The great horse power swindle

[300bhp/ton]

I guess the first question is - does it actually exist?

I think it does, with ever increasing HP claims there seems to be a parallel with even greater electronics. Which as far as I can tell have the ability to reduce engine performance under certain conditions.

I say this as I know my 1999 Camaro has "torque management" which limits torque and thus HP in 1st gear. I know the 1997 Ford Puma also does something similar with it's only 123hp.

So how many cars on sale today actually offer up all the horses in any gear?


And on a related topic, I wonder what the legal aspect is if a car maker sells you a "250hp road car" that might never attain 250hp except at speeds higher than the legal limit. Are you really then getting what you pay for?

[BorkFactor]

I had no idea normal cars like the Puma did this - watching this thread with interest! I know some BMWs have a clutch delay valve which has something to do with limiting the power going through the clutch to prolong its life - the American market got an E60 M5 with a proper manual gearbox but it was criticised due to this. No idea if that is the same idea or not!

I wonder if any of my cars had power limiters?

[Output Flange]

It's not uncommon for the ECU to restrict output in first (and sometimes second) to stop the gearbox imploding.

It's a good thing. I'd rather that than have to replace the gearbox each time I change the tyres.

[Dr G]

Very, very common for reasons already mentioned.

[Jakdaw]

300bhp/ton said:

So how many cars on sale today actually offer up all the horses in any gear?

Who cares? If it can't put that power down, who cares whether it'll produce the power in that gear?

300bhp/ton said:

And on a related topic, I wonder what the legal aspect is if a car maker sells you a "250hp road car" that might never attain 250hp except at speeds higher than the legal limit. Are you really then getting what you pay for?

I doubt you can find a real-world example of this - perhaps a bike?

That said - it seems pretty irrelevant - plenty of manufacturers top speed figures well in excess of the legal limit, and 0-60 times that I doubt you could reproduce on the public highway without (arguably) committing an offence.

[Jakg]

BorkFactor said:

I had no idea normal cars like the Puma did this - watching this thread with interest! I know some BMWs have a clutch delay valve which has something to do with limiting the power going through the clutch to prolong its life - the American market got an E60 M5 with a proper manual gearbox but it was criticised due to this. No idea if that is the same idea or not!

I wonder if any of my cars had power limiters?

I thought a clutch delay valve just slowed the clutch engagement speed, so if you remove your foot from the clutch quickly, it slowly disengages?

[sleep envy]

Output Flange said:

It's not uncommon for the ECU to restrict output in first (and sometimes second) to stop the gearbox imploding.

It's a good thing. I'd rather that than have to replace the gearbox each time I change the tyres.

or fill the tank if your name is LHD

[Some Gump]

Rs4 limits until 5.5k rpm. Still get full power in 1st, but only of use on a motorway

[Superhoop]

Power and torque limitation seems like a sensible idea to me. What's the point of having 500 hp at the wheels in first and second gear if all it's going to turn the tyre into a cloud of smoke?

And then there's the warranty point of view - Surely manufacturers are just giving the car a sporting chance of making it through 3 years/X miles without ripping itself to pieces every 5 minutes?

[Output Flange]

300bhp/ton said:

And on a related topic, I wonder what the legal aspect is if a car maker sells you a "250hp road car" that might never attain 250hp except at speeds higher than the legal limit. Are you really then getting what you pay for?

There is no "legal aspect". If it produces 250bhp then it produces 250bhp. Whether you can legally do the speeds required to hit that peak in the higher gears is irrelevant to the claimed output figure, which is typically mentioned on an engine dyno in a lab somewhere.

I'm slightly surprised you think there might be a valid argument to the contrary.

[sleep envy]

Output Flange said:

I'm slightly surprised you think there might be a valid argument to the contrary.

Really?

I mean, really?

[Azur]

Its pretty widespread....

Most subaru's I believe are torque limited in 1st and 2nd by the ecu to protect the drivetrain. Old saab 9-3 2.3 turbo and the new focus RS are torque limited in the same gears to preserve the dignity of the front tyres!

