Cayman S engine Vs. 911 enigne - what's the diff?

OK - I admit I am new to the Porsche engine design stuff. I have done some searching, and hope there are some sharp people on here whom can help educate me. I have heard that the 3.4L Cayman engine uses the cylinder heads and cams from the base 911 3.6L engine. Are the blocks different? Someone educate me on what we have here. I want to lease a new Cayman , but could be swayed into a purchase if I could do some nice engine work! Any chance the TT 911 engine would bolt into a Cayman ??? HHHmmm... -Kyle

Engine families Looking at a model year '06 list , the 3.4L engine in the Cayman S is in the same 'family' (M97) as the 3.8L in the 911 S. The 911 3.6L is an M96 engine.

Kyle - The blocks are slightly different - it's the actual cylinders that are different... that makes the displacement .2L different. the motors are kind of modular with separate crankcases, cylinders and heads. In a word, no - at least not easily. The TTs, GT3s and GT2s use a motor that is based on the old style split crankcase motors used in the air cooled cars until 1998. Last used in mass production in the 993 models. There's so much plumbing and then there's the intercoolers and other stuff that goes onto a TT motor that there's really not enough room in the Cayman engine bay to accommodate all of it. The news-style 3.6, 3.8 and 3.8 X=51 motors do practically bolt in, but they must be turned around 180 degrees (obviously), and their intake systems need to be turned around, too. brad

I am going to disagree with beez just a little. The bore (piston diameter - 3.78" / 96mm) of the Cayman S and Carrera are exactly the same, which should mean that their cylinders are probably the same too. I could be wrong. The cylinders may be shorter, but knowing the way Porsche likes to minimize parts, I would be surprised if this was the case. The big difference in the engines that results in the 0.2L difference is their stroke. The Cayman has a stroke of 3.07" where the Carrera gets a stroke of 3.26". This is achieved of course by using a different crank shaft. In the case of the 3.8L Carrera S engine, both the bore and the stroke are greater. (3.9" bore, same 3.26" stroke as the 3.6L) Because the Cayman uses the same M97 block as the Carrera S, there should be enough room in there for the 3.8L crank shaft. Of course that would mean you need new rods as well. This alone would bring a Cayman S engine to 3.6L. To further increase it to 3.8L, you would need new cylinders. In most cases, it is understood that a complete engine swap is best. In that regard, a 3.8L X-51 uses the same motronics system as the 3.4L cayman . With some reprogramming, it's ready to go. The 997TT has a completely different motronics system and would be cost prohibitive to install in a Cayman .

With my background, I am not concerned with making the electronics work properly. I am more concerned with the physical fitment of more parts in a small space... If the bore is the same between the M97 and the M96 , and the M96 has more stroke using the same heads, wouldn't the M96 have more compression? The Cayman already has to run 91 octane... I don't want to mess with AVgas in a TT M96 . It is comforting to know that I could swap a crank and gain back the 0.2L. Not too shabby! HHhhmm... But couldn't we all just find a TT setup and bolt on the turbos (with some fancy packaging)??? If the blocks are the same "family" why hasn't this been done before? Thanks for the info! -Kyle

Is the 3.8L X-51 turbo??

No, the X-51 is a normally aspirated 3.8 Liter M97. In factory form, it's good for 385hp. Modded, it delivers ~400. There are several shops installing these into the cars. Prices range from $20-$30K. No. By varying the length of the connecting rods, the proper compresion ratio can be achieved at top dead center. So the crank and rods would have to be changed together, or you would likely plow the piston right into the valves. I am not entirely sure what you mean by that. Either you don't care about the electronics because you are willing to swap out the entire harness, or you are willing to turbo charge the car the old fashioned way without the electronics. Either way you are going to run into a wall called PSM. PSM, aka Porsche Stability Management, will prevent the car from being able to use the power of say a 997TT engine. It has many sensors and measures lateral and longitudinal forces. A 500hp turbo charged engine is going to exert forces on that car that the PSM computer 'thinks' are impossible from the engine, so it will assume the car is out of control and it will intervene by lifting the throttle, applying brakes, and god knows what else. The cars are way to sophisticated now to do an old school shoe horn engine installations. As for room, I seriously doubt you could easily fit a Twin Turbo engine into a Cayman because of the different layout. There is also no room for the intercooler. And the heat build up in a mid engine layout would be far less than ideal for turbos. Anything is possible, but it would be so difficult it would likely be cost prohibitive. Take a look at this: F/L Cayman GTR

Good point about the PSM. That could be tricky. I'll have to think about that one... My background is in enigne controls. Electronics are my friends. Regardless of mods or complete custom setup, it won't be too difficult.

