987 3.4 into 986 Boxster S

[Cloudsurfer]

Has anyone tried this yet? Could this be as simple as swapping powerplants and doing some ECU tuning or do the 987/997 cars have completely different management? If the latter is the case, could running the 986 management on the newer 3.4 motor with a re-flash work?

Supposedly the 987/997 M96 motors are MUCH more reliable.

Patrick

[Adam]

The newer 3.4L boxster engine is designed to run with Bosch motronic 7.8. If you have a 2000-2002 boxster S then you have Motronic 7.2. I'm not sure if you have to swap out you're old computer with a newer one, but you very well might.

[Cloudsurfer]

Supposedly, by adding a few extra wires, 7.2 can control VarioCam Plus. Can this be verified by anyone here?

Patrick

[JP-s-in st. louis]

Originally Posted by bmwm750

Supposedly, by adding a few extra wires, 7.2 can control VarioCam Plus. Can this be verified by anyone here?

Patrick

tholyoak (member here) has a way to do it.

[easyc]

yeah it can, but it's not just as simple as adding a few wires of course. It would be pointless anyways to add the 3.4 out of a 987... if you are going to do the swap to 7.8, might as well use a 3.6 at least.

[tholyoak]

As stated, in order to run the new 3.4 you need to update to the later DME, actually a 7.8.X but the older 7.8 can run it with a custom map.
This isn't a plug and play where you just get the new dme and plug it in, there are other changes that need to be made. On a 2002 they aren't that involved but you have to know what you are doing.

The changes are the same as putting in a 3.6 or 3.8, so to me it really makes no sense to do all the work for a 3.4 that will have minimal gains over the 3.2 that is in the car. That is unless you are getting the 987 3.4 for VERY little money.

If you want to do a non-factory job, you can cobble together a solution with a piggyback controller to control the variocam plus (valve lift) but it isn't a very elegant solution.

The 987/997 engines are not that much more reliable than the 996/986 engines, they are still the M96 based engine. If you buy a reman motor from Porsche it will have all the updates that a newer engine has (revised IMS etc). The new engine in the series 2 997 is a huge update in engine design, stated to cure all the shortcomings of the old M96 motor.
-Todd

[Cloudsurfer]

So the 7.2 cannot control the VarioCam Plus? I was under the impression that it could?

I can pickup the 3.4 from a guy who pulled it from his brand new Cayman S for an attractive price, and would like something fresher than the ~60k 3.2 in my S.

As to the "not much more power" argument, given that the 3.4 is rated at 295, even without factoring in some gains from headers and free flow exhaust, thats still ~50HP more than the 250HP in the 3.2 unless I'm missing something?

Patrick

[2000SoCalBoxsterS]

I have also read somewhere (on a site that does this conversion) that you do need to upgarde to the 7.8 Motronic as mentioned. I also agree that for the 45 HP gain you may be paying a lot per HP. I would also go for the 3.6 engine swap as long as you're doing a transplant anyway.

Do you have a quote on how much the 3.2 to 3.4 engine swap will cost including labor and programming? What about SuperCharging the 3.2?

[Cloudsurfer]

I have decided against the 987 3.4 idea, as I cannot get a clear answer from anyone as to whether or not the 7.2 DME can control the VarioCam Plus.

I am still casually in the market for a 3.6.

Patrick

[fragdude]

http://cgi.ebay.com/ebaymotors/Porsche-02-911-996-3-6-3-6L-Complete-Engine-Motor-18K-m_W0QQcmdZViewItemQQ_trksidZp1638Q2em118Q2el1247QQ categoryZ33615QQihZ005QQitemZ150212125620QQrdZ1QQs spagenameZWD1V

There ya go! 8.5k for a 3.6 liter motor with 18k miles.

[tholyoak]

Well it seems you have been told several times in this post and if you read my posts at renntech you would already know that a 7.2 DME cannot control a variocam plus motor. You can ad a piggy back unit to get it to work but it won't be a factory solution.

Todd

Originally Posted by bmwm750

I have decided against the 987 3.4 idea, as I cannot get a clear answer from anyone as to whether or not the 7.2 DME can control the VarioCam Plus.

I am still casually in the market for a 3.6.

Patrick

[blinkwatt]

Originally Posted by tholyoak

Well it seems you have been told several times in this post and if you read my posts at renntech you would already know that a 7.2 DME cannot control a variocam plus motor. You can ad a piggy back unit to get it to work but it won't be a factory solution.

Todd

Hey Todd,

How do these piggyback programs work? Are they just a small electronic box that you have to mount in between the car's ECU and the engine? Who makes such a thing?

[2000SoCalBoxsterS]

If you're going to spend the money for the transplant doesn't that include the correct computer module to control the new engine? And even if not wouldn't you just spring for that too while you're at it?

[tholyoak]

Blinkwatt,

There are a number of companies that make these piggyback controllers, the one I have experience with is from Perfect Power, the SMT6. Yes they are wired in between the sensors on the engine and the DME, thus you can modulate the signal arriving at the dme in order to control the things you want. There are also programable outputs that can be used to control things like the variocam plus and injector drivers for additional injectors in supercharged/turbocharged applications.


2000SoCalBoxsterS, it has nothing to do with the DME being included, it is the incompatibility of the newer DME necessary to run the newer motor with the other electronic systems and wiring in the older chassis.

-Todd

Originally Posted by blinkwatt

Hey Todd,

How do these piggyback programs work? Are they just a small electronic box that you have to mount in between the car's ECU and the engine? Who makes such a thing?

[fragdude]

the link i posted sells their engines with the computer, so i guess you would have the appropriate DME controller for that engine?

[Cloudsurfer]

I had received mixed input on whether or not the 7.2 DME could control the VarioCam Plus system, which is why I decided against this.

I think for now the 3.2 is staying in the car. If it blows up at some point, well, I'll address that then.

Patrick