Revs, how high do they go?
Discussion
Mave said:
Captain Muppet said:
Bikes can't use much torque, because they flip over (unless you make them very long, which has implications for cornering). So you can design them to produce power without much torque, which means lots of revs.
Huh? I guess you're talking about torque at the wheel? For a given power and speed, how do you reduce torque at the wheel?
Huff said:
TREMAiNE said:
My RX8 R3 will to 10,000 rpm off the bounce. Apparently they're capable of hitting as high as 13,000.
One thing to note about the wankel - the output shaft is geared up to 3x the rotor speed. So in a Mazda with an output shaft speed of ~8000rpm the rotor is only actually spinning at about 2600rpm. (The gearing is required partly out of efficiency and rotor tip seal wear considerations, but also because the rotor runs an eccentric cycloidal path and gearing its inside face to a central shaft the only way to get a concentric rotary motion out of the thing)
TREMAiNE said:
Huff said:
TREMAiNE said:
My RX8 R3 will to 10,000 rpm off the bounce. Apparently they're capable of hitting as high as 13,000.
One thing to note about the wankel - the output shaft is geared up to 3x the rotor speed. So in a Mazda with an output shaft speed of ~8000rpm the rotor is only actually spinning at about 2600rpm. (The gearing is required partly out of efficiency and rotor tip seal wear considerations, but also because the rotor runs an eccentric cycloidal path and gearing its inside face to a central shaft the only way to get a concentric rotary motion out of the thing)
If it helps: parts of most 4 stroke engines rotate at half engine speed. It's the crank speed that counts.
I don't really consider turbines, rotaries or 2 strokes to be fair game. 4-stroke reciprocating is what I'm interested in.
I think the highest RPM engine you would buy for a road vehicle is about 16200rpm from a 2006 Yamaha R6 sportsbike.
It was originally advertised as having a 17500rpm limit, which was wrong (story: http://www.motorcycledaily.com/2006/02/01february0... )
In terms of cars, I think the highest rpm engines are:
If you're talking mass production, lets set a limit around 100 of them - then you're into things like the Ferrari 458 and (oddly) the Lexus LFA, both of which are up around 9000rpm.
The (European-spec) Honda S2000 is probably the highest revving (reciproacting) car that the average person could get their mitts on. The RX8 revs slightly higher, but of course is a rotary.
C
I think the highest RPM engine you would buy for a road vehicle is about 16200rpm from a 2006 Yamaha R6 sportsbike.
It was originally advertised as having a 17500rpm limit, which was wrong (story: http://www.motorcycledaily.com/2006/02/01february0... )
In terms of cars, I think the highest rpm engines are:
- Caterham Levante (about 10,000rpm - RS Performance development)
- Atom V8 (10,600rpm - Hartley V8)
- Caparo T1 engine (10500rpm).
If you're talking mass production, lets set a limit around 100 of them - then you're into things like the Ferrari 458 and (oddly) the Lexus LFA, both of which are up around 9000rpm.
The (European-spec) Honda S2000 is probably the highest revving (reciproacting) car that the average person could get their mitts on. The RX8 revs slightly higher, but of course is a rotary.
C
Edited by CraigyMc on Tuesday 30th July 09:46
CraigyMc said:
I don't really consider turbines, rotaries or 2 strokes to be fair game. 4-stroke reciprocating is what I'm interested in.
I think the highest RPM engine you would buy for a road vehicle is about 16200rpm from a 2006 Yamaha R6 sportsbike.
It was originally advertised as having a 17500rpm limit, which was wrong (story: http://www.motorcycledaily.com/2006/02/01february0... )
As been mentioned several times on this thread - over 20,000 rpm on a 1988 ZXR250. Yamahas FZR 250 was similar.I think the highest RPM engine you would buy for a road vehicle is about 16200rpm from a 2006 Yamaha R6 sportsbike.
It was originally advertised as having a 17500rpm limit, which was wrong (story: http://www.motorcycledaily.com/2006/02/01february0... )
Captain Muppet said:
CraigyMc said:
I don't really consider turbines, rotaries or 2 strokes to be fair game. 4-stroke reciprocating is what I'm interested in.
I think the highest RPM engine you would buy for a road vehicle is about 16200rpm from a 2006 Yamaha R6 sportsbike.
It was originally advertised as having a 17500rpm limit, which was wrong (story: http://www.motorcycledaily.com/2006/02/01february0... )
As been mentioned several times on this thread - over 20,000 rpm on a 1988 ZXR250. Yamahas FZR 250 was similar.I think the highest RPM engine you would buy for a road vehicle is about 16200rpm from a 2006 Yamaha R6 sportsbike.
It was originally advertised as having a 17500rpm limit, which was wrong (story: http://www.motorcycledaily.com/2006/02/01february0... )
An aside - looking at where these engines made power. The FZR may well rev to 22K, but it peaks at 15K?
C
Captain Muppet said:
Bikes can't use much torque, because they flip over (unless you make them very long, which has implications for cornering). So you can design them to produce power without much torque, which means lots of revs.
This is pretty irrelevant since the torque that makes them flip over is the torque available at the rear wheel, and that depends only on engine power and gearing, not engine torque (something that diesel drivers seem to have trouble grasping).A sports bike engine needs to be physically small and light, which limits the useable displacement (i.e. a larger bore or stroke makes the entire engine larger and heavier). You also need to keep rotational inertia to a minimum, since this has a big effect on the performance of a light vehicle. With a limited displacement, the only way to generate more power is either through forced induction (which has been tried several times on bikes, with poor results) or by making the engine work efficiently at higher RPM.
Big heavy bikes like cruisers use larger, lower revving engines such as the Triumph Rocket III which has a 2.3 liter, 3 cylinder engine making just 140 bhp, but 150 lbft. However it's a huge lump of a bike weighing 350kg and is about 2.5 meters long. A modern 1 liter sports bike (e.g. BMW S1000RR) can make over 190bhp and weigh around 200kg, but make only about 75 lbft and is around 2 meters long.
Mr2Mike said:
Captain Muppet said:
Bikes can't use much torque, because they flip over (unless you make them very long, which has implications for cornering). So you can design them to produce power without much torque, which means lots of revs.
This is pretty irrelevant since the torque that makes them flip over is the torque available at the rear wheel, and that depends only on engine power and gearing, not engine torque (something that diesel drivers seem to have trouble grasping).A sports bike engine needs to be physically small and light, which limits the useable displacement (i.e. a larger bore or stroke makes the entire engine larger and heavier). You also need to keep rotational inertia to a minimum, since this has a big effect on the performance of a light vehicle. With a limited displacement, the only way to generate more power is either through forced induction (which has been tried several times on bikes, with poor results) or by making the engine work efficiently at higher RPM.
Big heavy bikes like cruisers use larger, lower revving engines such as the Triumph Rocket III which has a 2.3 liter, 3 cylinder engine making just 140 bhp, but 150 lbft. However it's a huge lump of a bike weighing 350kg and is about 2.5 meters long. A modern 1 liter sports bike (e.g. BMW S1000RR) can make over 190bhp and weigh around 200kg, but make only about 75 lbft and is around 2 meters long.
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