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-   -   3.4l 996 intake manifold on 3.2S motor (http://986forum.com/forums/performance-technical-chat/73688-3-4l-996-intake-manifold-3-2s-motor.html)

Quadcammer 11-06-2018 09:18 AM

3.4l 996 intake manifold on 3.2S motor
 
Gang,
looking to install a 3.4 intake manifold in my 3.2 equipped boxster.

I have the 987 airbox and maf, 996 throttle body, and customer intake tube already, so I'd like to put on the 3.4 manifolds. Also have 987 engine cover for more clearance.

I think I understand the necessary steps, but correct me if I'm wrong:

1. Aluminum lower runners required
2. Plastic upper plenums
3. Fuel rail from a 996. Is this correct?

install:

1. Drill and tap holes in heads
2. run shifter cables under plenums
3. ??????

Any other tips or parts necessary?

thanks.

The Radium King 11-06-2018 09:58 AM

i looked into this and i *think* that you may have to fabricate a braze-on or somesuch out of JB weld to create a place to drill and tap for one of the spots required to attach the lower runners to the head.

and yes, fuel rail has to change - mounting points are different. you could fabricate new tabs on the rail if you are ballsy enough to weld a fuel line, but note that you have to be bang-on as it is only the two fuel rail fasteners per side that keep the injectors in.

Quadcammer 11-06-2018 10:25 AM

thanks. I don't mind getting new fuel rails from a 996. I'm assuming they just bolt on in reverse?

never heard the jb weld sitch on one of the intake runners though.

The Radium King 11-06-2018 11:28 AM

well, the fuel lines run over the transmission end in a 996, and if you put a 996 intake on a 986 you have to reverse the whole intake (to get the TB over the transmission end) so the fuel lines will be in the right place when all is said and done. you'll have to figure out how to adapt the 986 fuel lines to the 996 rails - porsche looks to use 1-time barbed fittings, but i've read that with heat you can get them off with no damage and then just hose clamp them when reinstalling (perhaps with some fuel-rated thread sealant?). you'll also have to extend your brake booster vacuum line to the other end of the engine.

you'll have to take a hard look at your head; here's a good pic of a 996 manifold; i think you'll find that there is no spot on the head to drill and tap in at least one of the required locations:


https://www.ebay.com/itm/99-05-PORSCHE-911-996-CARRERA-LOWER-INTAKE-MANIFOLD-ADAPTER-PLENUM-9961101017R-/291880861094

itsnotanova 11-07-2018 03:55 AM

I've put a 3.4 intake on a 3.2. I believe all I had to do was drill and tap the heads. I used the 3.4 fuel system but had to use the 3.2 boxster wire harness. I went over it on my build thread.
http://986forum.com/forums/show-tell-gallery/59449-woodys-build-thread.html

The Radium King 11-07-2018 05:49 AM

i stand corrected! post 243.

Quadcammer 11-07-2018 10:09 AM

woody, awesome, thanks. how did you run the shifter cables and were there any issues getting everything to fit?

thanks.

jaykay 11-07-2018 12:11 PM

Would Cayman 3.4 runners be more easily adapted?

itsnotanova 11-07-2018 05:50 PM

Quote:

Originally Posted by Quadcammer (Post 582566)
woody, awesome, thanks. how did you run the shifter cables and were there any issues getting everything to fit?

thanks.

I trimmed a little bit of the upper engine cover area in the back so the intake tube wouldn't rub and a little in the front to clear the intake. Other people said they didn't have to do any trimming but did have to drop the motor an inch or so. I tried to run the cables under the intake but that didn't work for me. I can't remember why. I have them going over the top now with no real problems. I wish I had gotten the 3.2 dyno'd with that 996 intake, custom exhaust and 996 ROW tune. I bet it would be putting out the same HP as the 3.4 I have in it now.

Sveach756 11-08-2018 04:07 AM

I also have the cables over the top of the intake but on a 3.4L. I currently have a hard top on but it’s coming out off soon when my suspension shows up I can grab pictures of the routing if needed. This is a 3.4 swap like woodys.
Shawn

Quadcammer 11-08-2018 04:42 AM

sounds like over the top it is. If I have to lower the motor a bit, that should not be an issue when combined with the 987 engine cover.

thanks guys.

Quadcammer 11-08-2018 06:04 AM

Can you guys discuss what modifications were necessary to the fuel system and or 996 fuel rail to make this work?

thanks.

j.fro 11-12-2018 04:57 PM

Very interesting! Does anyone have power numbers or Dyno charts showing gains from using the 996 manifold on the 3.2? I'm really interested to see just how much power could be made with our 3.2. Given that the 2.0 in the 1967 911R & 904 made 220, why can't we get 350 from the 986 S motor?

jaykay 11-13-2018 09:33 AM

Quote:

Originally Posted by j.fro (Post 583014)
Very interesting! Does anyone have power numbers or Dyno charts showing gains from using the 996 manifold on the 3.2? I'm really interested to see just how much power could be made with our 3.2. Given that the 2.0 in the 1967 911R & 904 made 220, why can't we get 350 from the 986 S motor?

