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3.4 to 3.6 swap

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Is it reasonable to swap a 2001 3.4 (blown) with a newer 3.6 engine. I have searched for links but haven't found any.


I think it's difficult. I've heard it's not an easy transplant.

Here's a linky:

Edited by Bus Boy
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This is the man you need to speak to. Tholyoak (his screen name.)


He has done many swaps and knows the correct way to do it. I had a 3.6 put in my 2000 996. It was not done properly and it was a real nightmare. It's going to require an ECU upgrade, new instrument cluster and some rewiring to get everything to work properly. Do your research before you get involved in this. It's definitely not "plug and play."

Edited by phillipj
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Thanks to all who responded.

I already have the car so I will need to work out a fix with this 911.

Todd, I noticed in your discussion from several years ago that you were doing a swap in your Boxster to the newer engine. You indicated at that time, that using the later car's engine controller required a lot of rewiring. Would this also be true with the 2001 911. And if so is there any info out there as to exactly what would be required?

Thanks again,


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A buddy of mine had Roock in Atlanta do a swap in his 99 from a 3.4 to a 3.6. The only real hard part apparently is getting the Variocam+ to work properly. Once you get it going, it's a screamer. Call Roock and let him know I sent you.


NO NO NO NO.:cursing: Stay as far away as you can from Fabian Roock! He method is flawed and you will never be happy with the car. THE VARIOCAM WILL NEVER WORK PROPERLY. His workmanship is shoddy and he's liar. DO NOT HAVE HIM TOUCH YOUR CAR! He is a smooth talker and will act like he is a big player, He has a terrible reputation. Call LN engineering and mention Fabians name and see what kind of reaction you get. Please do not call him. You will sorely regret it (ask me how I know...)

Edited by phillipj
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The primary challenge in upgrading from a 3.4 engine to a 3.6/3.8 engine is the VarioCam vs. VarioCamPlus issue. Other items like the lack of return fuel lines, AC lines etc. can be addressed more easily. Take a look at the thread I did last year to help you understand the difference between the functioning of the VarioCam and VarioCamPlus systems. Here is a link:

Basically the VarioCam system is a simple on/off switch, based on RPM and engine temp, and the amount of advance for the intake cam is fixed. The system uses a 7.2 DME. The VarioCamPlus system is much more complex. It has a varying amount of advance of the intake cam and also varies the lift of the intake valves. This is based on RPM, temp, engine load, etc. etc. The system is controlled by a 7.8 DME.

So to get true "dynamic" functioning of the VarioCamPlus system, along with cruise control and other functions, you need the 7.8 DME and the 7.8 DME is not compatible with the wring systems of earlier cars (MOST), the gauges are different, etc. etc. It would seem that someone could design a "blackbox" to interface the 7.8 DME to the systems in the earlier cars, not sure what all would be involved, but with the cost differential of the 3.4 to 3.6/3.8 engines (the 3.4 are much more expensive from Porsche), I would think there would be a market for this.

Any volunteers for such a project :thumbup:

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Many thanks again to everyone who responded. Dharn55, I will check out the link that you provided.

phillipj, I really believe you just might have a strong opinion on Roock's workmanship!!

I'm now going to check out the wiring on the 3.4 vs the 3.6 or 3.8.



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I think is more like Philipj got screwed pretty bad, nothing to do with opinions. How much more clear do you want it. Bty, philipj recommended a place to rebuild my engine and I couldn't be happier. I also looked into the conversion.

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The reason a piggy back or rpm switch coupled the 5.2.2 or 7.2 DME to control the variocam on a 3.6 or 3.8 motor is a bad idea has to do with drive-ability. The early variocam was all or none as stated above. This is fine with 25 degrees of advance and no variable valve lift with that system. The later system with the 7.8 dme uses a rotor and stator and is infinitely adjustable from 0-40 degrees via a pulse width modulation of the solenoid. This fine control depending on rpm and load is necessary for the greater valve timing change of 40 degrees. Couple this with variable valve lift and using an on or off type control results in poor drive-ability on the street where part throttle dominates and load and rpm fluctuate wildly. If the car is a track car operating at high load and throttle for most of the time, the piggyback approach can work fine.

The incorporation of the 7.8 DME into a 5.2.2 or 7.2 car is not difficulty once you figure out how to do it. The problem is it is not cost effective if you are paying someone else to do it, especially if you are paying them to learn how to do it at the same time. Simply, you will need a new 7.8 DME, a new ABS controller, new HVAC controller and new instrument cluster in addition to an egas pedal sensor setup if the car originally was cable operated. That is the easy part. Getting the wiring sorted out is the time consuming aspect if you have to figure it out from scratch.

Based upon the rising costs of the 3.4 motors from Porsche relative to the costs of the 3.6 and 3.8 engines, installing the later motors becomes more attractive. However, I would suggest the best solution for the 3.4 cars is to use LN engineering's parts, or if you aren't a DIY type, a rebuild from Jake Raby. This approach addresses the weak points of the M96 design and allows you to increase displacement without needing to update the electronics, all for about the cost of a Porsche 3.4 crate motor.


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  • 1 year later...

It's more than just the harness... read above, you also need totally different computers/etc.

Swapping all the wiring out would be insanely complicated and tedious, and if you got it to work it would be amazing to say the least.

Just for 0.2 liters? Really? A lot of the guys on the track say there isn't a whole lot of difference performance wise between the 3.4L and 3.6L cars...

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When I did my swap a couple years ago there were not too many options available to rebuild my 3.4. The reason I went for the 3.6 was the price. It wAs a mistake.. It turned into a nightmare..

Now you have a lot more people rebuilding the 3.4's. That is the route I would go if I were you..

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