PDA

View Full Version : Exceeding boost limit with std chip at 4500 rpm



#84
28-11-06, 14:28
Hello everyone.

I have just been re-mapping my Q4 and after a lot of trouble exceeding the maximum boost limit I studied the original settings and found a very steep decrese of allowable boost pressure from 3600 to 4000 rpm and a further decrease 4000-4400 rpm and then a small decrease to the final value at 4800 rpm. In the same speed range the boost duty cycle is only slightly decreased and logically the margin to the boost limit must be very small at the end.

3600 / 4000 / 4400 / 4800 rpm
1.49 / 0.96 / 0.86 / 0.80 bar

So, suddenly it was quite obvious why I experienced fuel cut of around 4500 rpm when running uphill at full throttle with standard turbo&chip when boost is kept at 0.86 bar at 4500 rpm and stabilised at 0.8 bar for the rest of the speed range.

So, have any one else experienced similar problems with standard chip?

Juan AR155Q4
12-12-06, 18:09
Never tried the original chip. I have to recalibrate my WG cause I´ve changed my WG spring and I`m having problems with my boost.
As soon as I solve that, I`ll tell you.

Wasn´t the original overboost of 1.1 bar??

#84
12-12-06, 22:26
I believe so, but when you update exhaust and inlet you gain a lot of performance. And what surprises me is that you reach almost 1.4 bar when braking and accelerating simultaneously. However I understand it is an open loop regulation and boost duty cycle regulates boost until boost limit is reached. What seems to be a mystery is what stationary boost curve really does to preformance.