s-spiff

I was at my mechanics yesterday getting my oil changed and we were just talking in general about the 996. He mentioned that, in his opinion, the best bang for the buck mod for power is to put 997S stock headers on my car ('99 996 C2). He said no remapping is necessary, takes about 1 hr to do and is straight bolt on. He figured it adds about 15-20hp and is by far more effective than any chip, intake, exhaust, etc.

I searched on this and couldn't find anything. Anyone hear of this? I'm doubtful of the amount of increase, but is there something to it at all? He's got quite a few years of Porsche experience, worked as a team mechanic on some 996 race teams, fwiw.

juankimalo

Are you sure that there is no extra welding work to do?

I have the 997 C4S cans installed in my 04' 996 C2, and there were a cut&welding work done to fit them correctly in my rear bumper.
I know you are talking about headers, but I'm not sure they would fit in your engine, just bolted on

https://rennlist.com/forums/showpost...&postcount=479

jumper5836

My mechanic said something like that to me as well.

htny

I remember reading a recommendation on renntech saying to go with the 997 3.8 x51 headers, that they were the only ones worth getting.

Your race mechanic buddy likely knows best here, but I don't think there's any way you'd unlock 15-20 bhp without the headers and a chip to match the new breathing abilities.

Most of the posts on the net re: headers, exhaust, and intake mods on 996s cite "throatier sound" and "improved throttle response". The sound is real, the rest is potentially psychological, but hey who knows? Without some dyno and 1/4 mile or hot lap comparisons on your own vehicle, it's highly debatable as to where in the rev range you would gain/lose power and whether it makes any difference in your life. If you can pick up some 3.8 X51 headers from a wreck real cheap, and he only bills you an hour to put em on, I'm sure you'll do fine. Pay retail? That I don't know about.

I'm in the "sc/turbo or bust" camp when it comes to thinking about performance mods to these cars, so please take what I wrote here with a grain of salt!

Paul 996

I have the 997 3.8 x51 headers on my 3.6. Straight bolt on.

Zookie

996 3.4 and 3.6 are interchangable with 997 3.6 and 3.8

Headers only... Cans and Pipes not without modification

philooo

thread revive

what is the part number on those 3.8 x51 headers ?
Are they 997 S headers or there need to be a X51 package on them ? If it is second one, I bet they are not that easy to find

Dharn55

I think you need the X51 headers. I remember seeing pictures of the stock 997 headers and they did not even look as nice as the stock 996 headers. Not sure if the S headers are different or just the X51. There is a thread out there on one of the boards with pics of them. Time to start searching I guess.

The issue with most headers is that you trade some additional HP at the upper rev range for a loss of power in the lower range. I love to rev mine up, but frankly I spend a lot more time below 4,000 rpm than above 5,000. One of the reasons I have not done headers.

JDSStudios

I have 997 S headers on my 02 996 C4S.
Doug you are right the OEM looks nicer, however the 997 S
headers are tuned to an engine that has 50 or so more hp.

I don't notice too much of a loss or gain, but maybe I just got used
to it.

I think to notice anything, you need to Flash the ECU.

I kept the originals.

Ale-Superbike

Your mechanic will have told you this way because of those 997's have a different diameter?


996 oem 42 mm - 54 mm diameter external
996 x 51 48 mm - 54- ???
997 s mk1 ?

jdsstudios you can control the diameter of the three collectors and exits?

JDSStudios

Ale, the 996 C4S has 20 hp more than the regular 996.
The 997 S headers were a straight fit.
I could be wrong but I think the diameter is the same on
the 996 S versions, C4s or S.

juankimalo

The 996 C4S has the same engine as 996 Carrera, Targa, Carrera 4, and Cabriolet versions of MK2 series

3.6 l. = 320 HP

There is no 996 Carrera S version


Mk1 series = 3.4 l. = 300 HP

jrgordonsenior

FWIW, I run the 3.8 (997S) headers on my 3.4 race car. I installed them with a GIAC street flash and switched to 98 octane fuel. I gained 33 rwhp on the same dyno 1 month apart. I don't often have that motor below 4500 rpms so I can't comment on low end torque loss if any. I also don't know if the 3.8 S headers are different than the 3.8 X51 headers...

Ubermensch

Any chance you have the dyno to look at? I guess most of us wonder about the change across the band. Since you're only interested at north of 4500rpm this wasn't much of an issue for you. For the daily drivers among us I'm sure we'd love to see it.

-Shawn

onefastviking

FYI - 3.8S and 3.8 X51 headers are different, although not much different in performance surprisingly. I think when the X51 is allowed to breathe better then the x51 headers may come more into play over the 3.8S headers. I'm in the same boat as JRG, we only see below 4500 rpm twice each time we drive.