1.1.81 boost control

[AVP]

im doing 3d and 4th gears as i have found that sometimes 3d gear can spike faster

what PID are you using Jamo?

you wouldnt be able to compare if you hadnt tried to 1.1.27

the difference comes after 1.5bar,where in megatune i got a climb of 0.2bar every 50-100rpm wheras in vemstune is much later

[Jamo]

I've tried various PID I was using 50/20/50 recently after my old 200 odd setting was brutal.

Are you using 21 or 31 hz? I found better response with 31 hz

[AVP]

i had a word from turbosmart initially and they had told me to use 10Hz. i have used anything from 10-12 so far, without any significant change in the reaction. Ill try 31hz as well. They said the higher the hz the most likely to get oscillations. but ill check it.

thanks

but mine anything more than 12 on I gets me a high overshoot

[Jamo]

Interesting, I'll load in your settings tonight and see at the weekend if I can find somewhere to do a run

[AVP]

ill see if there is any use of the 50/20/50.
any oscillations on that one?

ill try increasing the P as well to see how high it can go.

obviously different engine size and cams will have different affect as well

[Jamo]

I wouldn't bother with my settings for the moment, I've tried so many however it's only recently i've gone into high boost on regular driving and it is now I'm seeing i'm getting spikes

[AVP]

ah i see

look at my post on s2forum as well.

[AVP]

i feel positive that i may sort the boost control out today.

i looked through all my previous logs, and i have realised that there are 2 possible ways to keep boost sort of stable;

1) High PID values but fast moving solenoid---> this creates highs and lows on valve DC but the boost stays pretty much stable. I had one try on this before with a 0.3bar flactuation, which i assume can be improved. This gave me as fast spool as megatune used to give me, so good stuff. on this the DC target is set low though otherwise it will overshoot. eg: i had 220/70/60 PID and 60DC

2) Higher target DC values on areas of the turbo that is not very responsive to takle as fast spool as possible (reduce the lag a bit) and then reduce the DC and let PID take control. In this instance, PID needs to be much lower, otherwise you overshoot all the time, BUT the actual DC does not fluctuate therefore giving you a more steady boost. eg: 45/10/25 on PID and about 85DC on lower revs and 76-77 on the rpm that boost usually spikes. On this one, i did as well get an equally fast spool as i did in megatune.

So i have done a diagram of things to try and luckily as my most tests are done on 3d and 4th gear, once those 2 gears are set, then the rest are ok as well.
Today i will do more tests on these findings and im positive i will find the answer.

[GintsK]

I've also usually configure boost target little over real maximally reachable in areas where w-gate is closed. So that target boost curve copies real boost + some KPA. I mean area before 4000 in your case. 

As result PID don't go crazy before boost control really do something.

[AVP]

i see
thanks for that info.

boost control seems more logical now once you get your head around it. it's just that megatune with the boost offset feature had an easy solution for most applications

[AVP]

well i am at a loss...

i tried all combinations, i tried compinations which previously gave better results and today all i got was boost kicking in after 4000rpm. This cannot be explained. Maybe IAT was a bit higher today, but other than that, i cannot see why with IATs of 20C you would get boost later...

with DC being 100% and boost not climbing i can think of 2 things: either the valve is not working properly, or there is a boost leak somewhere? any other guesses?

[AVP]

anyone knows what the equivalent to the boost referrence is? which was evident to megatune?  i was using 4/5 there and it was one of the reason which made the solenoid very fast.

[GintsK]

IMHO 4/5 meant 4/5*100=80% DC

[AVP]

i see

after multiple tests today, a stiffer spring (0. and the turbosmart valve, i came to the conclusion that the boost can built up faster but unfortunatelly the turbosmart is not able to maintain boost on the higher rpm. Therefore an electronic boost controller would be the only solution, unless someone from vems developers, explain to a better extent how the PID should be used as well as the anytrim control

[gunni]

Are  you using an internal wastegate or a external?

If external then plumbing it to the top and bottom would yield the same results as a stiffer spring.