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IMS 996 question for the Illuminati.


Jason E
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Interesting comments on the for and against res delete. I haven't noticed any drop in performance since doing it and the sound difference is negligible. I've only used the old old cap in the resonator and left the rest stock.

I'll keep an eye on it. New mufflers may be the go so I can keep the originals as they're in great conditions still.

New mufflers are pretty XXy...about $3K, so it's a more considered mod compared to the Gundo/Fister mod.

I've been looking at these: https://www.sparesbox.com.au/part/milltek-rear-silencers-2-5-inch-ssxpo019-fits-porsche-911-996-carrera-carrera-s-ssxpo019?gclid=Cj0KCQiAuP-OBhDqARIsAD4XHpduo4TQMQNAgKQAsf_gaiC-ObX15YE7NQatM7rUOVywp2X5W44gskkaAiMXEALw_wcB

A bit confusing though as the description says to fit 996, but then when I go to check whether it fits my car it says no.

I know the Millteks are supposed to sound really nice.

 

Edited by RobCarrera
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Hi RobCarrera, Fantastic looking car and congrats. A couple of weeks ago - I bought my first Porsche - a Boxster 987.1 that is smack bang in the middle of the IMS of doom range. I'm not particularly concerned by it to be honest. I think the issue is quite a bit overblown, so I have adopted some others way of dealing with it, namely, "be alert but not alarmed". The car is only new to me, but seems to be in great condition. I plan to just ensure the oil filter is replaced inspected quite often and maybe deal with the IMS if we see any early signs or it somehow is bothering me and maybe get it done if additional work needs doing too.

I also think the IMS "hysteria" is probably what's allowed me to buy in to Porsche so in a way, I'm a little thankful for it, just like for some people the "ugly fried egg" headlights have helped others too.

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Thanks Sabotage. Congratulations to yourself as well, I can guaranty it won't be your last, they really get under your skin like no other car.

I think it the model that you own often dictates the level of hysteria/paranoia. The more you dig into it the worse it can get. I bought the car I did purely based on it's condition. I knew that it needed all of the big dollar maintenance items in the next two/three years and it's the model that has the single-row IMS bearing the highest failure rates. It also had all of the things that often precede an IMS failure...low Ks, not driven regularly or hard enough. The previous owner basically just changed fluids a set of tyres and a water pump in the 12 years he owned it. However, I was able to negotiate a better price once I'd pointed out all of these things. 

The 987.1, if I'm not mistaken has the non-serviceable IMS that requires the crankcase to be opened up to be changed. These double-row bearings are pretty good and most Techs recommend not changing them. I think the fix is to remove the seal at the back of it so it gets better oiling from the engine. was told by the guys at PRT who had serviced a 987.1 Cayman S I looked at before buying the 996.

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13 minutes ago, RobCarrera said:

Thanks Sabotage. Congratulations to yourself as well, I can guaranty it won't be your last, they really get under your skin like no other car.

I think it the model that you own often dictates the level of hysteria/paranoia. The more you dig into it the worse it can get. I bought the car I did purely based on it's condition. I knew that it needed all of the big dollar maintenance items in the next two/three years and it's the model that has the single-row IMS bearing the highest failure rates. It also had all of the things that often precede an IMS failure...low Ks, not driven regularly or hard enough. The previous owner basically just changed fluids a set of tyres and a water pump in the 12 years he owned it. However, I was able to negotiate a better price once I'd pointed out all of these things. 

The 987.1, if I'm not mistaken has the non-serviceable IMS that requires the crankcase to be opened up to be changed. These double-row bearings are pretty good and most Techs recommend not changing them. I think the fix is to remove the seal at the back of it so it gets better oiling from the engine. was told by the guys at PRT who had serviced a 987.1 Cayman S I looked at before buying the 996.

Yeah - I think that's half the problem - the more you dig the more you find that can scare us. I don't think anyway is necessarily the wrong way, but we will all have to live with any consequences of our decisions. Good luck with your journey and please keep us all updated on how you go.

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5 hours ago, RobCarrera said:

Thanks so much for that Jim45!!

I think that's made my mind up, I think I'll stick with the 'Plan A' and get Paul to do the work.

I've done the airbox mod with the oil cap in the resonator inlet, it made a tiny difference to induction noise above 4krpm. Is it better to replace the hose and add the cap over the top of the resonator? 

