730D B57 Engine Tuning

[samchuang33]

I just recently brought a new X7 which uses the same B57 3.0d engine as the 530d. The 30d uses twin scroll turbo charge where the turbo spoils up quicker compare to the 40d engine which I believe should still have 1 small turbo for low rev and 1 large turbo for higer rev (like N57/M57 40d). Dont quote me on it but if my assumption are right, twin scroll setup on 3.0d will allow the 2 smaller turbo to spool up quicker so response will be slightly better low down compare to 40d. However, the down side for twin scroll is it doesnt have much power higher up in rev range due to smaller size turbo.
So unless u really pushing the car hard or accelerating at high speeds, the difference between the 2 will be marginal.

I think what happens in a real world, the 30d will lauch slightly better initially before the 40d overpowers as the extra hp comes into play. Everyday driving, some may say the 30d may be easier to drive or feels faster due to better throttle response. This is the same discssion I had with someone else looking compareing the X7 3.0d vs GLS400d which is also a twin turbo setup like the 40d. Some commented that the 30d twin scroll is more responsive and faster down low.

[RaptorStrike]

Originally Posted by samchuang33

I just recently brought a new X7 which uses the same B57 3.0d engine as the 530d. The 30d uses twin scroll turbo charge where the turbo spoils up quicker compare to the 40d engine which I believe should still have 1 small turbo for low rev and 1 large turbo for higer rev (like N57/M57 40d). Dont quote me on it but if my assumption are right, twin scroll setup on 3.0d will allow the 2 smaller turbo to spool up quicker so response will be slightly better low down compare to 40d. However, the down side for twin scroll is it doesnt have much power higher up in rev range due to smaller size turbo.
So unless u really pushing the car hard or accelerating at high speeds, the difference between the 2 will be marginal.

I think what happens in a real world, the 30d will lauch slightly better initially before the 40d overpowers as the extra hp comes into play. Everyday driving, some may say the 30d may be easier to drive or feels faster due to better throttle response. This is the same discssion I had with someone else looking compareing the X7 3.0d vs GLS400d which is also a twin turbo setup like the 40d. Some commented that the 30d twin scroll is more responsive and faster down low.

30d = 1 Turbo
40d = 2 Turbo
50d = 4 Turbo

All are twin power (or twin scroll in normal speak) turbos.

Heres a comparison in acceleration of all 3.

[samchuang33]

Originally Posted by RaptorStrike

30d = 1 Turbo
40d = 2 Turbo
50d = 4 Turbo

All are twin power (or twin scroll in normal speak) turbos.

Found this article discussing the details between the 30d D57D30O0 vs 40d D57D30T0.
https://www.newtis.info/tisv2/a/en/g...ics/1VncH04m13

[RaptorStrike]

Originally Posted by samchuang33

Found this article discussing the details between the 30d D57D30O0 vs 40d D57D30T0.
https://www.newtis.info/tisv2/a/en/g...ics/1VncH04m13

Thanks. That shows both cars have variable turbine geometry turbo chargers.

[samchuang33]

Originally Posted by RaptorStrike

Thanks. That shows both cars have variable turbine geometry turbo chargers.

The main difference is how the power is delivered in the rev range. If u look at the dyno graph and compare the 2 engine, u can see at below 2500rpm the 30d and 40d is similar. So everyday driving, it will be hard to pick the difference. Above 3000rpm, the 30d drop off quite a bit after where the 40d keep going due to separate larger size turbo giving that more linear acceleration. The 30d sweet spot is 2000-3000rpm where it will feel like it has more jerk (change in rate of acceleration) hence possibly giving the sensation that it is more zippy but in reality is 40d is just more linear.

The dyno chart i found online were from celtic tuning
https://s3-eu-west-1.amazonaws.com/p...__586_lbft.jpg
https://s3-eu-west-1.amazonaws.com/p...__588_lbft.jpg

End of the day, 40d is superior engine but the 30d will be sufficient for most ppl everyday. It is relatively less complex and in the sedan configuration, most 40d are x drive which add extra weight to offset the HP increase so I can see why some of u like the 530d or 730d. For me, the X7 has Xdrive regardless what engine so the 40d will obvious choice. Too bad BMW Australia didn't bring in the 40d for the X7

There is this interesting explanation from an youtuber who I follow. He explain the jerk terminology very well. Skip to 9min mark if u want to skip to the explanation regarding "JERK" which what give u the fun factor

[RaptorStrike]

Originally Posted by samchuang33

The main difference is how the power is delivered in the rev range. If u look at the dyno graph and compare the 2 engine, u can see at below 2500rpm the 30d and 40d is similar. So everyday driving, it will be hard to pick the difference. Above 3000rpm, the 30d drop off quite a bit after where the 40d keep going due to separate larger size turbo giving that more linear acceleration. The 30d sweet spot is 2000-3000rpm where it will feel like it has more jerk (change in rate of acceleration) hence possibly giving the sensation that it is more zippy but in reality is 40d is just more linear.

The dyno chart i found online were from celtic tuning
https://s3-eu-west-1.amazonaws.com/p...__586_lbft.jpg
https://s3-eu-west-1.amazonaws.com/p...__588_lbft.jpg

End of the day, 40d is superior engine but the 30d will be sufficient for most ppl everyday. It is relatively less complex and in the sedan configuration, most 40d are x drive which add extra weight to offset the HP increase so I can see why some of u like the 530d or 730d. For me, the X7 has Xdrive regardless what engine so the 40d will obvious choice. Too bad BMW Australia didn't bring in the 40d for the X7

There is this interesting explanation from an youtuber who I follow. He explain the jerk terminology very well. Skip to 9min mark if u want to skip to the explanation regarding "JERK" which what give u the fun factor

I drove the 30d and 40d 7 series before I went with the 740Ld.

I wanted a 750Ld but they are rarer than hens teeth in the UK.

Agree with normal driving there isn't much in it. Certainly not much up to around 50mph. But in sport mode then the 740 is a different animal.

[740I_yeye]

Originally Posted by RaptorStrike

I drove the 30d and 40d 7 series before I went with the 740Ld.

I wanted a 750Ld but they are rarer than hens teeth in the UK.

Agree with normal driving there isn't much in it. Certainly not much up to around 50mph. But in sport mode then the 740 is a different animal.

Does it exist?? I was surprised to find out that the 725d exists, a 2.0 diesel. I was shocked and now I’m finding out that the 750d was released here too!! I thought my car was rare-ish ( 740Li) lollll

[Martin2C]

Originally Posted by 740I_yeye

Does it exist?? I was surprised to find out that the 725d exists, a 2.0 diesel. I was shocked and now I’m finding out that the 750d was released here too!! I thought my car was rare-ish ( 740Li) lollll

They’ve never sold the 750d in the UK. It’s the engine from the M550d (also not sold in the UK) and the X5/X6/X7 M50d

[RaptorStrike]

Originally Posted by Martin2C

They’ve never sold the 750d in the UK. It’s the engine from the M550d (also not sold in the UK) and the X5/X6/X7 M50d

That will be why I could never find one!

[samchuang33]

Originally Posted by RaptorStrike

That will be why I could never find one!

At the launch of X5/X7 in Australia, the M50d with quad turbo was available. But then they axed it and replace it with a M50i petrol v8. Diesel uptake in Australia has been slow and after the diesel gate, sales world wide seems to have dropped off the cliff unless it is an SUV. There r only a few per-owned M50d in Australia which I have considered. But problem is the quad turbo setup is very complex so maintenance might be a huge issues after warranty expired.