986 Porsche Boxster to 981 body update conversion

[scotty_917]

Beaker77 said:

Thanks scotty_917, I can understand that as we want to keep some nice original 986's on the road and there will likely develop a good market for these over the longer term, but there are a lot of unloved 986's out there that are being out of their misery so I feel I am just giving them a second life!

Not disagreeing with you at all...really interested to see how you progress!

[Escy]

Beaker77 said:

I think it will be ok, there are a few I know of in the states running around with more powerful chev LS engines using these transaxles. That being said though, it does have a lot to do with how you drive it! I will fabricate a decent oil cooler which will help too. I suppose proof will be in the eating...

Edited by Beaker77 on Friday 22 January 16:45

I'm planning on putting 500+bhp through a similar 987 3.2 transaxle. You might find you want to use the same transaxle, the 986.20 isn't a direct bolt on to the Audi V8 while the 987.20 is pretty much.

[cardigankid]

I am astonished by the professional looking results you are achieving in such a short space of time.

The 986 is a beautiful looking car in its standard form, simpler than the 981 but more classic. I'm not sure that I wouldn't rather make a 981 look like a 986. To that extent you are gilding the lily, but the interesting aspect of it is going to be how you get the Audi V8 into it. That on its own would be exciting, with updated gearbox and seats (the 986 was a tight fit for the taller motorist) . You would end up with a 986 that could tan a 981.

[Beaker77]

Escy said:

Beaker77 said:

I think it will be ok, there are a few I know of in the states running around with more powerful chev LS engines using these transaxles. That being said though, it does have a lot to do with how you drive it! I will fabricate a decent oil cooler which will help too. I suppose proof will be in the eating...

Edited by Beaker77 on Friday 22 January 16:45

I'm planning on putting 500+bhp through a similar 987 3.2 transaxle. You might find you want to use the same transaxle, the 986.20 isn't a direct bolt on to the Audi V8 while the 987.20 is pretty much.

I actually considered that Escy as the 987 transaxle does fit without any modification because it has a starter motor housing on the side like the Audi engine, however the 986 bellhousing bolt pattern does match the Audi engine (7 of the eight bolt holes in the transaxle line up, the eighth lines up but is a blank on the engine block that could be tapped out if desired). The issue is that the 986 bellhousing doesn't have the starter motor housing on the side like the 987 bellhousing. The Audi starter motor doesn't actually stick out to far so a small cut out of the 986 bellhousing will fix that with a little fabrication/welding to cover it over. Bit of extra effort, but saves £700 for another transaxle! I will set up a separate thread for the engine conversion with some pics. What are you building? Sounds interesting...

[Escy]

Here is a photo of an Audi V6 (same as the V8) spacer plate on the 986.20. You can see which holes line up as i've put bolts through them. The bigger issue for me was the crank sensor pickup. It's mounted on the bellhousing on the V6 and there is no casting for it on the 986.20 and as i'm using the standard management I decided it's worth going for the 987.20



I'm putting an Audi S4 2.7 bi-turbo in a Boxster S 986

[Dan911]

Love when I see an update..

Any news on the lights?? There is a chap on planet 9 who put a Gen 2 back end on his Gen 1, I'm sure there will help on there about power units.

[Beaker77]

cirian75 said:

holy crap !

so its a whole unit job if too many fail.

anyways, you Sir are mad and I salute you.

Yep, whole unit replacement as they are sealed units, but we have ways! ;-)

[dom9]

Escy said:

Here is a photo of an Audi V6 (same as the V8) spacer plate on the 986.20. You can see which holes line up as i've put bolts through them. The bigger issue for me was the crank sensor pickup. It's mounted on the bellhousing on the V6 and there is no casting for it on the 986.20 and as i'm using the standard management I decided it's worth going for the 987.20



I'm putting an Audi S4 2.7 bi-turbo in a Boxster S 986

Do you have a build thread running?

[Beaker77]

cardigankid said:

I am astonished by the professional looking results you are achieving in such a short space of time.

The 986 is a beautiful looking car in its standard form, simpler than the 981 but more classic. I'm not sure that I wouldn't rather make a 981 look like a 986. To that extent you are gilding the lily, but the interesting aspect of it is going to be how you get the Audi V8 into it. That on its own would be exciting, with updated gearbox and seats (the 986 was a tight fit for the taller motorist) . You would end up with a 986 that could tan a 981.

