Should I swap a V8 into my 2000 Boxster S?

[Bayley]

Before bolting the engine and trans together, I decided to pull the heads off and clean up the top end. I had the machine shop take off a previously-unheard-of-but promised -safe 0.030" from the heads. This bumped the compression up into low 11s. Additionally, I added a rather stout camshaft (~0.600" and ~230°@0.050" with 110° separation) and matching valve springs. This combo alone is said to make 450 - 470 hp at 6800 rpm. Truth be told, anything over 400 hp is gravy to me.





With the motor together, it was time to bolt the engine and transmission together. The pieces from Kennedy are a work of art. I felt bad knowing that I'd be the only person to ever see the craftsmanship that went into the flywheel on this adapter. Absolutely stunning!




For the clutch, I bought the SPEC "stage 3" that is supposedly good to 500hp. However, this comes with a solid clutch disc since the Porsche M96 engine uses a dual mass flywheel. Martinsink was fortunate enough to have his clutch disc replaced with a sprung hub, but I wasn't as sharp and didn't realize this was an option. I decided to roll the dice and try the solid disc out (spoiler, it's fine. A sprung hub would be easier to drive, but the unsprung is totally manageable.) On a side note, buying the clutch through a third party vendor saved me almost $300 verse the option price from the kit supplier.






STEP 4 - PREPARE THE CHASSIS

This step isn't for the faint of heart. Up until now, everything could have been undone. This was the moment of no-turning back. The biggest and most nerve racking part of this process is cutting the frame channel at the bottom of the firewall. This frame channel is used for the front motor mount in the original engine configuration. To make room for the engine and accessories, this must be removed. Additionally, the firewall access panel / hole needs to be significantly enlarged to accommodate the new engine. This means that the original engine cover will never be used again.

[Bayley]

Next, I test fit the new structural components that would be holding up the engine mounts. The kit manufacturer has mistakenly sent me two driver side rails initially. This turned out to not be an issue as I later decided to not even use these pieces.




Now it's time to start test fitting the engine in place and make some motor mounts. The front motor mounts were (kinda poorly, I've since gotten better) fabricated from scratch using a set of generic motor mount pucks I found on Amazon. The rear motor mounts were retained (even though the kit supplier said they wouldn't work and I needed to buy some fancy / expensive poly mount) after adding a spacer between the mount and cross member.





Oh wait, I forgot to mention that I DID wind up using those frame rails from the kit. The beauty of having a massive gaping hole in the firewall during initial test drives, is that you can watch how much the engine moves around during normal driving. I decided to add an outrigger to the lateral cross member to prevent it from rotating during acceleration and engine braking.



Now that everything is bolted in place nice and tight, let's rip it all out again and prepare for...


STEP 5 - START THE ENGINE

I will spare the wiring details. It's lost on most people anyway, but I LOVE a good wiring project. As an automotive powertrain controls engineer, it's part of my job. This project did not disappoint in terms of complexity. I estimate at least 50 hours of my personal time making the wire harness alone. To be fair I completely disassembled the entire GM harness, removed all unused wires and then custom fit each wire exactly to my specification. Again, I'm kind of a masochist when it comes to wiring projects.



Before putting the engine back into the car, I decided to start the engine on my bench. This required me to finish the exhaust down pipes off the headers and quickly mock-up an intake system (yes, I know. The MAF is too close to the throttle body. This was moved further upstream once the engine was back in the car.)

[Bayley]

This LS engine uses a static fuel pressure that can easily be set with a C5 Corvette regulator / filter combo. I hooked up an electric pump I had laying around for bench testing.



Redneck engineering at its finest!



Fire it up!
https://www.youtube.com/watch?v=09KfmWPU5b0

Before going back into the car, I needed to address the mismatch between the Porsche electronic pedal, and the one that the Chevy controller was expecting. I really tried to keep the Porsche pedal and replace the original potentiometer with the guts from the Silverado pedal, but it simply would not work. In the end, I simply replaced the entire pedal assembly with one from a Silverado. On the positive side, I positioned it just perfectly for optimal heel-toe activation.




STEP 6 - FINAL INTEGRATION

"Y0 dawg! I heard you like German Engineering, so we installed a German engineer into the trunk of your German automobile!" This is my friend and co-worker Ralf who lives in Frankfurt Germany. He had a free evening while in town so I decided to put him to use and help me test all the final wiring integration. The nicest thing about this project is that I able to reuse all of the original factory wiring for all of the engine functions. Cooling fans, fuel pump, temp gauge, tachometer and key switch all function exactly as they would in an otherwise stock vehicle.



In order to get the incredibly tight air intake elbow to fit, I did have to trim a fair amount from the engine cover hole.




Exhaust fabrication took a fair amount of time, but was pretty straight forward otherwise. I had no expectations of this ever being a quiet vehicle... I mean, come on. It's a fricking V8! The Dynomax Bullet mufflers did not disappoint.





https://www.youtube.com/watch?v=cc34uTyaJdY

[Bayley]

Cooling system was one of the final pieces of integration. I do not recommend the approach that was suggested by the kit manufacturer. I have a full schematic drawing (just can't find it at the moment...) that I reviewed with multiple industry level professionals whose specialty is automotive thermal management and they all agreed my approach was the 'least-worse' of all other solutions. The relay for the electric water pump was wired to turn on in parallel with the fuel pump. I also added a manual override to keep water circulating with the engine off. This is very helpful when filling / burping the system.




Time to wrap it all up by sealing that gaping hole in the firewall. Following J's success with fiberglass, I tried a similar approach. However, I decided to skip the wire mesh reinforcement and instead used extra layers of cloth for strength. The idea was that this would give me the tightest fitting firewall possible. with my height being 6' 4", I did not want to sacrifice any legroom. With the initial fiberglass piece complete, I covered all sides in fire resistant ventilation wrap and then secured it to the firewall. Rather than using the original mounting holes, I simply used sheet metal screws to attach the new piece to the existing firewall. Yeah, it's kind of a cop-out solution, but this will never be seen and I have no intention of removing this firewall on a regular basis.






Time to put the interior back in and take it for a rip!

[Bayley]

STEP 7 - DRIVE IT!

This car is an absolute riot. It's loud. It's fast. It infuriates purist to no avail. It's everything I ever hoped it would be, and then some.

https://www.youtube.com/watch?v=5VPJugPUTX8



In the end, I definitely spent more than what a junk yard engine would have otherwise cost me... but trust me when I tell you that is way more fun! Also, I'm sure I could do this for less money given another opportunity.

I still have a couple odds and ends to finish up like the AC lines, cruise control (yes, I plan on having full working cruise control) and the electric power steering pump from a 2012 V6 Durango that I picked up for $50... but it's good enough now for daily driving. I have logged about 200 miles on the conversion so far and have been loving every minutes of it.

I hope you enjoyed my quick little story. There are a lot of little details that I simply skipped in the interest of time. Feel free to ask any questions you might have.

Take care,
Andy

[Luv2Box]

Whew! I had to take a nap after reading all you did. Looks and sounds fantastic.