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In trying to reconcile a buy decision of the 2.7L vs. the 3.4L engine...as an engineer I've been considering the DNA of these 2 engines as a factor from a longevity perspective.

From what I currently know the 3.4L engine (A91 designation?) is used both in the 991 and the 981. In the 991 tune is produces 350hp and 325hp for the 981. So from that perspective the 3.4L in the 981 is somewhat 'detuned' and therfore not as 'tweeked'.

I know next to nothing about the 2.7L engine. Is it a relatively new engine and therfore not as 'mature' as the 3.4L? Is it only used in the base Cayman? I recall that I read in one post that it was claimed that the 2.7L is highly 'tweeked' for its displacement and therefore is this engine 'stressed' more than the 3.4L engine?

Thanks for all responses
 

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Re: Cayman 2.7L vs 3.4L Engines

In trying to reconcile a buy decision of the 2.7L vs. the 3.4L engine...as an engineer I've been considering the DNA of these 2 engines as a factor from a longevity perspective.

From what I currently know the 3.4L engine (A91 designation?) is used both in the 991 and the 981. In the 991 tune is produces 350hp and 325hp for the 981. So from that perspective the 3.4L in the 981 is somewhat 'detuned' and therfore not as 'tweeked'.

I know next to nothing about the 2.7L engine. Is it a relatively new engine and therfore not as 'mature' as the 3.4L? Is it only used in the base Cayman? I recall that I read in one post that it was claimed that the 2.7L is highly 'tweeked' for its displacement and therefore is this engine 'stressed' more than the 3.4L engine?

Thanks for all responses

Though not practicing, I too come from an engineering background and I'll give you my opinion.

I think you're over-analyzing the engines. They're both great engines, both will hold up to whatever you throw at them and both have a niche.

The 3.4 is more torquey and does have more power, the 2.7 likes to run in the upper rpms's.

Simple enough, do you feel you need the extra HP given by the 3.4?

I look at it as a practical, daily aspect. I like to be able to pass a car by simply depressing the gas pedal and not having to downshift to get around someone.

To me, that's the biggest advantage... a bit more power.


Mark
 

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Re: Cayman 2.7L vs 3.4L Engines

It's the same base engine, it's just a difference in displacement and some other components such as intake, ECU etc.
All flat sixes from Porsche share the same base engine block.

If you calculate HP per litre, you will find that the 2.7 is more tuned in relation to it's cylinder volume. How that translates to engine behaviour is not an exact science, but it usually means it feels somewhat "sportier" and more in need of high revs to perform. I have yet to drive a 2.7 981, so I can't testify exactly how that translates into driving experience.
 
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Re: Cayman 2.7L vs 3.4L Engines

I am a big fan of the 2.9 engine in my 2012 987 for street driving. So when I went to drive the new 2.7 in the 981 I wanted to see if there were any major improvements?

I found the small loss in torque in the 2.7 noticeable, and did not feel the benefit of the extra 10hp.

As I am sticking with my 987 for now, I'm happy with my high reving 2.9 for the public street. But, if I was going to buy the 981 I'd go with the "S" as the last thing the base car needed was a drop in torque (even just a little) :2cents:

The good news? - unless you are spoiled like I am by having a 2.9 you'd never notice the 2.7's loss of a few pounds of torque ;) The best advice if you want a 981 2.7 car (and not in a big rush) is lease now, and then buy after the mid-model refresh, as I'm sure Porsche will add back that torque and a little more HP in the 981.2
 

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Re: Cayman 2.7L vs 3.4L Engines

Having had both, I can tell you there's a big difference between the two.

The 2.7 needs to be rung out to go fast. The 3.4 doesn't.

So wouldn't it really depend on your personal driving style? I think that (and proper maintenance) has more to do with longevity than anything.
 

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Re: Cayman 2.7L vs 3.4L Engines

As mentioned by other members before, both the 2.7 base and 3.4S engines share the basic block and design.

The write-up below is adapted from my earlier post in Nov 2012:

The 2.7 H6 of the base Cayman is an over-square (bore>stroke) design, and we can expect it to be high reving but not particularly torquey. Hence delivering its max power at 7,400 rpm (vs 6,700 rpm for the 2.9) is consistent with our expectation. Pumping out almost 102 hp per litre, we can't really ask for much more for the price.

