[clivem2]

Surprisingly the graphs suggest the 30D is better from very low revs than the 35D, the 35D gets it's own back as revs rise, that's for sure with it's much broader powerband and faster response.

[swallowtail]

We don't get the 35d here in Aus, so I have not been able to compare unfortunately. It probably also saved me a few thousand $ as well... LOL.

[khaiql]

Anyone know if there is a throttle software update for our diesel engines? I read in the other throttle lag thread that it was only for N52 and N55 engines. I'm not very technically minded but does this refer to our engines too... specifically mine is the 30D.

[Cropwell]

I currently have a 335d coupe with an X3 30d on order.
Even with the 35d engine in the coupe you still get a bit a bit of throttle lag especially from a standing start. I don't expect it to be any different unless BMW have significantly changed the engine and mapping in X3.
Although the 35d is incredibly resposive in low and mid range rev bands I still sometimes drop it down a gear with the paddle shift to crank up the turbo if a really quick overtake is required.(Unfortunately no paddle shift on 30d so will need to use the semi auto change).
Due to shortage of demo models when I placed order I have not driven 30d or 35d.
From my experience you are going to get some lag with both engines-just because of the physics of how a turbo works.I would expect the 35d to have less lag simply because of the twin turbos but probably not significantly different from 30d. If price is not an issue then 35d is going to be more responsive.

[clivem2]

I think most of my issues are turbo lag, it's not something I ever had to think about with my 335i, there was simply no turbo lag. The X3 being an auto encourages me forget about managing the lag.

The 35D is more responsive but put the 30D in Sport or better still Sport+ to reduce traction control numbness, then it responds well.

[liviugi]

Hi, any ideas if throttle lag on a 20d X3 can be solved?

[dnw]

Originally Posted by liviugi

Hi, any ideas if throttle lag on a 20d X3 can be solved?

Yes, by trading for a 30/35d!

[troggy1969]

Most modern diesels have a 'soft' throttle due to the fuelling requirement for emission standards. You can't pump too much fuel in before the air is there to give a clean burn so the engine management has to wait for the turbo to give boost before giving more fuel, hence delay (it's the chicken and egg all over again). The only way to give good response would be to re-map or chip the engine which would over-ride the emissions management and you would see some smoke when you first hit the thottle until the turbo kicked in.

It happens with all emission controlled diesels, I had a problem with it on 700hp Cat C18 engines until Cat re-wrote the software and removed the Tier 3 emission control (earthmovers also have it!) and now they are fine.

[HighlandPete]

Originally Posted by troggy1969

Most modern diesels have a 'soft' throttle due to the fuelling requirement for emission standards. You can't pump too much fuel in before the air is there to give a clean burn so the engine management has to wait for the turbo to give boost before giving more fuel, hence delay (it's the chicken and egg all over again). The only way to give good response would be to re-map or chip the engine which would over-ride the emissions management and you would see some smoke when you first hit the throttle until the turbo kicked in.

I agree that emission control along with the current trend to be pushing for 'headline' consumpton figures, means something has to give. We can't have it both ways.

So if there is mapping for economy, it has to show. We went through this years back when the old test regime was being pushed hard and manufacturers were tweaking performance to get the old '56mph' constant figure up, to look impressive. Some cars had virtual holes in the power curve due to this and were not easy to drive.

I'm a bit surprised the 35d engine is looking on par, or even less impressive at low rpm, as the whole idea of the sequential turbo setup is to achieve boost threshold at lower rpm and also give top end performance.

When the 5-series 535d was first introduced, it felt much more lively even at the low end, compared to the 530d. If things have changed, I'd suggest it is the fuel/emission mapping, coupled with some gearbox trickery, all to keep emissions in control across the rev range and keep the economy figures high in the EU test cycle.

It's another reason why real world mpg shortfall is getting larger, figures look brilliant but it doesn't translate to all driving conditions. Especially if we think we need sport settings, to get the performance.

HighlandPete

[BBender]

BTW what is the difference between the SPORT mode which is turned on by pushing the "ECO PRO" button and SPORT mode of the transmission by switching the shift handle to the left if you dont have dynamic dampers?

[RSchneider]

Careful to over-interpret those figures on the graph. It's not the engine on a testbench, it's built into a 5 series, and I e.g. have no idea if there's a gearing difference between a 30d and a 35d.

[troggy1969]

Originally Posted by RSchneider

Careful to over-interpret those figures on the graph. It's not the engine on a testbench, it's built into a 5 series, and I e.g. have no idea if there's a gearing difference between a 30d and a 35d.

I'm not sure about the 5 series but with the X3 the gearing between the 30D and the 35D is the same. You can see it in the broucher.

[HighlandPete]

Originally Posted by RSchneider

Careful to over-interpret those figures on the graph. It's not the engine on a testbench, it's built into a 5 series, and I e.g. have no idea if there's a gearing difference between a 30d and a 35d.

Good point, also possible the conditions dictated gearbox torque reduction as well.

HighlandPete

[Alligator69]

Originally Posted by BBender

BTW what is the difference between the SPORT mode which is turned on by pushing the "ECO PRO" button and SPORT mode of the transmission by switching the shift handle to the left if you dont have dynamic dampers?

You might have the VSS (Variable Sport Steering), that for example in Italy is possible as a separate option, do it would harden/soften and increase/reduce the steering wheel demultiplication. And the setting affects both the gearbox (revs before shifting) and the response on the pressure over the accelerator.

[BBender]

When the car is in the "SPORTS" mode, switching the gearbox to the "S" will make any difference?

[calagod]

Originally Posted by BBender

When the car is in the "SPORTS" mode, switching the gearbox to the "S" will make any difference?

...from my experience there is no difference .

If you are driving the car in "Sport", putting the manual shift to left side "S" position makes no change.
It is different if you are in "Normal" mode - then the gear box works "quicker".