Bigger Throttle Plate and Injectors for More Horsepower?
charlyW » I’m going to fit an N/A Throttle Body on my T-5 manifold because the N/A body has a wider throat than the T-5 one.
Question: Once I fit the N/A Throttle Body is on do I need to widen the throat of the manifold openning to match or will it be ok fitting straight on?
Have I been given correct information on the N/A Throttle Body being 54-56mm and the T-5 being 52mm ?
JDS60R » Keep in mind that many of the N/A tricks do not apply as the turbo pressurizes the air and this offsets most intake restrictions.
The main thing that occurs is that the throttle body now gives higher air flow for a given throttle plate angle. This will cause the car to relearn the fueling curve which in our cars makes it seem slightly more powerful for about 1 day. After that you will be back to normal.
I would bring the motor up to top operating condition and then give it a tune. You normally get more from a proper crankcase, injector, valve and piston cleaning than the throttle body will provide (always do an oil and filter service after chemical cleaning). This is true of most cars as the added contaminants lead to earlier detonation and the car pulls back its timing to compensate. If you have a clean combustion chamber and let the car relearn its adaptations you will have increased power.
The larger injectors will change your ability to control the fuel output. They are sized specifically for a reason. larger injectors without a need or new map to control them leads to less accurate air/fuel mixtures and resulting lower power.
850 N/a Throttle Body on a T-5 manifold for performance
Last Updated on November 26, 2022
