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Discussion Starter · #1 ·
Audi 4.2 V8 in a Cayman S please take two…

Or should I say my start to finish putting an Audi 4.2 V8 into a 2007 Cayman S. This car was purchased from rkmann in an unfinished state. His thread can be referenced here Cayman S - Audi 4.2 Liter V8 in a Cayman S

I took the long trip from South Carolina to Michigan to pick the project up and had a wonderful day loading up the car and talking with rkmann about the car. The drive on the other hand sucked. I thought the roads in South Carolina wear bad, I hope I never have to see roads like were in Ohio again.

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With the car now safely home, the work has started.

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To start the work done on the car to this point was great. Rkmann did top notch work with tons of thought going into everything he did. There are however a few things I wanted to change about the build. The first was the frame that the engine sat on. After removing the engine the first time I felt I wanted an easier way to get the engine in and out of the car. With this said I redesigned the entire underside structure of the car. First with tape:

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Then what it actually turned out to be: (save some gussets to be added later)

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The biggest issue was how to deal with the rear cross member. The angle at which it bolts in does not allow it to be lowered straight down with the engine. This required it to be removed separately from the rest of the sub structure to be built.

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The next item I moved on to was the fuel rail. The fuel rail on the Cayman is a non-return style where the S6 was a return style. I found a mention from someone on YouTube that other Audi 4.2 fuel rails would eliminate the need for a return on the rail (sorry I do not remember who). I bought a 2006-2009 S4 rail and with a little finessing of the rail this seems to fit quite nice.

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Next was on to the intake / Coolant crossover tube. The intake on the Audi wanted to point toward the passenger side to the Cayman yet the stock Cayman intake was on the Drivers side.

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This took a bit of thinking, but after a few long nights searching the internet and maybe a drink or two the coolant crossover tube was removed and then welded up to change the clearances to allow the intake to point back to the drivers side of the car.

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I have also purchased the coolant crossover tub off a 2005 VW Touareg but it has yet to show up. We will see which is the best fit or which is the best to modify to fit.

Next up is the coolant system and the electric power steering conversion unless my attention is grabbed by something else on the car to work on.

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This is now where the car sits. Tons of things are rattling around in my head as what to do next and I hope to continue to post as progress is made, but forum posting is not my strong point so it might be slow going. I know I will have questions and hope many of you can point me in the right direction.

That is it for now, I will update as my time allows and answer as many questions as I can.
 

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Super cool and ambitious project. I wish you all the best. The power to weight ratio will be off the charts. How much heavier if the V8 compared to stock engine if at all?
 

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Cool project - wish you were closer to me so that I could help/learn! I watch the YouTube channel Home Built by Jeff where he has a project called the Roxster - an Audi V8 swapped Boxster. He does a lot of very interesting rebuilds/swaps and is amazingly talented, could be a good source of information:
 

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Great to see you with a thread on here, I believe you must be the guy that my buddy Brian was talking about, hope to see the car soon!
 

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When you said you purchased the car from me "in an unfinished state," were you referring to Michigan? Our roads certainly give that impression. ;-)

Great to see the new thread. You're off to a quick start, and I'll be looking forward to the progress.
 

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Cool… at least your staying in the VAP group…. I ran into a k24 into a GT3 recently…
I was speechless
 

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Discussion Starter · #7 ·
Progress update:

First to answer a few of the questions:

wmclarinf1: The engine is actually about the same weight as the original, might be a slight bit more weight up high but that is the only downside.

Hokie987.1: I do watch Jeff's rockster project, it has given me a few ideas.

fouckhest: yes, that is me, just let me know when you want to stop by.

rkmann: You are absolutely correct about the unfinished state of the roads in Michigan! Hopefully once the car is done, we can meet at a track day.


So, what have I been doing on the car?

Things are moving along but definitely slower than I had hoped, mainly due to not being able to get parts in a timely manner. The planning is still going well and has given me a chance to work things out in my head before trying them on the car.

The coolant system in fully planed out and pretty much done. Just need to have a few aluminum tubes welded to reduce the number of clamps needed. I did end up using the coolant crossover tub from the Touareg then swapping the main out and heater connection locations to make things line up better.

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Intake system: Done save a heat shield and mounting brackets to hold things in place. Once all the coolant crossover stuff and some more structure from the car was out of the way this really turned out to be a simple layout.

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Lower sub frame: I am so happy with the lower sub frame now. The engine can be installed or removed in less than 30 minutes. It will also allow for the engine, transmission and exhaust to come out as one piece which makes working on everything very easy.

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Upper structure: As I mentioned above more of the upper structure was cut out. The space was needed for the intake and rebuilding the top structure was always going to have to happen so straightening a few cuts out would make this easier in the long run. Look at all that space...twin turbo LS, a 4.2 out of an RS4..., no I need to finish what I started.

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After the removal of more metal some planning on how to re-enforce the upper structure. The plan is to be able to put most of the original panels back in the car to keep a factory look.

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Power steering: This seems to be the one step forward three steps back part. The adaptors to take the factory connections on the rack to AN did arrive and are great.

