determining redline
 

I was wondering how the manufacturers determine the redlines of cars. I know that having a smaller displacement allows for a higher redline. but there are also other factors. is it the strength of the rods, pistons, and crank etc? and do they just decide what internals they want to use for certain cars and then pick a redline, is there a formula or something, do they just rev an engine to see where its breaking points are? and if someone were to change out the internals would they have to get a new/ adjust the ECU to control rev limit cutoffs?

Thanks
fire

hehe, maybe, just maybe they do it like i did, got in the car, floored it and didnt shift, then said, "SHYT!! SHIFT SHIFT!!!" lol

(in case anybody is wondering, redline is about 7.2 or so.... couldnt tell with the rev-limiter thingy. and yes my car is ok... for now!)

Yeah, compression ratio and engine displacement are major factors.

When does the v-tec kick in on a 02 ex

It's all about engine balance, cam ratio's valves, valve springs... Engines redlines are generally lower than the engine can handle. COmpanies do this to the tolerances of engine components. Some factory freak cars can have all parts perfectly fit into optimal tolerance..some can ba at the far end of part tolerances.. They determine the redline by 3 major factors.

Vibration level(balancing),
Valve return
and component tolerances (heat, pressure)

Through analysis by computational means, or through testing. The analysis can be performed on a computer using special computer programs. The testing can be performed through various engine prototypes and dyno's. I bet that they do a combination of things, as well as use their older models as baselines. It's really all of the engine internals and how they perform that determine where the redline should be. Unless Honda just calculates the redline based on one component alone (like the valve springs). That would be wasteful though since all of the other components would be heavier and would fail a lot later (higher rpm's). Honda probably optimizes everything so that they reach their goal. Their goal for our cars when it comes to the engine is rather obvious. More miles per gallon than horsepower. That means lighter components and lower gas consumption. Efficiency was their goal. Hence I expect that we can not go over redline that easily. We would probably need to upgrade many of the engine's internals in order to do so. Who knows though? The tolerances may be large enough that we are able to bring it up to 7,800rpm by just changing the valve springs. [IMG]i/expressions/face-icon-small-confused.gif[/IMG]