[Voyager6]

My 2014 Cayman S will be undergoing a heart transplant starting the first week of May to a BGB Motorsports 3.8L X51 Powerkit engine. I will document the progress in this thread. Here is what the finished car is supposed to be like:

3.8L X51 engine, 430+ HP (Can't talk about the '+' right now)
Fabspeed Sport headers and catalytic converters (reused from 3.4L motor)
Cargrahics Sport Exhaust (Non-Flapper version)
Brembo GT 380mm 6 piston caliper front brakes, 345mm 4 piston rear brakes
GT3 Master Cylinder
Bilstein Damptronic PASM-compatible coilover shocks with custom Front end lift kit, pneumatically activated (raises front end 3 inches)
GT3 Front Swaybar
X73 rear swaybar (already on car)
BMC Air Filters
Exhaust headers, exhaust pipes, and Mufflers will be heat tape wrapped or insulated
Intake air box and piping will be insulated
Possibly plenum and intake runners will be insulated
Rear brake lines insulated from Catalytic converter heat
Upgraded brake air ducts
Metal shield added to catalytic converters
3rd radiator (installed by BGB in January)
Titanium Brake shims (likely after I get car back as Titanium sheets are on long term back order)

The car has PDK, PASM, PTV, Front and Rear parking sensors, NAV-TV backup camera, extensive replacement of Chrome interior parts with carbon fiber, and TechArt Rear Spoiler II (wing) and diffuser (front spoiler lip to be installed at later date). At a later date, if the GT4 side scoops can be retrofitted, they will eventually go on the car to increase RAM air and engine bay cooling. Wheels/Tires are factory Carrera S III 20" rims with Pirelli PZero N0s installed. Car will be dyno tested before pick-up.

There will be a lot of parts to be removed from the car and I expect that I will list them on Panjo. I have already listed the 3.4L engine on Panjo, available in June.

John Tecce of BGB Motorsports has been a wonderful person to work with. When this is done, I hope to find a way to work with him again in the future (4.0L upgrade?)

 

[Sportwagen]

Monster build indeed! Can't wait for the updates!
:drivingskid:

 

[rjpeaks]

Good luck V6!

 

[ElusiveDH]

Aren't you going to leave something for later?:cheers:

 

[PCA1983]

Awesome build, Dude! I've been thinking about it but only had my 2014 CS for 10 weeks and I probably should wait awhile to be sure. I live within 50 miles of BGB and would love to seer it when you come in to pick it up. Holler if u want somebody extra to Google eye it and take some pix for you. A guess is there will be some after market side scoops available soon. Maybe carbon fiber to. Can't be that hard to do.
Sounds like ur doing it right. You might want wider tires soon, especially in back, with that much power. If u get to that stage, remember that darker rims hide brake dust and I found they don't need much cleaning. I clean mine about every third time I wash it and they always look good. They are kind a dark aluminum color or some might call em titanium color.

 

[Voyager6]

Aren't you going to leave something for later?:cheers:

If I don't sell the 3.4L engine, I may turn the engine into a 4.0L or 4.2L in the future when the 3.8L seems a bit slow! There are also some uspension upgrades possible to add adjustable control arms and replace bushings and rear shock mounts with monoballs, but that would be very last. When the Pzero tires wear out, they will be replaced with a nice set of Michelin Pilot Sport Cup 2 tires.

I apologize for the long, semi-scientific off-topic discussion:

Hopefully someone will come out with better gear ratios for the PDK. The 0.62:1 of 7th gear is just too long, although it is great for gas mileage. The top speed of a Carrera GTS PDK is listed at 189MPH. I expect the lighter Cayman, with less frontal cross sectional area (and thus less total aerodynamic drag that requires less HP to go the same speed) and a few more ('+') HP than stock will let me redline sixth gear at somewhere near 195MPH. A new 7th gear ratio of 0.75 would cause a drop from 7800 RPM in 6th @ 0.88 to 6650 RPM in 7th @ 0.75. I would think the engine would pull from there to the 200 MPH mark.

The stock 0.62 7th gear would drop from 7800 RPM in 6th to 5500 RPM in 7th, too low in RPM to pull much further, even with a bigger engine. Of course the rest of the gears could be made to be closer, but 7th is the problem for top speed. The stock 3.4L engine, even with mods, can't do redline in 6th, so the drop to 7th would be even worse. Using the published 174 MPH top speed (PDK), that yields an engine RPM of 6960 at top speed in 6th. Shifting to 7th in a stock Cayman S would drop engine RPM to 4900 RPM, definitely too low to go any faster.

