Turbine Compressor way over its limits?

[gox]

Few weeks ago i got the E30 with m20b27 bottom end and b25 head,td manifold and turbo from 324td/524td mounted on the engine....I knew that wouldnt work out but that wasnt my problem.My job was to install VEMS and tune it to the injector limits (m30b35 injectors on ~5bar?!).
Last night i was doing boost mapping and started with 0.4bar.Engine is "haveing" really hard time above 5000rpm or even less,somewhere about 4000rpm,but what is the important part is that it is loosing boost in high rpms ... that should be compressor problem right? Its the flow far away from his limits?
None of the engine parts where touched,so i think is not a boost leak....
Strange thing is that when it was on the motronic it kept the boost to the redline,was it because of the wrong ignition timing,afr or something else?

This is not really a problem because he is going to upgrade the whole system now when it has vems (turbo,injectors,intercooler),but i`m curios about it....Is this typical situation of compressor going out of it limits?

P.S I think turbo is TD04 but i`m not sure,its a stock turbo from 324td/524td

Here is log from last night:

Check @ 2.04

http://www.vems.hu/files/MembersPage/MilanaPerisic/v3.3_n002834-2010.10.28-22.48.03.vemslog

[Kenny Watson]

My guess would be that the wastegate spring/actuator must be quite weak is base boost pressure is only 0.4 bar. It may be the compressor running out of flow, or exhaust backpressure may be getting high enough at higher rpms that it pushes the wastegate open.

If you have enough fueling to allow more boost, increase the preload on the wastegate and see if it still does it.

[NOTORIOUS VR]

looking at your logs, it seem to pull up to 5000rpms just fine.

Does it not want to turn past 5000?  The setup is exactly the same as with the Motronic?  The only thing different now is the ECU?

What are you spark plugs gapped to?

[gunni]

Engine has about 235hp or so at 0.2bar boost there in the end.

While it has about 130hp @ 2700rpm.

I think the compressor is not keeping up and/or the turbine backpressure is opening the wastegate.
It could probably also do with more advance at that little boost.

But air temps are not rising at all so more likely backpressure.

[gox]

Kenny: 0.4bar is just the first step in tuning,i will try to go up to 0.6 to see if injectors can make it at least @ 85% duty.

Notorios:
Well maybe i did little over reacted.I used to my H1C@1bar...so this is not big deal for me.
Yes,it does goes up to rev limit but it looks to me like its takeing too long to rev it up to 6.5k,maybe its just my feeling for much stronger car comes to the point...
Spark plugs are gaped to 0.6mm.
Setup is the same,i just made a wiring and fitted in VEMS.

gunni:
235hp? You think so? Well thats pretty good if its around that power level.

I didnt drove the car too much with motronic,i just took it in the morning and go for 4km to my garage and that was it...didnt have space to go high revs (city driving) or WOT but it was pulling realy nice with motronic and 0.4bar
I`ll go up for 0.6bar to see what happens and can injector handle that much.

I cant get anything above 95 Octane fuel,so i made some kind of a safe ignition...i`ll try to retard it for a few degrees....

I`ll keep you guys updated with the logs and results.

[Kenny Watson]

Yes,it does goes up to rev limit but it looks to me like its takeing too long to rev it up to 6.5k,maybe its just my feeling for much stronger car comes to the point...

It will feel this way if the turbine side is too small and backpressure is rising rapidly as revs increase , especially if boost is tapering.

if this is the case, then with more boost it will become even more noticeable.

[gox]

We just finished another tuning season,raised the boost up to 0.8bar but MAT is going up to 51C and raising on the WOT,also we experienced some at around 4500rpm,i managed to get rid of the knock by retarding the ignition but we still have knock on quick shift.After quick shift and going instantly WOT there is a knock and i thing its because of the lambda goes to 1.25 in that moment right after it goes normal to target lambda and no more knock.This has to do with AE right? With what value i have to play under the AE to get rid of the lean spot when instantly going WOT,FW 1.1.70

This turbo is way of its limits and we will leave it on the 0.5-0.6bar,car goes pretty nice,fuel economy is nice,and drivebility is awesome comparing to old firmwares i just cant believe it.When you take a look at the VE table its clean as eye that turbo is dieing after 4000-4500rpm...VE number after that goes lower....

Log is on the owners laptop since my battery died,but i will have it tomorrow and i`ll post it up over here so you can take a look.

I`m tired,going to bed now

[gox]

Here is log from last night:

http://www.vems.hu/files/MembersPage/MilanaPerisic/CustomerE30/v3.3_n002834-2010.10.30-22.54.20.vemslog

Also,while he was on the way home (another city 80km from me) he experienced knock in 5th gear @ around 5200rpm,but that is around 220km/h and we dont have a log of it....

[gunni]

Maybe his ambient temps where getting to high at prolonged boosting?
so retarding ignition based on air temps .

[gox]

I`m not sure i understand what you mean? 

[gunni]

When you keep boosting for a long time things get warmer as they don´t have a change to cool down.
so that leads to higher inlet temps, that lead to detonation.

So even if timing was fine at 30C , the required retard was not enough at 50-60C°

[gox]

Yes,i understand that...
What about Accel Enrichment when i kick wot instantly after shifting gears?
Is it dotrate vs scale table?

[rob@vems.co.uk]

dot rate vs scale sounds good
You might want to consider the accel retard function, it will pull a load of ingition out when you mash the throttle

[mattias]

Exactly what Rob said, with a warmed up engine all the acceleration enrichment is handled by the two tables, dotrate vs scale and RPM vs amount.

Put the car in a low gear (2nd) and cruise at different rpms, then try mashing the pedal as fast as you can (like you do when shifting). See what settings work, you can bring up gauges and watch the cursor in the tables. Watching the lambda live graph is the real key to success here.

[gox]

Ok guys,tnx for the advices.