V8 Conversion

[Dlirium]

Originally Posted by martsink

Today I started the engine for the first time. Ran into a couple of issues with the ignition and fuel pump. I had to jump the starter cable relay in order for it to crank. At this point I'm not really sure what the problem is, but I'm guessing it has to do with the immobilizer. The car came with no DME, so I had to purchase a matching key, immobilizer and DME.

The fuel relay also didn't switch, so I had to jump it. I'm thinking about just running it from another relay that is triggered by ignition-on wire, unless someone has a simple solution for the existing relay.

Heres a short instagram video. Sorry about the quality, we really weren't expecting it to start the first try.
https://instagram.com/p/6YWIQsASWc/?taken-by=porschelsx

Freakin awesome!!!

I had to buy a 72 240Z with a V8 to get my fix...

[martsink]

Originally Posted by shockandawe

Is your 2005 boxster wiring harder to work than a 2000 boxster?

I only own one Boxster, and that one is 2000. I can't imagine that 2005 would be any harder. Essentially its just a bunch of wires that you try to identify through diagrams. Keep the ones you need, and delete whatever you don't

[martsink]

The fuel system is pretty straightforward, just buy some reinforced fuel line and compression fittings. If you have an LS1 or LS6 fuel rail, you will also need a fuel pressure regulator/filter. The GM regulator mounts perfectly in the old location of the Porsche fuel filter. I cut the fuel lines just before the filter and used -6 AN compression fittings to transition to a flexible reinforced line.

GM fuel filter/regulator on the left, and Porsche fuel filter on the right

BTW, if you decide to run truck ignition coils (which are better than LS1 ones), the fuel rail connection will not clear. You have to cut the tab that holds it to the rest of the fuel rail and bend it off to the side. I don’t have an up close picture, but it should be visible in the one below.

[martsink]

I don’t have a hoist, so it was pretty difficult to snap good picture of the fuel system. Here is a basic diagram of how I did it. I decided not to run heater lines, since it will probably be hot enough in the car from the engine compartment. I do not plan to winter drive it.

This is a pretty simplified diagram. You will also need a tee on the vent line, to hook up the engine vapour lines. It was impossible to find a 0.5″x0.5″x0.25″ tee, so I just put one together from plumbing parts. BTW, if you are looking for hose fittings or connections, head over to JTR (Jaguars that run) website.

The line sizes are:

• Two big coolant lines running to radiators are about 1.5″
• The filler line is 0.75″
• The vent line is 0.5″
• Renegade fittings are 1.25″
• Thermostat housing is 1.25″

'
I suggest you get a reducing silicone sleeve on the main Porsche coolant lines (1.5″ to 1.25″), and then run the rest of the system in 1.25″. Make sure to stock up on unions and hose clamps. I think I used something like 30 clamps. Some 90 degree silicone or aluminum elbows will definitely come in handy.

So Renegade made this beautiful aluminum intake, yet they couldn’t make enough clearance for the timing cover bolts… The heads are already filed down in the picture below.

[martsink]

The wiring on this project just doesn’t stop… The entire harness in the trunk had to be replaced. The previous owner was building a track car and cut half the stuff off. He even cut the ABS/speed sensor, which I don’t think he was supposed to. Thanks to Woody on the 986 forum I was able to pick one up for cheap. The engine harness was a bit of a pain to tear up since the Porsche diagrams are a huge pain in the butt to read. Most of the connection pins come out easily, but for some you need to make a special tool. BTW if you need any help with the wiring, just send me an email.

http://i.imgur.com/ztQ4L3y.jpg

The pins on these types of connections will not come out easily. You need to remove the back cover and stick in a think metal tube (you can make one from a pop can) through the front of the connector, between the plastic and the pin. Pushing the pin forward from the back while inserting the tube makes it much easier to take apart.

I’m slowly making some progress cleaning up the wiring. I used a couple of no longer needed relays to power the GM PCM and the water pump.The LS1 PCM is massive and won’t fit on the firewall like the Porsche DME. I had a sheet of aluminum kicking around so I made a mount. I don’t have the latest picture of the wiring, but it is starting to look pretty clean.

[martsink]

The shell came with no headlights, but luckily I was able to pick up a decent set for $150 CAD. The lenses were so bad though, that I decided to take them out altogether.

