Any progress on V8 engine swap options? - Page 2 - 986 Forum - The Community for Porsche Boxster & Cayman Owners

B6T · 06-08-2017, 07:10 AM

When guys swap the VR6 into the B5 chassis they need to modify the hood latch due to interference with the engine. In the Boxster, this point would be the engine cover, much in the same area where the forward part of the V8 intake manifold is interfering.

SoloPierre · 06-08-2017, 12:33 PM

I am running the Cayman engine cover instead of the stock 986 cover on my '02 Boxster. Saves me about 4lbs since it is all aluminum. It is also a little taller to accomodate the 987 airbox. Not sure where you need the room, but it might help a liitle if you are looking for just liittle bit more room on top.

Pierre

78F350 · 06-08-2017, 01:11 PM

The Cayman engine cover should work with the 4.2L V8 if you mount the engine as low as possible and use a shorter throttle body arrangement. I plan to use material from the aluminum trunk from my A8 and the help of an airframe mechanic friend to fabricate a cover.

B6T · 06-20-2017, 07:10 AM

Does the Cayman engine cover interfere with the Bose subwoofer box and the top in the Boxster?

Things are pretty tight between the engine cover and the sub box already with the top down so I would imagine it's even worse, it not impossible with the Cayman cover.

SoloPierre · 06-21-2017, 12:12 PM

Top fits with the Cayman engine cover, but i use a towel instead of the heavy engine cover carpet between the two. The top of the Cayman cover is different. Not sure if the stock carpet fits on top of the engine cover. If i have time this weekend, I will check to see if it fits.

Pierre

rusty69911 · 10-17-2017, 10:09 PM

78F350 how is your progress? Im just starting mine, Im planning on cutting the rear of the engine bay so it is flat top as I dont intend having a soft top there to fold into the valley,
Cheers Russ...

78F350 · 10-18-2017, 07:40 AM

Quote:

Originally Posted by rusty69911

78F350 how is your progress? Im just starting mine, Im planning on cutting the rear of the engine bay so it is flat top as I dont intend having a soft top there to fold into the valley,
Cheers Russ...

Hi Russ (and any others that are interested), I have my soft top removed too and am also cutting into the rear of the engine bay. The car has a hardtop and a sun-shade made from a cut-up top that had a bad window.
I didn't work on it all summer, but started in again in September. Right now it's in the garage with engine, transmission, and rear suspension removed. I'm hoping to have the 4.2 and suspension back in tomorrow so I can roll it out of the way and change the clutch on a Honda.
What's done? ...engine maintenance, basic sub-frame, flywheel, clutch, piecing together the 6-speed to 5-speed swap (it's an S model), mapped out the harness from the 4.2 (2003 A8 AUX) engine and most of the Boxster connections. Yesterday I flashed an ECU with a .bin that has already been modified and tuned for the A6 and A8 with manual transmission.
I don't want to do a build thread, because it will make me feel time-pressured to get stuff done, and this swap is one of my lowest priorities right now. I do plan on posting some of the details much later, when I have a running car.
Here's my 5 year old grandson 'installing the clutch':

rusty69911 · 10-18-2017, 08:38 PM

78F350 the panel I got from you is in place but not welded haha

itsnotanova · 10-19-2017, 12:39 AM

Quote:

Originally Posted by 78F350

Hi Russ (and any others that are interested)The car has a hardtop and a sun-shade made from a cut-up top that had a bad window

Do you have any pictures of your creation? I've been thinking of doing one for a long time.

78F350 · 10-21-2017, 04:56 AM

Quote:

Originally Posted by itsnotanova

Do you have any pictures of your creation? I've been thinking of doing one for a long time.

