987.2 3.8 conversion

Hello, I am looking for information for 987. 2 3.4 dfi engine swap with 997s 3.8 dfi engine. I found several posts about BGB and Vision motosports but where I live, nobody do this kind of conversion. The plan would be to do the mechanical myself and be supported with a company which works remotely like Softronics for software. Several topics are not clear for me : Some people are talking about engine block machining for oil filter housing modification. Some other say not needed. List of components that have to be retained from 3.4 engine ? Engine positionning : can we keep 3.4 engine support ? Thanks for your help !

While I can't answer most of your questions, I have been looking into the info required for this as well and I looked at several pictures of engines on Ebay for 997.2 and 987.2 and from what I can tell, the only differences are the oil filter housing/cooler unit that mounts on the top of the driver side (LHD) bank and where it attaches to the block, there are different ports machined into it for the oil to pass. On the 997.2 engines, the holes are machined at the accessories end of the block, but on the cayman engines, the port is machined at the transmission end of the block. My understanding is that you would need to machine the hole for the oil cooler to go into and plug the other one (or maybe the other cooler unit has a way to plug the existing hole). Another option is to go with a 3.8 GT4 engine out of a 981 or a 4.0L Cayman engine out of a 718 GTS 4.0 or GT4 as both of those already have the correct holes machined and the correct oil cooler/filter housing. As for the rest, I think you can just swap over any existing 987.2 mounts/accessories if they aren't the same already. If you decide to go with the 997.2 engine without machining the holes and swapping the oil cooler/filter housing, I think you would just now have the filter housing at the accessories end of the engine and it may not be as easy to do an oil filter change. Not sure on that though.

Thanks this seems to be one of the most important topic ! I checked engines images too but only find a photo of oil cooler housing, not the block location.

Some results of my research regarding oil ports. Pictures of oil carriers for Ma1 engines : 911 : Cayman : Pictures of engine ports for Ma1 engine : 911 : Cayman : The 911 block has two separated ports whereas Cayman block has one port blank and the other with 2 holes. I suppose that tvey are inlet and oulet because there is a rail that link the two ports in the casting. If I am right, a 911 block conversion needs to close one port with a blank plate and drill the second hole in the opposite port. If this port directy goes into oil pump or crankshaft, for sure I would never drill without unmounting engine ! If it only feeds the oil rail, perhaps a cleaning an be done by blowing into the other port.

What might be interesting is if someone were able to modify the Cayman oil filter housing to use the 911 port on the other end of the block and plug the extra port next to the filter end. The advantage to this would be that you can do that without taking the engine apart. I doubt that's all that feasible, but it would make things much easier.

Could be done with an oil filter relocation kit?

Indeed I said a mistake. It is not possible to use an oil filter relocation kit on 911 ma1 oil carrier. You are right that easiest way is to go with a Cayman /engine but I understood that for harness and DME , it is better to stay within same generations. 987.2 with 997.2 . I will to try estimate the workload to open the block for oil ports machining. The most complex seems to find a comprehensive workshop manual for ma1 engines!

Believe it is plug and play with the 987.2S (non-S has a different ECU )

For both 997.2 and 991.1 engines ?

So, the 991 engines are still the same Siemens DME that is in the 987.2 / 997.2 cars, so wiring should be the same. The 992 /982 engines got a new Bosch DME that has a different wiring harness and would require similar wiring changes as a 987.1 to 987.2 conversion. However, I believe that you could in theory use the 987.2 / 981 wiring harness on the 992 /982 engines and just tune it for the larger displacement. Another thing about that picture you posted of the 987.2 with the 997.2 engine in it, look closely at the firewall where the oil filter housing is. There is a cut out section and an access panel made to be able to change the oil filter. That's the sacrifice that has to be made to make the 997.2 engine work in a 987, even with the lowering of the engine. I suppose it's easier to do than disassembling the engine to drill the holes in the block or making a custom oil cooler housing. Just depends on what you're comfortable with doing.

Indeed I didn't saw the cut in firewall for filter access. For the electric topic, I just found a thread on PFF about 991 to 997.2 engine swap. The guy mention this : But then a few more hurdles arose. Little by little, the following differences between the 997 and the 991 engine were discovered: electric water thermostat, load-dependent oil pump, modified oil filler neck, and a modified MAP sensor .

Hey all, I just purchased a slightly damaged GT4 engine from a 2016 car and will be swapping it into my 987.1 that I already converted to a 3.4 DFI engine from a 987.2 . I'll be swapping over the cooling system components, wiring harness and any other different parts from my 3.4 to it. The MAP sensor will probably just stay in the intake to fill the hole since my wiring harness doesn't have the wiring for it and I'll be keeping my existing DME to control it and using the Softronics 3.8 conversion performance tune to take advantage of the larger displacement. So far with the engine in my garage, I can't see a whole lot of differences, but I just got it home yesterday, so I'll still need to do some more investigation. I have no doubts that I can swap over whatever I need to from my 3.4 externally to make it work without any major changes. Softronics says horsepower should go up to about 410 bhp vs the stock 320 bhp of the 3.4, so it should be a noticeable increase. I plan on also doing some supporting mods like an LSD and maybe some 997.2 front uprights and 6 piston calipers to go with my girodisc upgraded brakes. Keep an eye out for my build thread on it shortly.

This is going to be great, looking forward to it!

Take LOTS of pictures. Hire someone if you have to...