Somehow I didn’t notice that I purchased mismatched headlights until I put them on. One is painted silver, and one isn’t.

[BoxsterLS376]

Originally Posted by martsink

Today I started the engine for the first time. Ran into a couple of issues with the ignition and fuel pump. I had to jump the starter cable relay in order for it to crank. At this point I'm not really sure what the problem is, but I'm guessing it has to do with the immobilizer. The car came with no DME, so I had to purchase a matching key, immobilizer and DME.

The fuel relay also didn't switch, so I had to jump it. I'm thinking about just running it from another relay that is triggered by ignition-on wire, unless someone has a simple solution for the existing relay.

First off, killer job man, motor sounds great! I know it's not easy and I think you had a bit of a bigger hill to climb then I did~ Go have a beer

For your starter problem I think you're right, those immobilizers are a pain in the ass and we could never get them working at my old shop and usually ended up sending the cars to the stealership for programming even though we had a factory Porsche PST computer.

Regarding the fuel relay I believe there is an easy solution for this, but it's early and I'm gonna have to put my thinking cap on... All of my notes and paperwork are at the shop but just took a quick look at the car to jog the brain. I have the GM fuel pump lead connected directly into the Porsche harness in the back of the car to a Yellow/White wire which I know leads to the relay panel in the drivers footwell... this is where we get fuzzy and you should rely on the wiring diagrams... I pulled down the relay panel and was basically able to wire around the issue there, pretty sure the fuel pump is looking for a ground signal and the GM ECU is providing a power signal so you have to do some trickery and wire around 1 relay I believe. I'll check my notes on Monday and give you more details if you need but it can definitely be done.

Good job man~
J

[BoxsterLS376]

Originally Posted by martsink

So Renegade made this beautiful aluminum intake, yet they couldn’t make enough clearance for the timing cover bolts… The heads are already filed down in the picture below.

HAHAHAHA Yep, I had the same problem and was like WTF MAN?!?! I just shaved the piss outta those bolts and made it work. Silly I say

So I've got about 850 miles on mine so far and all is pretty good. FYI I just ordered a 2014 Cayman engine cover to make my firewall with, I think it will work a lot better then the 07~ model version

[martsink]

Originally Posted by BoxsterLS376

First off, killer job man, motor sounds great! I know it's not easy and I think you had a bit of a bigger hill to climb then I did~ Go have a beer

For your starter problem I think you're right, those immobilizers are a pain in the ass and we could never get them working at my old shop and usually ended up sending the cars to the stealership for programming even though we had a factory Porsche PST computer.

Regarding the fuel relay I believe there is an easy solution for this, but it's early and I'm gonna have to put my thinking cap on... All of my notes and paperwork are at the shop but just took a quick look at the car to jog the brain. I have the GM fuel pump lead connected directly into the Porsche harness in the back of the car to a Yellow/White wire which I know leads to the relay panel in the drivers footwell... this is where we get fuzzy and you should rely on the wiring diagrams... I pulled down the relay panel and was basically able to wire around the issue there, pretty sure the fuel pump is looking for a ground signal and the GM ECU is providing a power signal so you have to do some trickery and wire around 1 relay I believe. I'll check my notes on Monday and give you more details if you need but it can definitely be done.

Good job man~
J

Thanks John! Fuel pump wise, I just ended up wiring it to a different relay that gets its signal from "ignition on" for now. Im not really sure if that's how it was in the Porsche, or if it got the signal from a crank sensor to ensure the engine is running. I'll try to dive into the diagrams today and figure it out.

[martsink]

Originally Posted by BoxsterLS376

So I've got about 850 miles on mine so far and all is pretty good. FYI I just ordered a 2014 Cayman engine cover to make my firewall with, I think it will work a lot better then the 07~ model version

Just to clear things up, is this the top engine cover that you plan to use to cover the hole behind the seat?

[BoxsterLS376]

Originally Posted by martsink

Just to clear things up, is this the top engine cover that you plan to use to cover the hole behind the seat?

That's correct sir... the cardboard I have now is good but doesn't do a tip top job

[martsink]

Starter Motor:

I picked up an $50 starter from a local scrap yard which came off a 2005 Silverado. The Kennedy Engineering adapter plate was designed around LS1 starter, so I had to make some modifications. The moulding in the dome is a little bigger I guess... I spent a good hour filing away, but eventually I got it to fit. The reason I got a truck starter over LS1 is because it's cheaper and I heard LS1 starters tend to crack.

