Quote:
Originally Posted by B6T
I love the car and the attention to detail with the wiring!
As much as I love the LS engines, I'd have a hard time cutting that much of the car up. I don't want to offend anyone, but if you have to cut that much structure of the car away to fit the engine, it probably isn't the best engine for the chassis. At that point, why stop at the LS, and not just swap in a VAG brand W12? I'm not a big fan of removing chunks of highly engineered structure from a vehicle, but that's just me.
With so many VAG engine options that bolt directly to the Boxster/Cayman transmissions, I don't understand why people go to the added expense and complexity of using an engine that requires transmission adaptors and that extreme amount of cutting. Is the added power really worth the extra cost and risk involved with the structural compromises?
Hopefully this winter I'll have an opportunity to see how one of those VAG engines fits.
Now that I've pissed you off, I'm wondering if you would be willing to share the Boxster-side wiring connections you made...  |
I was going to give you all my wiring information... but since you poo-poo'd all over my project, I'm instead reporting you to the moderator(s) as an unregistered sex offender!
:P
Joking aside,
There were 6 or 7 wires that from the factory harness that I tapped into.
The cooling fans (high and low speed) were pretty obvious. Both the Porsche and GM architecture use low side switching relays. This means that one side of the activation coil in the relay always has 12V applied while the other side of the coil is controlled by the ECU. When the ECU wants to activate this relay, it "sinks" the current on the pin... or in less fancy terms, it simply pulls the terminal to ground.
The fuel pump was a little tricky. The Porsche engine controller uses a low side side to power the fuel pump relay, but the Chevy ECU uses a high side switch. I had to swap the wiring around in the fuse box, but I got it to work with the factory Porsche relay.
Both the fuel pump and cooling fan relays pull power from a master power relay called T87. This relay is controlled by the engine controller and is designed as a safety function. If the engine controller ever goes dead, it will cut power to potential fire sources such as the fuel pump and fuel injectors (Chrysler calls this the ASD / 'Automatic Shut Down') The Chevy ECU has provision for it's own T87 relay, but the Chevy uses high side switching while the Porsche expects a low side switch. I fixed this issue by adding a poor-man's logic inverter with a simple 12V relay.
The ignition signal was a straight forward switched 12V signal, but the starter solenoid used a second redundant relay (for safety? Dunno...) The secondary relay for the starter circuit was bypassed.
Check engine engine light was a simple one-to-one connection.
I still need to hoop up the wires for the cruise control, but those too look like a simple one-to-one connection.
Like I previously mentioned, I'm a bit of a masochist when it comes to wiring stuff.
As for the structural integrity, you really need to poke around down there without an engine in place. The pieces that are removed are only used for the factory engine mount. There isn't any torsional rigidity that is lost. I didn't believe this either when I first started investigating this project, but once I had the engine completely out and the car on a lift that, I saw how this section of body wasn't important anymore.