how does z4is produce extra torque but no more power on over boost ?!

[Alext]

itmakes an extra 50nm or so torque when overboost kicks in but what about power?

[tot]

Originally Posted by Alext

itmakes an extra 50nm or so torque when overboost kicks in but what about power?

Well, since power = torque x rpm x constant, if torque increases 10% for given rpm, so does the power.

[Memphis1]

since hp maxes at 5900rpm, the torque boost probably does increase power but it's not noted because past 5900rpm hp is decreasing. max hp occurs at lower rpm than torque.

[Alext]

Thanks for the replies I understand what BMW mean now.

[richard in NC]

Originally Posted by Memphis1

since hp maxes at 5900rpm, the torque boost probably does increase power but it's not noted because past 5900rpm hp is decreasing. max hp occurs at lower rpm than torque.

Correct. The torque boost must occur at a lower RPM than would cause HP to increase.

[cdeslandes]

Originally Posted by richard in NC

Correct. The torque boost must occur at a lower RPM than would cause HP to increase.

I imagine that BMW let boost taper down to a similar level as the 35i near redline to avoid overclocking the turbos. Same thing Dinan did with their code. Hence the huge torque/modest power increases.