Oil:

I didn't want to start the engine without priming it, so I purchased a drill pump at Princess Auto for $15. One end of the hose clamps onto the filter threads on the oil pan and the other into a jug of oil. This pump has no problems reaching 45 PSI. I stuck a gauge on my remote mount oil pressure switch hose (I will eventually post part numbers and pics for this part).

As for the tranny, I called Porsche about gear oil, which they quoted me at $55 a liter!!! I ended up purchasing some Swepco 201 which is manufactured locally, but surprisingly difficult to find.

Engine Cover:

The engine cover still fits, but it had to be cut a bit to make room for the throttlebody.

Rennline Floor Boards:

Rennline hooked me up with a wicked deal on their racing floor boards. I really didn't want to put carpet back in this car, so these things are great.

Corbeau Seats:

I also gotta thank Corbeau for hooking me up with a deal on these FX1 Pro seats and rails. My friend started working on the brackets the other day while I was making brake lines.

Cracked Rear Subframe:

I noticed a crack on the rear subframe side section where it mounts to the body. It seems like it was put together with a bent stud by the previous owner that caused it to crack. While taking it off, one of the lower control arm bolts got stuck inside the bushing and pretty much pulled it apart. This was a huge pain in the ass, but at least I got a sweet deal from Woody for the replacement.

Brakes:

Pretty much all the brakes lines are gone on this car. I tried making some hard lines out of the copper-nickel stuff, but had a hard time getting them to flare properly. I ended up buying some poly vinyl fluoride coated metal lines from NAPA. This stuff is great, they flare perfectly and are easy to bend. I would also recommend Lisle tube pliers if you plan on doing any kind of brake line work.

[Bayley]

I used the starter that came on my L33 (2006 Silverado) as well. I had to grind a significant portion of the dome off, but it eventually fit.

I've had incredibly poor results with every single aftermarket starter I've ever used in terms of casting quality of the housings. It's difficult to find a more sturdy starter than a good 'ol GM truck starter. Also, I would have scrapped the starter anyway if if didn't fit, so it's a win-win all around.

As for the timing cover bolts, I replaced all the original hex head bolts with countersunk allen head bolts. I opened up each hold on timing cover with a beveled drill bit and the new bolts sit almost flush with the surface of the timing cover.

I love the progress updates from you and J. I went a different route with the motor mounts and fabricated my own design and omitted the longitudinal pieces that connect the front later bar to the middle lateral bar. My mounts land squarely on the front cross bar.

I was also able to reuse the stock transmission mounts. I made spacers out of the original trans brackets that offset the Renegade bracket to the OEM mount. Everything seems to mount up.

(cell phone pic, it's the best I got. Sorry)

(full size)

I'm currently stuck in wiring hell at the moment. I'm trying to keep the electronic throttle body / drive by wire form the original truck motor. It's been... challenging. There is little to no documentation online on what is compatible with what, and I was never given the original throttle controller when I bought the engine. I'm on my THIRD throttle body controller and I STILL can't get the goddamn module to talk to the ECU. It powers up for ~5 seconds, doesn't see any UART comm from the ECU and then eventually shuts off. Frustrating.

At this point, I'm probably going to drop the engine and restart a new harness for everything from scratch. Any resources you may have for harness info is appreciated.

-A

[martsink]

Originally Posted by Bayley

I used the starter that came on my L33 (2006 Silverado) as well. I had to grind a significant portion of the dome off, but it eventually fit.

I've had incredibly poor results with every single aftermarket starter I've ever used in terms of casting quality of the housings. It's difficult to find a more sturdy starter than a good 'ol GM truck starter. Also, I would have scrapped the starter anyway if if didn't fit, so it's a win-win all around.

As for the timing cover bolts, I replaced all the original hex head bolts with countersunk allen head bolts. I opened up each hold on timing cover with a beveled drill bit and the new bolts sit almost flush with the surface of the timing cover.

I love the progress updates from you and J. I went a different route with the motor mounts and fabricated my own design and omitted the longitudinal pieces that connect the front later bar to the middle lateral bar. My mounts land squarely on the front cross bar.

I was also able to reuse the stock transmission mounts. I made spacers out of the original trans brackets that offset the Renegade bracket to the OEM mount. Everything seems to mount up.

