3.4l 996 intake manifold on 3.2S motor

[BYprodriver]

Originally Posted by jaykay

Nice...good flow and no cracking? Details? Fitment on which engines?

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!

[BYprodriver]

Originally Posted by itsnotanova

Don't quote me on this but I'm pretty positive the difference between the 3.2 and 3.4 are the case and pistons when it comes to the long block. The heads are mostly the same but the 3.2 has slightly less compression. The only real difference between the two is the intake, tune and exhaust systems. I didn't feel much of a difference when I went from a 3.4, to a 3.2 with the 996 intake, fuel, and custom exhaust made with the same diameter tubing as a 996.
The seals inside the valve adjusters were going bad in my 3.4. I put the 3.2 in while i fixed the 3.4. I almost considered leaving the 3.2 in but I had lots of $$$ invested in the 3.4, so I reinstalled the 3.4. My box made 279hp at the wheels with the 3.4 and my friend mad 249hp at the wheels with his 3.2. Here's the thread Two modified boxsters on the dyno I contribute the difference in power between us to the length of the intake runners, mileage, tune and maybe the exhaust. I have a customer who owns a shop in Dallas. He claims to have made 300hp at the wheels with a 3.2. I tend to believe him as he works on some amazing vehicles and worked for Ruf at one time.

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.

[jaykay]

Originally Posted by The Radium King

well, the size of runners on the 996 plenum doesn't seem to be bigger than that on the 3.2, i think the difference is length - the 996 units are longer, so you will see more of a venturi effect and better cylinder fill at lower rpms. they may actually reduce max hp a bit as the increased length would be seen as a restriction at wot, but raise the overall torque curve up a bit. and more area under the curve is the goal, not necessarily the max number.

if you think about it from a porsche design point of view, the only reason the boxster runners are shorter is so they could fit the engine in the car.

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.

[Quadcammer]

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

[jaykay]

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

[Quadcammer]

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

[halo777]

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

996 Intake manifold and air box

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

[Quadcammer]

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?

[The Radium King]

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?

[Quadcammer]

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

[Quadcammer]

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

[The Radium King]

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).

[Quadcammer]

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

Will update as i go forward. Waiting on gaskets now

[jaykay]

Originally Posted by The Radium King

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).

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?

[jaykay]

Originally Posted by Quadcammer

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

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

[Quadcammer]

Stock is 73mm, 996 is 91mm

[jaykay]

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

[Quadcammer]

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.

[Quadcammer]

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.

[jaykay]

Originally Posted by Quadcammer

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.

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