Not rattle resistant. Actually every engines differs in their stability at low speed based on balancing, fittings, and construction materials. V6s are generally well balanced and smooth, hence being extra stable even at low speed.Thank you for explanation, xtremeleo Actually the Perdana and the Sentra are not the problem, these 2 cars don't rattle (the Perdana especially) even if their rpms drop to pretty low levels. My other two cars at home, a 1985 Toyota Corona with a 20v BT and a 1989 Honda Accord CA5 start to rattle when their engine rpms drop to less than 800. The Corona was like that even with the stock 4A carburetor engine. That made me wonder about the seemingly significant difference. At first I thought that it was due to engine age, ie. newer engine models are designed to be more rattle resistant, but the 20v BT is the same age as the GA16DE if not newer, no? The Perdana car design and engine is not new either. Got me thinking.. :hmmmm: But thank you for your explanation anyway..
About the vibration, your cars interior i.e dashboard, steering, switchgears are made from plastic, rubber, leather etc. Each of these are composed of particles (atoms or molecules) that have vibrational energy but you just do not feel it. Different materials have different particle vibration rate. Your engine that is running also generates vibration.
When you do not feel the rattling, this is when your engine's vibration is not in sync with the material's vibration. Meaning their vibration weakens or even cancle out each other. This is called destructive interference. Hence you feel smooth.
When you feel the stuff rattling, this is when your engines vibration is in sync with the material's vibration. The vibrational energy of your interior materials and of your engine builds one another up. thus vibrating the car more.