Another milestone for the S3….

So have spent the last few weeks driving the car, making tweaks and driving the car more… she does quite well MPG wise on the commute to work all things considered… 30+ indicated on the DIS but reality being a couple of MPG less… did a 24mpg average on a tank the other week (couple of days commute plus road map tweaks and a dyno run) which is pretty good as she has been sub 20’s of late…

Anyhoo… enough about the ‘economy’ as thats not what she is about… a couple of the areas I wanted to tweak was midrange and peak boost… I still get surge on a high gear/low RPM run (like a dyno run) but if driven properly its not an issue so tweaked the spool delivery around that…

I am not running as much boost in this area as I did on ME7 as surge really plays silly buggers with the fuelling with speed density tuning so had to be mindful of that… next planned mod will be to replace the coldside with a ported housing to help with surge control…

On the road she feels very quick (obvs) but did need to get her on the dyno to see what progress was made… today I had a chance to do that…
Another milestone for the S3....

Obviously logged the runs to be sure….
Another milestone for the S3....

Another milestone for the S3....

Nothing out of the ordinary there… next to no timing pull which is always a nice place to be…

…and of course the scores on the doors 🙂
Another milestone for the S3....

Another milestone for the S3....

Was not expecting that!!… last time she was on the dyno she did just over 560hp…

Now as mentioned before I have made torque sooner on the ME7 mapping but it was surging badly on the dyno (not on the road though as yo would drive in the right gears)… here is the graph from that and is the baseline I have been working too
Another milestone for the S3....

Boost is coming in a bit sooner and torque is right up much earlier but top end power is suffering a bit as torque drops off…

I don’t have logs from that run so not sure what everything was doing but I am running decent timing and ramping the boost in more gently (due to surge) plus I lifted the boost just before 7k rpm to try and lift torque up over the line…. this seems to have worked 🙂

I am now playing in the spool area to try and keep the wastegate shut for as long as I can before the turbo properly spools…

I have done this by increasing the ‘P’ gain of the PID controller for boost… a quick test after lifting the gain at 4k RPM…

In the right hand log the PID proportional is 3.4% at 4k, in the left hand log after the tweak the value is now 7.4%… this has increased N75 duty from 78% to 82%… not much of a difference but it was more to test the theory of using P gain increases rather than increase the i-max values and potentially over boost…
Another milestone for the S3....

Need to play a bit more but hopefully it might get me a bit of a result lower down the rev range..

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