I don't have any pictures, but I'll post some later. It is still very rough. The front is cut just outside the seams and generally follows the seams back. It is removed from the frame except for the front bar and an arch near the roll bar. It was set it up with fiberglass poles (from a tent) arching from the windshield to back under the clamshell and bungee cords securing it to the top of the struts. After testing it, I think it will be better with a support that clamps on over the roll bar. This one isn't going to be sexy, just a little ragged shade that I can carry in the trunk or frunk.

specboxCO · 11-26-2017, 06:12 AM

I have just got my Audi V8 swap up and running in a 2003 boxster S.

https://m.youtube.com/watch?v=SUHf4KtmP5Y

Using a 2001 A8 engine. DBW, Can Bus all working on Audi ECU. Currently has a Cayman 5 speed mated to it.

Transmission in standard location, had to cut the engine bay and fab a new cover.

This is a race car, so not concerned about packaging as much as practicality. Air intake has been moved to the trunk for ease of install.

Running electric power steering and no AC. Just the alternator driven from the engine.

78F350 · 11-26-2017, 01:54 PM

Quote:

Originally Posted by specboxCO

I have just got my Audi V8 swap up and running in a 2003 boxster S. ... Transmission in standard location, had to cut the engine bay and fab a new cover.

Did you modify the front firewall at all? My cam covers were pressed against the firewall until I hammered and cut a little more space.
It that a custom shifter cable? It's a tight fit over the top with stock.

Quote:

Originally Posted by specboxCO

Running electric power steering and no AC. Just the alternator driven from the engine.

The huge pulley on the PS comes very close to the parking brake cable. I haven't decided how I want to go yet. I am still considering keeping the AC, but will probably end up with an Ice-chest type cooler.

What do you have for a engine mount/subframe? I paid way too much to have a local fabricator make mine and after bringing it back 3 times gave up on him. I can make it work, but I'm not happy with it.

What axles, any modification? I'm not familiar enough with the Cayman 5-speed to know if it takes the Boxster S axle.
I've got an '01 5-speed going into an S and the 5-speed axles will work, but just barely fit for the nut:

specboxCO · 11-26-2017, 02:30 PM

Quote:

Originally Posted by 78F350

Did you modify the front firewall at all? My cam covers were pressed against the firewall until I hammered and cut a little more space.
It that a custom shifter cable? It's a tight fit over the top with stock.

No problem with the cam covers. Have maybe half an inch of clearance.

Cayman S shift cables re-routed to the rhs of the engine. A six speed will need the two cables split and run either side of the engine I think.

On mobile, so can't post photos. Will get some and post later.

Quote:

What do you have for a engine mount/subframe? I paid way too much to have a local fabricator make mine and after bringing it back 3 times gave up on him. I can make it work, but I'm not happy with it.

I built a custom cradle using the stock front mounting location and a custom cross piece much like yours. But mine doesn't sit as low. I used the Audi engine mount aluminum pieces with Jeep rubber blocks to provide a little isolation.

Have another car on the lift right now, but I'll post photos once it goes back on.

Quote:

What axles, any modification? I'm not familiar enough with the Cayman 5-speed to know if it takes the Boxster S axle.
I've got an '01 5-speed going into an S and the 5-speed axles will work, but just barely fit for the nut:

I used 2006 Cayman S axles, uprights etc. Basically all the running gear is from a Cayman S. The different abs sensors were plug and play with my abs unit.

78F350 · 11-26-2017, 06:21 PM

Good stuff, thanks.

Looking forward to seeing more of it and seeing more of these swaps get completed.

B6T · 11-30-2017, 02:24 PM

Glad to see some discussion and progress on this! I'm going to be getting starting on my project in a few weeks. I've got a 2003 Boxster S. I'm also a mechanical engineer and I've also swapped/wired up Audi engines before (2.7tt swap into a B6 chassis A4). I have a lot of shops in the area that I deal with through work who can support fabrication or machining for my project. I have lots of Solidworks experience and a little bit of FEA.

I've got a 4.2L sourced locally, along with wiring harness and ECU from a 2003 Audi A6. This particular engine is an 'AWN' code engine. As well, I have a 5-speed from a B5 chassis FWD Audi A4, which is the same transmission used in the non-S Boxster. So I'm still sourcing the 5-speed conversion components (through Woody actually

). I knew that the 6-speed from the Cayman was compatible with the 986, but as mentioned, it's also around $3,000 USD. So the 5-speed will have to do for now, until I come across that winning lottery ticket. Or until someone offers me $3,000 for my 986S transmission.

