I was just curious as to the rev limiters that I believe are built into the ignition boxes (such as MSD etc). If you had the ignition box/rev limiter set to limit the rpm at a safe level for your engine, would hitting the rev limiter be detrimental to your engine in any way? Obviously extended periods of high rpm don't exactly equal long engine life.... Like if you knew a hypothetical SBF at peak hp can produce 450hp at lets say 6500rpm (I'm assuming that this engine is capable of making those #'s safely even during hard driving because you are not constantly at that high of an rpm). Lets say you limited the engine to 6000 rpm or 6200rpm which would (hypothetically) be roughly 400hp (these #'s are totally just bs btw) and hit the rev limiter or got close whenever your driving hard. The type of driving I'm thinking about here would be things like autocross, open track events, aka not really drag racing but in the curves and straights. So basically does forcing the ignition boxes to limit your revs do any harm?

 

depends on the setup. a rev limiter works in such a way that it makes sure that cylinders don't get a spark.
there is the bad design which always cut's out the same cylinder and the good design which alternates those cylinders. in my opinion the latter design is the better as it won't cool down and flush out single cylinders. this is a known problem when 'staging' in drag racing, which is effectively the same technique
unfortunately I have no idea which system uses what technique. you'll have to ask the manufacturer

 

MSD Two Steps, which are rev limiters on a button, are used all the time in drag racing. I would think they are safe, but it will scare you the first couple of times you hit it!

 

ya. some have two limiters. one for staging and one for redline.
however there's some that just disable a single cylinder instead of all in turns (which they should).

anyway a rev limiter is a safety device you better have than not. especially iof someone else is driving or you mis your shift. it's not meant to hold your rpm for a minute, it's supposed to protect your engine from accidental overrevving

 

So these I'm guessing limiters for staging allow you to sustain that high rpm level whereas a normal one "forces" your engine to slow down for a quick moment. Is that correct? I know "force" isn't the right word, its just stopping the supply of spark but you catch my drift. And what does flush the cylinder mean? Unburnt fuel builds up?