Originally Posted by frankeyser
from what I understand, the boost model is being borrowed from the Kleeman supercharger that was used on both manuals and autosticks. It will be a set amount of boost and the extra fuel adjustments will be what is changed.
I do believe we are going to have boost gauges but I am not sure. Also there will be the possibility of a stage 2 turbo using an srt6 ecu. Rotrex I think is his screen name has recently had some success controlling boost levels with an srt6 ecu.
Boost level on a turbo is controlled by the wastegate spring rating. If an 8 lb spring is installed, you "should" see a boost pressure in the 7 - 9 psi range. Many things have an effect on this, pressure drop from cooling of the charge air, temperature of the spring, ambient temperatures, quality of both the spring and wastegate, overall design of the system.
An external wastegate performs better with less potential exhaust restriction, but will generally cost more. A wastegate controlled only by the spring rating, will actually begin to creep open long before reaching the actual rating. A wastegate with an 8 lb spring will be full open around 8 lbs of boost, not suddenly open at 8 lbs.
It is very common to see bost pressure fluctuations using only a spring to control the pressure. A manual boost controller can be used to help a setup to reach the full potential or to actually run more boost by bleeding off some of the pressure going to the wastegate. Because of the early opening of the wastegate before full pressure, this has a big impact on the potential torque and power curves. They become sluggish.
To get the most out of a turbo setup, one needs to run a "smart" style of electronic boost controller that can read the pressure and make adjustments to the solenoid via pulse width modulation. In this manner, the wastegate is held fully closed much longer, and reaches the desired boost much faster, and can make adjustments to counteract any boost pressure drop off that can occur as the vehicle moves faster and the actual engine load begins to drop off.
While many systems come solely with the basic wastegate, the vast majority will seek out a higher end electronic boost controller for the control and performance gains it provides.
Most system don't come with an AFR gauge, however, running a turbo without one is placing a lot of faith in the tuning, AND that nothing is going to go wrong or some other component fail. A $250 AEM UEGO afr gauge is cheap insurance and peace of mind.
Unless you have an OEM turbo setup where the PCM is designed to control boost either via the wastegate or BOV (sometimes both), an NA factory PCM will never be able to do this. The SRT6 PCM is not going to do this either, it is supercharged, and boost is a primary factor of engine rpm, not load which is what drives a turbo. While the SRT6 PCM might make an alternative for fuel and timing related control, boost pressure will always be a function of the wastegate control used and the external factors as mentioned above that can have an effect on it.
While I am not saying that electronic boost control and AFR gauge should be included, the serious owner will want them in short order. Two identical vehicles, running same boost levels, one only controlled by the wastegate spring, and the other running a smart EBC, the one with the EBC will always come out on top.