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With the new layout of the electric power steering pump in the frunk, power steering lines are going to be so short that they have time to dissipate the heat. I feel I need to add an oil cooler. First, I tried to fit a cooler in the driver’s wheel well but just could not find a good place for it. That left adding one somewhere in the front of the car. This is when I stumbled across a thread about adding a third radiator kit tor the car, something along those lines with an oil cooler added might work. The problem is taking air from the front of the car and then forcing it out under the car did not sound like a good idea for the aero of the car. Remembering an add from Rennline that showed a retrofit of the gt3 simle vent got me thinking maybe the air can be made to go out the top like on the gt3’s. So now how to make a gt3 smile vent functional on the 987. I ordered a ton of parts, gt3 smile vent kit from Rennline (still on backorder), the factory third radiator kit (none of this kit is going to work for up venting, anyone want to buy one?) and a few bits and pieces from a 997 gt3 front end. The pieces from the gt3 front end fit, with a ton of modification, but I still have to buy a ton more pieces and hope it will all work.

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Audi computer: this has been reprogramed to remove the immobilizer, soon to start the wiring.

Fuel system: This just needs the fuel line connected all items are here and routing is decided on.

The next items I plan on working on are the clutch and then wiring.

That is it for now, I am still working and will update again. Hopefully sooner than this one.
 

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'11 Cayenne TT, '09 Boxster
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Very impressive progress and work!
 

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It's great to see this project getting a second "life".
Personally, I would use the Porsche-designed third radiator ducting that exits out the bottom of the bumper cover. There are four rectangular cutouts required through the cover, and their locations are embossed on the cover's inner surface. Also, you can cut open the closed slots in the front wheel well liners to increase airflow over the side radiators -- or simply replace them with their equivalent Tiptronic/PDK variants.

Sent from my SM-N910V using Tapatalk
 

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Discussion Starter · #11 ·
Got a little more work done this weekend. I was originally not going to be working on the car but after receiving a surprise delivery of the GT3 smile vent kit some time was squeezed in.

The smile vent kit went in very easy, about an hour later the bumper was done.

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Things did not go so good with the test fit of the bumper. It did not fit at all over the mounting bracket for the GT3 radiator. Time for some re-planning. What I ended up doing is using most of the original 3rd radiator kit that was purchased and heavily modified almost everything. Fussing the GT3 mounting bracket and the original kits brackets together, modifying the original side scoops for the main radiators, cutting and changing the scoop that fits between the radiator and the bumper, a few choice words and it now fits.

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The only other progress was on the engine cover area. Support was started to be welded in and the engine cover cut to fit in the rear (Picture before structure welding started)

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More to come soon.
 

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With the new layout of the electric power steering pump in the frunk, power steering lines are going to be so short that they have time to dissipate the heat. I feel I need to add an oil cooler. First, I tried to fit a cooler in the driver’s wheel well but just could not find a good place for it. That left adding one somewhere in the front of the car. This is when I stumbled across a thread about adding a third radiator kit tor the car, something along those lines with an oil cooler added might work. The problem is taking air from the front of the car and then forcing it out under the car did not sound like a good idea for the aero of the car. Remembering an add from Rennline that showed a retrofit of the gt3 simle vent got me thinking maybe the air can be made to go out the top like on the gt3’s. So now how to make a gt3 smile vent functional on the 987. I ordered a ton of parts, gt3 smile vent kit from Rennline (still on backorder), the factory third radiator kit (none of this kit is going to work for up venting, anyone want to buy one?) and a few bits and pieces from a 997 gt3 front end. The pieces from the gt3 front end fit, with a ton of modification, but I still have to buy a ton more pieces and hope it will all work.
I've built one and owned two cayman race cars. Two things to think about (apologies if you know this stuff already)

1) I did a gt3 3rd radiator venting upward through the bumper cover following this link. Includes all part numbers, super useful if you haven't seen it. Your point on aero is exactly why I did it

2) On both of my race cars I have EPS, and you don't need a cooler. The cup cars that run endurance races don't have coolers either. The reason the stock stuff snakes all over the place to dissipate heat is the proximity of the pump and the lines relative to the engine / exhaust. This is why a lot of race cars w/ stock pumps add a cooler. When you pull the pump out of the engine bay you eliminate the heat issues.

You are in SC and mentioned meeting at a track day. I'm in Jax and up for Roebling or SCMP.
 

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I've built one and owned two cayman race cars. Two things to think about (apologies if you know this stuff already)

1) I did a gt3 3rd radiator venting upward through the bumper cover following this link. Includes all part numbers, super useful if you haven't seen it. Your point on aero is exactly why I did it

2) On both of my race cars I have EPS, and you don't need a cooler. The cup cars that run endurance races don't have coolers either. The reason the stock stuff snakes all over the place to dissipate heat is the proximity of the pump and the lines relative to the engine / exhaust. This is why a lot of race cars w/ stock pumps add a cooler. When you pull the pump out of the engine bay you eliminate the heat issues.

You are in SC and mentioned meeting at a track day. I'm in Jax and up for Roebling or SCMP.
A major reason engine-driven P/S pumps need cooling on the track is that they are sized for parking lot maneuvers, when you need it most. In other words, when the engine is running at idle (say, 750 RPM) it puts out the most flow you'll ever need. Now, take that pump at an engine speed of 7500 RPM. It's trying to pump 10 times that much fluid, most of which gets bypassed back to the inlet. Each time through the pump, the fluid gets heated by the friction in the pump and in the bypass valve. All the power driving the pump (5-10 HP?) ends up as heat in the fluid.

For EPS on the other hand, the pump (I imagine) runs at a constant speed, equivalent to idle. Very little heating of the fluid then.
 
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