Not sure tbh - think they all aim to achieve the same goal. Mine has the hose and cap like the clip I posted. And also Cargraphic mufflers which is probably 95% of the improved sound! I also removed quad tips from the car and replaced with after market dual ones and i think it sounds different again. I think i prefer how the quads sound but don't like how they look! From all the reading / you tube clips the Gundo / Fister mod looks like a great start for more sound. I thought about doing it to my Cargraphic mufflers!

Was interesting to read about why "not" to do the air cap mod. I've also read that after market solid engine mounts cause knock sensor issue but didn't go too far down that rabbit hole.

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Congrats - lovely looking car!

FWIW I have a receipt from the previous owner for $4500 when he went with the oil-fed "solution" product. 

I'll offer a couple of observations - if you think the IMS thing has been done to death, don't go down the M96 bore-scoring rabbit hole ;) You'll never get any sleep! 

The muffler outlets definitely differ between the Carrera and the C4S - it's because of the differing bumper designs.  The original exhaust is adjustable, but some aftermarket units are welded to Carrera and C4S/Turbo spec respectively.

Lastly, another rabbit hole (and I don't want to start anything!) but Porsche's original Mobil 1 0w50 spec seems to have been superceded through 20 years of independent maintenance... Pretty much all the independents recommend a thicker 5w or even 10w oil to protect these engines long-term in hot weather.  Mobil 1 has 5w50 if you must have Mobil.  I'm running Castrol Edge 5w50 A40 Porsche spec.

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So many rabbit holes!!!!

I'm pretty sure the oil used in the service I got done was Castrol Edge, I'd have to double-check though. From what I understand the 3.4 M96 has very few instances of bore scoring.

And then there's the chain tentioners....Oh, I think I need a beer now!!

I love Lee Sibbs analogy...most people think that the M96 is made of chocolate!

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I went through the exact same thing when I bought my 996.1 with about the same k’s as yours six years ago. You will eventually stop worrying and come to realize the 3.4’s are much more robust than you’ve been led to believe. 

The likelihood is that your car being a revvy 3,4 manual has been driven as designed from new and maintained appropriately with regular oil changes. If so, your original dual row IMS bearing when it comes out will more than likely feel like a new one, and your camshaft deviations will be within spec.

The AOS is much more likely to need replacing if it hasn’t been already, tricky job but DIY-able and not an expensive part. Your RMS may be a bit misty/weepy, sure replace it if you’re in there but otherwise who cares? Your DMF might be out of spec..mine was, does the new one feel any different? Not really. Your coil packs might have a few cracks but likely not causing issues, few dabs of high temp silicone sorts that out. Your bump stops will likely be perished and your engine mounts a bit ‘compact’. Easy, cheap, fixes. 

Spend a lot, spend a little, likely the car will pretty much feel the same. Best preventative maintenance advice for a 996 is; change the oil regularly, drive it regularly, and drive it properly,. In other words the most important maintenance with a 996 is ENJOY IT!!

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Yep, I completely understand. I've gone into this with open eyes and prepared to do as little or much as it takes, as this car is going to need a new clutch in the next 5-10k kms I may as well get it all done at once. But the premise is to enjoy driving this thing as much as possible.

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Not sure about the later Porsche model used car markets that don't have the potential IMS thing, but in the used Boxster market at least, the price difference for a 987.1 vs 987.2 seems to be about the same for a full engine replacement or at least rebuild if it ever happened. The later 981 used Boxster's are way too high, in my opinion. I know there were other improvements with the cars with the new engines, but if you want to experience a Porsche and are not concerned about future resale prices, the "IMS engine" Porsche's are almost laughably cheap due to people's panic over them. I look at it almost like investing. I think the worst case model failure rate is 10%. That means you have a 90% chance of Winning. If I knew before hand with my investments, that I had a 90% chance of winning, I'd be laughing! Irrational markets provide bargains for the brave!

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On the IMS front, I pulled the bearings from both my '98 911 and '98 Boxster both with well over 100k kms and they were both perfect. Those are both of course double row bearings. 

As for 996 mufflers. I absolutely believe the gundo hack is by far the best exhaust mod for the 996. All of the aftermarket ones I have heard end up being too loud and drone on the highway and drive you mad. Gundo gives you a great sound when you are on it and still perfect and comfortable on the long trips. Also it is by far and away the cheapest way to get it sounding good. It is basically the exact thing that Porsche did on the 997 with the switchable sports exhaust.

