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Discussion Starter #1
Well, I evidently over-revved my M97 3.4 liter engine by downshifting too early entering a curve at GingerMan in late July. I don't remember the over-rev happening, but it's in the ECU. But going down the front straight, the engine stopped, and I coasted into the grass outside Turn 1. Flames shot out my exhaust when I restarted it, and my oil pan is scattered with chunks of what looks like bearing material.

I went through the options of new engine (costs more than the car), a used M97 (still expensive and no guarantees on its future), a GM LS engine (won't fit without moving the seats forward, and I can't give up the legroom), or an Audi 4.2 V8.

After a lot of research, the Audi seems to be the best choice for me because it will bolt up to the Cayman's 6-speed manual, is the same length as the M97, and weighs about the same. It also has a similar generation Bosch ECU.

What really tipped the scale was that I know someone who's interested in doing the same thing, and we're going to team up on it. I'm familiar with engineering power train mounting systems and accessory drives, and he is a long-time Porsche mechanic who knows electronics (of which I know very little!). I wouldn't have started this without some help - two heads are better than one.

We've looked at the Audi V8 as mounted in his A6, made measurements, etc., and haven't found any show-stoppers. So we've decided to go ahead, and expect a couple of snags along the way. From studying other people's engine swaps (some on Planet-9, including Fingers' LS3), I think we've got a pretty good plan.
So here goes! I'll start posting thoughts, figures, and progress in the next day or two.
 

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Between you and the member installing the GM LS engine these will be some seriously fast and cool Caymans. As with the LS can't wait to read about the progress. What you finish with will likely eat Ferraris.
 

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Sounds cool, that's a great choice. I loved that engine when I drove an S4. Gobs of torque everywhere and really smooth. I'm sure you've done the research on it ... but if you're getting an engine from a salvaged car or a high mileage B6/B7 S4, see if the timing chain was already serviced.
 
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Discussion Starter #4
Yeah, I'm watching the LS3 swap pretty closely.

One thing I forgot to say in my first post was that the choice of the Audi was mainly to avoid taking out a mortgage if I break another engine. The fact that I'll have about 50 more HP and 50 ft-lb of torque is just a bonus!

But the other thing about the Audi is that I think we can make it so that the car looks and acts like it is a production Cayman S, except for the sound and power.
 

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Discussion Starter #5
I'm planning on getting the earlier V8 with the belt-driven cams. I looked at the later chain-driven ones, and I couldn't find a good place for the engine mount brackets. The whole left side of the engine is covered in accessories! But I'm going to replace everything I can on the front face of the engine before installation. Might not be so easy later!

So my plan is to find a complete 1st generation V8 with accessories and wiring, and hook all that up to the Porsche body. I'll post my plans on the engine mounting system soon. That's the first hurdle, but it looks like it might work out pretty clean.
 

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Discussion Starter #6
I attached a cartoon of the engine mounting system we'll start with - I'm sure it will be tweaked. I used a photo I found on Rennsport: The German Car thread - Page 2 - Zilvia.net Forums | Nissan 240SX (Silvia) and Z (Fairlady) Car Forum that shows a Cayman with an Audi 4.2. I covered over the crossmember in their photo and put together my idea for a cradle. It has two diagonal square tubes going from the control arm inner attachment, to right behind the seats. The front part is a short crossmember that goes cross-car and bolts to the four holes that the Cayman front engine mount bolted to. The diagonal on the right slides in between the oil pan and the alternator (I'd like to keep things symmetric, but we'll see). The actual engine mounts (shown in blue) sit on the crossmember that goes across under the slot in the oil pan. We might sandwich the rear ends of the diagonals between the existing aluminum diagonal brackets and the control arm attachments.

The idea is to weld the entire cradle together, bolt it in, and install the engine with the production Audi mount brackets and mounts (although I will track the car hard, I still want the noise to be bearable on the road). The existing mounts on each side of the transmission are pretty close to the location in the Audi V8 installation, so we'll leave them as they are.

Once installed, the diagonal tubes will reinforce the chassis by connecting the suspension attachment forward to the structure behind the seats. Along with each existing aluminum diagonal, they each complete a triangle between the inner control arm pivot and two points on the body.

The other attached photo is of an arm reaching off the front of the engine, to the right. Audi uses this to contact a "snubber" mount that limits travel. I'm planning to connect this, with a vertical strut of some type, down to the right (passenger) end of the front crossmember. This would be used to "fine tune" the mounting system to add stiffness or damping (with rubber bushings like in a stab-bar link, or a shock absorber). After all, it probably won't be perfect on the first try. Front Snubber Bracket.jpg

Not sure the photos both attached, so it might need to be fixed.
 

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If you search YouTube there is a video of a guy who did this conversion to a Boxster. Now would be the time to go to electric power steering to lose one accessory drive. Good Luck and keep us posted.
 

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Love the Audi 4.2 V8. For my money its the best sounding V8 on the planet. Great choice.
 

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Good luck with your project! I'm excited to see how it turns out. If there is anything I can help with let me know. Our projects are so different I'm not sure much of my experience will be much help but...
 

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Discussion Starter #11
Fingers, thanks, I am certainly learning from your project! And rjpeaks, does the coil pack question apply to the earlier belt-drive cam engines?
 

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not sure if that coincides with the earlier belt-drive engines..

there was an issue with the mfr of the coilpacks back at that time. i had a few fail on me. I would order some new ones - if you cannot find them, i can order them for you and send them out to you.

you know it takes 13+ qts of oil right?

