Simple question, how much power does a stock 60 put down on the road in terms of power & torque? I may get a chance to put my 60 on a dyno and I have a distinct distrust of extrapolated 'at the clutch' figures.

This is why I use rolling roads that can measure the transmission losses. One of them (fortunately for me) is just in walking distance.

Due to tire compound, dimensions of wheels, ambient temperature, wear of gearbox, number of gears and type of lubricant used (and some other factors) the figures will vary.

The stock output varies too depending on how well the car is run in, maintained and the fuel being used (on the Alfa 147/156 GTA we have seen anything from 220 to over 250bhp on stock engine, where they often range on the lower end of the scale). The ones we have put on the rollers were between 57 and 64bhp.

before I started fiddling my 60 I got 47 from a rolling road (albeit this was withou a service and it had a vacuum air leak), I wouldn't expect too much more, but as a very rough estimate take a manual transmission to loose about 10% of power and 10% torque

Oldschool said:

The ones we have put on the rollers were between 57 and 64bhp.

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57~64 bhp at the wheel with no compensation for drive losses? :slayer:

StoneNewt said:

57~64 bhp at the wheel with no compensation for drive losses? :slayer:

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This was at the flywheel.

so 47 is about right for a std car? I thought it should have been more like 52-54 (thats 10%?) but then my car was running a bit doggy at the time, and I suppose 4-5bhp is a hard amount to register on a rolling road, especially when they are all different

Personally want at the wheels for 2 reasons..
a) I prefer direct measurement methods
b) actual power transmitted by the wheels to the road imo, is more meaningful

faster4_tec said:

before I started fiddling my 60 I got 47 from a rolling road (albeit this was withou a service and it had a vacuum air leak), I wouldn't expect too much more, but as a very rough estimate take a manual transmission to loose about 10% of power and 10% torque

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This doesn't represent the real losses.

Example 1
Transmission loss
@ 2500rpm = 11%
@ 3000rpm = 11%
@ 3500rpm = 11%
@ 4000rpm = 12%
@ 4500rpm = 12%
@ 5000rpm = 12%
@ 5500rpm = 14%
@ 6000rpm = 16%
@ 6500rpm = 19%
@ 6750rpm = 24%

@ peak power 17%

The car was a modified Punto FIRE with 6 speed gearbox.

Example 2
Transmission loss
@ 2500rpm = 17%
@ 3000rpm = 17%
@ 3500rpm = 18%
@ 4000rpm = 20%
@ 4500rpm = 21%
@ 5000rpm = 23%
@ 5500rpm = 26%
@ 6000rpm = 29%
@ 6500rpm = 34%
@ 7000rpm = 39%

@ peak power 29%

The car was a FIRE engined Seicento with a 5 speed gearbox.

Both vehicles were tested on the same rolling road. This particular rolling road is known to be accurate within 1bhp!

Oldschool, thanks for proving my very point... what you want to know is the power/torque at the wheels

StoneNewt said:

Oldschool, thanks for proving my very point... what you want to know is the power/torque at the wheels

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Ultimately it counts what you get on the wheels. All the power in the world isn't any good when it is being lost somewhere along the lines.

At the same token I would like to point out that the power on the flywheel also has got its point. When you do improvement on the engine side it is necessary to have clear figures from the transmission losses to be able to evaluate the gains. If only the wheel power is evaluated the readings might improve but no actual power gain might have been achieved on the engine side.

Also when being able to assess the drive train losses, measures can be taken to improve giving naturally more power to the wheels.

Please note the two examples where both using the same gearbox type. The car with the 6 speed gearbox (with one more gear than the other one) did not only have less losses in percent, but also in absolute power despite the fact being the more powerful unit.

Oldschool said:

Ultimately it counts what you get on the wheels. All the power in the world isn't any good when it is being lost somewhere along the lines.

At the same token I would like to point out that the power on the flywheel also has got its point. When you do improvement on the engine side it is necessary to have clear figures from the transmission losses to be able to evaluate the gains. If only the wheel power is evaluated the readings might improve but no actual power gain might have been achieved on the engine side.

Also when being able to assess the drive train losses, measures can be taken to improve giving naturally more power to the wheels.

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Totally agree, however flywheel, or even crank, hp (or more accurately torque) is an analytical tool for 'trouble shooting' the drive train etc. When it comes down to driving all that really matters is the amount of torque delivered to the wheels

Please note the two examples where both using the same gearbox type. The car with the 6 speed gearbox (with one more gear than the other one) did not only have less losses in percent, but also in absolute power despite the fact being the more powerful unit.

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I'll restate that as I read it. Not only did the car with the 6 speed box lose less power as a percentage it also lost less power in quantitative terms (ie car 1 lost 7lbft, car 2 lost 12lbft at the same RPM)?

Edit: I still want to know what an 'average' stock 60 produces at the wheels