If you have bought or are thinking of buying an aftermarket camshaft (anything not made by smart) you may like to consider the pro's and con's of ownership and what you want from your car with the new camshaft fitted.
First off, depending on how the cam is designed the engine will no longer be as smooth as standard. Generally, you will have to sacrifice some bottom end torque in favour of mid/top end power.
A full race cam on the road is an absolute nightmare if it's your only car. Not only will your fuel bills be the same as a Skyline in traffic but its terribly uncomfortable.
A fast road cam (depending on manufacturer) can be much more manageable, although if its your only car its probably best to stick with something in the smart range as they are more suited to the everyday driver wanting something slightly extra.
On our project car we went for a fast road cam as we wanted something more aggressive than anything smart had to offer, yet still drivable. After fitting we experienced several problems such as:
- Stalling when stopping.
- Problems starting.
- Engine warning light coming on.
- Car falling into safe mode (limp home).
- Fault codes.
These problems usually arise as a result of the management system being too far out of its range and not being able to control idle speed efficiently for the cam. We also learned that the hydraulic tappets require compressing to squeeze out all the oil that builds up in them before refitting. After compressing the tappets and a remap to suit, the power delivery was improved and the lumpiness reduced.
To solve the remaining problems, we simply drilled a 2mm hole through the throttle body butterfly, (see picture below) this quite simply allowed more air to pass into the inlet manifold regardless of the throttle position. This method is a little crude but is very effective.
The only noticeable change to the cars behavior using the method is the engine will idle slightly higher (approx 1,000 rpm) but if you've made the decision to buy one of these camshafts then I doubt its really going to be an issue.