997 Engine to 996 Swap
10-08-2009, 07:22 PM
#1
Three Wheelin'
Thread Starter
997 Engine to 996 Swap
Anyone swapped a 997 Mk I engine into a 996 MK II? Besides the crate engine from Porsche, what else do I need to do the swap? Both are E-Gas so I think the harness is the same. Does the ECU need to get swapped too? Anything else?
10-09-2009, 08:17 AM
#2
Racer
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I don't know anybody who has done the swap you refer to, but my experience with another swap leads me to believe that there will be many costly issues that you will be dealing with.
My swap involved putting a 2004 3.6 X51 engine into a 1999 C4. I had this done by a professional Porsche tuning shop. This would seem to be a straightforward process, since all of the auxillaries (alternator, AC compressor, exhaust system, etc were interchangeable. However, after that, everything went downhill very quickly. It seemed, as we went along, that just about everything else was no longer compatible. Remember, this was just a "newer" 996 engine going into an earlier 996 car.
I had known from the start, that we would be replacing the ECU, and both the rear car and engine wiring harness. Also the pressure air conditioning line from the front condensor to the engine had to be changed. These are costly items, even if you can find used ones from a salvage yard. Muffler brackets had to be changed.
After this, the engine was running, but many "new" incompatibilities emerged. The cruise control did not work. The ABS and PSM did not work. The air conditioning did not work. So, now we needed the 3.6 type of ABS and PSM modules, we needed a 2002-2004 type of instrument panel. We needed a separate circuit and switch to make the AC system work. As you can imagine, the component costs and labor were astronomical.
It seems that Porsche makes many changes from year to year, even in the same model range, the 996 in this case.
So, not to discourage you, but be prepared for many incompatibilites and the need to replace harnesses, modules, instruments, etc. The installation of the engine into the chassis will be the least of your problems.
....Rickker
My swap involved putting a 2004 3.6 X51 engine into a 1999 C4. I had this done by a professional Porsche tuning shop. This would seem to be a straightforward process, since all of the auxillaries (alternator, AC compressor, exhaust system, etc were interchangeable. However, after that, everything went downhill very quickly. It seemed, as we went along, that just about everything else was no longer compatible. Remember, this was just a "newer" 996 engine going into an earlier 996 car.
I had known from the start, that we would be replacing the ECU, and both the rear car and engine wiring harness. Also the pressure air conditioning line from the front condensor to the engine had to be changed. These are costly items, even if you can find used ones from a salvage yard. Muffler brackets had to be changed.
After this, the engine was running, but many "new" incompatibilities emerged. The cruise control did not work. The ABS and PSM did not work. The air conditioning did not work. So, now we needed the 3.6 type of ABS and PSM modules, we needed a 2002-2004 type of instrument panel. We needed a separate circuit and switch to make the AC system work. As you can imagine, the component costs and labor were astronomical.
It seems that Porsche makes many changes from year to year, even in the same model range, the 996 in this case.
So, not to discourage you, but be prepared for many incompatibilites and the need to replace harnesses, modules, instruments, etc. The installation of the engine into the chassis will be the least of your problems.
....Rickker
10-09-2009, 09:10 AM
#3
Rennlist Member
A lot changes. I believe these guys do it all though if you're interested: http://www.roockusa.com/service/index.html
10-09-2009, 03:13 PM
#5
Rennlist Member
The swaps are not as scary as everyone thinks. Typically it is recommended to stay within your generation of 911. The 996, 986 interchange well across the years regardless of actual year. Some years are easier than others, but there is a well solved approach to each of those nowadays.
The 997 Gen1 and 987 also interchange well. when you mix 9x7 to 9x6 you have a higher level of issues. It can be done. There are a few 996s running around with 997 3.8 x51 motors in them.
The key is that your shop must have exp doing the swap that you wish to perform and have a plan for each issue ahead of time not as they run into it head first.
I have a 99 car with an 03 3.6 engine. No issues. Cruise, AC, everything works as new and the dealer or smog inspector can't even tell something is done unless I tell them.
The 997 Gen1 and 987 also interchange well. when you mix 9x7 to 9x6 you have a higher level of issues. It can be done. There are a few 996s running around with 997 3.8 x51 motors in them.
The key is that your shop must have exp doing the swap that you wish to perform and have a plan for each issue ahead of time not as they run into it head first.
I have a 99 car with an 03 3.6 engine. No issues. Cruise, AC, everything works as new and the dealer or smog inspector can't even tell something is done unless I tell them.
10-12-2009, 11:35 AM
#6
Three Wheelin'
Thread Starter
I would image swapping something newer into the 99-01 would be the big challenge as it is a non CAN-bus car. Once you get past that, mixing a 996 mk II and 997 mk I should not be that bad. I don't need A/C or cruise so that probably makes it easier. I am intrigued by the fact that the 3.8 X51 is thousands cheaper than the 3.6 X51. The core is more, but the reman is cheaper.
10-12-2009, 03:15 PM
#7
Drifting
You might want to talk with Phillipj here and on Rennlist. He spent alot of time and money with Roock having a 3.6 put in his car and it turned into a nightmare. He finally sold the car and got a 997. Just thought he might have some insight on this.
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10-12-2009, 03:22 PM
#8
Just another alternative to consider: the Mk 1 997's M96 engine is of the same basic design as the 996, including the beloved intermediate shaft. More displacement and lots of improvements for sure. Still, for the money and risk involved in a swap, I wonder if it would be more fun and ultimately a longer term proposition if you rebuilt the original motor?
I'm all for building 'outlaws', but if it was me I'd be tempted to upgrade the original powerplant. When it's good, it's very very good.
