I would like to know as well...

That being said, dyno your car at sea level and then again at 4000ft and the difference is going to be more than a simple intake mod....

Jason

 

from what I have heard from just about EVERY ONE they keep saying that the ECU will adapt, just give it 500 miles or so. But I think it will adapt to small changes, like elevation but not a turbo or something, you know?

 

The ECU can perform no magic to defy the laws of physics. If you add volume/capacity to your intake system, then at less than peak flow, that additional volume results in less responsiveness. The more parts you modify in this way, the more pronounced the effect. However, in the same way, due to outright capacity gains and proper air/fuel ratios at peak flow in the head, the peak HP will similarly increase.

As long as you're willing to sacrifice midrange and responsiveness for peak power, then increasing intake capacity is for you.

 

Thats why I said, Forced Induction not included in my original post about ECU adaptation....

Don't underestimate the difference 60 degrees makes or 4,000 feet of altitude change..

The ECU is expected to be able to adjust for a very large range of operating conditions. If you have ever tracked your car, either on a road course or on the 1/4mi strip then you are well aware the difference favorable conditions can make.

Although I am not 100% positive, I can say with some confidence that there is no need for ECU tuning if you simply change out your intake and exhaust system. Are there more gains to be had from these mods by optimizing the ECU?....Yes probably, but its not a requirement. Someone correct me if I am wrong here....

Jason

 

I did a throttle body on my 993 back in 95. Different car but there was a slight enhancement but I felt the throttle response was somewhat un natural feeling .

 

Never mind..it's all been said..

 

So, would changing to the X-51 air box provide any additional benefits to a 997 or 997S in your opinion?

 

Hi there

Major thread resurrection, but my car had stock plenum, stock throttlebody and stock intake though with BMC filter. It also had NHP 200 cel straight pipe cats and X51 manifolds along with PSE. Also loaded with softronic!

The car made 371BHP flywheel!

I've since fitted the X51/GT3 throttle body (76mm upto 82mm) along with plenum to make it fit and full carbon X51 intake with extra inlet.

The result is a smoother power delivery and what feels like way more power beyond 4000rpm, low-end torque seems pretty much un-changed but the cars throttle response is not as crisp as it was, it is marginal but I can feel it for sure.
I am heading to the dyno this Friday to see what power the car makes, but also if I get time I am going to re-fit the stock plenum and throttlebody to see how if effects the power plot and overall power, as if the difference is minimal I shall stick with the smaller throttle body simply for the much better throttle response.