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BMW 3-Series (E90 E92) Forum > E90 / E92 / E93 3-series Powertrain and Drivetrain Discussions > N54 Turbo Engine / Drivetrain / Exhaust Modifications - 335i > Poor power and upshifts - MHD Log advice sought.



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      07-19-2018, 04:31 PM   #67
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Originally Posted by Aus335iguy View Post
This is part of the reason why Z4is DCT cars are the fastest from a dig stock. They also break diff pinions more readily as well.
Dude, their Sport mapping is crazy high. I imagine it would break a diff or a neck on a high torque map lol
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      07-19-2018, 04:58 PM   #68
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Originally Posted by Aus335iguy View Post
This is part of the reason why Z4is DCT cars are the fastest from a dig stock. They also break diff pinions more readily as well.
Dude, their Sport mapping is crazy high. I imagine it would break a diff or a neck on a high torque map lol
It's the closest thing to a 1M DCT car from the factory. Essentially it was BMWs way of inching towards the new M3/4 before it was in production. A test bed if you will....
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      07-19-2018, 06:15 PM   #69
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I guess they didnt flush it out thoroughly. S55s are having expensive issues with high power DCTs being enough to spin the crank hub out of time with only the friction plate holding it.

Z4 Sport is damn peppy either way. It's also in spool mode almost constantly though 7 gears during low/mid throttle.
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      07-20-2018, 05:06 AM   #70
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That explains why the car feels different now I have MHD stage 1 on it. Its effectively behaving like a 3'er now? Feels flatter in daily driving but more hellish when you drop a cog or two.
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      07-20-2018, 07:26 AM   #71
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Essentially, but there are many tuning strategies. It doesn't mean less power, just how it's requested. Even though Stage 1 OTS may feel less stout from the driver seat in certain conditions, it's surely making more power than your stock 9psi map.

It explains why some other things are the way they are in the Z4 map. It requests more as a %, but has less to get as a maximum than 335is. I had a snappy pedal map once on a high torque tune and it was an annoyance to drive. No matter how lightly I tried to accelerate from a stop, it was like launching at the track. Not great when you're at a light behind a cop or trying to go up a minor incline at cruise and wind up accelerating at full boost.

335is and Z4 normal modes are the same. Sport mode is another story. 335is top, Z4 bottom. X axis is pedal position, Z is % torque requested. Basically, Z4 is WOT at between 35-40% pedal in Sport and has no taper as RPM increases.
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      07-23-2018, 02:15 AM   #72
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Unfortunately I didn't get chance this weekend to conduct much more in the way of tests however I did try one thing quickly, I reflashed stage 1 with a change to the wastegate rattle setting, moving it to the less lag end of the slider.

I'm shocked how much difference this has made to the car. Not only has the sound of the exhaust improved hugely but turbo take up is much improved and the problems on the gear changes have lessened massively. I understand why this is, given what the so called fix is, but I hadn't expected this to have been so big.

The only crappy gear change I felt this morning was the first shift from D1 to D2 as I pulled away from home. This is in normal mode. Sport mode still feels snatchy.

More tests later on the commute home... I've had one off improvements before...

Last edited by ManiacGT; 07-23-2018 at 04:25 AM.
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      08-06-2018, 07:20 AM   #73
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So I’ve not had chance to try the altered map as yet but I have been studying the engine a little more and I wonder if I can test this theory with you all;

I recall when I first got the car back from the injector/water pump repair hearing a new relatively quiet warbling type noise entering the cabin from the engine area. I had no idea what this was and it’s either subsided or I’ve gotten used to it now as I don’t notice it any longer.

However having studied the forced induction system and some of the reasoning and side effects parts of it are designed to address I’ve started to focus on the blow off system.

Reading up on this there are two reasons for this system, one is to reduce an unwanted pressure noise when the throttle flap closes due to the oscillating back pressure and the other to reduce axial wear on the turbos / avoid a stall like situation on the blades.

Now this made me think, if the blow off system wasn’t functioning properly, this may explain the warble/flutter I heard and possibly also the power drop just before and just after the gear change as first the turbos slow due to back pressure from throttle closure and then take time to spool back up once the throttle opens post shift...

Does this make sense?

So I’m going to perform some further diagnostics. I’m going to perform the diverter to BOV change where you unplug and cap off the diverter to turbo intakes. That will allow me to hear if they are working or not. One at a time.

Also I’m going to disconnect the vacuum feed to the BOVs, plug the intake (carefully, I've read the horror stories of snapping this) and drive around the block carefully to see what the impact is. It’s either going to be much worse or no different if I’m on the money with it.

If this does indicate something then there is either a leak in the intake manifold or something wrong with the vacuum pipes or BOVs.

Last edited by ManiacGT; 08-06-2018 at 07:41 AM.
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      08-25-2018, 02:05 PM   #74
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So one thing Iíve checked today after getting INPA working is the injector coding.

are the deviations on 2 and 4 due to coding error or adaptations and more importantly are they out enough to be causing issues?

Injector coding


DME
1 58.6 2.08
2 58.3 2.16
3 59.4 2.08
4 58.3 2.31
5 58.0 2.06
6 57.8 2.48


Injector (1 front of car, 6 firewall? sequence 1,2,3,4,5,6?)
1 586 208
2 583 217
3 594 208
4 583 233
5 580 206
6 578 248
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