Next is a discussion related to acceleration and comparison to the GT3:

The effective torque at the wheels are multiplied by the selected gear and the final drive ratios. I have observed the published FDR of the GT3 is 3.97:1 and the Carrera GTS is 3.44:1. If you multiply the GT3 FDR by the ratio of the redlines, look at what I found: 3.97*7800/9000 = 3.44. Coincidence? I think not. What this says is that for the engine redlines, the FDRs are essentially the same in both cars. However, the GT3 engine with its 9000 RPM redline can give up more turns, producing more effective torque at the wheels. The FDR ratios suggest this is 15.4 percent more for the GT3. Coupled with closer ratio gears is the reason why the GT3 accelerates so well.

What this means is that it will take 15.4 percent more engine torque to compensate for the inability to gain the mechanical advantage of the GT3 engine. For a normally Aspirated engine, this is usually a linear function of displacement. To get 15.4 percent more engine torque, you need a 15.4 percent larger engine. So starting with a 3.8L engine, this means you need a 4.4L engine to have the potential for similar acceleration.

There are other things affecting the equation that I have left out such as a large engine has more rotating mass and it take even more displacement to compensate, and it also means more intake and fuel modifications as well. But I hope you see my point. That may be beyond current upgrade capability although a certain Cleveland, GA engine builder told me he was working on extending his 4.2L 9A1 engine design to 4.4L for GT4 use and expects it to be available next year. A balanced blueprinted engine should be able to compensate for these other issues and maintain the 7800 RPM limit in a bigger engine, although it will take work to do so. to be honest, a turbo would be a faster way to that performance point.

Finally, has anyone gotten a word from Porsche on the actual final drive ratio (FDR) of the Boxster/Cayman S PDK? As mentioned before, the Carrera GTS is listed at 3.44:1. The published FDR for the Cayman S is 3.25:1. Observing 2000 RPM in 7th gear yields 70 MPH on my speedometer. The math says the Cayman FDR is closer to 3.44 than 3.25. Using the formula: RPM*60 sec per minute/FDR/GearRatio/Tire Revs per mile)=Speed in MPH gives 2000*60/3.44/0.62/790= 71Mph. Using 3.25 gives 75.4 MPH, so 3.44 is closer to observed speed. So I am guessing the published FDR figures are incorrect for the 981 S PDK.

 

[Voyager6]

Awesome build, Dude! I've been thinking about it but only had my 2014 CS for 10 weeks and I probably should wait awhile to be sure. I live within 50 miles of BGB and would love to seer it when you come in to pick it up. Holler if u want somebody extra to Google eye it and take some pix for you. A guess is there will be some after market side scoops available soon. Maybe carbon fiber to. Can't be that hard to do.
Sounds like ur doing it right. You might want wider tires soon, especially in back, with that much power. If u get to that stage, remember that darker rims hide brake dust and I found they don't need much cleaning. I clean mine about every third time I wash it and they always look good. They are kind a dark aluminum color or some might call em titanium color.

My winter tires are on Oz Ultraleggra rims and they are 1/2 inch wider and fit the wheel wells better than the stock 20" rims. They are black and can be seen in my gallery photos. I do prefer the dark platinum of the factory rims, though. Tonight, I hope to photo the Techart rear spoiler (wing) and difffuser, as well as the installed carbon fiber air vents and upload them to the gallery.

 

[DFW]

Monster is a good description, I hope it turns out perfectly.
Have you recorded any lap times or drag times to measure against later?

 

[Voyager6]

Monster is a good description, I hope it turns out perfectly.
Have you recorded any lap times or drag times to measure against later?

At Christmas, I bought a VBOX Sport and was unable to use it as it needs an iOS device to run the Performance Test App. I recently bought a cheap ipad mini and promptly upgraded to iOS 8.2 and its bluetooth issues cause the App to freeze when talking to the VBOX sport. The recent iOS 8.3 update didn't help anything. It still freezes and I haven't been able to get a 0-60 or 1/4 mile time out of it. I may try using the logging function and bring the data into a supplied Windows program that I might be able to pull those times from. I've only got 10 days before I have to leave, so it may not get done. The diagnostic app does not freeze, so I am assuming the problem is in the App. I may resort to a stop watch.

 

[Voyager6]

Spent most of the weekend dealing with the TechArt Rear spoiler II. The wing and mounting base was put on about 10 days ago. However, I have been avoiding driving it because I had not disabled the factory rear spoiler. The Techart mounting base overhangs the factory spoiler and if the factory spoiler would try to lift, it would break something. I have driven the car twice and got to 73 MPH both times, narrowly avoiding disaster. With my trip to BGB this weekend, I decided that I would not have the time to do the Techart mod if the dealer was unable to disable the spoiler this week.

