Automobile Engine Power and Torque

Car manufacturers do not always supply the correct information on the power of the engines in their cars. Sometimes, the figures are too high, sometimes too low. While the "too high" case might be obvious, there are also good reasons for giving too low figures. An example is the scaled down "100 kW" Audi V6-engine for the A6 to satisfy Swedish tax rules. Another is the BMW 2.5 6-cyl. engine, which gives more power and torque than specified. It is listed to be mid-way between the 2.0 and the 2.8, but in reality it is much closer to the 2.8 than to the 6-cyl. entry level 2.0.

The tables below are compilations of various car tests over the last five years (1995-1999) and contain both power and torque figures. For most engines, results from different tests are roughly equal and averages have been used for calculations.

There is no easy way to translate horse power and torque into the experience of driving different cars/engines. Of course, the distribution of torque over the entire revolution range is important, perhaps even more important than the power curve. But as a very rough rule of thumb, a mid-sized car (like Audi A4, VW Passat, or BMW 3-series) "comes alive" above 160-170 hp and 200-220 Nm. As examples, the VW Passat became markedly different when the 2.8 litre (Audi) V6 replaced the VR6, and the BMW 323 behaves markedly different from the 320.
 

Audi / Volkswagen

The VAG engines find their way into Audi and Volkswagen (of course!) but also into Skoda and Seat. The VR6 is also the top-of-the-line engine in the Ford Galaxy.

One exception to using averages for calculating the table figures is the Audi/VW 1.8 litre turbo with 150 hp nominal (the "Hungarian" turbo), which comes out anywhere between 141 hp and 153 hp, and thus probably is a family of engines rather than one model. Or engines fitted with different turbos.

It is interesting to note that the VR5 is almost equal to the VR6 in terms of both power and torque. Since I have not tried the VR5, I cannot tell whether this reflects driving experience. But the Passat VR5 was priced exactly the same as the 1.8 Hungarian turbo when they were introduced in the fourth generation Passat in 1997, making the VR5 good value for money. Since both were rated 150 hp, customers were a bit confused.

The VR6 never became the killer it was set out to be in the Sharan, Alhambra, or Galaxy. It is well known for its thirst, which is remarkable since it does not have even close to its specified power or torque. Maybe the 30-valve Audi V6 engine will find its way into these models as well.

Another interesting engine is the "de-chipped" 100 kW 2.4 litre V6. It actually has more torque than in its original 121 kW ancestor. The 100 kW was a chip "anti-trim", i.e. the physical engine is exactly the same as the 121 kW but the control program was modified to give less power, albeit not the reduction Audi claimed. And since the torque is better, the engine is a very good choice. It seems the second hand market for Audi A6 has recognized this fact and rates them about the same, even though the 100 kW was a lot cheaper to buy first hand. To create an artificial difference between them, the 100 kW came with much less options, such as no 4WD and no automatic transmission.
 
Audi / Volkswagen Claimed power Actual power Claimed torque Actual torque
1.8 / 4 cyl. (8-valve) 90 hp 90 hp 145 Nm 142 Nm
2.0 / 4 cyl. (8-valve) 115 hp 112 hp 166 Nm 171 Nm
1.8 / 4 cyl. (16-valve) 125 hp 125 hp 173 Nm 171 Nm
1.8 / 4 cyl. turbo 150 hp 141 - 153 hp 210 Nm 195 - 216 Nm
2.4 / V6 cyl. (100 kW) 136 hp 153 hp 230 Nm 229 Nm
2.4 / V6 cyl. (121 kW) 165 hp 166 hp 230 Nm 216 Nm
2.3 / VR5 cyl. 150 hp 160 hp 205 Nm 212 Nm
2.8 / VR6 cyl. (12-valve) 174 hp 167 hp 240 Nm 225 Nm
2.8 / V6 cyl. (30-valve) 193 hp 198 hp 280 Nm 255 Nm

BMW

BMW have tried to stay on top of the horsepower game by offering almost equidistant steps in power and money as you climb the 6-cyl. model steps. And much money for each step at that! But the steps are not that equal. The 2.5 litre engine was originally listed as 192 hp (from 1991 when it became 24-valve) and the models were called 325 and 525. For the 3-series, this was the top-of-the-line model. When the 2.8 litre 328 was introduced in 1995, the 2.5 litre model was renamed 323 instead not to intrude on the 328's top model status. The engine was also "de-trimmed" down to 182 hp and listed as 170 hp, thus creating more smooth hp spacing to reflect the pricing scheme. (The 525 engine stayed with the E34 until the end, and when the E39 was introduced in 1996, it was called 523 and the 528 emerged).

