Any differences between early and late 3.6 engines (and e-gas)?

I’ve recently done a lot of driving in two seemingly identical 996.2s. It’s hard to be sure, but one seems to sound better: maybe a bit louder, with a more pronounced flat-6 bark (probably especially when opening the throttle half way somewhere near 4000 rpm – but again, hard to be sure). I'm also wondering if what I perceive as a sound difference might be a more sensitive throttle on the car which seems to sound better, so that it more suddenly opens it's throat and changes its tune. Whatever it is that I'm noticing, it makes me wonder if one of the engines doesn’t have a problem. So I’m very interested in knowing if there are any differences between ’02 model year engines and ’05 model year engines that could account for this. (I know the ‘05s have a different RMS and IMS – not sure if that could have any effect.) (The only other difference I know of between the cars is that the one that seems to sound better has the optional Porsche/Tequipement quad tips – I started a different thread to ask about this.) Thanks for any insight into this!

I didn't think there were any M96 powered 996s made for model year 2005 - just turbos and GT3's. I don't believe there were any changes in the 3.6 M96. Maybe one of them had some exhaust mods.

Look like they changed engine ID codes with some years, I'm sure Raby knows what changes were done between years with MY 05 but I have one of the 600 or so 996 C4S built alone with Turbo's and GT3's for the 2005 model year.

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Never mind.

Well, I stand corrected. Good info, TAXFREE.

The 02-04 used an M96.03, but there's an early and late version of this. The AOS plumbing changed, and so did the cam sensors, but nothing internally. While I have seen some very early 997 models (so early they had a full 996 interior) with an M96.03, the proper engine for a non S 997 in 2005 is an M96.05. Secondary air plumbing, front console, and AOS did change between these.

It appears that 03, 04, and 05 had a very slight power increase over the 02... EXPLANATION OF ENGINE NUMBERS ============================= DIGIT: 1 2 3 4 5 6 7 8 EXAMPLE: 6 6 W 0 0 1 3 6 = = = ========= ! ! ! ! ENGINE TYPE (6 = 6-CYL.-ENGINE)-----------------------+ ! ! ! ! ! ! ENGINE VERSION ----------- --------------------------- + ! ! ! ! MODEL YEAR -----------------------------------------------+ ! ! SERIAL NUMBER ------------ --------------------------------------+ ENGINE VEHICLE TYPE TYPE MY ENGINE NO. TECHNICAL DATA 911 CARRERA M96.01 98 W 66W 00501>60000 6ZYL/3,4L /220 KW 911 CARRERA M96.01 99 X 66X 00501>60000 6ZYL/3,4L /220 KW 911 CARRERA +M620 C4 M96.02 99 X 68X 00501>60000 6ZYL/3,4L /220 KW 911 CARRERA 2/4 M96.04 00 Y 66Y 00501>60000 6ZYL/3,4L /220 KW 911 CARRERA 2/4 M96.04 01 1 661 00501>60000 6ZYL/3,4L /220 KW 911 CARRERA 2/4/4S FL M96.03 02 2 662 00501>60000 6ZYL/3,6L /232 KW 911 CARRERA 2/4/4S FL M96.03 03 3 663 00501>60000 6ZYL/3,6L /235 KW 911 CARRERA 2/4/4S FL M96.03 04 4 664 00501>60000 6ZYL/3,6L /235 KW 911 CARRERA 2/4/4S FL M96.03 05 5 665 00501>60000 6ZYL/3,6L /235 KW

Those power increases did not come from the internals... Doing that would have cost money. The internals on all M96.03 engines are the same.

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So would the later engines (therefore) sound different? Would they have a bit more pronounced flat-6 bark when accelerating, and be a bit bassier at low revs (these seem to be the differences I'm hearing between the two cars - but it's hard to say exactly). Also, would the cam sensor change have any impact on how the variocam functions and the engine performs, or is the difference something like better fault detection, more reliable or cheaper sensor, etc.? Thanks!

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No, when I perform dyno comparisons on these cars, for before and after evaluations for our preventative procedures (IMS Retrofit, etc) the cars will all make the same power, no matter if they are an 02, or an 04. The differences are not even measurable, despite what the factory rated them at in flywheel HP numbers. I drive about 100 of these cars a year, and these are driven at least 50 miles after we perform repair work, or even reconstructed engines (I drive those around 200 miles each before they ship home) and some cars are just faster, and sound different than others, even in bone stock form. This is always the case, some cars are just stronger than others, and drive differently, no matter what the dyno says. As to the cam sensors, the PET lists both sensors for the M96.03, and they both scope the same, and interchange, so it is a mystery why they were changed. The only difference is one sensor (the later one) has a plastic shroud that covers the entire magnetic tip of the sensor, where the earlier version is open. It appears this was done to keep engine oil out of the sensor better than before, but thats not conclusive.

It may have the sport exhaust. I have it on my 99 996 and it sounds great!

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Alas, no. Still sounds good, but not that good.

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Is your source by chance that giant .pdf Porsche parts catalog (the PET?)? I saw the same thing near the very end of that document a while back. But then I looked at the technical papers for my '02, and it says 235 kw (320 hp), not 232 kw (316 hp). And when the car was introduced in '01, all the reviews said it had 320 hp (235kw). Except the UK reviews, which said it has 316 bhp. But 316 bhp = 320 ps (German/metric hp - which is what people usually mean when they say hp (outside of the UK of course)). And 320 ps/hp = 235 kw. So my guess is that someone at some point confused bhp and hp/ps and got the conversion to kw wrong for 2002. I'd also take your source with a grain of salt because it shows that all 3.4 liter 996s have the same power, but unless I'm badly mistaken, they started with 296 hp and later increased to 300 hp. (Or perhaps there was another bhp/ps error??) While it doesn't really matter, I'm nonetheless curious. So if anyone knows the definitive answer, it would be interesting to hear.

Here is the source of that info: http://www.porscheclubgb.org/clientf...sion_codes.pdf I am in no way vouching for its authenticity or reliability. I also thought all the Gen II 996's (MY 02 to 04) had the same engine power output so was surprised to see any different numbers quoted.

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Hi Jake, Not so relevant to my question, I know, but I can't help but be curious - how much power is it that they all make? And does it vary much with the weather? Thanks!