So.... I have to remove the rear bumper cover. Start taking the factory wing off. 6 T-15 screws to get the top half of the wing off. Then two nuts holding the underside of the wing. There are two screws that hold the bumper cover under the wing. then there are two screws under each taillight, so taillights have to come out next. Two in each fenderwell, two at bottom at the diffusers. One on each side of the exhaust outlet. That works out to 16 screws, not counting the wing or taillight mounting screws. All were T-30. Put something on the ground to lay the cover on when it comes off. Start at the wheel wells, pull outward to clear the plastic wheel liner. then up and out. There is one cable to remove to the reverse light and license plate bracket, parking sensors, etc.

Now the hard stuff starts. First, the two electrical plugs, one for the rear bumper stuff and one for the lift, have the mating connector covering a nut that must be removed. Short story, no easy way other than to just bust the mount and uncover the nut. Eight 13 MM nuts hold the drive assembly to the rear of the car.

The factory operation is a middle mounted motor with shafts from each end that turn worm gears that raise the scissors mechanism that lifts the wing. The driver's side has a magnet attached to the scissors unit and you remove two pins and then the scissors can be removed from the lift assembly.

Techart has you throw away the passenger side lift assembly. Good thing. I used it as practice to get into the gearing and mangled it while learning what should have been in the instructions or documented in pictures.

Long story short. Techart supplies a subset of the scissors mechanism. You transfer the magnet from the factory scissors mechanism to the Techart piece, mount the Techart piece where the factory part went, reassemble and done. The wing is clamped to the rear cover. This covers two of the bumper cover screw holes and you can't get to them. So Techart supplies a allen head screw, a clip for it to screw in and the bumper cover overhangs the head of the allen screw, proving some support.

Anyway, getting the worm drive assembly open, removing the factory lift lever and replacing it with the Techart piece is a nightmare. The hole in the techart piece that is to connect to a boss on the worm drive did not fit and I had to sand the hole to get clearance to fit the plasitic part.

Anyway, the whole purpose is to basically have the magnet fake out the hall effect sensor, telling the computer the spoiler is up, when it isn't attached anymore. About 10 hours start to finish. A lot of work to do something the dealer could likely do in software. But at least I can do 75+ MPH without worrying about a disaster.

This took so long and I discovered so much dirt that I will wash and wax the car and take the long-delayed photos tomorrow night.

 

[mwilson]

Did you take it to the dealer to have them disable the spoiler? I know they can do that.

 

[Voyager6]

I have an appointment with my dealer tomorrow for a final oil change (it is due) so when the engine is removed, it won't be full of acid-rich old oil. I was going to have the dealer disable the spoiler via software at that time, but the engine came quicker than I expected and I have to drive the car to Florida this coming weekend. The sooner BGB gets it, the sooner I get it back (I want to be able to enjoy it this summer while it is still summer - hoping for a mid-June delivery [No pressure, John!]). The TechArt spoiler mod took 10 hours to remove the bumper cover, hack the lift unit, and replace everything. I would not have had time this week to do this mod if the dealer option failed, so I went ahead and did it as I had the time this last weekend. I just couldn't take the risk of driving to Florida and having to stay below 75 MPH.

I was also afraid that the software option might turn off the automatic up/down nature of the factory wing, but the center console switch might still work and I could break something if it inadvertantly was pressed. I have driven the car twice since the wing was mounted and both times, I got careless and got up to 73 MPH and nearly had the spoiler raise. That is not a concern now!

The actual removal and reinstall of the bumper cover was pretty easy. The majority of the 10 hours was figuring out how to modify the lift unit. If anyone ever does this mod, please PM me and I will help to the best of my capability. I also have an idea on how to mount the wing/base with less tendency to smear glue all over your trunk lid.

I emailed TechArt USA a month ago with questions (as well as the distributor that I bought the kit from) and got no response. They leave you on your own.

If I had to score this item: On a scale of 0 (bad) to 10 (good), It would get a 10 for cool looks; a a 4 for being engineered with some issues, and a 1 for the quality of the instructions and the photos included therein, for an overall score of 15 of 30 possible, or an overall score of 5.

 

[Ynot]

When it comes to modding the 981, you have everyone beat by a mile. Looks like a great build, can't wait to hear the final results.

