What is the weakness in the engine that determines a vehicles redline? More specifically, why does my E55 redline at 6k when my S2000 reached 9k? Is it because of stronger internal parts or less mass within the engine on the S2000?
School Me: What determines our vehicles redline?
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Our E55's are a SOHC 24 valve motor with a compression I can't quite remember right now. I think it's 10.5:1 not sure... The S2000 motor is a DOHC 16 valve motor... with a higher compression.
So the Honda engine has an extra cam and an extra valve for each cylinder. Correct me if I'm wrong, but this is partly why the S2000 revved higher.
This is the same reason Ferrari's and Lambo's rev high as well... along with M3's and so on.
From what I've seen, motors that rev higher have less torque but a good amount of horsepower. Our E55's have more torque than the E60 M5... but the M5 has much more of an exotic sound due to the fact it revs higher, more valves and it is a 10 cylinder.
This is my basic understanding... I'd like to hear more, I was thinking forged internals, iron block, aluminum block have a bit to do with it but I'm not an engine builder so I can't say. lol. :thumbsup:
It's not just "your engine."
Every engine is designed around certain basic desires and assumptions. Generally speaking, a smaller piston (bore, plus) means less mass to decelerate to zero and accelerate to blinding speed twice every revolution...and the forces imparted to the rod and big-end bearings are dramatic. A shorter stroke means lower piston speeds, so it can rev higher, but it's producing less power in each stroke. An inline 4 means a shorter crank, with forces acting in fewer directions, so it has less of a tendency to deflect as compared with a V8 (or 10 or 12). As you increase revs, though, frictional forces rise as well, and of course everything gets hotter and works harder -- and you have to manage more flow patterns (both intake and exhaust) and valve float. But that's a tradeoff choice as well. A smaller engine revving higher to produce a workable powerband describes most motorcycles (some with redlines way up near 20,000) and that's what the S2000 was going for, a workable powerband with improved economy in a small package.
The big V8 under your hood has a useful powerband at lower revs, and makes tremendous amounts of horsepower while generating loads of torque, too. So there is no reason for it to rev high, so it's not designed to do that.
There is lots of information on the internet about this, and if any of Kevin Cameron's articles are floating on the web he often discusses such things in ways layman find more approachable.
Hope that helps a little.
Every engine is designed around certain basic desires and assumptions. Generally speaking, a smaller piston (bore, plus) means less mass to decelerate to zero and accelerate to blinding speed twice every revolution...and the forces imparted to the rod and big-end bearings are dramatic. A shorter stroke means lower piston speeds, so it can rev higher, but it's producing less power in each stroke. An inline 4 means a shorter crank, with forces acting in fewer directions, so it has less of a tendency to deflect as compared with a V8 (or 10 or 12). As you increase revs, though, frictional forces rise as well, and of course everything gets hotter and works harder -- and you have to manage more flow patterns (both intake and exhaust) and valve float. But that's a tradeoff choice as well. A smaller engine revving higher to produce a workable powerband describes most motorcycles (some with redlines way up near 20,000) and that's what the S2000 was going for, a workable powerband with improved economy in a small package.
The big V8 under your hood has a useful powerband at lower revs, and makes tremendous amounts of horsepower while generating loads of torque, too. So there is no reason for it to rev high, so it's not designed to do that.
There is lots of information on the internet about this, and if any of Kevin Cameron's articles are floating on the web he often discusses such things in ways layman find more approachable.
Hope that helps a little.
Good info from both of you guys. Thanks gentleman.
I was reading the other day where the original DTM W124 had an idle rev of 5000 and 13k redline. What did they do to that engine to be able to achieve those kinds of numbers?
Not that I have any interest in doing it as my car is a daily driver, but could someone not conceivably do the same thing to our engines?
I was reading the other day where the original DTM W124 had an idle rev of 5000 and 13k redline. What did they do to that engine to be able to achieve those kinds of numbers?
Not that I have any interest in doing it as my car is a daily driver, but could someone not conceivably do the same thing to our engines?
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