[RaihaX]

Originally Posted by pavo335

Rey do you have it?

On the last version (v301) I had it, was quite noticeable, with the new beta (v401) I cannot feel anything but my logs still shows a bit of oscilation down low.

Main thing is that I can't feel it now so I am happy

[adrian@vishnu]

Be aware that even though the boost curve shows oscillation, the power curve does not show much in the way of power oscillating in response to this. This is because the throttle would be closing as the boost goes up on the oscillation and opening as it goes down. This is because the DME uses a load targetting based load system. It targets a certain airflow, and raises boost to achieve that airflow, but if boost goes too high it closes the throttle to achieve desired airflow (throttle can respond much quicker than turbine speed).

So you may or may not feel this boost oscillation to drive... which is good or bad depending on how you look at it... good because it does not effect the driving experience, but bad because your turbine speed is oscillating when there is no real need for this to be happening. Personally I feel that the most efficient way for an engine to operate is for it to run with the throttle fully open and boost controlled by turbine speed. Closing the throttle is just introducing a restriction not unlike a poor flowing intercooler or chargepipe. This results in turning excessive boost energy into heat rather than power which is not efficient in my eyes... but that is just my opinion.

[RaihaX]

Originally Posted by adrian@vishnu

Be aware that even though the boost curve shows oscillation, the power curve does not show much in the way of power oscillating in response to this. This is because the throttle would be closing as the boost goes up on the oscillation and opening as it goes down. This is because the DME uses a load targetting based load system. It targets a certain airflow, and raises boost to achieve that airflow, but if boost goes too high it closes the throttle to achieve desired airflow (throttle can respond much quicker than turbine speed).

So you may or may not feel this boost oscillation to drive... which is good or bad depending on how you look at it... good because it does not effect the driving experience, but bad because your turbine speed is oscillating when there is no real need for this to be happening. Personally I feel that the most efficient way for an engine to operate is for it to run with the throttle fully open and boost controlled by turbine speed. Closing the throttle is just introducing a restriction not unlike a poor flowing intercooler or chargepipe. This results in turning excessive boost energy into heat rather than power which is not efficient in my eyes... but that is just my opinion.

Interesting - definitely a good thread, a wealth of knowledge in here

[BMWPWR]

Doesn't this car have an M3 diff? The diff ratio may be different to Pete's original diff.. This can alter the dyno figure?

[Freefreefive]

I'm off to the track tomorrow so if Pete can send me he details then I can report back on how the procede with the maps performs on the track.

I'll also be doing data logs. 3rd gear pulls to redline!!!

[Stuart@BMRAutowerkes]

Originally Posted by BMWPWR

Doesn't this car have an M3 diff? The diff ratio may be different to Pete's original diff.. This can alter the dyno figure?

Could be...

Pete, what's the baseline number

[Kiwi Peter]

Originally Posted by Freefreefive

I'm off to the track tomorrow so if Pete can send me he details then I can report back on how the procede with the maps performs on the track.

I'll also be doing data logs. 3rd gear pulls to redline!!!

Hi there Freefreefive
I will send you the info in the morning price will be $335.00 Just kidding, there will be no charge send me an email peter@advanperformance.com.au
regards Peter

[Kiwi Peter]

Originally Posted by BMWPWR

Doesn't this car have an M3 diff? The diff ratio may be different to Pete's original diff.. This can alter the dyno figure?

Yep i do have the M3 diff and love it as far as power goes there may be a slight increase 2-5kw due to the diff, but the difference is so small between ratios it is not likely. Our car has a power base line of 197kw stock 4th gear @ 6000rpm

[Freefreefive]

Email sent. Thanks Pete. I'll report back tomorrow night.

[BMWPWR]

That's a good jump in power for tune only!! I better get myself a tune soon

[MO3]

Great work Peter! Can't wait to get my Cobb, hopefully next week!

[Kiwi Peter]

Originally Posted by BMWPWR

That's a good jump in power for tune only!! I better get myself a tune soon

That is why i have put so much time into the BMW turbo cars. There is still very much more to come. the tune ability of these cars reminds me of the Skyline GTR 20 years ago, we have just started the BMW journey

[BMWPWR]

I can just imagine! I almost want to buy another 335i in manual for a project car! But still exxy for a starting point..

I have the DCT in mine hopefully it holds up well with the tune

[RaihaX]

Originally Posted by BMWPWR

I can just imagine! I almost want to buy another 335i in manual for a project car! But still exxy for a starting point..

I have the DCT in mine hopefully it holds up well with the tune

You should be good until you start going to FBO + Meth, that is when things start slipping from what I hear!

[BMWPWR]

That's fine as I'm going to start out with an intake and tune and won't be using meth

[RaihaX]

Originally Posted by BMWPWR

That's fine as I'm going to start out with an intake and tune and won't be using meth

The lure/temptation of meth is too strong that is what I said as well, just a tune is fine, then FBO then meth....

Now I want upgraded turbos

[Alpina_B3_Lux]

Originally Posted by adrian@vishnu

Be aware that even though the boost curve shows oscillation, the power curve does not show much in the way of power oscillating in response to this. This is because the throttle would be closing as the boost goes up on the oscillation and opening as it goes down. This is because the DME uses a load targetting based load system. It targets a certain airflow, and raises boost to achieve that airflow, but if boost goes too high it closes the throttle to achieve desired airflow (throttle can respond much quicker than turbine speed).

COBB does not use a load targeting approach like the stock DME does, at least not for their stage 2 and stage 3 tunes. That was already mentioned on several occasions in the US forums.

Alpina_B3_Lux

[woosh]

Originally Posted by MO3

Great work Peter! Can't wait to get my Cobb, hopefully next week!

We're in the same batch I think =)

[Stuart@BMRAutowerkes]

Originally Posted by woosh

We're in the same batch I think =)

Yes you are lol

[pavo335]

Originally Posted by RaihaX

You should be good until you start going to FBO + Meth, that is when things start slipping from what I hear!

No meth yet :-( still waiting on gramps to get me a tank
I have been fbo for a while and no slippage on the dct.

[shu]

Originally Posted by bmroxm5

Yes you are lol

I hope I'm in that batch too

[adrian@vishnu]

Originally Posted by Alpina_B3_Lux

COBB does not use a load targeting approach like the stock DME does, at least not for their stage 2 and stage 3 tunes. That was already mentioned on several occasions in the US forums.

Alpina_B3_Lux

Given the 2psi boost oscillations without corresponding oscillation of power, it must be something very much the same... The throttle is closing during those boost spikes... or you would see the power oscillate with boost. So maybe it is not load targeting as such by their definition, but there is definitely some throttle activity happening as part of the boost control that could be easily verified by logging throttle during the oscillation.

There is nothing wrong with load targeting as such anyway. A certain airflow equates to a certain boost anyway. If you set the boost or the airflow, the result is the same. It is the throttle being part of the boost control that I do not like.