Boxster V8 project log

[Marc_986]

I do have a M96 engine with flywheel attached, but the issue is that it is currently in the car, fitted with a clutch and bolted to the G87.21 gearbox. I don't plan to take that apart for the coming year as I will be building up my V8 swap in a spare tub.

There seem to be quite a few people on the forum working on their engines at the moment, so I would suggest to look around the recent post and see if someone is willing to take measurements. Otherwise I can do that in a few weeks time when I pick up the tub. That company always has a few engines around.

[cooler]

Originally Posted by Marc_986

I do have a M96 engine with flywheel attached, but the issue is that it is currently in the car, fitted with a clutch and bolted to the G87.21 gearbox. I don't plan to take that apart for the coming year as I will be building up my V8 swap in a spare tub.

There seem to be quite a few people on the forum working on their engines at the moment, so I would suggest to look around the recent post and see if someone is willing to take measurements. Otherwise I can do that in a few weeks time when I pick up the tub. That company always has a few engines around.

Thanks so much Mark
Please do measure for me when you get the opportunity. I have tried to urge others to do so without success. My adapter development depends on that measurement.
My adapter will result in a adapter that is about 30mm thinner which should interest those performing swaps that are longitudinally challenged for space.

[Marc_986]

The measurement should come any time soon, hopefully this week. I was there today to pick up the carcas, but the only engines with flywheel where high up. So he will pick one down and measure.

So, on to the carcas. As said, I was able to pick it up today. It was a 03 S, so has the right wiring loom and ABS unit for me to use. Also all cooling pipes (thicker than base) and radiators are on. Brake system is complete (I have the calipers as separate parts with me).

Some parts will go back in a few weeks and will be replaced with my own. Having them on the car now was easier for transportation and ensures no hoses are cut etc.

Rough plan is to transplant ABS and all associated parts coming winter. I might put the S brakes on as well. In parallel I intend to source my V8 and start the mechanical fitting part. Also I could move to electro hydraulic power steering.

For now I am finishing the car as it is. Final wires for the radio etc. will be soldered tomorrow so I can put the interior back together.

Picture to show what I picked up:

[cooler]

Hi Marc,
It's great to see you moving forward on your project. Are you still planning to use an Audi V8?

[Marc_986]

Yes, plan is still to source an Audi V8 for this project. With this scrap car I likely have all the parts needed from the Porsche side (just checked that it also has the DBW 'sensor' for example).

Just was able to confirm the ABS unit it has is the correct one for my needs, so all green lights so far.

Little set back on the radio though, the little harness I soldered works fine, but the Porsche microphone doesn't work on the radio. So I need to mount the new microphone in place of the old Porsche one.

[cooler]

So there are many variants of the Audi v8. I posses an ABZ I can provide information if you would like. I have also decided not to use it in favor of an Chev LS4.

Funny, I had a dream last night of a guy that was trying to sell me an air cooled 911 engine. One which he developed a fix for cracks in the heads (even though this is not an issue with those engines).

This reminded me of an air cooled 2.7 that I rebuilt 15 years ago. I spent 10K then, on parts alone for an engine that make only 200hp weighed 500lb and continued to cost thousand on fuel injection part to keep running. I spent more time working on it than driving it.

That said, this is why we swap out Porsche engines. I do not know from experience but it seams the M96 also is plagued with issues.

The Audi V8 appeared to be a natural for rear mid-engine swaps. They are very compact longitudinally, bolt directly to many Porsche and Audi gearboxes and are relatively light weight (340lb bare).

I hope I'm wrong but unfortunately it appears that many parts are no longer available and on line talk of working on them has fallen silent 15-20 years ago. I am not a machinist and can't make my own parts so I have moved on to the LS engine which will be a more difficult swap but it will always have parts availability and serviceability at least in North America.

You can have mine if you pay shipping.

[Marc_986]

Yes, fortunately here in Western Europe there is a good supply of Audi V8 engines, so it is the logical choice for me. I am strongly leaning towards the engine from the VW Phaeton. It seems mechanically the best fit, has good power and is a bit more modern than the ABZ (which is a great engine, but difficult to find with reasonable mileage). Also this era of Audi V8 runs on DME7.1.1 which is close to the ECUs used in the Boxster. It shouldn't be hard to get it to run in a Boxster.

Do you have a build log of the LS4 swap? Always interested to see what others are up to. What I have seen so far on Chevy swaps is that they do require more modifications to the car....

Still hoping someone is working on an Audi V10 swap, should be possible to get it to fit with the right gearbox. Too big of a step for me now.

[cooler]

Hi Mark,
Compatibility of electronics definitely deserves careful consideration. My project car is a 914 so no electronics interface to speak of.

I do not have a build log but will, when I've developed a solid plan for the engine conversion. There are several kits available but all of them add about 50mm longitudinally to the assembly. My plan is much simpler and adds only 6mm longitudinally. Popular longitudinally challenged LS swaps like the 996, 986 and A4 should require little if any body modifications.

