Power & torque curves

[rwb]

Lots of interesting statistics at http://www.superchips.co.uk

In particular: http://www.superchips.co.uk/roadtest/psahdi110.pdf
The point seems to be that ironing out an unexpected wiggle in the torque curve was just as important as the power/torque increases per se.

I was also surprised that the power and torque curves for the 110 are very different from the 90.

In both cases: look how the torque drops off after 2500PRM! Clearly that's why they "run out of puff", especially on the 90 where the power curve is almost flat here.

[Mastiff]

Lots of interesting statistics at http://www.superchips.co.uk

In particular: http://www.superchips.co.uk/roadtest/psahdi110.pdf
The point seems to be that ironing out an unexpected wiggle in the torque curve was just as important as the power/torque increases per se.

I was also surprised that the power and torque curves for the 110 are very different from the 90.

In both cases: look how the torque drops off after 2500PRM! Clearly that's why they "run out of puff", especially on the 90 where the power curve is almost flat here.

Awsome find mate

[lozz]

ithink the differnt gear ratios add to the mix too
110 is differnt ratios to the 90

im thinking a 90 box plonked into a 110 wouid make it quicker off the mark with shorter ratios

also the 110 is not actualy a 110 bhp standard its 109 the 90s are 89 so ivery much doubt the what people are saying the remaps are adding are gospel withought having it on a rolling road to confirm

[rwb]

I've been compiling these onto a single graph to make it easy to compare. In order of quoted power output I've included:
HDi 90
HDi 110 (2.0)
HDi 110 (1.6)
HDi 136 (2.2)
HDi 136 (2.0)
Mercedes 168 (2.7)
Audi 170 (2.0)
HDi 170 (2.2)
BMW 184 (2.0)

However, if the power was measured at 2000rpm then the pecking-order would be rather different:

HDi 110 (1.6)
HDi 90
Audi 170 (2.0)
HDi 110 (2.0)
HDi 136 (2.2)
Mercedes 168 (2.7)
HDi 136 (2.0)
HDi 170 (2.2)
BMW 184 (2.0)

On the power graph there's a clear step up from the HDi 90 to the HDi 110, and it's blatantly obvious why the 1.6 HDi 110 should be avoided like the plague. You don't want an Audi either. Among the more powerful stuff the 2.2 HDi 136 looks surprisingly weak compared to the 2.0 HDi 136. Even more surprising is that up to 2500RPM there's nothing between the 2.0 HDi 136, 2.2 HDi 170 and BMW's 2.0 184.



Similar story on the torque really:



As lozz says, how these feel in practice depends on other factors such as the gearbox. This also says nothing about efficiency.
Conclusions? Well if I wasn't coveting XUDs then I think the 2.0 HDi 136 would be my pick.

[Busman]

Well, what can I say? What a brilliant piece of work. Very informative.
Well done rwb, another good graph.