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3 hours ago, MFX said:

On the IMS front, I pulled the bearings from both my '98 911 and '98 Boxster both with well over 100k kms and they were both perfect. Those are both of course double row bearings. 

As for 996 mufflers. I absolutely believe the gundo hack is by far the best exhaust mod for the 996. All of the aftermarket ones I have heard end up being too loud and drone on the highway and drive you mad. Gundo gives you a great sound when you are on it and still perfect and comfortable on the long trips. Also it is by far and away the cheapest way to get it sounding good. It is basically the exact thing that Porsche did on the 997 with the switchable sports exhaust.

While Gundo exhaust modification is undoubtedly good for both noise and for your bank balance, it is not in my experience a universal truism that aftermarket exhausts drone on the highway.

I have a Gemballa exhaust and a cold air intake (zero performance improvement but an addictive throaty induction roar!!) on my 996 and it is reasonably loud, albeit not obnoxious, when you rev it or even better when you run through a tunnel in a low gear with the windows down the noise is intoxicating. 

However on the highway with cruise control on, it rolls along with barely a murmur (I mean it's not Lexus quiet but its a sportscar) and the tyre noise is more noticeable then the exhaust, similarly I can leave my garage early in the morning without waking up the entire neighbourhood!! 

It is an entirely pleasant place to be for long distance driving, but when you arrive at your destination and some twisties appear and you decide to get up it, the docile noise quickly disappears and it fires up with a satisfying bark to assuage your adrenaline requirements.

However, I cannot imagine a full Gemballa exhaust system was cheap and the Gundo hack is vastly better value!!  I know someone who bought a full Sharkwerks system for his car, and similarly while that system was very loud at high revs it was not unpleasant for long distance drives and did not drone or make your ears bleed on the highway :).

Respectfully a well designed sports exhaust system is also an entirely reasonable option from an aural perspective, if perhaps (definitely? :)) not a financial one, and is not necessarily unpleasant to live with on a daily basis.  You do however need to select one that makes sounds you can live with in all situations, not simply one that sounds fantastic when driving fast, and unfortunately that is in my experience an expensive option.

 

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My experience with a Cargraphic Sound exhaust is similar to Carrera28’s. It’s pleasant to drive on the freeway for long distances, doesn’t drone, will relatively quietly pootle along in traffic and doesn’t blow the neighbours windows out in the morning.

However give it some beans over 4000rpm and row between 2nd and 3rd on your favourite road and combined with the intake the car is totally transformed. Like a lion and a cheetah are having an argument in the back seat. I open both windows and the sunroof for the full aural experience. It’s very addictive, and soooo much more enjoyably sonorous and characterful than the horrible, deafening farts of a lot of modern modded offerings.

Bonus with a good aftermarket is you may find a nice little bump in hp. 10ps with the Cargraphic and apparently a few kg lighter too.

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On 14/01/2022 at 18:16, Fishcop said:

Congrats - lovely looking car!

The muffler outlets definitely differ between the Carrera and the C4S - it's because of the differing bumper designs.  The original exhaust is adjustable, but some aftermarket units are welded to Carrera and C4S/Turbo spec respectively.

Lastly, another rabbit hole (and I don't want to start anything!) but Porsche's original Mobil 1 0w50 spec seems to have been superceded through 20 years of independent maintenance... Pretty much all the independents recommend a thicker 5w or even 10w oil to protect these engines long-term in hot weather.  Mobil 1 has 5w50 if you must have Mobil.  I'm running Castrol Edge 5w50 A40 Porsche spec.

Agree, congrats on the car.

The outlets between a C4S and a narrow body Carrera definitely differ. I have the IPE full system (extractors, cats, cross over pipe, mufflers & tips) on mine with the variable sports exhaust and the original tips woudl not fit as they were for the narrow body. I have the original  C4S tips on it now and the quad tips aside for a rainy day.

The resonator mod on the intake is an interesting one. Fitted the Samco hose and cap to the 996 airbox and a small difference, however I found a 997 airbox for a decent price and fitted that instead (as well as an 82mm throttle body). The rumour is they flow much better so a little more power (maybe) however I noticed more of a sound difference with it than the cap modification.

Oil is always an interesting one. I ran 5W40 Liqui Moly originally and am now running 5W50 for summer on advice from a Porsche mechanic. seems OK but will know after next oil change.

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