Visual Differences between updated Intake Manifold

I went down this rabbithole last night reading up on every comment and was dismayed to learn that x91 was not a new, better designed part. My Prius probably has x50, so I will just clean it up for now and call it a day.

 

I'm pretty sure Toyota introduced it because they did consider it an improved design.

On the other hand, maybe it won't matter to you if you don't experience the issue they improved it over.

 

It is certain the intake was an improved design. It is designed to eliminate codes stored in certain cold starts when combined with an ecm software update.



Toyota also updated their gen3 head gasket, pistons, rings and egr valve. All in an attempt to make the gen3 engine more reliable. In fact 2017-2021 gen3 engines sold overseas have a good reliability record even though they share the same gen3 engine. Which makes JDM engines of that vintage good options now or professionally rebuilt engines using those parts a better choice.

 

Somehow I keep forgetting that more than one TSB announced revisions to the gen 3 intake manifold.

T-SB-0010-12 was the one about snorting condensed water from the EGR passages. That's the one I usually remember. It said to update to a -52 manifold in the first revision, then later to -54.

T-SB-0103-12 was about the throttle body sticking open. Looks like I knew about that four years ago but I usually don't remember it. It says to update to a -91 manifold.

I don't think I had ever even stumbled on T-SB-0116-15, which is also about replacing the manifold, this time for misfiring when driving with EGR active (the usual effect you'd get if the passages were gunky, fixable by cleaning them). That one also pushed the -54 manifold (rather than taking the time to clean the existing one).

The most interesting one I forget to think about is T-SB-0103-13. The symptom is a P2111 code, which is when the ECM tells the throttle to close and that doesn't happen, and apparently that was (not) happening below 23 ℉ (−5 ℃), and they somehow meant the -91 manifold to improve that. Hard for me to guess why, but that might be the one that comes closest to giving a reason for the weird griddy gasket under the throttle body.

 

As has been discussed earlier in this thread, there is no x91 manifold. The x91 is a reference to a x54 manifold kit with all the gaskets included. So the latest design seems to be x54.