[zltm089]

I would like to know when does the twin turbo kick it in? at what rev? cheers.

[dxb335d]

LOL...

Pretty much right away there sooo small.. Hence hardly any lag.

Aint like the old cossies when you would have to wait till 3500-3750 LOL.

[zltm089]

Are you sure Carlos?...I told my mates at 3k rpm....I wasn't too sure though....because i normally feel the pull from the start, but didn't expect the turbo to kick in from the start!!!.....I though it was just because of the awesome torque!

[Dougie335]

See attached doc.

[G33]

Originally Posted by Dougie335

See attached doc.

Where did u get that data from??? Stock/remap?

Ive attached the image frm Dougies attachment to make it easier for every1

[trixman]

Should be pretty much instant... why bother with twin turbos otherwise.

[DaveC]

Originally Posted by zltm089

I would like to know when does the twin turbo kick it in? at what rev? cheers.

You mean when does the second, bigger, turbo join in? Not sure exactly but from about 3-3.5k up would be a reasonable guess I think.

[E92Fan]

Originally Posted by DaveC

You mean when does the second, bigger, turbo join in? Not sure exactly but from about 3-3.5k up would be a reasonable guess I think.

On the petrol 335 the two turbos are the same size running in parallel, each one feeding one bank of three cylinders. On the diesel, the turbos run sequentially, one larger than the other, to sustain boost across a larger portion of the rev range

The 335i petrol is designed to give maximum torque from about 1400rpm - therefore the turbos should logically already be at full boost by this point

[DaveC]

I didn't know that Tony, I thought they were both sequential. Now I'm no sure I understand why they would do it that way round, from a logical point of view the petrol has a much bigger rev range to deal with and would seem the more likely candidate for sequential turbos whereas two small ones on the denzil would make more sense to my mind. Still, BMW do seem to have got it right so I wont write them a letter of complaint

[creepy coupe]

In my 135 it comes in cleanly at 1400 rpm

[doughboy]

Originally Posted by zltm089

Are you sure Carlos?...I told my mates at 3k rpm....I wasn't too sure though....because i normally feel the pull from the start, but didn't expect the turbo to kick in from the start!!!.....I though it was just because of the awesome torque!

they are working from idle upwards i reckon.

the turbocharging is what makes the torque low down.

as the wastegates are shut even at idle, the turbos are producing boost from idle upwards, more revs&throttle = more boost (limited by wastegates)

obviously the boost is low at low revs/ throttle, but there is no real 'kick in' as such, look at horsepower curves for 335i, they are very smooth with no real jumps.

[Dougie335]

G33,
V3 does wonders and that was with half a tank of fuel and two people in the car. Should be even better when I get the launch control working.

Dougie.

[dxb335d]

Originally Posted by doughboy

they are working from idle upwards i reckon.

the turbocharging is what makes the torque low down.

as the wastegates are shut even at idle, the turbos are producing boost from idle upwards, more revs&throttle = more boost (limited by wastegates)

obviously the boost is low at low revs/ throttle, but there is no real 'kick in' as such, look at horsepower curves for 335i, they are very smooth with no real jumps.

I assume it makes full boost at just over 1500rpm and holds it to 6.5k

[doughboy]

Full boost pressure maybe, but thats easier at low revs, the air flow increases with revs, so the turbos have to spin much faster to maintain the same boost pressure at the higher flow rate.

[zltm089]

cheers for the info guys...I knew I could feel something from 1500rpm!!! :-)