[Andystobbs]

Hi all, I'm after people's opinions

I currently have a 320d E91 manual, which is my baby. All the options I want and some more mods in the pipeline.

Its a shame its not a 6 cylinder though.

I have designs on retrofitting active cruise control. I know that's a lot of work on the 4 cylinder so we'll leave the technicalities aside. I already have all the needed parts for my ACC retrofit.



Now I've just bought a 330d E91 Auto to harvest some parts off.

I've just driven it and it blew me away, really pleased with the extra performance.


So does the ACC suit an auto better?

Perhaps I am wrong, and that's why I'm seeking other inputs.

I can envisage a situation where with the manual the ACC would need a gear change in order to maintain set distance, perhaps down from top first as traffic slowed, then back up as things improve on the road.

The auto would of course cater for this, well automatically. Improving the overall experience and the whole idea of cruise control, let alone active cruise control.


Please chime in with opinions.

Also please provide general opinion on what is preferable a 330d manual or a 330d auto.

Thanks

[Boston4]

I'm not familiar with how the BMW system works - as it's an early one, it could go either way for whether it would work a very low speeds. So that's the first question - does it work at speeds from 0-20?

If the answer is yes, how much bumper to bumper traffic are you actually in on a week to week basis? If it's a lot, then maybe an auto beater is the answer. Otherwise, I think it'd be helpful for highway or fast-back-road driving. Situations where you're going from 60-80-70-55-65 are pretty much all going to happen in 6th, and the system would definitely be able to do that. If it doesn't work at low speeds, then go for a 6 speed.

Personally I'd add it to my 6 speed if I already had all of the parts. Traffic jams suck but I spend more time highway cruising than I do in bumper to bumper traffic. I also think the 6MT is a better transmission - it's more reliable and just more fun to drive.

[pmorg4]

Reviving an old thread, but I thought I'd chime in as I've fitted ACC to my manual E91 330i. As asked above, the system doesn't support "stop and go" so will not operate below 20 MPH. It can be coded to operate down to slightly slower speeds (I think the minimum is 20 km/h which translates to around 12 MPH) but I don't know how well it works at such speeds.

I think you're right in that ACC is most beneficial in motorway driving where the traffic speeds may vary and you can't really use normal cruise control, but it's continually flowing. You generally don't need to change gear often, but if you do the cruise control will remain engaged so changing gear isn't a problem. I get the point though that an auto gearbox would make the process more effortless.

I generally strongly prefer a manual gearbox with the petrol engines so for me the trade-off for ACC being slightly less effortless is worth it. However with a diesel engine it is naturally more suited to an auto with its narrower power band and power produced at lower RPM, so it's a more nuanced decision. One factor would be the age and mileage of the car, I'd be much less worried about an expensive bill with an older and higher mileage manual gearbox.