I have seen others online working on V10 and W12 conversions using the G86.20 and the newer Audi transaxle that has the axle through the bellhousing, I think on the GT40 Forum.

[Marc_986]

Big step forward today for getting the car back on the road. One of the things to resolve was getting the speedometer to work. The reason it didn't work is that the driveshafts are not compatible with this ABS unit (ABS 5.3).

So my plan was to repin the ABS connector and swap the rear wheel sensor providing the speed signal with a front wheel sensor.

There was a trick which took me a little time to find out. The terminals in the connector are held in place by a little strip as well as by the regular tabs. Two strips in total, one pink, the other white. These come out from the sides:




Once these are removed, the terminal come out easily using a removal tool;


Swapped the pins I wanted to swap and put the connector back together. I did a quick test and I now see an indicated speed when I turn the front left wheel by hand. Hooray

[Marc_986]

Great step today for getting the car back on the road (with flat six still). The right catalytic converter showed up yesterday. Today I was able to transfer the o2 sensor, some plug bolt and block off the second O2 port. Then the pipe was mounted and after a bit of wiggling all fits now

Also hang the rear bumper cover to check clearance, positioning, angle.. The muffler clears my gearbox (which was the whole intention behind getting this sausage type muffler as the stock muffler doesn't clear the G87 gearbox) and also enough space to the bumper cover. At the moment it sits a bit off-center, but I hope I can wiggle it some more to get it right.

Next step is to make a bracket to hold the muffler to the gearbox. Part one of carboard template is done, part two to follow any time soon. Then I'll make a metal version. That should allow me to mount everything back up.

[maxbottomtime]

Originally Posted by Marc_986

Yes, fortunately here in Western Europe there is a good supply of Audi V8 engines, so it is the logical choice for me. I am strongly leaning towards the engine from the VW Phaeton. It seems mechanically the best fit, has good power and is a bit more modern than the ABZ (which is a great engine, but difficult to find with reasonable mileage). Also this era of Audi V8 runs on DME7.1.1 which is close to the ECUs used in the Boxster. It shouldn't be hard to get it to run in a Boxster.

Do you have a build log of the LS4 swap? Always interested to see what others are up to. What I have seen so far on Chevy swaps is that they do require more modifications to the car....

Still hoping someone is working on an Audi V10 swap, should be possible to get it to fit with the right gearbox. Too big of a step for me now.

Why stop at V10? Give me the XJS V12 swap. European V12 mid engine roadster!


I almost bought an XJS about 20 years ago, but my brother talked me out of it. Absolute train wreck of a project, but damn do i still pine for one.

[Marc_986]

Well, I think the Audi V10 would fit as it is a compact engine. Probably similar in length as an LS. I don't know any V12 that would fit without a good stretch ;-)

Anyway, back to business. Tomorrow is crunch time for my 986. I took it off the road for a year, but that is due to expire next Tuesday. So I better get an inspection now instead of renewing the off-road status.

So after the catalytic converter arriving last week it is now mounted and a bracket was made this weekend to secure it to the gearbox. All solid now. Then I bolted the rear braces back. This morning I was able to start the car It sat for a year and a half and so much was done that it was actually an exiting moment. Just a few turns and it sprung to life. Little lifter noise, but that was about it. Then I was even able to move it forward and backward a bit on its own power (which was another great deal as I mounted this unknown condition G87 box and had some difficulties in bleeding the clutch slave.).

This afternoon I did a coarse alignment of the rear suspension, such that I can at least drive it safely to the test center. Rear bumper mounted back up, engine cover closed and quite a number of small things that needed to be done still. Then this evening I took it for a drive (sorry mr. policeman). All gears functional . So far, all systems green. It did smell rather strong after the drive, likely due to burning of grease and sticker stuff from the exhaust. I guess that should become better in a few drives. Alignment is off a bit, but it isn't scary to drive.

So tomorrow it will be tested. Fingers crossed it passes and I can solve minor things at my own convenience and actually start to enjoy the car for the first time

[Marc_986]

Some observations after the short drive:

- The car drives soo much better with the M030 suspension on. The original suspension was still in good shape, but this just feels a lot better in reaction. Really happy with it already.
- It is quite a bit too loud for my liking. Not a real issue when hammering it down some country roads, but I already feel it can wear me (and the cars around me) out. I'll see whether I get used to it, or whether moving to the final exhaust is in order (have my eye on either 981 or 982 OEM PSE exhausts).
- The speedo works with the ABS unit connector terminals swapped. Already checked it by hand before, but happy to see it as it surely is a requirement for the test
- Visibility is really poor. Basically I am looking straight at the window frame. Can see the road fine, but looking in the distance or even up to traffic lights is near impossible. I'll need to lower my ass at least 2" to have good visibilty.
- The new clutch (just SACHS OEM 2.5L clutch) is making the drive much more enjoyable. Previous one was worn to the rivets and made clutch actuation like driving a truck.
- Shifting is soo much improved. The old 5sp was very notchy, the lever throw was long and there was enough play in the mechanism to need to guess the gear. The G87 box is much (!) smoother and the 987 mechanism more precise. Still not as good as I would want it to be, but miles better than before.

