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When 147kW loses to 135kW. Toyota 86 vs BMW 220i

How come a light, powerful car is no faster than a heavier, weaker competitor?

The Toyota 86 automatic weights 1278kg and has a motor good for 147kW.  It does the 0-100 sprint in 7.6 seconds, which is the same time as the BMW 220i convertible (review here).  But the BMW manages only 135kW and weighs 1530kg.
 
Here’s the figures, and within that table is the answer:
 
 Toyota 86BMW 220iDifference
Length424044325%
Width177517740%
Height132014137%
Weight1278153020%
    
Power147135-8%
Torque20527032%
Gears6 auto8 auto2
    
Max speed 2nd95km/h80km/h15km/h
Power/weight8.79.59%
Torque/weight6.24.7-24%
    
0-1008.17.6-6%
 
The BMW pegs back its power to weight disadvantage in three ways.  First, it has a quick-shifting automatic, far quicker than the 86’s.  It also has eight gears, which is crucial.  Both cars need two gearchanges to make 100km/h, but the 86’s is at 95km/h.  The BMW’s is at 80km/h. The BMW’s narrow gear ratio means its engine can be in its best power band pretty much all the time.
 
The third and most important BMW advantage is a wide power band.  Peak power is maintained from 5000 to 6250rpm, quite a wide powerband.  When you change from second to third at the 6500rpm redline you drop 2000rpm to 4500, so you’re only 500rpm off maximum power.
 
The 86’s peak power is 7000rpm, and it is peaky, so below 7000 the power drops off dramatically.  And when you change from the 7500rpm redline the revs drop 2300 to about 5200rpm…which is way more than 500rpm off peak power, so the car wouldn’t be developing 147kW at 5200rpm, and probably not even 135kW.
 
So that’s how it’s done.  No great mystery – quicker shifting gears, more gear ratios, and and engine which produces nearly the same power but over greater rev range.
 
Yet the 86 feels no slower, because it’s lower, the engine has more of an abrupt punch compared to the BMW’s linear power delivery, and towards redline the 86 is deliberately racous, whereas the BMW is more understated.
 
Just goes to show that looking at power figures has never been, and never will be a reliable indicator of performance.
 
 RMP_6814
 

RMP_1836


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Mark
Mark
5 years ago

And the BMW has 32% more torque, so it would perform much better in between gears and rolling acceleration times.

Robert Pepper
5 years ago
Reply to  Mark

True-ish…that meaty torque gives it the ability to produce its 135kW over a wide powerband and that’s one of the BMW advantages. For acceleration it’s power than matters, not torque. Power is only torque over a specified time period.

marc
marc
5 years ago

This is a terrible article. The gearbox is inconsequential compared to major issue of around 33% more torque, that is offset by the 250kg weight. Gearbox ratios (6 v 8) and time changes count for very little in a 0-100 sprint of passenger cars. Crunch the numbers before writing such rubbish.

Robert Pepper
5 years ago
Reply to  marc

What good is torque if it doesn’t translate to power?

What good is a peak power output if the engine can’t be run at its best power band?

You can have masses of torque but not power. Consider a windmill or waterwheel for example.

And gearing is all about torque, it’s a torque multiplier so yes, gearing is important. How would the 86 go with just the one gear?

As for speed of shifting, we’re talking tenths of a second difference…people obssess over 7.6 vs 7.4 seconds. In both cases there’s two gearchanges. If each take 1/10th of a second longer then that’s a difference, no?

Lots of torque is only good for acceleration if it translates to more power, and that is not always the case.

marc
marc
5 years ago
Reply to  Robert Pepper

1. There’s basically no power difference. 10kw is nothing.
2. Torque difference is significant
3. Research the 0-100 times of the 4/5/6 speed gearboxes of the BF/FG Falcon. There’s virtually no time difference. The 4 speed is archaic in comparison.
4. Weight. 250kg difference. For 0-60 times and less so for 0-100, weight is one of the biggest factors for/against acceleration. Most small cars will beat a heavy powerful SUV over the first 50-75metres.
5. Get a 4 cyl Camry (1500kg) and drag it with a Ford Territory (2000kg). Both reach 100km/h in about 9 seconds, but the Camry is about 4 car lengths in front.

Robert Pepper
5 years ago
Reply to  marc

Good points, Marc. Agree 10kW is neither here not there, and that assumes both cars in real life operate to their maximum. Not sure what the Falcons have to do with it. The point of the article is to highlight that mere headline numbers cannot be relied upon for all the reasons in the article, and the extras you point out.

Prateek Kumar
Prateek Kumar
5 years ago

It’s simple – the 8.1 second time 0-100 km/h is a load of bollocks. Many independent videos on youtube show that the 86 does it in under or around 7. the 0-60 mph (0-97km/h) time has also been recorded as low as 6.2 seconds in the manual

Robert Pepper
5 years ago
Reply to  Prateek Kumar

Yes, there’s a few such tests. I’m not sure if the 0-60mph tests involve a change to third gear. If they don’t then the 86 would shine. However, the basic point remains the same – a less powerful, heavier car isn’t necessarily slower.

Scotty Weir
Scotty Weir
5 years ago
Reply to  Prateek Kumar

Gee, my 220D outran an 86 at a “Happy Laps” day recently from a standing start and was 3/4 car length ahead at 100kmh by my speedo left in auto. He ran in “change the auto by himself” mode so I said, leave it in auto and see how it goes. Next time out we lined up and went together and it was only 1/2 car length at 100????? Go figure.

PracticalMotoring
5 years ago
Reply to  Scotty Weir

Hi Scott, I’ll leave Robert to come back to you about the particulars of his test, but I’m a huge fan of diesel engines. I could be wrong, and it wouldn’t be the first time, but I think it’s the initial slab of lowdown grunt a diesel offers that allows a diesel car to get up and running quickly. Whether they’re faster on a race track will always be an argument people will have, but in the real world I reckon a performance diesel feels smoother and more effortless when overtaking and the like. Isaac

Robert Pepper
5 years ago
Reply to  Scotty Weir

Not surprised, Scotty. The 220D has a 0-100 of 7.1 seconds, slightly quicker than the 86 and that is the only stat to look at.

But…so many variables. The state of tune of each car, the driver’s reaction, extra weight in each car (even fuel load), whether the 86 was running 95 or 98RON, tyre inflation pressure and so much more. Technique plays a big part as well. If the 86 driver just floored the car from a standstill that will be slow as it’ll take a while for engine to rev up to 7000. The correct technique is to hold the car on the brakes with the left foot, build revs and off you go.

If the same technique is used in the BMW 220d it’ll be quicker as while the diesel is slower revving, it’ll get into its maximum power band more quickly.

Anyway, all this is theorising which is my point….tenths of a seconds in stats mean nothing. It’s all about the feel and enjoyment.

AUSDAVIDZ
AUSDAVIDZ
5 years ago

Sorry, this is plain stupid
NOBODY would cross shop these 2 vehicles, the prices are miles different
About as close as a Falcon Glove-box v;s a Commodore Glove-box v;s a wheelbarrow….

Robert Pepper
5 years ago
Reply to  AUSDAVIDZ

You would be amazed what people cross-shop. Anyway, this article wasn’t about cross-shopping.

Robert Pepper

Robert Pepper