Discussion and questions related to the course Boost Control
Hi folks !
As title say when we tune a diesel car how do we know the turbo max pressure before explote? Its a tricky question I know.
Some say 10% more some 15%...
It's a lot easier to do if you have a compressor map and enough information to plot where you are now and where you will be with more boost. Damage can occur from over speeding the turbo, but if you reduce restriction in the intake and exhaust you will not work the turbo so hard. Also, altitude is a big consideration. If you are at sea level the turbo will be able to increase pressure more safely than if you are in the mountains.
So i have to look infor at manyfacturer web?
I am surprised that when they tune a oem car they know what max boost set at high torque point and at max rpm, 4000 to 4500 rpm
Actually in a diesel engine boost is your friend as it provides more airflow (assuming you're still running in an area of the compressor map that's efficient). This airflow helps cool the combustion temperature. The more dangerous aspect of diesel tuning is adding additional fuel as this then creates more heat. So the tuning process is really a balance of boost and fuel but kind of in the opposite way as to how it's approached in a petrol engine.
So the answer is very much dependent on your specific engine and turbo. Specifically we've also seen several turbo failures now on the stock Toyota turbo fitted to the 1KD so weakness in this area is a big consideration. If you're dealing with a stock CRDI engine then a 10-15% increase in boost should be very safe but you will want to also adjust the fuel delivery to really see the power benefit of the boost increase.