996 3.4 intake manifold on 986 boxster S

[evrren]

Hello. I own 2001 boxster s. My car has 3.4 heads. Since I don't have a 3.4 manifolds, I was using a 3.2 manifolds. Now I have 996 3.4 manifolds and I have them installed in their original holes in the heads. My problem is the right manifold is touching the top plate of the engine compartment (red marker) I think I need to lower the engine by 1.5" inch. I also thought of cutting the area where the manifold touches, but this time I think I can't pass the shifter cables from the top, I would have to tighten them under the manifold. I don't know which way to follow. Just lowering the front of the engine without touching the trans is it very difficult? Is there anyone who can help with this?

[Robert986]

If you search the forum you'll find that this topic is quite well covered. Lowering seem to be the way, search for details..

Btw, I thought the 3.4 heads where the same as 3.2... Maybe I'm wrong.

[ike84]

Lowering the engine on an already lowered car is asking for trouble imo. If you don't believe me, crawl underneath and see how many of your transmission cooling fins are still intact.

I would cut the metal around the intake. If you keep it localized to the seal area, you will never notice the difference. Woody and I both did this to facilitate intake mods without problem. Running the shifter cables under the headers are inconsequential so long as you don't damage anything while threading the cables through.

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[Robert986]

Originally Posted by ike84

Lowering the engine on an already lowered car is asking for trouble imo. If you don't believe me, crawl underneath and see how many of your transmission cooling fins are still intact.

I would cut the metal around the intake. If you keep it localized to the seal area, you will never notice the difference. Woody and I both did this to facilitate intake mods without problem. Running the shifter cables under the headers are inconsequential so long as you don't damage anything while threading the cables through.

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Any pics of how you cut it?

[Robert986]

Bumping this one...

@Ike any chance you'd share a picture or a little more info on how you did the cutting?

[78F350]

Originally Posted by Robert986

Bumping this one...

@Ike any chance you'd share a picture or a little more info on how you did the cutting?

Here's how Woody did the cut for the 3.4 intake. Note: This car is a salvage car that was rebuilt for rallycross, not made to look pretty.

[Robert986]

Thanks 78F350!

Thats's a bit to brutal for me, thinking of resale value.
I wonder if one can cut down the edge of the actual intake a bit or find some other way?

[The Radium King]

or bend it and bend the cover to match. noting 987 cover has a bit more clearance.

also lower the motor 1" or so - spacers at the motor mount, 993 transmission mounts.

[ike84]

Sorry, I missed that post. I'll get pics posted this weekend.

I used the stock 986 intake runners, just had to make a small notch for the new intake tubing. You can't even see it with the cover on.

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[ike84]

Pics

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[Mangosmoothie]

Any updates? Juice worth the squeeze?

I already have intake and exhaust on my 986S. I saw a Dyno video of intake/exhaust vs intake/exhaust/IPD plenum/TB. The plenum and TB caused like a 20 HP drop at certain points for very minimal gain up top. Curious peoples thoughts on going with the 996 Mani/plenum/tb

[Newsguy]

The guy I had assembling the bottom end (yes, I'll do it myself next time!) wanted me to put some 996 heads on it, but I already had some originals machined so I passed. He says it makes a difference. He should know since he works with one of the big Boxster parts sources and builds many engines--including the 4.0 in his 996.