[Dandanbmw]

Has anyone noticed that the 30d is more instant in its power delivery over the 35d lump?
I thought it would be the other way round but from the ones I've driven the 30d definitely has hardly any turbo lag and the 35d engine has a little bit. Seems odd to me?

[dopper99]

Can say I've ever notice turbo lag in my 335d. Surely that's the whole point of two turbos?
I've not driven a F30 330d, but maybe it just the power delivery between the two that you are feeling is different? The 330d more urgent and 335d more linear?

Or maybe you should get your car checked out.

[subsy]

Originally Posted by dopper99

Can say I've ever notice turbo lag in my 335d. Surely that's the whole point of two turbos?
I've not driven a F30 330d, but maybe it just the power delivery between the two that you are feeling is different? The 330d more urgent and 335d more linear?

Or maybe you should get your car checked out.

Depends. If the turbo on the 30d is smaller, and more so if it's twin scroll, the spool up time will be intrinsically shorter than a pair of larger turbos on the 35d -that being said I have no idea at all whether it is smaller, whether it is a twin scroll design, or the size and design of the 35d turbos.

[Andrewthefirst]

[snipnoob86]

ive driven both engines and noticed no difference really in terms of turbo lag, is it an sdrive 330? because the sdrive 30d feels much more urgant than the xdrive 35d. which is a traction thing

[ukbeemerboy]

Originally Posted by Dandanbmw

Has anyone noticed that the 30d is more instant in its power delivery over the 35d lump?
I thought it would be the other way round but from the ones I've driven the 30d definitely has hardly any turbo lag and the 35d engine has a little bit. Seems odd to me?

I'll bet it has something to do with the map you've uploaded to your car.

[HighlandPete]

Originally Posted by subsy

Depends. If the turbo on the 30d is smaller, and more so if it's twin scroll, the spool up time will be intrinsically shorter than a pair of larger turbos on the 35d -that being said I have no idea at all whether it is smaller, whether it is a twin scroll design, or the size and design of the 35d turbos.

330d has a single VGT (variable geometry) turbo.

335d has sequential 2-stage turbos, small (low mass/inertia) turbo for fast spool up at low rpm and gas pressures, and the "big un" for mid and extended top end boost.

The 335d engine should by design (and BMW claims) develop boost lower down the rpm range and faster than the 330d.

The engine feel may be different but can't see how lag is greater. The whole purpose of the 2-stage turbo(s) setup is to make more instant, (less lag) power development at low rpm and a strong linear power development to maximum rpm.

[creepy coupe]

I drive my 435d and a 330d and can't say there's any difference. I did notice the 330d changes down sooner when giving it a little squirt. I'd imagine due to the lower torque output.

OP maybe the 330d is dropping down a gear and feels livelier?

[335dJa]

My dad has a 330d with ppk and there is barely any difference in overall performance. You can feel his is later to build up and quicker to run out of puff but makes up for it with a slightly harder pull in the middle. You'd be hard pushed to notice it unless you drive them back to back.

[HighlandPete]

Originally Posted by Dandanbmw

Has anyone noticed that the 30d is more instant in its power delivery over the 35d lump?
I thought it would be the other way round but from the ones I've driven the 30d definitely has hardly any turbo lag and the 35d engine has a little bit. Seems odd to me?

What rpm is the 35d engine showing this feeling of lag? From idle or around the 1500rpm range? Torque graphs show a very linear crossover as the large turbo starts working. Torque definitely climbs faster from 1,000rpm in the 35d lump, EMP (Effective Mean Pressure) is significantly higher, even at 1,000rpm.

[HighlandPete]

Originally Posted by 335dJa

My dad has a 330d with ppk and there is barely any difference in overall performance. You can feel his is later to build up and quicker to run out of puff but makes up for it with a slightly harder pull in the middle. You'd be hard pushed to notice it unless you drive them back to back.

What you say makes absolute sense. The constraints/limitations on the single VGT mean the mid range is where you can get gains. It is simple turbo physics, the variable geometry enhances the boost range, but has limitations at both ends of engine rpm, due to the turbine itself.

[Ss66]

Having owned both back to back the 335d Feels more instant in its power delivery to me

[NISFAN]

Originally Posted by Dandanbmw

Has anyone noticed that the 30d is more instant in its power delivery over the 35d lump?
I thought it would be the other way round but from the ones I've driven the 30d definitely has hardly any turbo lag and the 35d engine has a little bit. Seems odd to me?

I know what you mean, but I don't think it is lag. I drove a 530d and 535d back to back and noticed what you might think of as lag, but I think it is just the power delivery of the two different turbo solutions.

As Highland Pete has pointed out, the twin turbo should be the ultimate 'anti lag' solution. I find in practice it doesn't quite work as well as the theory might suggest.

Technically, the 330d Turbo is rated at around 315hp is a VTN design and is made by Honeywell/Garrett. Whereas the 35d turbos are made by Borg Warner, the small one is of unknown capacity but is a VTN type, the big turbo is clearly rated at more like 400hp but is a very simple (dumb) design. These turbos are in series with each other, which is simpler (in theory) of the handover between when one is doing the work or the other, but it still requires a mechanical hand over in the form of an exhaust valve. It is both the handing over that creates a problem and the management of the exhaust gas to focus it onto the small turbo in the early stages, but still feed the big turbo so that it is 'on song' when the handover is made. I have a feeling these aren't quite perfect in all situations and that gives what you might feel as turbo lag.