My guess is the 3.2 heads won't flow enough to get it.....so intake, exhaust and significant head work are required. Porting, camshafts, valves / springs, cam timing. This restriction was of course put in place by design. I believe one can approach 300 with bolt ons but I have not heard of any being able to break through

Woody posted some surprisingly good dyno results from bolt ons and ECU tunning. I would link it if I could find it.

If we get into the heads and start doing it, how is the 3.2's propensity for head cracking mitigated? One could asks this for a total engine build as well.

I feel your frustration ......I remember track days where I just couldn't shake old 993 on my tail...

The Radium King 11-13-2018 09:52 AM

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.

BYprodriver 11-13-2018 02:33 PM

1 Attachment(s)
Quote:

Originally Posted by jaykay (Post 583055)
My guess is the 3.2 heads won't flow enough to get it.....so intake, exhaust and significant head work are required. Porting, camshafts, valves / springs, cam timing. This restriction was of course put in place by design. I believe one can approach 300 with bolt ons but I have not heard of any being able to break through

Woody posted some surprisingly good dyno results from bolt ons and ECU tunning. I would link it if I could find it.

If we get into the heads and start doing it, how is the 3.2's propensity for head cracking mitigated? One could asks this for a total engine build as well.

I feel your frustration ......I remember track days where I just couldn't shake old 993 on my tail...

These heads do,

Racer Boy 11-13-2018 08:31 PM

Quote:

Originally Posted by j.fro (Post 583014)
Very interesting! Does anyone have power numbers or Dyno charts showing gains from using the 996 manifold on the 3.2? I'm really interested to see just how much power could be made with our 3.2. Given that the 2.0 in the 1967 911R & 904 made 220, why can't we get 350 from the 986 S motor?

Back in 1967 the HP numbers were gross, not net. The difference is that they could measure the output with no accessories attached, open exhaust, no air cleaners, etc, in whatever temperature and conditions the maker wanted. Now the numbers are far more accurate, because the conditions of the measurement are standardized, and all the accessories are attached and functional.

Your 220 HP in 1967 would probably measure under 200 HP using the SAE net ratings.

You can read up about it here - https://ateupwithmotor.com/terms-technology-definitions/gross-versus-net-horsepower/

itsnotanova 11-14-2018 03:25 AM

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 http://986forum.com/forums/performance-technical-chat/71568-two-modified-boxsters-dyno-2.html 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.

jaykay 11-15-2018 08:28 AM

Quote:

Originally Posted by BYprodriver (Post 583083)
These heads do,

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

j.fro 11-15-2018 08:54 AM

Quote:

Originally Posted by BYprodriver (Post 583083)
These heads do,

Indeed. Care to share specs? Bigger valves? where in the heads was the porting done, and how much larger are the runners now?

I've got the 74mm TB & a splitter in the intake (Pedros Garage). the rest of my intake is 3.2, but I know the TB made a difference. I wonder what an 82mm TB (GT3) would do. I've put this out there before, but my car made 244RWHP with all of the bolt-ons.

BYprodriver 11-16-2018 03:58 PM

Quote:

Originally Posted by jaykay (Post 583207)
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 11-16-2018 04:13 PM

Quote:

Originally Posted by itsnotanova (Post 583114)
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 http://986forum.com/forums/performance-technical-chat/71568-two-modified-boxsters-dyno-2.html 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 12-09-2018 01:58 PM

Quote:

Originally Posted by The Radium King (Post 583060)
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 01-15-2019 04:16 AM

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

jaykay 01-15-2019 11:05 AM

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

Quadcammer 01-15-2019 02:12 PM

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 01-17-2019 08:15 AM

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

Quadcammer 01-23-2019 05:27 AM

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 01-24-2019 12:14 PM

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 01-24-2019 01:15 PM

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 01-26-2019 12:03 PM

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 01-26-2019 06:50 PM

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 01-27-2019 04:29 AM

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

Will update as i go forward. Waiting on gaskets now

jaykay 01-27-2019 10:12 AM

Quote:

Originally Posted by The Radium King (Post 588064)
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 01-27-2019 10:17 AM

Quote:

Originally Posted by Quadcammer (Post 588053)
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 01-27-2019 06:11 PM

Stock is 73mm, 996 is 91mm

jaykay 01-27-2019 06:58 PM

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 01-28-2019 05:19 AM

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 01-28-2019 12:57 PM

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 01-28-2019 08:05 PM

Quote:

Originally Posted by Quadcammer (Post 588125)
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


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