Planet 9

It was nice and easy until TPC; now...

1. Turbo for $ 13K -- out the door price -- only 5lbs pres. added; 1 year warranty
2. X51 for $ 29K -- out the door price -- naturally aspirated; 2 year warranty; can add super charger....

Am going to test drive both in the next 30 days

Yes, it's enough to drive you crazy trying to decide. I suppose X51 would be the most reliable, but not quite as much power as turbocharging. I guess the question to ask would be the differences in performance between the options.
Does any one out there have any idea how significant the difference would be in the performance of a Cayman S with: 3.8L X51 vs. TPC turbo vs. supercharged 997 motor? I know this is a difficult estimate to make.

If I do one of these, I would definitely plan on keeping the car for a while. I would just love for my CS to have the performance it ought to have instead of the performance Porsche marketing has determined it should have.

Of course, just about the time I would get my CS back after spending the bucks to do one of these significant engine mods, Porsche would spring a turbo Cayman on us.

I'd like to believe in Santa Claus too, but that's not going to happen.

Check out AutobahnAmbitionMag.com...it has a good article on the TPC kit. At only 5 lbs of boost, there's not that much stress on the engine.

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After thinking about this 1000 times, Tach and Sleeper did this... in the correct order... If the turbo does stress the engine a little, let it die an earlier death, then do the swap....all in all, not a bad financial option when considering trade-ins, depreciation and sales tax to try to keep up with new....... $ 42,000 plus base car cost over 5 years vs cost of 997 turbo .... all the while, dragging the tail

That 1st customer car (Carmona Red) has been at TPC so long because it has been used with the owner's consent as a development test bed since he wanted the "full monty" and is willing to pay the price in both time and money. There have been extensive dyno runs to compare and optimize all the components. The car has also been used for instructional/promotional photos and videos.

It arrived w/a Softronic flash which is now gone. Among the other improvements are a LWF and tweaks to its PSS9 suspension. It already had a Quaife TBD. A factory aero kit and body painted wing were added. The last dyno sheet I saw was 417 to the wheels with the stock headers. A bit more HP is likely.

Delivery should be in the next couple of weeks with a track testing opportunity shortly thereafter.

The car doesn't lose its warranty unless the problem is related to the mod. I.e., if a head gasket blows it likely won't be covered, but if the ACC malfunctions it should be covered.

I doubt anyone contemplating this mod expects to "get some real money back." It's an expenditure for the owner's enjoyment, not an investment. The same can be said about buying a Cayman. The ROI is measured by the size of the smile it brings every time you light it up.

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Dan

These are all good points. If we are really worried about reliability, we shouldn't be adding a turbocharger in the first place. It sounds like the turbocharger is the best bang for the buck. An X51 swap won't give near the same amount of power, and a 997 with supercharger motor swap may give similar power but is going to cost a lot of bucks. Am I correct? Please let me know, I really would like to know.

Updates on TPC.

I have scheduled a time to test drive one of their cars in several weeks.

1. They are in the process of finishing 3 more cars -- will be returned to their owners next week.

2. The plenum they use for the turbo install is a standard Porsche part -- and is used for ease of installation and service -- , nothing else...again, Tom says the plenum adds nothing with respect to power.

3. For what it is worth, Tom has checked into the x51 swap with other race team/retailers... and without getting into all the details, you end up with considerably less power then advertised when they put the 3.8 liter engine into a Cayman S...Many other people in this club are better versed in this subject than I. He challenges us to find dynos after the swap is made without adding further mods. The AWP he quoted is so low, that I will not repeat....Checked with another well know dealer/race team -- said they would not perform the x51 swap -- not much net benefit -- poor fit -- etc... What do I know...

I think there is some anecdotal evidence on this site that supports this. The Cayman that ran this year's One Lap with a 3.8 X51 posted unimpressive 1/4-mile times. The Farnbacher-Loles GTR that was tested by Car & Driver also posted acceleration times that weren't much of an improvement. The 1/4-mile time of the GTR was 12.8 instead of the stock CS time of 13.3 (other tests have been as low as 13.1 - see Caymanclub faq). Really, you'd expect to pick up more than 0.5 sec if the power of the GTR was actually the claimed 395 HP. Maybe the 3.8 X51 in the Cayman isn't as strong as it should be... This would be an interesting question for Scott Slausen of Softronics.

Thanks for the info... how does 307 AWP sound?

Wow, that's pathetic. There's no reason to think those engines don't produce their rated power in the 997S X51. That car is about as quick as you'd expect for 381 HP. I wonder why they perform so poorly in the Cayman. DME problems, maybe??