Thanks cardigankid, I am pretty happy with the results so far, but still a long way to go.

[Beaker77]

Escy said:

Here is a photo of an Audi V6 (same as the V8) spacer plate on the 986.20. You can see which holes line up as i've put bolts through them. The bigger issue for me was the crank sensor pickup. It's mounted on the bellhousing on the V6 and there is no casting for it on the 986.20 and as i'm using the standard management I decided it's worth going for the 987.20



I'm putting an Audi S4 2.7 bi-turbo in a Boxster S 986

Thanks Escy, I have added pics of my test fit below too.









You can see in the pic below the issue with the starter motor housing, but as mentioned I think this can be cut out and a cover fabricated.



As you stated, the bigger issue is the crank sensor location. You can see the reason for this in the pic below. The reluctor ring on the 986 is behind the flywheel (hence the engine block mount) and the Audi reluctor ring is in front of it (hence the bellhousing mount). Once I have decided on the flywheel/clutch combo I will be using, that will determine where I need to mount this. Have you decided what you are using yet?

Edited by Beaker77 on Wednesday 3rd February 13:35

[Bieldside]

Just picked up on this thread

I too salute you and assume the new car will drive you to the local hospital for a therapy session

Good luck

Clearly there is a massive cost saving at the start but is the car worth anything at the other side?

[Ozzie Osmond]

Ye, these projects are insane. Keep up the good work!

[Beaker77]

Dan911 said:

Love when I see an update..

Any news on the lights?? There is a chap on planet 9 who put a Gen 2 back end on his Gen 1, I'm sure there will help on there about power units.

Hey Dan911, only that I've decided to go the microcontroller route (for CAN bus signalling). I have setup a prototyping rig and will hopefully be reading and writing CAN bus signals through the controller in the next week or two. Will let you know how I get on. I believe the guy on Planet 9 just needed to upgrade the existing Gen 1 light control module to a Gen 2 control module (and have the new module coded in by a dealer). The problem with the 986 is it doesn't have a light control module to begin with, it is just being controlled on an analogue circuit. In effect I am creating one to spoof the signal the 981 light would expect from the 981 light module.

[Beaker77]

Bieldside said:

Just picked up on this thread

I too salute you and assume the new car will drive you to the local hospital for a therapy session

Good luck

Clearly there is a massive cost saving at the start but is the car worth anything at the other side?

Thanks Bieldside, I suppose long term value will be determined by how the 986 market fairs. I think it will be a very long time before 'classic' 986 values get anywhere near 'old' 981's in the future (or if they ever will) so I don't think that will be an issue. Who knows, maybe some day somebody will convert it back to a 986 to increase it's value! ;-)

[Bieldside]

I certainly have to admire your objectives
And you have the desire and knowledge
I just about cope with putting petrol in my cars !!!
Beyond that no chance ....

[Escy]

dom9 said:

Do you have a build thread running?

I've just started one in the reader rides section.

[Escy]

Beaker77 said:

Have you decided what you are using yet?

I've gone with the 987.20 as it has the casting for the sensor. My engine is a manual anyway so I don't need to get anything made up. I be using an off the shelf lightweight flywheel for an Audi S4. The Audi V6 clutch plate is the same size as the Porsche one so it all fits fine. The release bearing and the slave cylinders are also the same as the Porsche. I wonder if the V6 flywheel could be a bolt on option for the V8?

[Beaker77]

Made some more progress on the rear end. Have the bumper and lights mocked up now.

[Beaker77]

Escy said:

Beaker77 said:

Have you decided what you are using yet?

I've gone with the 987.20 as it has the casting for the sensor. My engine is a manual anyway so I don't need to get anything made up. I be using an off the shelf lightweight flywheel for an Audi S4. The Audi V6 clutch plate is the same size as the Porsche one so it all fits fine. The release bearing and the slave cylinders are also the same as the Porsche. I wonder if the V6 flywheel could be a bolt on option for the V8?

I think the V6 flywheel could work depending on spacing etc. or maybe the RS4 V8 flywheel.

Edited by Beaker77 on Saturday 6th February 18:56

[crosseyedlion]

Just stumbled across this. Bookmarked!