Does Length Matter?
Someone recently asked, “Why a longer rod?”  Someone else answered, “Longer dwell time.”  I never really thought about it before, so I thought I’d look into it.  Using some basic math, we can prove that a longer rod does indeed create a longer dwell time around top dead center.

As you can see in the diagram, the piston with the longer conrod spends more time around top dead center (0 degree crank angle) due to a slower acceleration rate towards and away from TDC.  A longer dwell time around top dead center makes better use of the combustion pressure and turning the pressure into torque; a rule of thumb is that you want peak combustion pressure around 15-17 degrees after TDC.  Furthermore, the combusiton pressures are higher while the crank angle is lower resulting in less side loading of the piston into the bore.  Less side loading results in less friction between the piston and bore freeing up power and reducing wear.  The reduced piston acceleration also improves piston ring life as the lower acceleration equals less force on the rings (remember F=ma?).

length

Read the rest of the article at Moto IQ

Project R32: S-Max Oil Catch Can

When tuning your car it is easy to overlook the finishing touches. The best approach to modifying your car is a balanced approach to every system. Even the smallest hydraulic, cooling or lubrication items might…
Read More

aFe Takeda: Lexus IS-F Intake

When Lexus took a serious swing at the BMW M cars, their first attempt was nothing short of spectacular. To run with the Germans, the interiors had to be luxurious, suspensions had to be on-point…
Read More

Stoptech Pad and Rotor Bed-In Theory

In order for any brake system to work optimally, the rotors and pads must be properly bedded-in. Getting your brakes properly bedded-in and keeping them that way is critical to the peak performance of the…
Read More