The table explains why the 323 feels almost like the 328 (except heavy acceleration above 100 km/h) and far from the 320. And it also explains why so many seem to dislike the E39 520 as much as they like the 523. Could it be that BMW already back in 1995 realized that the E39 when introduced would need a bit more than 170 hp to be a winner? It is, after all, a bit larger than the E34.

This also explains why it is easy to chip (reprogram the tables, really) the 323/523 up to almost 200 hp, since it is only 8-12 real hp up from the original 188-192, and get less fuel consumption as a bonus. It is rumoured that the 2.5 litre engine will soon be chipped back by BMW to its original 192 hp and once again be called 325/525. *)

This change will occur as soon as the 2.8 litre 328/528 is replaced with a 3.0 litre engine (possibly called 330/530), thus again creating the proper steps in power and money. It will not be the return of the 218 hp 8-cyl. engine from the 530 E34 of 1993-96, since it would not fit in the 3-series body (and not fit the 3-series image either, even the M3 is a true 6-cyl. machine). It could be a 24-valve Vanos version of the 6-cyl. 185 hp 530 E34 of 1988-89, but more likely, it will be a new design.

Finally, the newly introduced American built 3-series Z3 "sports car" (based on an ordinary E36 compact chassie), was from the start - at least in Sweden - available as Z318 (116 hp in a BMW "sports car"???) and soon Z328. More appropriate, a ZM3 version appeared a year later. As the 3-series evolves into E46, the Z3 is supposed to stay on the older base for a while, even further developing e.g. the old M3 E36 engine.
 
BMW Claimed power Actual power Claimed torque Actual torque
1.6 / 4 cyl. (316) 102 hp 102 hp 150 Nm 147 Nm
1.8 / 4 cyl. (318) 116 hp 115 hp 168 Nm 160 Nm
2.0 / 6 cyl. (320,520) 150 hp 150 hp 190 Nm 189 Nm
2.5 / 6 cyl. (323,523) 170 hp 182 hp 245 Nm 245 Nm
2.5 / 6 cyl. (325,525) 192 hp 188 hp 245 Nm 245 Nm
2.8 / 6 cyl. (328,528) 193 hp 193 hp 280 Nm 268 Nm
3.2 / 6 cyl. (M3) 321 hp 320 hp 350 Nm 359 Nm

To see that the measurements are indeed reasonable, consider the following factory performance table for the 3-series E36 4-door sedans. It shows that the 325 is almost identical in performance to the 323, and that both are quite close to the 328. The 320 is far behind in acceleration and also lags behind in top speed. It is the entry-level 6 cyl. machine, and not a particularly good representative of the BMW driving experience. The 323 seems the optimal value-for-money choice.
 
BMW 0-50 km/h 0-80 km/h 0-100 km/h Top speed
320 2.0 / 6 cyl. 3.0 s 6.5 s 9.9 s 214 km/h
323 2.5 / 6 cyl. 2.6 s 5.6 s 8.0 s 227 km/h
325 2.5 / 6 cyl. 2.6 s 5.6 s 8.0 s 233 km/h
328 2.8 / 6 cyl. 2.5 s 5.2 s 7.3 s 236 km/h

Volvo

Volvo is infamous for not having all the claimed horses in the stable. This turns out, though, to be true only for some models. Others seem to be under-specified instead. And the variation seems less than discussed in some car magazines.
 
Volvo Claimed power Actual power Claimed torque Actual torque
2.5 / 5 cyl. 140 hp 136 hp 220 Nm 209 Nm
2.5 / 5 cyl.  170 hp 162 hp 220 Nm 213 Nm
2.5 / 5 cyl. turbo 193 hp 198 hp 270 Nm 277 Nm

(more to be added later)
 

Toyota

I once considered acquiring a Toyota until I found out the true meaning of the adage "rust never sleeps". But the 2.0 is fairly good for being a "lean burner" and a bit more powerful than they admit.
 
Toyota Claimed power Actual power Claimed torque Actual torque
1.8 / 4 cyl. lean-burn 110 hp 107 hp 155 Nm 151 Nm
2.0 / 4 cyl. lean-burn 128 hp 134 hp 178 Nm 188 Nm

(more to be added later)

*) Normally, I tend not to believe chip trims on non-turbo engines above 5-7%. Of course, on turbos the sky is the limit, but at what cost?


Disclaimer: The figures in the tables are my compilations of various car tests. They are not official data of any kind. The interpretations are also mine, and do not constitute an official standpoint of DSV, KTH, or anyone else.

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