(cell phone pic, it's the best I got. Sorry)

(full size)

I'm currently stuck in wiring hell at the moment. I'm trying to keep the electronic throttle body / drive by wire form the original truck motor. It's been... challenging. There is little to no documentation online on what is compatible with what, and I was never given the original throttle controller when I bought the engine. I'm on my THIRD throttle body controller and I STILL can't get the goddamn module to talk to the ECU. It powers up for ~5 seconds, doesn't see any UART comm from the ECU and then eventually shuts off. Frustrating.

At this point, I'm probably going to drop the engine and restart a new harness for everything from scratch. Any resources you may have for harness info is appreciated.

-A

I like what you did there with the mounts. Its interesting how everyone has their own take on the same project.

I did plenty of research on the drive by wire setup a few months back, but I can't remember much. From what I recall there are very few combinations that will work together. I think your best bet is to get in touch with LT1 Swap guy. He has all the answers.

My wiring is much simpler since I went with the drive by cable setup, so I'm not sure if these resources will help you much. Here are some good links:

https://www.facebook.com/media/set/?set=a.570183759682543.1073741827.148224325211824& type=3
LS1 harness: Start to finish - Third Generation F-Body Message Boards

[martsink]

I had a bit of an accident that set me back a week or so, but I'm back on track now. Below I posted some recent car pics.

I bought some sheet aluminum for $20 and made a firewall cover. I wish I had fitted the seats first because there isn't enough leg room for me at the moment. I will have to add a bit of an angle to the cover in order to move the seats farther back. I mounted the hand brake housing just above the "tranny tunnel" just to simplify things. Putting it where Renegade does is a pain, and it requires twisting the wire a little more than I like.

I also got a new intake manifold due to some serious defects in the old one. A 1-3/8" freeze plug from Napa worked great to plug the EGR opening.

The car is 95% done at this point. I’m just waiting on a couple of intake parts and need to get the exhaust made. I am also looking to install a fire suppression system in the trunk.

The big things to do now is get insurance, safety, and emissions done.

Another quick video of it running https://instagram.com/p/7Qi5nigSR_/?taken-by=porschelsx

[BoxsterLS376]

Very nice!

[martsink]

Another quick update. I've been trying to get insurance for the car with no luck. Regular insurance will not take it, and classic car insurance requires 10 years driving experience. Unfortunately for me the 10 year mark is this December 17th. I just gotta wrap things up now and throw it in storage till next year. Here are some pics of what I've done recently.

The intake just needs to be wrapped. I don't like the location of the MAF, but it's the only place it will work.

The doors are a huge pain in the ass. The previous owner was converting it into a track car, but I have no idea what he was thinking of doing with this:

I think it's safe to say that the windows won't lower when opening doors, since all the wiring has been cut out. The original door lock switch no longer works for me due to the above, so I got a Jetta window switch and swapped out the rockers. It's a sketchy setup, but at least the doors lock now.

[martsink]

I've also been trying to get the tach working. Unfortunately for me, all the older LS based engines use a 24 tooth reluctor wheel to keep track of the crankshaft speed and position (LS3 uses 58x. Lucky you!). The Porsche engine uses a 58X reluctor, meaning I cannot just plug in the GM sensor into Porsche DME. The other option is to use the tach output signal directly from the ECU. Unless both engines have the same number of cylinders, this will not work without some modifications to the signal. I've got something worked out with Arduino, but I still have to test it in the car. If you are interested, you can see more on this in my blog.

[BoxsterLS376]

Originally Posted by martsink

I've also been trying to get the tach working. Unfortunately for me, all the older LS based engines use a 24 tooth reluctor wheel to keep track of the crankshaft speed and position (LS3 uses 58x. Lucky you!). The Porsche engine uses a 58X reluctor, meaning I cannot just plug in the GM sensor into Porsche DME. The other option is to use the tach output signal directly from the ECU. Unless both engines have the same number of cylinders, this will not work without some modifications to the signal. I've got something worked out with Arduino, but I still have to test it in the car. If you are interested, you can see more on this in my blog.

It took pulling some teeth from Renegade but apparently someone who did this conversion ran into this problem as well and created the solution I had envisioned~

All your tachometer worries can be solved by spending a few more bucks... about $80 of them I believe...

Check out Ashlock Technologies~

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[GTA_G20]

Bravo boys. Good work