1.1.81 boost control

[AVP]

i did send you an msq file with a 100%TPS from megatune i think.

i have so many logs which make it very hard to look for one with excact same circomstances, but the fact that i have faster spool even on non full throttle must mean something, that the vemstune settings are not up to the job.

the car seems to have an area from 110 to 160kpa which does not spool as fast as before. I know that is an area of the turbo which does not respond anyway, as the hotside is big, but now that the fueling and the spark is also similar to the previous maps(on 1.1.27) i have no doubt that the issue lies with the way VEMS is adjusting the solenoid.

one thing that i havent tried is the OEM style of connection, just to compare, but i doubt i will have any different response. I will give it a go once im back from Greece.

[mattias]

I don't have the specifics of your setup in my mind right now.

This is not so hard to verify. If you don't spool as fast as before in the same gear, then it's either different tuning or health of the engine, a mechanical issue with the turbo or wastegate, clogged catalytic converter,  or other piece of equipment.

If you have a single solenoid top-side, set a reasonable fuel-cut then apply boost directly from the compressor outlet at all times, that should lead to the best spool-up you can possibly get with that setup - until you bump into the fuel cut limit. Blaming any loss of spool at that point on the software is pointless.

Move old logs to an archive, or categorize your datalogs. It would be bad if what you're comparing to are numbers from WOT runs in a higher gear.

[AVP]

1) I am not comparing WOTs of different gears. It is very easy to understand which gear i am in from old and new logs, as the characteristics are so different that you can tell immediately. On 3d gear i had 305kpa on 4100 and on 4th at 3780rpm. On higher gears, even sooner, so there is no way i can be mistaken there.

2) As far as tuning is concern, i think i have exhausted every possibility.Unless there are hidden/ unrealised by me at least features of vemstune which are contributing to the poor results. The mechanical setup is the same, and the maps are 1:1 transfer from the megatune files. The last bit of the puzzle were the lamda values which had appeared to stay lean and we thought this was the cause of the poor initial spool BUT as this was corrected and matched to the megatune files, spool did not improve

3) Mechanical issue? How unluckly could that be? Just as i changed ECU and a week before the car was flying, now all of a sudden there is a mechanical issue causing this? Car has metal cats, and have been there for a while,never had an issue with them, have done less than 90K kms. Turbo is 6 month old and as mentioned before never ran out of it's specs, downpipe is new, cat back is old, but stainless and custom made.All lines to and from the solenoid were recently checked for leaks and cracks and are OK.

4) What do you mean a single top solenoid? i really need to check this thing about the fastest mechanical spool possible, you are right.How else can it be done? if i take the hose from the turbo compressor side and plug it to the lower chamber of the wastegate(external) will it work? i can put a fuel cut at 250kpa or whatever..  yes if that turns out to be identical with the current spool i will probably have to look for something in the mechanical aspect.

[GintsK]

Mattias, AVP switched back firmware. And calibraton file which is different. Looks like spool-up on 1.1.27 setup is better.
But we do not saw clear WOT datalogs. It is hard to help then.

[AVP]

im sorry gintis, i thought i did send you one with WOT

ill do that this afternoon so that you have an identical WOT on the 2 firmwares

[Kenny Watson]

Plug the boost signal into the top chamber and leave the bototm chamber unplugged. Boost will forcibly hold the wastegate closed and minimize the potential for wastegate creep etc. You MUST have you boost cut set appropriately though of course as the wastegate will not open!!!!!

[AVP]

yes, i will do this now and report back in about an hour

i will use a fuel cut at around 270

[AVP]

spot diagnosis:

on the rev limiter, and fuel cut @ 300kpa

3d gear: just before 3000rpm

4th gear: well before 4000rpm


ON LOGS::::

both appear to be 200-300rpm later than what my car's rev counter showed!!!


is there a lag in the log? where is the setting of the vemstune regarding rev counter of the car?


edit: after closer look i can see that there is only minor difference early on regarding how fast the boost starts early on, but then the whole boost curve seems to be identical to the vemstune boost curve. What i dont understand is how is it possible to have that when my rev counter shows to cut much sooner than what vems is reading.

so i can say that the final outcome of this test is that either i have some kind of increased backpressure, OR maybe there is no good correlation between what vems is reading as rpm signal and what it actually is true.

Which is the actual? the mechanical rev counter from the car? or vemstune? should i check it's calibration? and where is that?

[rob@vems.co.uk]

VEMS is the most accurate RPM, theres no doubt about that at all - or the spark would be random.

[AVP]

ok
but doesnt vems need to be calibrated first?

i know that on megatune there was a calibration at 3000rpm

doesnt vemstune have anything similar?

[GintsK]

Here it is!
You have wrong Rpm reading on 1.1.27 caused by wrong constant for Rpm calculation. It should be 12000/cylCount=2400
From 1.1.27 msq:

[GintsK]

On 1.1.81 Vemstune reading is OK because user do not calculate this confusing constant any more.

[AVP]

i see. i remember changing that a long time ago on megatune as at the time it seemed that the rpms matched the rev counter better when i used 2300 rather than anything else.

well, it may have been that then and therefore the boost acquisition is ok. I wasnt expecting that though.

does that mean that the rev counter on the car is not accurate then?

[gunni]

does that mean that the rev counter on the car is not accurate then?

It´s a mechanical device trying to keep up with the input into it. the motor driving the tacho is not strong enough to keep up.
Such is the case with almost all tachos.

[billman]

The end of this is so unspectacular??? Just a wrong setting in megatune?? nice....i think there is no mechanical problem then at all.

AVP send me now please a 4. gear full throttle run.