Looking at the standard 335d dyno plots I often see a peak of torque quite early, a definite spike, then it drops....I suspect this is where the two turbo's are doing the handover.

Now imagine, a lets say 100hp rated 'small' turbo, which is doing a good job at making boost at powers levels under 100hp, it then hands the baton onto a 'big' turbo that at 100hp is not really very excited and doesn't have VTN to enhance that lack of motivation. You get a lull before the bigger turbo comes into it's own. Whereas the 330d turbo is, let's call it a 'medium' sized turbo with VTN, so although not able to come on song quite as early as the 'small' turbo, it isn't far behind, but as there is no handover, just a constant adjustment of the VTN, it is quite a smooth constant control of boost pressure.....until it runs out of capacity.

The other fly in the ointment is that the ZF8 has control over the power delivery in the form of communications to the engine ECU. It could be that this is a bit softer on the 335d engine in anticipation of a larger torque value to deal with. I know on track there is a 'lag' coming out of corners in my 330d, which I think is 100% due to the gearbox torque limiting the engine (revs high so not in a lag range). On the spirited drives I have had in a 35/40d engined cars I have felt the same.....can't say whether it is worse than the 30d though as no experience of 35/40d on a track, but can't say I have felt it to be significantly worse if at all.

[SDH]

Originally Posted by Andrewthefirst

My thoughts exactly, wouldn't surprise me if someone brings petrol vs. Diesel lag to the party

[DaveH28]

I wrote a post last year after having a test drive in a 335d.

I felt my 330d was responsive, but I put it down a run-in 330d and a brand newish 335d.
but maybe the 335d is more deceptively quick...motorway speeds and pickup for overtaking was just ridiculous.

But that initial off-the-mark feel....the 330d had something different.

[Dandanbmw]

Here is my graph for the 640d before & after.

Maybe as some of you say it might not be lag but just a different power delivery.
I did notice though the 30d engine is more aggressive than the 35d engine and it does have a tendency to drop a cog where the 35d engine will have a linear push. Also in Comfort the the 30d was certainly more aggressive than the 35d engine.

Basically two different cars the 330d & 640d with weight differences etc but when my 640d was standard the 0-60mph time of the six was slightly quicker than the 30d but the 60-100 time in 30d was actually quicker making it faster 0-100mph overall?

[Dandanbmw]

Originally Posted by ukbeemerboy

I'll bet it has something to do with the map you've uploaded to your car.

No no the map has brought it alive this was from before the map being done.

With the weight of the six I did expect low down speeds to be very close but @ 60mph onwards to be able to pull away from the 330d but from 60 onwards the 330d was quicker!
Doesn't make sense to me as in my mind the heavier more powerful car should start pulling away once you start getting some speed behind you. And it's not just my six either as I went up the strip at the pod in the 330d and raced two guys I know one in a 335d & 435d take away the start line where the X drive shot off the 30d kept up or even a little bit gained once over 60mph which I found odd.

[teaston]

Originally Posted by Dandanbmw

Has anyone noticed that the 30d is more instant in its power delivery over the 35d lump?
I thought it would be the other way round but from the ones I've driven the 30d definitely has hardly any turbo lag and the 35d engine has a little bit. Seems odd to me?

No, I have noticed the complete opposite!

The 335D has a much more linear power delivery almost like a naturally aspirated engine. The 330D had some turbo lag which gives you a big lump of acceleration when the turbo cut in!

[Rukka]

Originally Posted by Dandanbmw

Has anyone noticed that the 30d is more instant in its power delivery over the 35d lump?
I thought it would be the other way round but from the ones I've driven the 30d definitely has hardly any turbo lag and the 35d engine has a little bit. Seems odd to me?

I think you're just too scared to fully floor the 335d.... your mind is making your foot hesitate in anticipation of the huge rush of torque...




.

[Dandanbmw]

Originally Posted by Rukka

I think you're just too scared to fully floor the 335d.... your mind is making your foot hesitate in anticipation of the huge rush of torque...




.

Haha lol

[JustChris]

Really? Aren't they the same unit but the tri turbo effects top end?

Maybe not though

[Tengocity]

I think Nisfan's comment regarding the gearbox is interesting as I had both a manual and auto E90 330d and the auto one by far had a greater sense of "lag" coming from off-throttle situations than the auto one, so I'm really not sure it's turbo lag as such, but "drivetrain lag". I notice it in my 335d as well and find it the most frustrating thing about the car (now the suspension is sorted), and suspect that the xdrive drivetrain adds to it further perhaps.

There is no doubt that after the fraction of second delay between throttle press and torque actually reaching the wheels the 35d engine is much more linear than the 30d, so for me this is just those fractions of a second when you want to start accelerating out of a corner, or adjust the line, and the drive reaches the wheels a few metres further round the bend than when you intended.