One of the significant requirements of this swap is that it passes an OBDII smog inspection. This is a requirement in the area where I live in order to be able to renew your vehicle registration.

I'm not really worried about mechanical issues because I can sort those out. What I am worried about is more related to the electrical side of things...

My concerns are:
- Tachometer compatibility (some Audi ECUs communicate tach via CAN and other through a signal wire)
- A/C idle up (usually through CAN)
- Rad fan switching (some Audis have relay modules (early 2.7tt) and some use a PWM signal from the ECU (3.0L V6)
- Engine compartment fan switching (not a big deal, but anyway)

There are a number of swap online which show a functioning tachometer, which leads me to believe this isn't really that big of an issue.

Does anyone have any insight on the wiring for these swaps? I've started laying out wire functions and colours for the Boxster in a spreadsheet but haven't done so for the engine side of things yet.

itsnotanova · 12-01-2017, 04:23 AM

B6T, If you go with a five speed, go with a 987 five speed. It's suppose to be stronger internally and uses the bigger CV bolts too. Sorry I can't answer the other questions
Specboxco, I recommend moving your ECU off the bottom of the trunk. I've seen the heat from the exhaust cook ecu's placed there

B6T · 12-01-2017, 07:24 AM

Hey Woody,
If I go with a 987 5-speed then I have to look for a "Porsche" transmission and not a "VW" transmission... and the cost increases exponentially.

The FWD B5 A4/Passat 5-speed (016?) is really a temporary solution until I get the engine up and running. Once I sell the M96/G96 from my car I should have the funds available to buy the proper 987S 6-speed.

78F350 · 12-01-2017, 10:11 AM

Quote:

Originally Posted by B6T

... Does anyone have any insight on the wiring for these swaps? I've started laying out wire functions and colours for the Boxster in a spreadsheet but haven't done so for the engine side of things yet.

I think that the harness coming from my A8 AUX engine is bundled differently than the A6 harness.
The engine harness in this thread by '4Loops' swapping an ART into an A4 may be closer to your engine:
Detailed V8 Swap: B5 A4 4.2L - Page 5

I traced these connectors and came up with a spreadsheet (still rough and unverified). If you want a copy of it in .xls PM me your email. My intent is to share it (post it publicly for download) after I clean it up and verify. -I'm not likely to do any work on this in December.

titaniumdave · 12-06-2017, 01:49 PM

Hey all,
I'm just getting started on a 2001S build with a 4.2L Audi. We are planning on using the 6 speed 986 trans and cut it to clear the starter of the Audi motor. Anyone done this?

What clutch did you use for your build?

78F350 · 12-07-2017, 05:32 AM

Quote:

Originally Posted by titaniumdave

... planning on using the 6 speed 986 trans and cut it to clear the starter of the Audi motor. Anyone done this?

What clutch did you use for your build?

I'm currently building with a 986 5-speed and a flywheel/clutch arrangement for an Audi A6 2.7T (C5 platform). I may pull my 6-speed off the Boxster engine in a week or two and get a look at if there are any issues using the 6 speed transmission with that clutch and flywheel. I'll post if I do.
What engine are you using, 32 valve or 40 valve?

I ran into an unexpected problem with mine, where after I bolted the transmission on the engine wouldn't turn. My clutch pressure plate was in contact with the transmission housing. I'm currently waiting for a "01E103551H" spacer to correct it. Most swaps have not needed it and I'm still not sure why mine did. I'm using a late 2003 AUX engine and I don't see other swaps with that particular one.

An Audizine thread about the spacer: http://www.audizine.com/forum/showthread.php/766013-Audi-Engine-To-Transmission-Spacers-Function-When-Are-They-Needed

Here's some clutch and flywheel discussion that should be helpful (also mentions spacers): http://www.audizine.com/forum/showthread.php/508044-V8-Models-What-Flywheel-And-Clutch-Combo-Are-You-Running