I’ve started this thread so that we can discuss the ‘soon-to-be-released’ Softronic Race Plenum modification (or SRP for short ). This would appear to be one of if not ‘the’ most highly anticipated and considered modification available to Cayman S owners out there today. I also thought that by starting the thread I could keep this top posting updated in a FAQ format to allow quick answers to most people’s questions (as we learn them).


I’d like us to really discuss and share all ideas and questions, both the positives and the if they exist the not so positives. I hope (and expect) that this modification will be a huge success and provide all Cayman owners (and yes, I own one too) the bump in power you might be looking for but let’s begin by getting a balanced list of risks and rewards so potential customers can understand what they get for their money.

Please help add to the following list of good potential Frequently Asked Questions;
(*Credit and thanks to Gator Bite on many if not most of the answers below. His original replies can be found lower in the thread).

**Note, the following are only questions and wherever possible the best answers available I could find. They are not all FACTS, some or simply my or other members opinions.

Q: What exactly is the Softronic Race Plenum upgrade and who is Softronic?
A: The best answer to this is presented below by Gator Bite but essentially it is a combination of an aftermarket ECU software flash offered by Softronic (modifies your engine management computer) with a few Porsche parts made originally for the 3.8 liter Carrera S that are also compatible with the Cayman S engine.
Q: When will it be available and how do I order it?A: Full product release has yet to be announced but is expected very soon. Check the Softronic website directly to stay up to date. There was a “pre-order’ option on the forum (The List)_but that’s been closed here, it’s probably still an option if you contact Softronic directly.
Q: How exactly and by how much does it increase power?A: It’s really just a Jedi Mind Trick. Actually I’m looking for the best explanation to post here, will update soon. Gator Bites post below does a pretty good job.
Q: Where is the power on the curve? Are there dynos?
A: Yes, there will likely be many posted on the forum in the next few week but here is the first ones from Softronic - Softronic Race Plenum
Q: Will it void my warranty?
A: Technically it should not void your warranty due to the Magnuson Moss Warranty act however it is possible for a manufacturer to deny a warranty claim if they feel an alteration has caused a failure, and in a case like this you will have a hard time battling an auto manufacturer that has very deep pockets. Remember the authoritative source is your Warranty Manual from Porsche.
Q: What aspects of the car if any might be impacted by adding the extra power?
A: The general consensus is that Porsche over engineers their products and adding the claimed HP shouldn’t put any one component anywhere near its limits. That said if you add 10% more load, heat, pressure… you’ll probably accelerate your normal age and wear by a similar amount. Only time and reports by the user community will help us more fully understand any impacts but again the majority of opinions suggest its low risk.
Q: Does it affect emission laws?
A: I want to say I read a post by the vendor who said “no” it doesn’t but we’ll need to verify that.
Q: Does it affect fuel economy?
A: As Gator Bite points out, if you want more power, you spend more on making it. It would be nice if those who are about to perform the mod would track some MPG numbers pre- and –post mod to share with us.
Q: Does it work well with other modifications?
A: It should not affect most other mods unless those also change the ECU or affect the plenum.
Q: Can I install it or do I need a mechanic?
A: We’ll wait until someone has done it and hopefully shared back on the difficulty.
Q: How long does an install take?
A: Same as the above but I’d like to suggest we all share the time both for DIY and also dealerships/mechanics so we can be empowered with the knowledge if we bring the car in to have it done.
Q: Will it affect the car long term?
A: We won’t really know about any serious impacts until there are several thousand miles on member cars, but the prevailing opinion is that we should not expect any serious impact, only the increased wear of normal parts due to the additional power (and possibly the way you drive when you get that extra power)
Q: Does it change the behavior or drivability of the car?
A: People have looked at the Dyno provided to date and suggested it should absolutely make the car more fun (good mid-range torque increase) and does not appear to have any downside driving behavior. We will anxiously await reports from the field.
Q: If its just Porsche parts, can’t I get them myself and save money?
A: It’s not just Porsche parts. Softronic ECU programming must be used to manage the plenum/air change. It also looks like there are several extra hoses and clamps that Softronic provides to custom fit the race plenum to the standard engine. Let the professionals handle those!
Q: Will I need to add a more free flowing exhaust to handle the increased pressure?
A: Not necessary but would probably further increase the benefits. By how much is unknown at this time.
Q: Are there any other mods that might work against or affect this one?
A: You can’t use another vendors ECU flash programs for sure. At this time I would also assume you can’t use another vendors race plenum setup, or even if any others are available.
Q: Is there a different version for manual versus tiptronic transmissions?
A: No difference at this time.
Q: Does it work with the OEM Sport Chrono option? Does it change anything about it?
A: Yes it works with it and we have been told it doesn’t change anything about it.
Q: How does it compare in power and price to other mods available today?
A: This is what the forum is for, discussing and sharing thoughts on this modification, including comparisons to other competing modifications. So please post and discuss below.
Q: Since this is new are there possibly more improvements to come that I should wait for?
A: Someone will always build a better mouse trap but I’d assume that someone will be Softronic as they improve upon the original software flash and possibly even the custom connecting hoses. If that happens I believe you are covered with free updates for the software and more than likely can pay some fee on the hoses if its really just an upgrade and not a required improvement (like a bad clamp or something).
Q: Does this type of mod affect what auto competitions I can participate in?
A: Yes. Check the rules and regulations of the club or event that you want to participate in. In PCA, any modification will knock you out of the stock class. In SCCA, there are some things you can do before being pushed into the 'improved' class.
Q: Does Chillie even own a Porsche?
A: Yes, I really do. I bought a 2008 Cayman S (Arctic silver, Tiptronic, PASM, Nav) as my daily driver to replace my Audi S4. It had to be ordered (Nov) and arrived in January.

