Hey guys

I was just thinking how the stroke of the motor usually plays a big part in determining the engines redline. Well, i took a look at the b16a2 and the b18c1 and notied that the stroke difference between those 2 motors is almost 10mm apart, yet the b18c1's redline is just a tad higher than that of the b16's. My question is, how can a stroked motor run at a higher redline and have the same, if not better, reliability of its cousin? Is there a point to where a certain stroke is bad, and everything else before that is realitivly safe? Sorry if it sounds confusing. Thanks in advance.

 

Many things are used to set stock factory redline.Piston speed is determined by stroke and rpm.There are limits to a reliable piston speed.The stength of the rods is important in figuring max piston speed,and redline.The weight of the valves,springs, and retainers is a factor.The strength of the valve springs is a factor.Camshaft design is a factor in the redline setting.The engine managment system is another factor.The peak hp number is also important,there is no reason to rev. to 11,000 rpm if it stops making power at 9,000.Hope this helps.
Glenn

 

When the GSR was new, the piston speed at redline was the highest of any production car sold in the US. The ITR replaced it a few years later. Honda did this in part by using high quality parts possible due to the cars being more expensive than the ones that got B16's. The B18C used a special coating on the rod journals on the crank that allowed a higher psi loading than usual due to holding oil better. That allowed smaller than normal journals for the load so the crank and rod big end could be lighter. For a given stroke, lighter parts allow higher revving.

 

Thanks guys for the replies. I had just always gotten the feeling that the stroke played one of the biggest parts in determining redline. But of course, you have your cam profiles, fuel mappings, valve train and stuff like that.