To Trev's point, the JB4 does not override the overboost, as it just intercepts the ECU signals. There was talk the JB4 would have an override function but that would be invasive to ECU, so the additional power is added to the base power with or without overboost.
The JB4 does indeed over-ride the over-boost and here's the description from George of BMS himself:
"On two of the maps it retains the over boost and then in map 6 which has absolute targeting (i.e. you punch in total boost you want) we over ride the over boost giving full power at all times. The mode of map 6 can also be changed to allow the overboost so users are not restricted when wanting to custom tune."You must be familiar with how the JB1 works right? Traditionally, you just enter how much
extra boost you want the car to make per rpm on top of what it makes as stock. The problem is in this situation you take for granted the car always makes the same boost on the same conditions which is true for 99% of the cars, but on a car with over/underboost mode like the CS, the car can make x.xx bar if you are in 2nd but y.yy bar when you are in 3rd and above and then drop back to x.xx if you flor it for more than 10". So the total boost every time depends on what base boost the car decides to make at each condition. The way to defeat this is to forget about boost increments and just enter absolute boost targets instead, that's only possible in JB4's map 6. Like that, even when the car makes less base boost because you're in 2nd or because you are on the throttle more than 10" the JB4 just fills in more to reach always the same boost target.
Just a note here, the car, this car in particular with this engine and turbo should have been hitting the same boost target at all times from factory so there is no "preserve the engine" argument really. That's how it works on all other variants of the same powertrain like the R, the S3 and even the fwd Cupra. The reason the over/underboost nonsense is present on the CS is because VW likes to separate it's models and wouldn't like the CS treading on the R's toes too much (a car that pulls faster than its flagship would't look good for the R which is anyway a model with far more importance for VW than an occassional special edition).
Paul, what mode are you running your JB4 on? Have you tried mode 6? I don't really see why would anyone run a JB4 on the CS and run it on anything other than map 6 having to bear with the stupid overboost. You can tone down the entire map slightly or at certain gears/rpm (another beauty of the JB4) but nowhere as close as 30bhp less as the stock overboost does.
I'm glad you lads running JB1/4 replied as that's what I had on my R and was unsure of how it would work with the overboost and therefore what settings it would have to be run with to prevent over-overboosting.
Rest assured there is no over-boost possible. On the contrary, the only thing that exists is under-boost as unless using JB4 on map 6, the car will always make less boost in 1st and 2nd, and on 3rd and above after 10" of WOT.
