[Dormermike]

Hi

Not an E90 but an f10 with zf8 auto and also I'm not sure if I'm imaging this but in second gear with a 30-50% throttle the acceleration is not linear, rate of acceleration seems to slow briefly around 2500 rpm and again later in the rev range, maybe 4000rpm and then pulls hard up to redline. After each hesitation it seems quicker. Not sure if this is surge or not. Definitely not a misfire.

Wondering if this could be blocked up inlets ? Feels like airflow pauses for a moment like momentarily backing off the throttle but I'm sure I'm not doing that.

Full throttle acceleration is fine - linear and pulls hard as I'd expect.

Any ideas please ? No codes.

Thanks
Mike

[Will_460cs]

Originally Posted by Dormermike

Hi

Not an E90 but an f10 with zf8 auto and also I'm not sure if I'm imaging this but in second gear with a 30-50% throttle the acceleration is not linear, rate of acceleration seems to slow briefly around 2500 rpm and again later in the rev range, maybe 4000rpm and then pulls hard up to redline. After each hesitation it seems quicker. Not sure if this is surge or not. Definitely not a misfire.

Wondering if this could be blocked up inlets ? Feels like airflow pauses for a moment like momentarily backing off the throttle but I'm sure I'm not doing that.

Full throttle acceleration is fine - linear and pulls hard as I'd expect.

Any ideas please ? No codes.

Thanks
Mike

If it has a 3 stage manifold then I'd expect that it possible this opening causing the surge..

My e91 has a distinct power increase when the manifold 3rd stage opens.