FactoryMatt

sorry if it's been discussed.

i've got a 2.9 987.2, but assume this question would apply to 3.4 as well. it seems more economical to bore/stroke existing engine, along with some headwork, than paying 30K to swap in 3.8DFI and deal with the attendant ECU headaches (and in the case of the 2.9, the addition of DFI pump etc), intake manifold and tube, oil filter placement modifications etc etc. yes i know you get 2yr Porsche warranty bla bla.

does anyone know if the deck heights are the same between the 987 9A1 and the 997/991 9A1? if so, it would seem pretty straightforward.


it seems all you would need for a nice 3.6+ motor would be:

-camshafts (maybe not even)
-minor port work
-stroker crank (OEM even?)
-shorter forged rods
-pistons
-bore and plate/line cylinders

i would rather massage the engine than go through the headache of retrofitting another. this is done all the time in JDM land (subaru, honda, etc)

Thoughts??

Schmidts Cat

Try checking with vision motorsports in Orange County? Won't make as much power as a 3.8, but may be a great improvement. At a better price. Might want the plenum and gt3 TB as well.... I have those used for sale if you decide to do it. Headers too for sure. Keep us posted!

mcipseric

+1

Voyager6

From a quick check of 2010 Cayman spec sheet from Porsche, the 987.2 2.9L has the same stroke (77.5mm) as the later 981 3.4L and 991 3.8L engines, so unless the piston pin height was altered, there is some chance the deck height is the same.

I would guess there will be cam differences, but whether that is important or not will be in dyno testing.


It might be easier and cheaper to buy a low mileage 3.4L and move the non-DFI heads over.

V6

Dr. Danny

I would like to bump this thread, as I currently have the same exact question.

TX911

Reviving an old thread that faded away without resolution. Has anyone done a head or cylinder swap on a 2.9 and can share their experience? Interested in a little more power for my base 987.2 and a dfi engine swap seems like a headache.

Zach L

I haven't done it, but for the 3.8L crankcase, you'd have to machine it to accept the mid-engine oil filter housing setup, and engine builders recommend full disassembly for that. To avoid that, I'd look at a 3.4L from a 987.2 or 981 Cayman S. That'd be an easier DIY. If you're thinking about paying anyone to do this, then it doesn't make sense. Would be more cost efficient to just sell the car and buy an S with the 3.4L ...that's probably why it hasn't been done. Even the DIY route will come close to it not making sense (cost of engine + rebuild parts + custom tuning), which is why this probably hasn't been done.

Ubermensch

LN has been doing this work for years and lists many displacement upgrades on their site: Porsche Boxster, Cayman, and 911 M96/M97 Engine Parts and Upgrades (lnengineering.com)

I don't see anything about increasing displacement on a 2.9...which suggests there may be a good reason. You may want to give them a call to discuss things.

sasilverbullet

My engine was a stock 3.4 and was upgraded by Flat six Innovations to a 3.8. Runs like a rabbit and pulls strong!