So in many aspects the car is starting to come my way

[Marc_986]

The seating:

So my issue is that my head is far too high in the car. Not really surprising, but something to fix.

I am not that tall at all, about 6' to 6'1. But I have an odd aspect ratio having relatively short legs and a relatively tall body. Many cars have a similar issue in that the seat bottom moves up when it slides forward. So I need to slide it quite a bit forward, giving me a high position. Add my body length and you might see the issue.

Open to suggestions. Sport seats would be nice, they don't need to be racing seats (I do intend to attend some track days in the future, but primary purpose is street). The seats should be low in the forward position (don't care about the rearward position). I prefer lighter seats (no power seat stuff needed, but heated would be nice to extend the top-down driving season).

[maxbottomtime]

I'm guessing you've lowered the OEM seats as much as possible? I'm 6'1, and with seats lowered haven't run into an issue.

[Marc_986]

Yes, they are most downward indeed. But the main issue seems the rising of the seats when sliding forward, which I need to operate the pedals

[Marc_986]

The annual inspection was delayed till today. I received a phone call this morning that it failed After all the work done, it failed on the horn So I went there and indeed, no horn. Hmmm, I did remove the front bumper, pretty sure I connected the horns again, but worth a check. They were connected. Next step, the fuse. Check location B3..... no fuse. Put a fuse in and voila, it hunks. But it doesn't stop. On to the switch, removed the airbag to confirm the rubbers of the metal plate are weak. Did a short research, read that some solved it with a few washers. So that's the easiest way. I put 4 washers in and mounted the plate back. Now the horn works as expected. Remounted the airbag and voila: PASS

Drove off with the car and at the end of the street; no gear selection It was still in 2nd gear so I guessed it would at least get me home. It did. Checked it this evening and expected the outer cable to have come loose from the gearbox (the plastic clips were broken, so I ty-rapped it). But no, the cable end popped off. I'll need to do some research on a fix. I don't want to buy new cables as I might need a different length when the V8 goes in.

Also noticed that one of the keys has a tendency to keep rotating in the ignition. Guessing the end of this ignition switch is coming close? Other key seems fine still. The remote on one of them also doesn't function, I hope it can be fixed with a new battery?

So some work to do, but at least I can legally test drive it now

[maxbottomtime]

Originally Posted by Marc_986

The annual inspection was delayed till today. I received a phone call this morning that it failed After all the work done, it failed on the horn So I went there and indeed, no horn. Hmmm, I did remove the front bumper, pretty sure I connected the horns again, but worth a check. They were connected. Next step, the fuse. Check location B3..... no fuse. Put a fuse in and voila, it hunks. But it doesn't stop. On to the switch, removed the airbag to confirm the rubbers of the metal plate are weak. Did a short research, read that some solved it with a few washers. So that's the easiest way. I put 4 washers in and mounted the plate back. Now the horn works as expected. Remounted the airbag and voila: PASS

Drove off with the car and at the end of the street; no gear selection It was still in 2nd gear so I guessed it would at least get me home. It did. Checked it this evening and expected the outer cable to have come loose from the gearbox (the plastic clips were broken, so I ty-rapped it). But no, the cable end popped off. I'll need to do some research on a fix. I don't want to buy new cables as I might need a different length when the V8 goes in.

Also noticed that one of the keys has a tendency to keep rotating in the ignition. Guessing the end of this ignition switch is coming close? Other key seems fine still. The remote on one of them also doesn't function, I hope it can be fixed with a new battery?

So some work to do, but at least I can legally test drive it now

Nice work!

You can buy shifter ends I believe.

For the key, it’s a pain - the fob cannot be reprogrammed. My second stopped working so trying to get it reprogrammed (and ordered a new chip). Dealer said they could do it before I bought the chip online but they are dodging my calls.

[Marc_986]

Thanks for the info

I'll need to address the shift cable issue first. I did a bit of a search and concluded the following;
- 987 6-speed shift cables are known to break. So OEM replacement doesn't make that much sense, I've seen quite a few reporting new cables failing in a few years.
- Options seem to be:

1. Replace the cable. OEM is expensive, Numeric is actually cheaper
2. Function first cable end inserts. Will fix my current issue, but about half the price of a Numeric cable set
3. Fab up a custom fix

Considering the prices of a fix I'll try the custom fix first. I intend to make a steel plate, slightly larger than the cable end, and slot a hole in from one side. The hole will be smaller than the ball diameter. I'll make another plate and screw them together with the cable end in the middle. This way the end can't slip off the ball anymore.

Any comments on the suggested fix are welcome.

Overall it seems the way the cables are routed are the biggest reason for the end popping off and the cable snapping. It has an odd angle as it crosses over the engine, then moves steeply down again and bend back towards the mechanism. Apparantly this has improved in the 987.2 and 981 generations of the gearbox (having a different bellhousing). I do wonder why they have chosen to route the cable over the engine creating such a big loop. It would make more sense to route it low, along the sump towards the back?