and lift of the valves, that's the job of the camshaft lobes (profile) as dictated by the cam manufacturer.

*TIP - Always make sure your cam gears are tightened correctly to combat cam gear slippage. Slippage refers to the bolts that hold your cam gear to the settings you desire loosening up and allowing the cam timing to advance or retard fully often with catastrophic results. DO NOT LET THIS HAPPEN TO YOU. And not to state the obvious, but... make sure your car is in tip-top working order before you adjust your cam gears.

Generally, advancing a cam gear opens a valve sooner, and closes it sooner... retarding the cam gear, opens the valve later, and closes it later... since all you've done is "move" the fixed event.

Advancing Intake and Exhaust : This will provide the car with more bottom end power, and will decrease top end. Advancing both cam gears will move overlap earlier but will not increase it.

Retarding Intake and Exhaust : This will increase the cars top end, but will decrease low end. Retarding both cam gears will move the overlap later and but will not change the amount of overlap.

Advance Exhaust Only : This will help the cars top end, and it reduces overlap.

Retard Exhaust only : This will help the cars mid range power, very useful for cars with big turbos / big cams. By increasing overlap, It decreases lag significantly. Doing this will bring the boost on all at once. Very common DSM modification.

Advance Intake only : This will increase overlap and helps the cars bottom end and mid range power. This mod will bring the turbo on all at once, although isnt a very common mod for DSMS.

reallyslowcolt

Great information. Now only if I can get my 4g63 swap done for my colt. Once I finish the swap I will change my name to reallyfastcolt.