When I bought my Cayman S at the end of Feb., I didn't even know what a catback was... Driving, reading this forum and asking questions allows me to understand this "foreign language" you all speak, but speaking the language is harder....

it goes something like this... tuning or throttling down the engine (can't remember which), funadamentally different designs for air intake, increased temp/dec power, different exhaust size, and other things...

The statement was ended by noting that very few, if any dyno's were to be had... why not?

As previously stated on this thread, I was going down the x51 path before turbo... I want to believe in this option, but...Maybe that's why some of more experienced members/racers of this club have not jumped on that bandwagon and have settled for the "modification lite" versions which increase power and torque in such painfully small increments......If there was I way, "they" would have found it by now...until TURBO....

EDIT!

Really it is the trap speed that matters when looking at engine HP upgrades, not so much the time, and the F-L Cayman GTR went from 107 to 113 in the QM...

Considering a like weighted/more powered 2008 Vette traps in the 116 range according to C/D, 113 is about right for +100HP.

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'07 CS, '07 335i

I am waiting for some official 0-60 and 1/4 mile times on the turbo Cayman S. I would guess sub 4 second 0-60 times. Quarter mile in high 11's, low 12's?

Well, according to dragsource.com (http://www.dragsource.com/index.php?...s&calctoview=5), if the Cayman weight including driver is 3100 lb, and the RWHP is 260 (295 FWHP with a 12% drivetrain loss - numbers near 260 RWHP have been reported from dyno tests of stock cars many, many times), then the expected 1/4-mile time & speed would be 13.3 @ 102 mph. This agrees well with reported times and speeds in the various magazine road tests (see the faq, times range from 13.2 - 13.4, with speeds ranging from 104-107).

By increasing the FWHP to 395, the RWHP goes up to 348. The time/speed estimation calculator shows that this increase of 100 FWHP should drop the 1/4-mile time by 1.2 seconds and should increase the speed by 11 mph. The F-L GTR only gained 0.5 sec and 6 mph - about half of what would be expected. So, the 1/4 data on the F-L GTR supports the suggestion that the 3.8 X51 in that car is not providing the 100 FWHP gain that is being claimed. It looks more like 50 FWHP.

To gauge what the 3.8 X51 upgrade really does in the Cayman, we need to see before (3.4L) and after (3.8 X51) dyno plots, taken on the same dyno. I've been leaning towards the 3.8 X51 myself, rather than a turbo upgrade, because all the driving responses of the Cayman, including throttle response, are so instantaneous. With turbo lag, you will lose some of that in the throttle response. I have owned several turbo cars (VW 1.8T, Saab 2.3T, Porsche 944T), so I am well acquainted with turbo lag. IMHO a NA engine upgrade would preserve the overall character and driveability of the Cayman a little better, even if it's down on power from a turbo. YMMV.

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John
'07 997 GT3

Previous cars:
'07 Cayman S
'89 944 Turbo
'86 944

Agreed. The lightning-quick reflexes of the Cayman is a very big part of what makes it special.

And this calculator:
TunerCalcs - Calculate Wheel Horsepower from 1/4 Trap Speed (mph) shows my assessment to be spot on, as does your referenced calculator, with an estimated trap speed of 113 mph.

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'07 CS, '07 335i

I read your posts to indicate that you think the F-L GTR trap speed indicates that the claimed 100 HP increase is actually present. Please correct me if I am reading your posts incorrectly.

However, using the calculator you cite in the link, at a test weight of 3100 lb the HP for the baseline trap speed of 107 is 296 HP. The HP for the modified trap speed of 113 is 349 HP. This confirms my claim that the F-L GTR is not putting down an extra 100 HP. The calculator I cited shows the same result - the F-L GTR only appears to have 50 HP or so above a stock CS.

What am I missing here? It seems like we are disagreeing, but yet your calculator proves my point. ????

I don't believe you can mix and match calculated versus actual in the manner you are doing. Both calculators point to RWHP around 350 with a trap speed of 113 mph.

In reality, I would expect trap speeds to vary in the 112-114 range just as stock trap speeds vary in the 103-106 range with a few outliers above and below. I use the trap speeds from dragtimes.com, as it is my experience that sometimes C&D/R&T is given a "runner". I also think the Cayman S is slightly underrated.

Based on my experience with adding +45 and + 80HP to the 335i, and in comparison to the Corvette, I think the 112-114 range is right on for the claimed 381 HP which is actually + 86HP versus 295...although we both rounded that to +100HP.

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'07 CS, '07 335i