;)
 

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This may help with the ECU system for the Audi V8. I have yet to talk to anyone who has used this system. Good Luck!

The Syvecs R8/LP560 Kit brings a new level of Engine Management control to the Audi R8 and Lamborghini Gallardo with the Worlds first Complete Standalone Engine control Module!

Audi R8 / Lamborghini LP560/570 kit – Syvecs

Audi R8 / Lamborghini LP560/570 kit – Syvecs
Quote:
By simply plugging in the kit a whole new level of control is available for both the Manual and E-Gear models, offering the following and more!
• Live Tuning of every aspect of the engine’s calibration, including signals sent to the E-Gear and S-Tronic ecu
• Ability to select desired engine map, boost level, traction and launch control levels through 12 Position switch or via OEM Cruise control
• Fully adjustable Launch control with Anti-lag strategies and Ramp in Maps
• Full Variable Valve Timing control
• Closed loop Dual Lambda Control using OEM lambdas
• Flex Fuel control
• Cruise Control add on
• Control the OEM Direct Injectors and additional 10 injectors for high power installations where staged injection may be required
• Fully adjustable closed loop boost control with launch level adjustments and trims for turbo speed, air charge, engine coolant temp, exhaust gas temperatures etc
• Monitor and trimming of exhaust gas temperatures
• Built in data logging using a market leading analysis software of up to 8 hours, with data rates at up to 1000hz
• Rolling Antilag / Pit lane limiter strategies, great for building boost on a roll
• Antitheft and valet modes
• Super fast connection via RJ45 Ethernet port for live tuning anywhere in the world or evenremotely if on track if connected to a wireless unit.
• Adjustable traction control strategies based on lateral g, steering angle and/or individual wheel speed monitoring.
• 4 programmable and selectable target slip maps. An immediate torque reduction can be applied by the ECU via ignition retard or a fuel cut.
• Configurable Engine Safety Trips on all important parameters like oil temperature, oil pressure.
• Fuel pump control of both main Direct Injection pumps, and sub pumps, as well as Relative fuel pressure monitoring and limiting in the event of fuel pressure dropping on boost.
• 4 different Pedal to Throttle Angle maps with multipliers for different parameters e.g. speed. Again adjustable via steering wheel buttons
• Configurable individual cylinder closed loop knock control, to suit any cylinder modification with adjustments to frequency, windows for listening and gains for each cylinder. Ability to trigger full cylinder shutdown in severe knock conditions.
• Ability to change torque levels and demand levels sent to the E-Gear ECU/ S-Tronic Ecu for changing clutch pressure and Pull away drivability
• Change torque reduction levels on shifts. Essential for very high power Gallardos where the Oem levels of reductions are not enough with the added torque from a Twin Turbo Kit
• Ability to change Torque ramp in after launch
• Change throttle blip requests to match your torque band. Especially useful on oversized turbo installations.
• Run up to 7bar map sensors
• Control high or low independent injectors
• Change injector dead times based on voltage levels for proper control
• Change injector end angle to ensure injection point is properly calibrated
• Ability to fit any type of external sensor to monitor and trigger safety trips from anything from crank case pressure to damper position
• Ability to use any size DBW throttle body e.g. Chevrolet LS7
• Wet and Dry – Wet and Dry nitrous control with ability to drive solenoids directly and control n20 heaters via pressure monitoring
• Ability to control any external vehicle features based on sensor inputs e.g. Adjustable rear wing linked to G force or exhaust control valves
• Connect any race series dash or even one of our partners’ Touchscreen CANBUS adjustment /display units
• View any input live with built in scope up to 1000hz
• And much, much more!
 

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Discussion Starter #14
Rob VN, rjpeaks, and Bodhii, all good info. Thanks for putting it here to refer to!
 

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Discussion Starter #15
I didn't get a lot more torn down this weekend (Michigan Football takes more of my time now that it's worth going to), but I did get a 1000-pound hydraulic table lift so I could move the powertrain straight up and down when I pull the mounts. I'm in the process of disconnecting and labeling hoses and wires, trying to be patient and not have to kick myself later (it's killing me!). That's the only thing left before removing the M97 powertrain.

I'm to the point where I need to hunt down a donor Audi, but I need to pin down models and years to search for. I want a 40-valve version with belt-driven cams, but I know that includes quite a range of models. In the meantime, I found a really good reference for anyone who would want to perform a transplant like this. Audi calls it the Self-Study Programme 217:

http://www.kpematop.com/S6/V8-5VEngine.pdf

It tells you, in general terms, what all the different hoses sprouting from the engine do, how the oiling system is laid out, what the ECU is, etc. Already I've found out that the engine has an AIR pump that I'll have to mount somewhere, and that it comes with hydraulic engine mounts with damping that can be increased/decreased by switching power on to them. All the more reason to use a donor car, so I can see where it's all tucked away.

Does anyone know of any versions I should prefer, or shy away from? I want to take the time to get the right one.

A little more looking at photos showed me that connecting a link straight down from that snubber bracket isn't straightforward, because it would go right through the alternator! But at least there are places to bolt to on the front of the engine, and I can probably find another way to do it.
 

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Yeah, I'm watching the LS3 swap pretty closely.

One thing I forgot to say in my first post was that the choice of the Audi was mainly to avoid taking out a mortgage if I break another engine. The fact that I'll have about 50 more HP and 50 ft-lb of torque is just a bonus!

But the other thing about the Audi is that I think we can make it so that the car looks and acts like it is a production Cayman S, except for the sound and power.
I give you an A+ for thinking out of the box.
 
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