 

[Voyager6]

Bad news, the 'fake the computer out spoiler mod' failed and the dealer was unable to find an option to eliminate the spoiler without an activation code from Porsche. So I am going to have to remove the cover and figure out what went wrong to get rid of the instant at 75MPH and annoying 'Spoiler failed - Please slow down!' message.

Failure possibilities include: Techart part fell off the worm drive, the motor drove the spoiler to the limit and bound, the hall effect sensor not working (wiring strain during modification), loose electrical plug, magnet fell out of Techart part, TechArt Part was very tight in scissors housing and may be too much for the motor to drive, and square shaft from motor slipped out and is no longer driving the worm mechanism at all. My bet is magnet fell out or hall effect sensor is not working. I tested it three times using the console switch before putting the bumper cover back on.

This time it should only take an evening since I know how everything comes apart and goes back together. Hopefully in 3 hours.

Grrr. At least there is no chance of damage to the car by the spoiler rising inadvertently.

 

[Lukeb817]

I notice you have PTV and plan to to do the GT3 master cylinder swap, I seem to remember another forum member with PTV was unable to use the GT3 master cylinder. Has BGB come up with a work-around?

My 2014 Cayman S will be undergoing a heart transplant starting the first week of May to a BGB Motorsports 3.8L X51 Powerkit engine. I will document the progress in this thread. Here is what the finished car is supposed to be like:

3.8L X51 engine, 430+ HP (Can't talk about the '+' right now)
Fabspeed Sport headers and catalytic converters (reused from 3.4L motor)
Cargrahics Sport Exhaust (Non-Flapper version)
Brembo GT 380mm 6 piston caliper front brakes, 345mm 4 piston rear brakes
GT3 Master Cylinder
Bilstein Damptronic PASM-compatible coilover shocks with custom Front end lift kit, pneumatically activated (raises front end 3 inches)
GT3 Front Swaybar
X73 rear swaybar (already on car)
BMC Air Filters
Exhaust headers, exhaust pipes, and Mufflers will be heat tape wrapped or insulated
Intake air box and piping will be insulated
Possibly plenum and intake runners will be insulated
Rear brake lines insulated from Catalytic converter heat
Upgraded brake air ducts
Metal shield added to catalytic converters
3rd radiator (installed by BGB in January)
Titanium Brake shims (likely after I get car back as Titanium sheets are on long term back order)

The car has PDK, PASM, PTV, Front and Rear parking sensors, NAV-TV backup camera, extensive replacement of Chrome interior parts with carbon fiber, and TechArt Rear Spoiler II (wing) and diffuser (front spoiler lip to be installed at later date). At a later date, if the GT4 side scoops can be retrofitted, they will eventually go on the car to increase RAM air and engine bay cooling. Wheels/Tires are factory Carrera S III 20" rims with Pirelli PZero N0s installed. Car will be dyno tested before pick-up.

There will be a lot of parts to be removed from the car and I expect that I will list them on Panjo. I have already listed the 3.4L engine on Panjo, available in June.

John Tecce of BGB Motorsports has been a wonderful person to work with. When this is done, I hope to find a way to work with him again in the future (4.0L upgrade?)

 

[Voyager6]

I am not sure but there are at least three variants of the 2014-2015 GT3 master cylinder available now. Hopefully one will work.

 

[futurz]

I ended up using the MC from the 991S. Same diameter piston as the GT3.

 

[PCA1983]

Your nice low mileage 3.4L engine with intake upgrades is a steal. One would think that by now there are some high mileage 981 2.7L owners who would be interested in a fresh engine that adds more than 50 hp and 60 ft-lbs torque. Sooner or later, even the usual Porsche boneyards will be offering a lot more than Porsche's "core charge". Their standard offer is pretty close to a screw job, as it seems to assume the engine is worn out toast.

 

[Voyager6]

Your nice low mileage 3.4L engine with intake upgrades is a steal. One would think that by now there are some high mileage 981 2.7L owners who would be interested in a fresh engine that adds more than 50 hp and 60 ft-lbs torque. Sooner or later, even the usual Porsche boneyards will be offering a lot more than Porsche's "core charge". Their standard offer is pretty close to a screw job, as it seems to assume the engine is worn out toast.

The fact is Porsche offers an $8.9K core refund for a 2.7L engine! I could almost let the engine go for that (minus the plenum). Someone wants to do that 2.7L engine could do so for about 1/2 the cost I am paying. It is still up there, but not astronomical. BTW, the 9A1-based GT3 engine lists for over $70K! I only considered it for a fraction of a second.:burnout:

 

[Voyager6]

I ended up using the MC from the 991S. Same diameter piston as the GT3.

Thanks! Good to know!