I admit I know NOTHING about engines...I am the arrive and drive guy you all like to make fun of.... I really can not seem to get interested in tweaking a car, modding it (much)..etc. I like to buy what I want....the way I want it. I am not against these things and admire those who can do this stuff. I wish I could. At any rate....my question is simple. In looking at the above link to the 400 Hp Cayman GTR at a full on cost of 118,000....why not just buy the 911 turbo? Is it because of mid-engine design of the Cayman ? For me...I prefer to have a full on warranty from Porsche . For those of you who do these mods...are you not concerned with voiding your warranty? Becuase if something goes wrong...you are skilled enough to just fix it yourself? Just curious curious curious.

Great question! You should submit as a separate post to get better responses.

Good point... I wasn't comparing the Cayman GTR - More interested in what enignes I could swap into this beast in the future. I am looking more at ownership and modifications into the future. I wouldn't pay 118k for a Cayman . 911 TT with AWD. Yeah buddy.

I too would find it real hard to part with $118K for a modified Cayman . Although, such a Cayman is likely to be a far more capable track car than a comparably priced Turbo. I guess it comes down to different strokes for different folks. You guys need to stop being such cheap skates...... Man up and get yourself a Sudio Torino RK Coupe for about $250K. http://www.autoblog.com/2006/08/18/studiotorino-unveils-cayman-based-rk-coupe/

For less than $200,000 you could get an F430 Ferrari , with a 4.3l V-8 with 480 bhp. Put a Porsche Crest on the hood and no one will no the difference. Oops: This just in: WASHINGTON, D.C. — The federal government may ban sales of Ferrari's bread-and-butter F430 in late 2006 unless the National Highway Traffic Safety Administration grants the company a waiver on airbag requirements. It isn't that the F430's airbags aren't safe — they meet or exceed most NHTSA guidelines. But the F430 lacks sufficient protection for a small number of female occupants who aren't strapped into the correct position in the event of a crash. The same problem applies to child occupants. If the waiver isn't granted, Ferrari will be unable to sell cars built after September 1, 2006.

No, you can't. The engine used in the TTs, GT2s, and GT3s (normally aspirated) are completely different from the new, water-cooled M96/97 motors that are in the new cars, and they don't bolt directly into the new cars because they also have different pick-up points for the engine mounts, and the bolt pattern for the transmissions don't match either. Nor does the turbo stuff bolt directly onto the new motors. The TT, et al motors are based on the older v-bottomed, split-case crankcase used in the 911s from their inception through the 1995-98 993 models. The cases are not water-cooled like the new motors - they are air-cooled (technically oil-cooled) with water-cooled heads. They are also true dry-sump motors with pressure-fed oil and a separate oil tank. They use 13-14 quarts of oil. There's a lot of plumbing to find room for - there's a turbocharger on each side and each has its own intercooler - in the TTs the intercoolers and associated plumbing, including the waste gates are in the rear fenders - hence the air scoops in the top of each side's rear fenders. You'd also need to find room for the oil coolers, oil tank and associated plumbing, too. And, oh yeah, a way to dissipate all that heat. brad

What about the CS's balance? Won't putting in a larger block significantly disrupt the balance of the CS? It seems that to tune this car the way it has been suggested, requires not only a larger engine, but a rework of the suspension also. The price is going to be much closer to the $120K suggested for sure. :crazy: If you want more HP, why not use the turbo charge kit that was mentioned in a previous post?

Orbit racing will put a new 997S motor in a 987 for 20K and an X-51 for 5k more.:dance:

If someone picked up a Cayman for 55 and put 25 into it, 80 grand, less than a lot of 911 's!

Orbit reference Hi If I was in the US I would use Roger at Orbit to do the 3.8 conversion for a Cayman. He is a Porsche purist and comes highly recommended by his peers. PM me for further information. Cheers Herman

Farhnbacher Loles in CT did my conversion. They also have an excellent reputation and I am very happy with the results.

Hi Cayman in CT Do you have a 3.8s or X51? Can you show us picture of your 3.8? Do you have any performance figures? Cheers Herman

Cayman Mods Herman, I do not do any further work for Orbit Racing in conversions or modifications. Scott SLauson

1. What, in layman terms, is the X-51 kit? (I know it adds 30 or so hp to a M97 engine ). 2. Is such a kit available for the CS? 3. If not, any rumors that such a kit may become available for a CS? Be kind - I'm not a techy.

1. Carbon fibre air cleaner housing, larger throttle bodies, cylinder head and exhaust mods, a sports exhaust system, reprogrammed ECU and optimized air flow. 2. No 3. Rumours are that when hell freezes over Porsche will make one for the CS