Install: OEM 2.3L Throttle Body (NA & ST)

It’s always nice when you can just go through the Ford parts bin and find some parts there to upgrade and personalize your car with. Going back to the early days of the Mk3 community, this was all we had really; the aftermarket hadn’t quite gotten start yet so we were left to our own devices and would play around with swapping on parts from different trims (for example) to make our cars either look different and/or perform better.

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While the aftermarket has since grown massively, OEM parts are still worth looking into. As new model year updates and new trims/versions roll out, naturally that means new parts become available to play with and one such example was the throttle body from the 2.3L EcoBoost. A little while ago it was discovered that this unit would bolt onto the 2L engines found in Mk3 Foci – both the EcoBoosts and naturally-aspirated versions – so owners started picking them up and tossing them on. For today’s post we’ll be looking at this swap, on both an EcoBoost and N/A Mk3.

These photos are two sets taken on two very different days; the ‘ST’ in question is naturally my car, Mustard (2012 sedan with a 2013 ST heart) and the NA used is Brian’s 2013 Titanium sedan. By waiting on this post for a little while I’ve been able to combine the two sets of photos and install notes into one post so it can serve as one point of reference for ST and NA owners alike. Furthermore, below is a video of the swap on Brian’s car as well. I didn’t film the install on the ST engine as I was working by myself, and in the evening so the light quickly went. When we tackled Brian’s install it was mid-afternoon and sunny, and he was able to do the swap (which is SO MUCH easier on NAs) while I filmed it.

I couldn’t say for sure how long the install would take on an ST engine as I was multitasking and tackling other jobs at the same time (this was when I had the car parked for a couple of weeks to prep it for Driven) but in Brian’s case, if we weren’t filming we could have had the swap completed in a matter of minutes.

We might as well start with the parts list, so here it is – it’s listed in the video as well.

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-GASKET – 9L8Z-9E936-A

-BOLTS – W716585-S437

-*FOR STs ONLY* – 2.75″ to 2.5″ Silicone coupler of your choosing. (I used a Mishimoto piece)

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All of the OEM parts (that’s excluding the required coupler for the ST install) come to just over $100 CAD (at the time of this writing). Thanks in our case goes to Marshall at Advantage Ford for ordering these parts!

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This is a fairly inexpensive upgrade and for NAs at least, extremely easy; in fact, this would be a great place to start with doing more DIY jobs on your car if you don’t have much experience as it’s merely a few bolts and one connector – very straight forward. The install on STs isn’t too difficult but you need to know what you’re doing as the entire intake manifold has to be removed whereas on the NAs due to their throttle body placement, only the intake arm has to be pulled. For Brian’s car we pulled the airbox as well incidentally, so as to give better access for the camera; that step is optional.

The ‘why’ behind this swap, in case you’re wondering, is to improve throttle response. It seems to be more pronounced on NAs and big turbo STs, and to back this up Brian commented on a noticeable improvement whereas mine was harder to detect; though, he was able to almost immediately drive his car post-swap whereas mine was parked for two weeks as previously noted. That said, given the ultimate plans for my car I didn’t mind tackling this now given the low cost and I’m pleased to have one more part in place; I never mind putting pieces in place ahead of time if I know it’ll all work towards a longer-term goal.

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I hope you didn’t think we’d skip over a visual comparison of the throttle bodies! On the left is the new 2.3L unit – the original 2L piece (from my car) is on the right. Measurements come in at 65mm and 63mm for the inlet and outlet of the new piece, respectively; the original measures at 57mm. Incidentally, the ST’s intake manifold inlet is 65mm as well.

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With the increase in the inlet size the outer diameter of the throttle body is naturally larger as well and that is why the new silicone coupler is required for STs. The original unit could perhaps be squeezed over if you really (really) tried but for a few bucks, a properly-sized coupler is a good idea especially given how hard it is to get to once reinstalled; if it were to blow off or fail in some way it wouldn’t be fun to get it reseated. A 2.75″ to 2.5″ piece will fit over the larger throttle body and securely fasten to the OEM charge piping (or aftermarket 2.5″ piping) and keep everything together.

For NAs, the original intake arm will fit over and the clamp will still hold securely as well. It takes a bit of effort (we used a touch of vaseline to aid in getting it seated) but no new pieces are required there.

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For anyone not familiar with the ST engines and/or intake manifolds, this hopefully gets the point across of why it’s not nearly as easy an install on these engines. The intake manifold isn’t necessarily hard to remove but it can be a bit tricky with tight clearances and all of the fittings to reach and undo. Adding to the complexity of the install is the fact that the harness for the throttle body has to be rerouted (or extended to fit properly). I did the former, by cutting back the loom to have the throttle body wiring leave the main harness earlier, and then it could be routed around to the new location for the throttle body connection. There’s more on this in the video but essentially the 2.3 unit connects in a different location once installed so the harness has to take a new path to reach it. Once done, be sure to re-wrap the cut loom with electrical tape to seal it back up if you used that method.

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Likewise, the harness needs to be rerouted in the NAs as well but there’s nothing more you have to do than physically move the wiring over; no cutting back of looms or extensions are needed. The video of the full install is below – it really is easy on these cars!

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Given the ease and more pronounced improvements, we’d recommend this to NA owners looking for an easy, inexpensive modification to make to their cars. For ST owners who already have or are planning to go big turbo, it should be a worthwhile swap as well; as mentioned earlier it’s apparently more pronounced on cars with larger turbos, though I’m happy to have it in place now because we all know that a larger turbo will happen…but that’s an install for another day.



  • What about California cars? will the throttle body swap trigger an engine check light?

  • Bill,
    I installed the 2.3L throttle body to my N/A 2.0L 2012 base model Focus sedan and the improvement in power and smooth power delivery was excellent. My concern was that the swap would trigger the engine check light in a California car but it was not the case. Thanks for your website! I love the fact that most of the parts that fit the RS and ST models fit my car also. Keep up the good work.

    • Hey John,
      Just want to check with you that this would fit on my 2012 sel with only the parts mentioned above. Thanks.

      • Hey David,
        Yes these parts will fit your ’12 SEL. The engine is the same as the one shown here, in Brian’s car.

  • Can I install a 2.0 l or 2.3 l body throttle on my Normal Ford focus 2013 1.6 l to improve performance?, please help.

  • Hi,
    Great write up. Are the bolts you purchased used longer than the standard ones?

    • They are; the OEM bolts for this throttle body are longer than those for the original N/A unit.

  • Can I do this too my 2017 Ford focus titanium sedan 2.0

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