I read elsewhere that Porsche had also lightened some moving parts of the 9A1 engines to allow higher rpm.

The 3.4 H6 of the new Cayman S is slightly less over-square than the 2.7 H6 of the base Cayman, so it delivers a max power of 'only' 94.5 hp per litre. Of course, everyone knows it is easy to 'find' an extra 10 - 15 hp if Porsche really wants to.

Please note that the 2.7 H6 of the 987.1 had a smaller bore of 85.5mm (vs 89mm for the 981) and a longer stroke of 78mm (vs 72.5mm for the 982), rendering it a much less over-square design. The 2.7 H6 of the 981 is a different design from that of the 987.1, even though both displace about 2.7 litres.

Observation of the 'new' 2.7 H6 of the 981:

(1) The 2.7 H6 of the 981 seems to be a de-stroked version of the old 2.9 H6 of the 987.2, because they share a similar bore but have different strokes, and both belong to the 9A1 engine family.

(2) Assuming both the base 981 and 981S have similar air pumbling, the 2.7 H6 should be relatively less restricted in breathing air in and out than the 3.4 H6. Therefore, it is logical for Porsche to take advantage of the 'plentiful' airflow and install a high rev design engine in the base Cayman.

(3) Since both the 2.7 H6 and 3.4 H6 share the same engine block, the 2.7 H6 engine should be stiffer than the 3.4 H6 and the moving mass lighter (lighter piston, etc), allowing higher rev operation without penalty in harshness and vibration.

(4) The useable power of the new 2.7 H6 is not just 10 bp more than the old 2.9 H6. Because there is less parasitic loss from the power steering and lower drag from charging the alternator (during acceleration), not to mention 20kg of weight reduction.

http://www.planet-9.com/981-chat/76325-10-bhp-exa-base-cayman.html#
 

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Re: Cayman 2.7L vs 3.4L Engines

I am a big fan of the 2.9 engine in my 2012 987 for street driving. So when I went to drive the new 2.7 in the 981 I wanted to see if there were any major improvements?

I found the small loss in torque in the 2.7 noticeable, and did not feel the benefit of the extra 10hp.

As I am sticking with my 987 for now, I'm happy with my high reving 2.9 for the public street. But, if I was going to buy the 981 I'd go with the "S" as the last thing the base car needed was a drop in torque (even just a little) :2cents:

The good news? - unless you are spoiled like I am by having a 2.9 you'd never notice the 2.7's loss of a few pounds of torque ;) The best advice if you want a 981 2.7 car (and not in a big rush) is lease now, and then buy after the mid-model refresh, as I'm sure Porsche will add back that torque and a little more HP in the 981.2
Thanks, that's good to know. I am getting ready to order a 981 and I have been going back and forth between a "base" and an "S". The original 2.7 on the first generation Cayman had a lot of torque . . . as does the 2.7. Maybe I need to get an "S" when the time comes to get a 981.
 

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Re: Cayman 2.7L vs 3.4L Engines

Lest I take the chance of being called a "marketing guy" I will say that "it depends".

What percentage of the time will you be driving at the engine's peak horsepower output level?

How much peak horsepower does most of your driving require?

Will you be racing the car in 24 hour events where the car will live at the redline?

I had a 2.7 liter 2007 Cayman and with a rating of 245HP (peak) it had plenty of power for a 3100 pound car. My 5000 pound minivan has same 245 HP and we never feel like we are pushing it.

Any engine in any Porsche can be beaten to death.

Of course, all things being equal...all things are never equal.
 

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Re: Cayman 2.7L vs 3.4L Engines

In trying to reconcile a buy decision of the 2.7L vs. the 3.4L engine...as an engineer I've been considering the DNA of these 2 engines as a factor from a longevity perspective.

From what I currently know the 3.4L engine (A91 designation?) is used both in the 991 and the 981. In the 991 tune is produces 350hp and 325hp for the 981. So from that perspective the 3.4L in the 981 is somewhat 'detuned' and therfore not as 'tweeked'.

