Should I swap a V8 into my 2000 Boxster S?

[Bayley]

Originally Posted by B6T

It would be interesting to see what happens if you wired the GM CAN wires into the Porsche CAN circuit. I'm not an automotive controls engineer... I just work in the plants and figure out how to assemble them and keep the lines running... so you'd probably be better versed to figure that one out. Are the communication protocols consistent across all makes, whether it be a Motronic or Delphi based ECU...

There are many, many, many facets to the CAN bus that make them difficult, if not impossible, to play nicely with each other. In addition to (sometimes) different baud rates, manufacturers also use different message IDs on a platform-by-platform basis. Even if the message IDs match, each 8 byte (max) message is often broken up into multiple signals. Even when you're dealing with the same manufacturer, the CAN database descriptions are often modified for each platform and updated every couple of years with new information. Chrysler, surprise-surprise, is the only major OEM that updates their CAN definitions the least.

GM CAN bus is a whole unique beast unto itself. A "normal" CAN bus uses two wires; CAN_HIGH and CAN_LOW. The signal is a differential measurement between the HIGH and LOW wires. The two wires are used as a redundancy. If one of the two wires fail (shorts / disconnects) the CAN bus will still be operational albeit in fault mode. Good ole' GM decided to save a nickel on every vehicle and eliminate the CAN_LOW wire and force the CAN bus to operate in error mode at all times. This wonderful "invention" was named GM-LAN.

So yeah... wiring the GM and Porsche CAN nodes together will do nothing.

Originally Posted by Smallblock454

Hello Andy,

well the centre of Stuttgart at the rail station area is still a very big building site now. But it's getting better. Worst was over the last year or so. Only one lane, where normally are 2 or 3 lanes. So always big traffic jams everywhere not only at rush hours. But as you might know this not only a project that concerns Stuttgart centre, it tries to change the whole infrastructure in the Stuttgart area. So railways, airport connections and also the complete old railway station area is now a building site.

http://bilder1.n-tv.de/img/incoming/origs17859416/3932732395-w1000-h960/Stuttgart-21.jpg

And they again run out of money. They wanted to finish the project in 2021, now they say 2023. We will see.


Regards, Markus

I haven't been to Stuttgart since spring of 2011, would be interesting to see the progress. Looks like I'll be in Munich and Regensburg the first week of August. I might have to pay the extended family in Esslingen a visit.

[Bayley]

Whelp, had my first drive-line failure:



To be fair, it was my own stupid accord that caused it.

I added some axle spacers to put the CV engagement back to stock geometry. These spacers required 15mm longer axle bolts. I scavenged the parts bin at work and found some M8 x 1.25 x 65 mm recessed hex head screws. I checked the grade and saw 8.8 and figured "Grade-8, these will be fine!"

Yeah, not so much. My dumb@ss forgot that these were METRIC bolts and 8.8 is more like a grade 5 bolt. I needed to find a 12.9 bolt.

Anyway, the threads of the 8.8 metric bolts ripped cleanly off the bolts and separated my axle from the transmission.

The good news is that the transmission flange and housing are both undamaged. Thankfully I was only going ~2 mph when the axle bolts gave up the ghost. Even the axle itself is rebuildable.

I ordered up a set of el'cheapo replacement axles and another spacer to get me back on the road. The long term plan is to buy a custom set of 23" long chromoly axles for 930 CV joints from a dune buggy shop. They cost $230 for the pair and will eliminate the need to run the spacer that (kinda) caused this problem in the first place.

[Robbe986]

Ops Metric 8.8 bolts is nono on a High Power machine .