I wouldn't say its a swindle - I would rather have an intact drivetrain rather than a few quicker tenths to 60 or leave the majority of my front tyres on the tarmac after a burst of acceleration!


EDIT: Oops.. I didn't mean to repeat others.. I started typing at 3.17!

Edited by Azur on Tuesday 10th April 15:27

[Output Flange]

sleep envy said:

Really?

I mean, really?

>checks who the OP was<

Ah, ok.

[300bhp/ton]

Jakdaw said:

300bhp/ton said:

So how many cars on sale today actually offer up all the horses in any gear?

Who cares? If it can't put that power down, who cares whether it'll produce the power in that gear?

Erm, how do you know it won't put the power down? And how do you know it can just because it's restricted?

Jakdaw said:

300bhp/ton said:

And on a related topic, I wonder what the legal aspect is if a car maker sells you a "250hp road car" that might never attain 250hp except at speeds higher than the legal limit. Are you really then getting what you pay for?

I doubt you can find a real-world example of this - perhaps a bike?

That said - it seems pretty irrelevant - plenty of manufacturers top speed figures well in excess of the legal limit, and 0-60 times that I doubt you could reproduce on the public highway without (arguably) committing an offence.

I don't have any proof or stats, but I do wonder about some of these modern high performance hot hatches. Isn't the new Astra VXR and possibly a not yet released Alfa meant to have 300hp? But at what road speed do you need to travel to actually see those power levels?

20-30 years or so ago you didn't have this. If you bought a performance car it made the power it said on the tin regardless of gear selection.

[redgriff500]

One of the first racers to use micro switches on the gear stick to limit power in the lower gears did very well by it's use.

Limiting power, hence wheel spin, frequently makes the car faster.

[BorkFactor]

Jakg said:

I thought a clutch delay valve just slowed the clutch engagement speed, so if you remove your foot from the clutch quickly, it slowly disengages?

I honestly have no idea - it was the closest I could think of!

(Can you tell I don't know much about this sort of thing? )

[Output Flange]

300bhp/ton said:

don't have any proof or stats, but I do wonder about some of these modern high performance hot hatches. Isn't the new Astra VXR and possibly a not yet released Alfa meant to have 300hp? But at what road speed do you need to travel to actually see those power levels?

You can do it at zero mph - leave it in neutral and rev it to the red line, you'll have made peak power somewhere on the way up.

So there you go, anyone can do it any time they like, and the manufacturer's claims are entirely valid.

[300bhp/ton]

Superhoop said:

Power and torque limitation seems like a sensible idea to me. What's the point of having 500 hp at the wheels in first and second gear if all it's going to turn the tyre into a cloud of smoke?

I'm not sure I understand this point of view. On that logic why would anyone want a more powerful car at all?

[Output Flange]

300bhp/ton said:

I'm not sure I understand this point of view. On that logic why would anyone want a more powerful car at all?

Really?

Traction is an issue if you try to dump 500bhp through a pair of wheels from a standing start.

It's less of an issue if you try to dump 500bhp through a pair of wheels that are already rotating.

Or are you being deliberately stupid?

[Superhoop]

doogz said:

I'm kidding, but really, a throttle isn't a digital device, and if putting it down is a concern, that's what TCS is for. Most cars with such limiters in place are there to preserve clutch and 'box life.

Indeed, but if the power/torque weren't limited, there will always be someone that tries to launch at full throttle, then complain when something breaks, then the manufacturer is expected to pick up the pieces (literally in some cases) under warranty - Anyone remember the GTR transmission complaints not long after launch?

I watched video on youtube the day (PH's own resident Monkey) from Driver's Republic - He was driving one of the GT500 Super Snake, and talking about it being unusable, and therefore pointless

http://www.youtube.com/watch?v=oYWDjtsx25c

300bhp/ton said:

I'm not sure I understand this point of view. On that logic why would anyone want a more powerful car at all?

Edited by Superhoop on Tuesday 10th April 15:46