I'm all for building 'outlaws', but if it was me I'd be tempted to upgrade the original powerplant. When it's good, it's very very good.
10-12-2009, 07:21 PM
#9
Nordschleife Master
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I would image swapping something newer into the 99-01 would be the big challenge as it is a non CAN-bus car. Once you get past that, mixing a 996 mk II and 997 mk I should not be that bad. I don't need A/C or cruise so that probably makes it easier. I am intrigued by the fact that the 3.8 X51 is thousands cheaper than the 3.6 X51. The core is more, but the reman is cheaper.
http://www.renntech.org/forums/index...pic=15712&st=0
10-14-2009, 09:28 PM
#10
Three Wheelin'
Thread Starter
Its looking like a 997.1 motor into a 996.2 is just install and flash. The harness is the same, both are CAN-bus and Motronic 7.8 DMEs. This might work.
10-15-2009, 01:57 AM
#11
Addict
Rennlist Member
Rennlist Member
sounds like something that happened to me in a different kind of car, doing a motor swap and a performance modification. In short, what I feel like to this day, is that when you spend $20K+ on a mod that is supposed to make you happy in the end is spending much dollars to ruin a car that apparently was better prior to the change. Now my Benz is not even operable and reliable. The worse thing about it is that it upsets you it probably would be more trouble to put it back to it's original form and you're so pissed you rather just get rid of the car so you're never reminded again.
I don't know anybody who has done the swap you refer to, but my experience with another swap leads me to believe that there will be many costly issues that you will be dealing with.
My swap involved putting a 2004 3.6 X51 engine into a 1999 C4. I had this done by a professional Porsche tuning shop. This would seem to be a straightforward process, since all of the auxillaries (alternator, AC compressor, exhaust system, etc were interchangeable. However, after that, everything went downhill very quickly. It seemed, as we went along, that just about everything else was no longer compatible. Remember, this was just a "newer" 996 engine going into an earlier 996 car.
I had known from the start, that we would be replacing the ECU, and both the rear car and engine wiring harness. Also the pressure air conditioning line from the front condensor to the engine had to be changed. These are costly items, even if you can find used ones from a salvage yard. Muffler brackets had to be changed.
After this, the engine was running, but many "new" incompatibilities emerged. The cruise control did not work. The ABS and PSM did not work. The air conditioning did not work. So, now we needed the 3.6 type of ABS and PSM modules, we needed a 2002-2004 type of instrument panel. We needed a separate circuit and switch to make the AC system work. As you can imagine, the component costs and labor were astronomical.
It seems that Porsche makes many changes from year to year, even in the same model range, the 996 in this case.
So, not to discourage you, but be prepared for many incompatibilites and the need to replace harnesses, modules, instruments, etc. The installation of the engine into the chassis will be the least of your problems.
....Rickker
My swap involved putting a 2004 3.6 X51 engine into a 1999 C4. I had this done by a professional Porsche tuning shop. This would seem to be a straightforward process, since all of the auxillaries (alternator, AC compressor, exhaust system, etc were interchangeable. However, after that, everything went downhill very quickly. It seemed, as we went along, that just about everything else was no longer compatible. Remember, this was just a "newer" 996 engine going into an earlier 996 car.
I had known from the start, that we would be replacing the ECU, and both the rear car and engine wiring harness. Also the pressure air conditioning line from the front condensor to the engine had to be changed. These are costly items, even if you can find used ones from a salvage yard. Muffler brackets had to be changed.
After this, the engine was running, but many "new" incompatibilities emerged. The cruise control did not work. The ABS and PSM did not work. The air conditioning did not work. So, now we needed the 3.6 type of ABS and PSM modules, we needed a 2002-2004 type of instrument panel. We needed a separate circuit and switch to make the AC system work. As you can imagine, the component costs and labor were astronomical.
It seems that Porsche makes many changes from year to year, even in the same model range, the 996 in this case.
So, not to discourage you, but be prepared for many incompatibilites and the need to replace harnesses, modules, instruments, etc. The installation of the engine into the chassis will be the least of your problems.
....Rickker
10-15-2009, 02:01 AM
#12
Addict
Rennlist Member
Rennlist Member
can you give approx costs in these type of transplants?
The swaps are not as scary as everyone thinks. Typically it is recommended to stay within your generation of 911. The 996, 986 interchange well across the years regardless of actual year. Some years are easier than others, but there is a well solved approach to each of those nowadays.
The 997 Gen1 and 987 also interchange well. when you mix 9x7 to 9x6 you have a higher level of issues. It can be done. There are a few 996s running around with 997 3.8 x51 motors in them.
The key is that your shop must have exp doing the swap that you wish to perform and have a plan for each issue ahead of time not as they run into it head first.
I have a 99 car with an 03 3.6 engine. No issues. Cruise, AC, everything works as new and the dealer or smog inspector can't even tell something is done unless I tell them.
The 997 Gen1 and 987 also interchange well. when you mix 9x7 to 9x6 you have a higher level of issues. It can be done. There are a few 996s running around with 997 3.8 x51 motors in them.
The key is that your shop must have exp doing the swap that you wish to perform and have a plan for each issue ahead of time not as they run into it head first.
I have a 99 car with an 03 3.6 engine. No issues. Cruise, AC, everything works as new and the dealer or smog inspector can't even tell something is done unless I tell them.
12-08-2010, 10:54 AM
#15
Drifting
I thin a lot of owners would like to hear more details on your swap. How did you deal with the 7.2 DME/VarioCam to 7.8 DME/VarioCamPlus issue? Or maybe your 99' was a 5.2DME cable throttle. How about the difference in the fule system (no return line)? MOre details please.