I want to thank Scott for posting the dyno of his SRP.

I would also like to see the results of the dyno Scott says he did on the base Cayman S with just his standard flash and the dyno from when he said he was doing all his testing with a full fabspeed exhaust.

IMO posting those two dynos would give many Cayman Club members with different levels of present or future planned mods some idea of what increases the SRP would produce compared to the increases produced by the standard Softronic flash and the increases that the SRP with additional ehxaust mods would produce.

I'll take a crack at some of these, just to shorten your list, but I can not answer all of them. I am in no way affiliated with Softronic. Most of my knowledge of these topics has been obtained by simply paying attention and reading information posted here at the Cayman Club.

The Softronic plenum package is a combination of hardware and software that replaces the original 'Distribution Pipe' (called Plenum by us) that supplies air to the intake manifold and re-tunes the engine for this modification. More on this after we talk about the hardware.

The entire intake manifold on the Cayman looks like this:



The 'Plenum' (or what Porsche likes to call the 'Distribution Tube') is highlighted here:



If you look closely at those two pictures you will discover that the intake manifold is very sophisticated. There are two electro-mechanically controlled flaps in the intake. This is what Porsche likes to call the '2 Stage Resonant Intake System'. One of the flaps is in the 'Plenum'. It is called the distribution flap and it opens from 3,500-4,900 RPMs, and again from 5,200-7,300 RPMs. By opening and closing this flap, the intake system can act as two small individual intakes, or one large volume intake. By running the engine as two small individual 3 cylinder engines in the low RPM range, the system will deliver more torque. But in the upper RPM range, the engine will benefit from a larger volume intake that runs as a single 6 cylinder engine.

The other flap is called the 'Resonance Flap' and it can be seen here:



The Resonance Flap opens from 4,700-7,200 RPMs. When an intake valve closes, the rushing air compresses and bounces off in the other direction, toward the valve on the other side. This makes high and low pressure points inside the intake. The Resonance Flap's job is to make sure there is a high pressure point at the valve when it's time to open. This helps improve the charging effect of the cylinder. The air resonance and engine speed come into play to calculate the right time for this. It's very sophisticated and my explanation here barely scratches the surface.

Another manufacturer had suggested that changing the stock 'T' type distribution pipe with their 'Y' pipe 'Plenum' would deliver 24 more horsepower (see this thread for more info). This claim ranged from optimistic to down right ridiculous, depending on your subjective interpretation and understanding of how an internal combustion engine works. But interestingly these claims were never questioned and people lined up in droves to spend $1,000 to have one. This product didn't generate 10% of the skepticism that you are showing toward the Softronic package Mr. Chillie.

The problem with a simple replacement plenum is that you are breaking up the sophisticated intake system that I spoke about earlier. By removing the distribution flap, the remaining resonance flap is no longer tuned properly.