I know next to nothing about the 2.7L engine. Is it a relatively new engine and therfore not as 'mature' as the 3.4L? Is it only used in the base Cayman? I recall that I read in one post that it was claimed that the 2.7L is highly 'tweeked' for its displacement and therefore is this engine 'stressed' more than the 3.4L engine?

Thanks for all responses
All I know, besides fairly superficial stuff about these flat six engines, is that the 3.4 in my car feels very strong even at low rpm whereas the smaller engine felt a little weak off the line (when I drove the base Boxster). Both sounded very similar during the test drive. In the end, I decided to splurge and buy the bigger motor. I love it. :)
Check out the gearing in the two engines. Mine revs at a little over 3000 rpm at 75 mph in sixth. If the gearing is shorter in the smaller motor, I think minimally, fuel economy will be adversely affected. The shift indicator in my car is a killjoy and asks for early upshifts. I disabled it but it was mysteriously back on again during my morning commute. Plus the mirrors had reset themselves to a different position. Strange.
 
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Re: Cayman 2.7L vs 3.4L Engines

All I know, besides fairly superficial stuff about these flat six engines, is that the 3.4 in my car feels very strong even at low rpm whereas the smaller engine felt a little weak off the line (when I drove the base Boxster). Both sounded very similar during the test drive. In the end, I decided to splurge and buy the bigger motor. I love it. :)
Check out the gearing in the two engines. Mine revs at a little over 3000 rpm at 75 mph in sixth. If the gearing is shorter in the smaller motor, I think minimally, fuel economy will be adversely affected. The shift indicator in my car is a killjoy and asks for early upshifts. I disabled it but it was mysteriously back on again during my morning commute. Plus the mirrors had reset themselves to a different position. Strange.
I have to laugh (not at you) when you talk about "fuel economy". Made me think of something. Before I bought a vette, I expressed my concern to my younger brother that I may be making a mistake buying such a gas hog. He said, "people who buy those cars don't care about gas". I think he had a point. I owned that car for 3 years and never agonized over the gas. Every drop was worth it. Fast forward to present - we had good weather last Sunday so I took a 100 mile drive with one of my sons along "River Road" in Buck's County where I live. It is a road that runs for several miles in parallel with the Delaware River and is twisty and just a scenic blast to drive. During the drive I kept it in 3rd gear at about 4,000 to 4,500 RPM and it just screamed. Using this technique, I had the engine available at all times to help brake the car if needed. Driving like this (spirited but not speeding) is surely not in the "fuel economy" range (I could have been driving in 6th gear I guess) but these engines are made to be driven at high RPM and that's the fun factor for me and why I bought this car. Even driving the car this way, my gas gauge does not exactly plunge.
 

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Re: Cayman 2.7L vs 3.4L Engines

Sorry for the OT, but that River Road drive is terrific.
 

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Re: Cayman 2.7L vs 3.4L Engines

Agree with DaveN007........in support of his comments, I had a 295 hp 08 Cayman S 6MT, I had a Cayman R 330 hp 6MT, I now drive a 981 Cayman 2.7 with PDK. I can tell you that in Sport mode, I have no problem with driving around in or out of traffic. I regularly leave most cars far behind starting up with just reasonable (i.e., not mash the throttle) acceleration. While I did not buy for fuel mileage for sure, I can tell you that even the 2.7L with PDK turns about 800 RPM less at 70 than either my S or R did and accelerates with spirit when I want to pass. I do not question nor dispute those who feel the need for the 3.4......I am just surprised at how totally satisfied/happy I am driving my 2.7.
 

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Re: Cayman 2.7L vs 3.4L Engines

{snips} . . . . I had a 2.7 liter 2007 Cayman and with a rating of 245HP (peak) . . . . .
Just to be clear, here and in another reply to the OP's question on Base vs. the 3.4L "S" are there any 2006 - 2012 2.7L engines: or are we talking the '06 to ?? 2012 MY non-DFI 2.9L?

