76mm throttle body replace 65mm
 

C

If you have a 76mm intake manifold to go along with it, then why not?

I run a 72mm TB on the red MY17 IM. It is port matched to 72mm as well and totally worth it. I believe the black IM opening is ~67-68mm.

correct me if im wrong but you shouldnt get a code because the air is already metered

There are many reasons it could throw a code if the air flow is suddenly changed.
Going from a 65mm diameter throttle body to a 76mm diameter (quite a large jump, in my opinion) is a ~37% increase in flow area (bore of the TB), which is huge.

That much increase in flow area is going to significantly change the pressure inside the manifold, which is measured by the MAP (manifold absolute pressure) sensor. It is also going to change air velocity. Not sure if velocity is directly measured by the computer, indirectly, or maybe not at all. :iono:

As air velocity changes, it will change how the air interacts with the incoming fuel - both the port injection and direct injection inside the cylinder.
I suspect port injection will not change much, but I do know that direct injection is heavily dependent on strong air velocity, creating a 'swirl' effect inside the cylinder.

Even if there were no official codes thrown, I would fully expect the car to 'run like shit' if handicapped with that huge of a throttle body.

oh yeah without a tune its gonna run like shit. i just meant that it shouldnt throw a lean code because its all metered. at least from my understanding

The throttle body is not the restrictive part of the intake. It may be 37% larger but you are not going to get 37% more air. Look at the size fo the intake just before it, it is probably 40% smaller. Airflow will slow down, pressure and temp will drop. Then it will speed back up pressure temp will increase again when the air hits the restriction of the intake ports. The ECU will figure out any minor changes this made and be happy.

I am not saying it is not going to help, and the price you have in it is reasonable for a 2% improvement. I just do not see the 37% more air coming in is going to confuse the ECU theory.

I think it’s more about initial throttle response than power. People report just that when they install a larger throttle body. It’s because the air rushes in faster through a larger opening but then it reaches a plateau so you might shift your power curve a bit but unless you’re FI, I doubt there will be more power

Motor doesn't need 37 percent more air, unless it's being pushed in

Gotcha. Thank you

The air will run slower through a bigger diameter! That't not a Bollywood movie where the physics don't apply man!

Slower velocity and greater air mass. Like quickly breathing through a straw vs an open mouth.lol

You sure about that? I'll bet the intake runners or even the head are still more of a restriction.

With the bigger throttle plate it'll feel more responsive because you're getting more air at smaller throttle openings (unless you remap the throttle curve), I'd be shocked if it actually makes a significant amount more power (even boosted) over the stock one unless you replace the intake manifold and open up the head (and cams).

I'd compare a log of the raw MAF reading before and after the swap to see if it's actually flowing more air at WOT or not. It doesn't matter if the TB flows more air, if it can't get into the combustion chamber it'll still be backed up before the TB.