GT3 82mm TB
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Joined: Jul 2018
Posts: 56
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From: Sierra Vista AZ
Welcome to the debate... There is the theory that any improvement in airflow is an "improvement" no matter how small. For some they want to see a dyno graph before and after or else anything you change is meaningless. Others like to tinker and are ok with taking dyno graphs from others as proof some improvement happened.
So here is the thought process. 74mm throttle body is stock on 997.1 S and lets air in according to its size. Adding a larger throttle body, 82mm, will let more air in than the 74mm at all throttle positions, even the smallest throttle input. So in theory you should get better throttle response and the potential for more power throughout the rev range.
Now here is something interesting to consider. The MAF sensor housing, on the stock OEM 997 air intake box, is also 82mm in diameter already. So from the airbox, rather than shrinking down to the stock 74mm TB, it should be a nice straight air intake shot using the 82mm GT3 TB with IPD Competition plenum.
In reality, on some dyno graphs, at wide open throttle the 74mm works just fine and can compete with 82mm opening until about 5000 rpm, which is then where the 82mm volume advantage helps the most. What those dyno graphs don't show is the nice partial throttle improvements the 82mm throttle body adds over the 74mm. In some ways I think of it like adding a sport chrono button to those cars without, because at partial throttle you are getting much more air into the system with the 82mm, therefore it kind of acts like a sport button where you are opening the 74mm throttle body much faster with a more aggressive throttle curve.... does that make sense???
Of course, some will argue that this is all useless without proper sport exhaust upgrade and ecu tuning... Of course those will add their own benefits, but it has also been proven that no ecu tune is necessary even for a 4.0 liter upgraded engine. Our stock ecu software will make the adjustments necessary for any additional air flow. I believe you still get an added benefit by improving your air intake system. It may not be night and day difference, but I have the IPD plenums with upgraded throttle bodies on a couple of my cars and I feel they have added some nice benefits in throttle response.
The truth is... the bolt on power rabbit hole is a deep one. Most of these bolt ons are not night and day difference, but more of a subtle improvement that you will notice when attacking a familiar road or on ramp and think to yourself... "wow, that power felt better than before, nice! "
So here is the thought process. 74mm throttle body is stock on 997.1 S and lets air in according to its size. Adding a larger throttle body, 82mm, will let more air in than the 74mm at all throttle positions, even the smallest throttle input. So in theory you should get better throttle response and the potential for more power throughout the rev range.
Now here is something interesting to consider. The MAF sensor housing, on the stock OEM 997 air intake box, is also 82mm in diameter already. So from the airbox, rather than shrinking down to the stock 74mm TB, it should be a nice straight air intake shot using the 82mm GT3 TB with IPD Competition plenum.
In reality, on some dyno graphs, at wide open throttle the 74mm works just fine and can compete with 82mm opening until about 5000 rpm, which is then where the 82mm volume advantage helps the most. What those dyno graphs don't show is the nice partial throttle improvements the 82mm throttle body adds over the 74mm. In some ways I think of it like adding a sport chrono button to those cars without, because at partial throttle you are getting much more air into the system with the 82mm, therefore it kind of acts like a sport button where you are opening the 74mm throttle body much faster with a more aggressive throttle curve.... does that make sense???
Of course, some will argue that this is all useless without proper sport exhaust upgrade and ecu tuning... Of course those will add their own benefits, but it has also been proven that no ecu tune is necessary even for a 4.0 liter upgraded engine. Our stock ecu software will make the adjustments necessary for any additional air flow. I believe you still get an added benefit by improving your air intake system. It may not be night and day difference, but I have the IPD plenums with upgraded throttle bodies on a couple of my cars and I feel they have added some nice benefits in throttle response.
The truth is... the bolt on power rabbit hole is a deep one. Most of these bolt ons are not night and day difference, but more of a subtle improvement that you will notice when attacking a familiar road or on ramp and think to yourself... "wow, that power felt better than before, nice! "
I was thinking the same with the extra airflow. Car has the fabspeed intake, cat deletes, AWE mufflers along with the vivid tune. TB alone at $160 I figured would be decent cost return for the buck paired with the exciting parts.
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Joined: Aug 2019
Posts: 2,149
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From: Only in Texas
I noticed you got a Works1 dual inlet box that was a nice surprise when you purchased the car. Do yourself a favor, out of curiosity, and measure the diameter of the MAF housing on the Werks1 intake. It should be close to 82mm. Then you will see what I mean by the "shrinking down" to 74mm intake. The IPD helps to smooth out some power dips around the 5500 rpm mark. That's where most of the "positive" dynos show the most improvement. Between 5000-6000 rpm. If/when you do any intake mods it is recommended you reset the computer by unplugging the battery for several minutes. Install the mod and then go for a long drive running through all the gears and all kinds of throttle inputs. This will give the ECU time to adjust the fuel maps for the added air flow. Sometimes even subtle improvements add up to the overall experience. 
