orthojoe

Vet, I'm not so sure about this anymore. That has always been the assumption since nobody knew why the 987.2 aftermarket exhausts were quieter than the 987.1s. I don't know why a DFI system would make an exhaust quieter, do you? To me, it makes more sense that there is no cat in the exhaust on a 987.2. Something that nobody bothered to look into until Gert did some R&D

987s987

I thought my 987.1 had a 500 Cell cat in the headers. I replaced my headers with NHP 200 cell cats which if my assumption is correct would make the car less restrictive and louder...which it has.

If what Joe says about the 987.2 in that aftermarket CB Exhaust doesn't have as much volume of noise increase as the 987.1 is true, and if we assume they are both roughly around the same DB stock (I don't know this) then wouldn't the headers on the 987.2 HAVE to be more restrictive than the stock ones on the 987.1?

And I agree with Joe on this about the loudness of DFI. How exactly does that decrease exhaust DB? Not criticizing, just asking.

the_vetman

Good questions.

Stock Gen 2/DFI cars are quieter than Gen 1's, period. I've had both 987.1 and 987.2. No question at all which is louder stock. And this is not just me blowing smoke. Many, many Porsche people and auto journalists have remarked on the same thing. 987.2 and 997.2 became significantly quieter, stock, than 987.1 and 997.1, stock.

I don't know for a fact whether this is a function of DFI or just that 9A1 engine is quieter-running. But the "fact" is that Gen 2's are quieter. So when you "open up" the catback exhaust with an aftermarket one, Gen 2 is still quieter (started out quieter stock) than Gen 1. Yes, you do remove 2 cats with Gen 1 catback exhausts, and this WILL increase sound, but it's an additive effect meaning Gen 1 (louder to start) + delete 2 cats = even louder. Gen 2 (quieter to start) + open up catback (i.e. less muffling) = now louder but still quieter than Gen 1.

Let me explain another way. Fabspeed Race exhaust is interchangeable between Gen 1 and Gen 2. You do need a longer inlet tube on 1 side for Gen 2 application, but this does not affect sound nor is there any cat or muffling removed. Fabspeed catback race exhaust has no cats and very little muffling. Anyway, Gen 1 + Fabspeed Race = LOUD. Gen 2 + same Fabspeed Race = Loud but quieter than it was on Gen 1.

How could this be? 9A1/DFI engine is quieter. Remember, cats not only restrict flow but DECREASE sound. So even with no stock cats in Gen 2 "catback" exhaust, it's still quieter than Gen 1.

Let's think of it one more way. Take a stock Gen 2 (or Gen 1) car and replace headers only with catless or sport cat headers. Less restriction -> LOUDER. If you look at various scenarios - cats, no cats, 2 cats, whatever - Gen 2 is quieter in a comparable situation.

As to the question of wouldn't Gen 2 headers have to be more restrictive: no, they do not. Why? In Gen 1, the 2 cats in the exhaust pipes are redundant systems and considered unnecessary. You remove those 2 cats and it's louder, but still no CEL and you'll still pass emissions inspections with flying colors. This is exactly why all AM exhaust manufacturers delete secondary cats in the exhaust pipes. They're not necessary for all practical purposes.

So, the 2 "catback" cats in the exhaust pipes are unnecessary. Therefore, Gen 2 headers do not have to be more restricted/need higher cell cats since exhaust cats were not needed in the 1st place. You'll pass emissions and still have no CEL!

Something just occurred to me, however. I don't know for a fact whether Gen 2 header cats are higher cell or not. AFAIK no one (including header manufacturers) ever said they were different from Gen 1, but I don't know if anyone's ever cut them open then reported whether cats or same or different. I suppose the only way we may know is if you put straight pipes (race headers w/out cats and race exhaust w/out cats or muffling) on Gen 1, put the exact same system on Gen 2, then measure dB throughout RPM range. AFAIK no one has done or reported this.

So I have to admit that I don't know for a fact whether Gen 2 headers/cats are more restrictive. So I suppose it's not definitively known whether Gen 2's are quieter due to DFI engine or more restrictive headers. However, do Gen 2 headers HAVE to be more restrictive? No. So other than for keeping sound minimal for those "gentlemen drivers", I don't know why Porsche would do this.

Hopefully all the jibberish I wrote above make some sense!

orthojoe

Makes sense, vet. Thanks.

987s987

Ok, someone take their stock 987.2 and mangle their headers and count the cells so we can figure this out....well...I'm waiting...

Chris@Fabspeed

too many!

987Holland72

So to sum up....
I can actually, if I wanted remove everything in the last muffler, since there are no sensors ect... in effect, this is what many of the tuners have done with their CAT back systems...

987s987

Sounds like it... but for the $$ you can't go wrong with a Fabspeed exhaust. I wouldn't waste the time cobbling up my stock exhaust but that's just my 2 cents.

the_vetman

Yeah, you can do that. Though some air flow direction may be needed to get the desired sound coming out of the pipes...

tetzlafh

I gutted a spare system back in 2007 (?) can't exactly remember and went the route of just straight pipes all the way through the muffler having removed the seconary cats and all other internal things. It was a nasty sound but holy heck did it suck to drive at certain RPMs so I put the original mufflers back on, sounded cool outside the car.

Chris@Fabspeed

to the OP, if you want to play with the original exhaust and make it louder, try enlarging the pipe and putting the exit closer to the flared tube. I would make it 1.75" OD to start.

panicosc

I recently got a cayman Gen 2 (2009) 2.9 lt.
Im thinking of doing some exhaust mod using electric valves so I can have the option of stock sound or loud!
Does anyone have any photos of the exhaust dissected (Gen 2)? Many photos on the net but cant be sure for which generation are they.
Please post, any help is most welcome.

fhp911

An unresolved question: Is the DFI engine quieter than the older type?

Follow-up: if so, why?

Lee Michigan

Did anyone actually mod their standard exhaust like this please?

John@Fabspeed

We now have several valvetronic exhaust solutions for the boxster/cayman platform, including out TrackTec and Valvetronic Exhaust. If you'd be interested in pursueing any of these options i'd be happy to work with you

I could tell no noticeable difference when I had a 987.1 Cayman S and 987.2 Cayman S in at the same time, both were non-PSE. All very very subjective of course haha.

I haven't spoken with anyone directly that has done it but Planet 9 forum may have some more people that have. What are your goals with your exhaust note? We have a lot of products that effect the exhaust note in different ways, i'd be happy to work with you to come up with a solution that best fits your goals