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It's been suggested on another topic that 150bhp in a large saloon is a barely adequate amount of power. I drive a Saab 95 base model that happens to have 150bhp, does 0-60 in about 9secs. and has a top speed of around 130.This is better performance than most family cars and small hatches. I consider this perfectly adequate performance and wonder why anyone should need more?
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I think the issue is that in some cars the peak power is only available at the top of the rev range and that the peak torque of these engines is also biased towards the upper end of the rev range.
For releaxed driving you want the peak torque at as low revs as possible and a flat response curve, the sweet spot for driving is then with the engine working between the torque peak and the power peak.
Unfortunately many of the very revvy (VTEC?) Japanese engines have a torque and power peak close together and at very high revs.
Ian L.
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Ian L's correct. It's part of the Saab philosophy that maximum torque should be accessible from low down in the rev range (2-3000rpm). This is why even their light-pressure turbo engines are flexible and driveable - and why even the 2.0 LPT in a large car like the 9-5 is satisfyingly responsive.
Honda has a completely different approach - which finds ultimate expression in the Type R variants; power extracted from small displacement units via high revs. This philosophy may well represent greater engineering purity than forced-induction, but there's an argument that it's a lot less well suited to real-world driving conditions.
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Exactly. Does your Saab happen to have a light pressure turbo by any chance, Lordwoody? If so that's no doubt why it feels ok.
Cars have got so heavy. It's not that long (ok, maybe it's 15 years now) since a Citroen AX would go rather well on 85hp, and a 205 or Uno would go very nicely on 105hp. Wasn't the Rover SD1 Vitesse considered rather a performance vehicle (and big), and what did that have, about 190hp? Nowadays they're having to put 180hp in a Peugeot 206 to make it a hot hatch!
Which reminds me - do I seem to remember signs in carparks often saying no parking (or was it overnight parking) for vehicles of more than 30 cwt? That must include an awful lot of 'family cars' these days.
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Dont the original Golf GTI and latest R32 have exactly the same power to weight ratio?
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tunacat - Your observation is so correct! Indeed cars are becoming heavier and heavier in this (endless?) persue for 'total quality', began by our friends the Germans of course.
I remember my dad's 1992 Mazda 323 1.6 that with 87hp and 930kg had decent performance. My 2001 clio weighs almost 1000kg and with 98hp has almost the same weight-to-power ratio!
Well, (sigh) at least they're safer and quiter...
Vagelis.
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How true, ALL cars could do with a metal diet!!VW Polo, Golf etc. have all put on pounds around their middles.
Also in some cases it still appears too difficult for cars to do more than 35 - 40 mpg, unless they are diesel powered. We have made great technical advances but at what cost??
K2
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I drive a Saab 95 base model that happens to have 150bhp, does 0-60 in about 9secs. and has a top speed of around 130.
How did you manage to screw 150bhp out of that old ex-ford, 65 bhp V4 engine. ? ;-)
I have to grow old - but I don't have to grow up
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90bhp in my Cavalier TD is barely adequte. There's enough torque to accelerate safely but only just. My Imprezza Turbo with more than twice the power has more than enough power for any situation I've ever encountered on the road. Turning left from a T junction onto a main road, with traffic streaming past at a steady 60mph means that you only need a gap of about 5 car lengths to ensure that you can pull out without the car you're pulling out in front of having to brake. He will however brake, because he won't beleive just how fast a car can accelerate, so I always wait for a bigger gap. More power would gain me no advantage here, just give me nore opportunity to panic drivers that aren't aware of what is possible in a genuinely quick car.
For real panic to be induceed, the same act of pulling into a stream of traffic can be done in a Caterham 7. As second gear is selected the back end will usually step out of line by at least three feet. You then continue to accelerate down the road with the car still sideways until you ease off and then you can see the panic that's set in behind you. This is why I sold the Seven. Driving sideways on a public road causes too much panic and I never learned how to exit a mini roundabout in the wet keeping that car in a straight line. It was a lot of fun and sadistically interesting to see the fear in other drivers eyes, but the public road is not the place for this.
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I read often, only post occaisionally
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I thought this thread was for larger cars until I saw the mention of the Cav, so I thought I'd chip in :)
I find 92bhp in my Xantia TD perfectly adaquete. It's reponsive enough for safe overtaking but not quick enough to get my into trouble due to inexperience (I'm 19). I'm moving up to a 130bhp Ford Mondeo but not becuase of lack of power - purely becuase it's the least powerful engine available at the trim level I want.
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Surely you only have enough power when you can wheelspin all the way from the apex of one bend to the braking point of the next?
Better make sure that there's no stickyness in that throttle linkage then....
Gareth
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I think the critical factor is the weight-to-power ration. Having as a reference point the value 10Kg/hp, I'd say that higher values tend to be "slow" and lower values tend to be faster or "sportier".
There is also the aerodynamics factor: have you noticed that longer cars can more easily reach high speeds (around 200kph) and maintain them than smaller cars?
Personally, a Subaru Impreza WRX or a Focus RS would make me more than happy, car-wise...
Vagelis.
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When I was much younger and I had Fiat Abarths, Abarth always stated the minumum BHP to reach 100 mph was 45BHP in a suitable car body, time was around 60 seconds if I remember correctly
K2
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