|
Originally posted by Ducking_Fumbass Some people actually like shorter rod motors. A short rod engine will exert torque on the crank earlier after TDC than will a long rod engine. What is interesting about this is that the power stroke contributes the most torque in the first 100 degrees or so, which is why I like the idea of biasing the crank force towards TDC (shorter rod). Botttom end torque is vital, especially to a turbocharged engine. There are advantages to a long-rod motor, too. At higher RPMs, it can potentially make more power. Because they dwell longer at TDC, less attention can be paid to the ports, and still have power made. The volume in the intake runners can be reduced, as well. On top of this, there is the obvious advantage of reduced piston wall side loading, and an increased rod to crank angle, which should transmit power more effeciently. For the same reasons that knock is more likely at lower RPMs, the short rod engine is less prone to detonation. The piston has a better chance of outrunning errant outcroppings in the flame front. Personally, I like a shorter rod design. In this way, I am very much in the school of thought of Grumpy Jenkins. I just think that any losses because of decreased TDC dwell time can be overcome by a well designed intake manifold, and a properly ported (for the application) head. The increased propensity for a short-rod engine to suffer reversion can be overcome with a properly designed exhaust manifold (and head). Everybody has a different opinion on this subject, though, and most of them are wrong. There are merits to both. Read up, learn, and make up your own mind. Also: your bottom end will not be your limiting factor in selecting a redline. Maybe with an underengineered 2.4, but not with a 2.0. Your limitation is in the valvetrain.
The short version of this is essentially, unless you can design your own cylinder head and intake manifold, you'll want the long rod.
______________________________ If a sentence found online has 35% misspellings or greater and includes at least two racially charged expletives, chances are it is a YouTube comment.
'95 Eclipse TurboGS (garage deco) '95 TSi AWD (restoring a survivor) '97 Talon ESi-T (poor impulse control) '99 Eclipse RS-T (daily beater) '13 Evo X (mostly stock) '17 Sienna (Middle Aged Dad Mobile)

Factory Service Manuals: http://nawdu.de/files/
|