It's been my understanding the 987 base cars, from 2006 to, thru and including 2012, all got 2.9L fuel injected, but NOT DFI motors. With the new 981 chassis, the 981 base cars got a new 2.7L motor, down on displacement, but up in power over the 2.9 due to the base model engine also now getting DFI and all the improvements, i.e. higher compression ratio, better A/F and burn metering, and possible head aches, i.e. the carbon build ups reported in some (i.e. Audi V8's) engines, that the DFI technology brings to the plate.

PS - one other consideration, at least in our neck of the woods, is altitude. Where I and the car spend most of our time driving we already start out down @ 18-20% on power, which generally only gets worse if one heads into the mountains, or runs track days in the heat of the summer. Makes the 3.4L into a 2.7/2.9, so I'd be reluctant to downsize to the smaller displacement engine. If your driving takes you over mountain passes and into a lot of tall hills, . . . . . the extra 0.7 liters might be beneficial.
 
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Re: Cayman 2.7L vs 3.4L Engines

Though not practicing, I too come from an engineering background and I'll give you my opinion.

I think you're over-analyzing the engines. They're both great engines, both will hold up to whatever you throw at them and both have a niche.

The 3.4 is more torquey and does have more power, the 2.7 likes to run in the upper rpms's.

Simple enough, do you feel you need the extra HP given by the 3.4?

I look at it as a practical, daily aspect. I like to be able to pass a car by simply depressing the gas pedal and not having to downshift to get around someone.

To me, that's the biggest advantage... a bit more power.


Mark
Agree 100%
 

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Re: Cayman 2.7L vs 3.4L Engines

mipor said:
It's been my understanding the 987 base cars, from 2006 to, thru and including 2012, all got 2.9L fuel injected, but NOT DFI motors. With the new 981 chassis, the 981 base cars got a new 2.7L motor, down on displacement, but up in power over the 2.9 due to the base model engine also now getting DFI and all the improvements, i.e. higher compression ratio, better A/F and burn metering, and possible head aches, i.e. the carbon build ups reported in some (i.e. Audi V8's) engines, that the DFI technology brings to the plate.
[/QUOTE]

All 981 engines are DFI, so your concerns about DFI in the 2.7 apply to the 3.4 as well. If anything I'd expect the last engine to get the upgrade to get the most updated (least problematic) system.
I agree with your comments about hp. Just depends on your needs and wants. :)
 

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Re: Cayman 2.7L vs 3.4L Engines

The shift indicator in my car is a killjoy and asks for early upshifts. I disabled it but it was mysteriously back on again during my morning commute. Plus the mirrors had reset themselves to a different position. Strange.
Is it possible you used a different key? Some of these settings are key dependent. Not sure about the up-shift indicator. I just always ignore it.
 

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Re: Cayman 2.7L vs 3.4L Engines

It's entirely subjective... I drove a 2.7 as a courtesy car and was massively impressed at how much more you could 'use it'. I was pushing the tail out at every opportunity and loving the howl. My 3.4 did feel more muscular when I picked it up but it did make me think, I never push my car as hard as I pushed that 2.7 but that maybe because it was simply not mine! I still found it a very enjoyable motor whatever the reason.
 

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Re: Cayman 2.7L vs 3.4L Engines

It's entirely subjective... I drove a 2.7 as a courtesy car and was massively impressed at how much more you could 'use it'. I was pushing the tail out at every opportunity and loving the howl. My 3.4 did feel more muscular when I picked it up but it did make me think, I never push my car as hard as I pushed that 2.7 but that maybe because it was simply not mine! I still found it a very enjoyable motor whatever the reason.
This is an interesting/intriguing comment. Which transmission did it have, and which do you have in your S? Thank you!
 

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Re: Cayman 2.7L vs 3.4L Engines

It's entirely subjective... I drove a 2.7 as a courtesy car and was massively impressed at how much more you could 'use it'. I was pushing the tail out at every opportunity and loving the howl. My 3.4 did feel more muscular when I picked it up but it did make me think, I never push my car as hard as I pushed that 2.7 but that maybe because it was simply not mine! I still found it a very enjoyable motor whatever the reason.
The power of the 2.7 is much more useable in the sense that you can push it so much more. I think people dismiss the engine bc the power figure is less, but when you are in the car and hear the engine, you don't notice.



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