The folks that actually knew enough to question this contacted an expert. What better place to start than with the Porsche Club of America's Technical Chairperson and resident expert on 986, 987 and Carrera GT. This guys name is Scott Slauson. You may have read some of his writings in Panorama where he answers technical questions about the three cars mentioned, or maybe you've seen his name in the many other magazines like Road & Track, and so on. He's widely considered to be one of the worlds leading experts in Porsches, especially Boxsters and Caymans. He's been working on Porsches for decades. He builds many race engines and has become the leading expert in Porsche software and engine conversions. He started a company to share that expertise. It's called 'Softronic'.

When questioned about the viability of a replacement plenum, Scott immediately echoed and confirmed the concerns about the broken up 2 stage resonant intake system. He said, "People are paying what for that? What's the big deal? You can buy a similar plenum right off of the Porsche parts shelf for $44? They use one on the 3.8 liter 997 Carrera S engine. But on that car they have re-tuned the remaining resonance flap and Vario Cam control."

So, the idea was born. Why not take the 'plenum' that was used on the 3.8 liter Carrera S and install it onto a Cayman S. But why stop there? That larger plenum isn't going to flow more air if that air can't get through the throttle body. So lets change that too. But at the same time, let's also apply the same tuning to the resonant intake flap and cams, ignition and fuel control that the 3.8S engine uses. Since the Cayman S has the same camshafts, the only real remaining difference would be it's displacement and compression ratio. So we can make the 3.4L Cayman engine into a mini Carrera S engine? This is exactly what Scott set out to accomplish with the 'Plenum Package'.


Sorry bud. There is no answer to this question at this time. But it should be available real soon. If you keep visiting here, you will likely find out when it is available as soon as it is.

When it is available, you can order it from the Softronic website.


Perhaps you missed this post: Softronic Race Plenum


Perhaps you missed this post: Softronic Race Plenum


OK, be nice Gator. This question has been asked so many times about so many mods that it's painful to even answer it. The answer is 'NO'. It is impossible for a car manufacturer to ever void your warranty because it is protected by the Magnuson Moss Warranty act.

However, it is possible for a manufacturer to deny a warranty claim if they feel an alteration has caused a failure, and in a case like this you will have a hard time battling an auto manufacturer that has very deep pockets. Sorry, no easy answer for you here.


The power increase is not substantial enough to really hurt any of the components. I would expect a reduction in fuel efficiency. You can't get more energy out without putting more energy in.


Scott has indicated that this kit is 100% compliant with all US emmisions laws.


It all depends on how you drive it. If you are constantly using the extra power, it is likely to use more fuel. If you drive the same way you do now, it is likely that it will use the same or less fuel than you do now.


There is nothing in the nature of this modification that would make it incompatible with others.


Impossible to answer. This depends solely on your technical and mechanical abilities and no one here has any knowledge of those abilities. Scott is recommending professional installation for all but the most capable of owners.


Again, impossible to answer and very subjective. If you asked me how long it takes to remove the factory exhaust system, I would tell you 1 hour because that's how long it took me. But several other members have spent 10 hours getting theirs off. It all depends on your abilities.


An answer to this can only be guessed at. This modification is not pushing any of the components beyond their design limitations, so there should not be any reduces reliability. However, only time will tell.


I haven't driven one, but based on my theoretical understanding, and reinforced by the dyno chart posted by Scott, I would say "hell ya". Look at the whopping addition of torque in the mid range. That would make the car accelerate better and drive more easily.


Sure, but as I sated in my first answer, the hardware is just a part of it, and a minor part of it at that. It's all about the software really, and that's what you are paying for here. If you compare the price of this package to the price of a regular Softronic software package, you will discover that Scott isn't really adding much for the parts.


No, you don't 'need' to replace the exhaust, but it would likely help you get the most out of the modification.


Other software flashes, other plenums.


Both. It depends on the buyer. Like most mods, some buyers don't want a modified car, some do. I wouldn't expect to get any money at time of sale for this.


No, this kit works on manuals or Tiptronics.

Yes, it works. No, it doesn't change anything.


Very hard to say because there are just way too many modification to compare. I suggest a search here.

You don't need to wait for anything. If Scott develops a software improvement, he distributes the new improved update for free to his existing customers.


Yes. Check the rules and regulations of the club or event that you want to participate in. In PCA, any modification will knock you out of the stock class. In SCCA, there are some things you can do before being pushed into the 'improved' class.

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Gator Bite
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Sounds like Gator Bite answered everything to me. Good job Gator Bite.

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