Just a good valve job & new springs with light port cleanup & crack prevention welding from Costa Mesa R&D. 99mm cylinder bore helps to increase airflow too! ;)

3.4 & 3.2 have the same case Casting, 3.4 has bigger bore & pistons. Heads are the same except different bolt hole placement, cams are the same, crankshafts are the same but the bigger bore gives the higher compression ratio. This is why the best way to boost torque & HP in a 3.2L is to increase bore size.

The 996 3.4 / 3.6 left and right plenum chambers appear to have significantly more volume than the 3.2s by my eye....perhaps this yields a more consistent / higher manifold pressure giving more power. Also the entry diameter looks to be larger.

Anyone have this dimension at hand? It is probably the same diameter as the outlet of a 996 or 997 diverter tee.....recall way back when we first put 74mm TBs in and used reducers or did the stretch to make it fit with 3.2 boots.

got a 996 setup for the cost of shipping, so I'm gonna give this a go.

nice...would be interested in your drill set up for the additional holes.

They are m6 holes that go down no more than 15mm. I intend to mark, center punch, and then drill using a drill block.

If anyone is looking for a 996 intake, I have a full setup for sale, including throttle body

http://986forum.com/forums/boxster-cayman-parts-sale-wanted/74393-996-intake-manifold-air-box.html#post587539

I had planned to upgrade my Boxster with this setup, but the car just sold. I also have a 987 airbox in the Classifieds to work in conjunction with this setup

so I believe I have a setup that will allow me to use the standard boxster fuel rail on the 996 intake and its shockingly simple. I'm not 100% convinced yet, but I'm pretty confident. Extending the vacuum hose is no biggie.

Did any of you 3.4 cable throttle guys have issues with the throttle cable being too short?

right on. let me know what you are sorting out for the fuel rail (hopefully less work that running new fuel lines?). also advise if you'll be able to drill the heads without dropping the motor - thinking a drill block and a flexible drill extension?

I would think there would be no issue drilling. I dont recall the fire walls getting in the way of the intake ports but i could be wrong

So stock intakes are off. Bit fiddly but really no biggie. Fuel lines i think will be a non issue. The plenum will clear the 997s oil cooler. Vac line is a trivial change.

Drilling...well, it aint gonna be fun qnd im gonna have to move alternator and ac compressor i think, but ultimately if i mark well, center punch, and use drill block properly it should be fine. Prolly gonna end up with a right angle drill.

Finally, id be amazed if the cayman cover clears. These plenums are seriously high. I may need to lower the motor about .5"

Happy with progress so far

thanks. keep the updates coming. i've got my 996 intake enroute and is the final step in the de-stupification of my 3.2. i'm thinking flex drill attachment or see if my dremel with flex attachment has the cojones to do the work. the intake i have coming (thanks halo) has fuel rails for a single line system so i am watching your fuel rail conversion with interest, otherwise i hope to use a mercedes 3.8 bar fuel filter/pressure regulator to convert my two line system. a quick seach shows that there are infinite adaptors to convert our fuel lines to barbed connectors for easy fuel line installation.

also interested in the clearance issue, and whether convincing the engine bay to let the intake fit, or dropping the motor is the soln. if you do drop, think about making the change to the rennline transmission mounts; they beome just incrementally more $ than getting the 993 mounts and really improve shifter feel. they come with longer studs that will take a spacer to let you drop the transmission to match the drop at the engine mount (which will also require a spacer and longer studs or bolts).

I already have 993 rs trans mounts so no issue there.

Will update as i go forward. Waiting on gaskets now

Rennline also has longer studs you can put in if needed. My mounts arrived a little while ago.....they came unanodized which was annoying as all the images of the pieces showed a nice gunmetal finish

Any problems with lowering the engine / trans at the back and not at the front?

Would be able to measure the entry diameter of your plenums and post it?

Stock is 73mm, 996 is 91mm

thanks man.....that is a very significant difference! I will be very interested in how this changes the performance of the engine.

I may be mistaken but I believe that this diameter is bigger than anything upstream on the 996 intake.

This change may really enhance the effect of a larger TB, putting the relationship of throttle body diameter to plenum entrance at 80 to 90 percent while allowing for more air volume vs the smaller 3.2 plenums

so I have the 987 airbox, custom i believe 3.5" intake tube, 996 throttle body, and headers/exhaust.

I think on a stock 3.2 this would have only minor benefits, but on an engine moving more air, it may be beneficial. You also pick up what looks like 2" or more of runner length, which should help lower rpm torque.

I'm no expert but this is apparently something jake does on his motors.

drilling has generally gone ok. I have 3 holes in, but I snapped a tap in one of them, so I'll need to find a solution there.

Thanks yes I believe you are correct, good luck getting this under the Cayman cover. I am pretty sure I remember Jake indicating that these 2.7/3.2 plenums (left and right intake runners) were not even adequate for the 2.7. If I find the post...I will link it.

He didn't offer any further explanation