I think Honda makes different height Injector Seals for the different intake manifolds (depending on engine compression ratio).

Ive noticed that a non-vtec intake manifold has taller Injector Seals than a b16a manifold. Both come with the same flow rate Injectors (240cc). The manifold seals from the b16a manifold are 60% shorter than the non-vtec. This means that b16a injectors sit closer to the plenum. I wonder if this has to do with the programmed injection. Or maybe tuned injector heights for optimum fuel atomization for specific power band. What do ya think?

 

The injectors with the shorter manifold seals usually have a plastic ring that sits in the manifold just below the rubber gasket- this plastic and the thin rubber gasket is the same thickness as the thick gasket. I just looked at some today. I put injectors in a 92 Accord lx today that had the plastic rings and thin gaskets. I compared them to injectors from a 94 civic Dx. Maybe there are different setups, but I haven't seen any yet.

 

While your on the subject of injector seals, which ones do I need to make my dsm 450's fit into my Itr intake manifold? The stockers I have,have too small of a ID for the larger OD of the dsm's.

 

Interesting, plastic sitting under the rubber seal to keep the rubber away from extreme manifold heat ..prevents seal from deteriorating fast. What color is this plastic ring? So far I havent seen it in 89-91' Intake manifolds. Seems like Honda learned that the rubber seals are vulnerable to the manifold heat, and started putting them in 92'.

thats interesting, I thought the dsm 450cc's wouldn't have any fitment problems. You might wanna try using the manifold injector seals from the dsm ..just a guess

 

They are black or dark brown- but they don't have them in some newer models- I don't think there is any real benefit here- just depends on what manifold is used.