Customer Q&A #2 (with Peter Treydte, Banks’ Director of Technical Communication)

QUESTION #2:
My situation is that I don’t have a problem with my power output once the engine downshifts and the RPM’s go up, but I want more power low down (1750 RPM) so that the engine does not have to down shift as often (and use more fuel). (One thing that I have noticed is that it downshifts when the turbo boost reaches 20 psi., is there any way to raise that figure?) This is why I am looking for figures in that range, apples and apples you know, which I understand you are unable to provide. I guess the factory figures that show lower power curves must be done on an engine dyno, instead of a chassis dyno. Speaking of the figures with a manual transmission, at least that would provide a reference point. Right now I am in the “dark”, so to speak.
Another nice to have thing would be to have a second setting, or a desensitized cruise control, whereby it would act more like driver input in that it would not down shift with minor 1 to 2 mph speed losses.
Read on for the answers…

ANSWER #2:
The addition of a Six-Gun will most definitely reduce the downshift characteristic. The reason that the vehicle downshifts is because the engine cannot produce the power needed at a given RPM as load is increased. If we consider the scenario that I described in my previous answer, lets say that you are cruising at 60 MPH on level ground at a horsepower requirement of 100, but then the road reaches a slight incline. As the slope increases, the power requirement increases, lets say to 150. The engine is only capable of producing 140 at 1700 RPM (for the sake of this example), so the transmission downshifts, increasing the engine RPM to a higher point at which more power is available to meet the demand of the 150 HP requirement. If you could have just 10 more horsepower under those load conditions, the transmission would not need to backshift. That is exactly what the Six-Gun would provide. Since the scenarios that I have been describing are all partial load conditions, I cannot tell you based on test data exactly what that power increase is, but based on the curves that are available to us, if I were to extrapolate to a lower RPM value, I would feel confident in saying that the Six-Gun would increase the power potential by at least 50 HP at your cruising RPM. That would mean that in our example, the power requirement could be increased to 190 HP before a down shift would be required, which would translate to a 35% improvement.
In general, I would say that this is only loosely related to boost; boost is a basic indicator of what the load on the engine is. The primary load indicator is throttle position, which would be dramatically reduced with the Six-Gun.
You are correct that factory power curves are produced on an engine dyno, but they are also usually produced without many of the accessories and the exhaust system that would be found in the vehicle. This is why rear-wheel horsepower is so much more meaningful in our line of business; it is an indication of what you will experience in the real world.

Leave a Reply