I have some X51 headers off my C4S 996.2 and wondering if they would make any difference on my all stock C4S 997.1?

Anyone with the S model try different headers? Any benefit in sound? Not going to ask about power because at 355hp 5-10hp would not be noticeable.

 

I know the engine's the same, but will they fit on a 997? I've considered the x51 headers, and concluded at the time that x-pipe cats would do. They've done nicely, but the two mods aren't exactly mutually exclusive.

The x51 sounds great alone. I can't say what I'd sound like with other exhaust mods. You're probably right about the hp increase. If you go with headers, I the x51 is probably on the very short list of the ones to get. If you have them, and they fit, there seems to be little downside to bolting them on.

 

if for some reason you decide not to install them, i'll take them off your hands.

Thanks

 

The 996.2 C4S has a 3.6 motor and the 997.1 C4S has a 3.8 motor. Not sure if the exhaust ports are any different in size. Just don't want to unbolt and break any bolts along the way to find out they don't fit or make no difference in sound enjoyment (meaning something different then stock 3.8 headers).

 

theoretical they should bolt on, except from headers alone you wont get much. from what i've read you'll need to do everything down the line to get any effect.

 

IF they were to fit (?) be aware that when I changed just headers on my S.1 car seemed to lose tq on bottom end. For sound change the mufflers and/or cats not the headers. Sell 'em.

 

One more item to consider; are they truly x51 headers (48mm tubes) or just look like it? My c4 has headers that are same design as x51 but smaller diameter.

 

True X51 headers. Didn't know Porsche made fake ones LOL.

I went catless on my my 996.2 4S and was too raspy and ford fiesta racer wannabe like. Also, don't want to be that guy in my neighborhood with the car that sounds like he has a broken muffler or no muffler.

I am just curious because the X51 headers are just sitting around. I took them off my 966.2 4S and put on some of the long tube headers with the scavenging collector. The loss of torque your talking about is so minuscule it didn't really bother me as I don't race the car on the streets. I did notice the car rev'ed easier during acceleration and the sound was slightly different.

Guess I should just put them on one day when I'm bored and report back about the sound if any. Again, not expecting a power gain as the 355hp is enough for me on the streets.

 

Even though the stock 997 headers are somewhat restrictive the well known problem is the cats. If you don't change them any exhaust modification is worthless. Since you don't have cats, the X51 headers should make a good improvement.

 

All the X51 headers I've seen pictures of have a part number that begins with 996, if that helps...

 

FYI

here are the part numbers left and right:
99611110240
99611110140

 

LA Dismantler has a pair

http://www.ladismantler.com/porsche-911-997-upgrade-carrera-s-4s-power-kit-x51-exhaust-headers-pair/?page_context=category&faceted_search=0

They list part #'s as 996.111.105.00 and 996.111.106.00 however.

 

Corey, those do not look like 997 headers... in any case suncoast has X51 set brand new for 1200.

 

Okay, update. Confirmed my X51 headers from my 996.2 C4S 3.6 liter engine fits perfectly on my 997.1 C4S 3.8 liter engine. Fresh oil change on the 3.8 and newly installed X51 headers. Just need the rain to stop and roads to dry up. Excited to hear the new headers and see if there is a power change or shift in the power band.

 

I felt a good change when i installed mine, but i already had Tune GT3 TB/Plenum, filters and 200 Cell cats.
I almost ran in to the back of a car on highway first time i took it out. Didn't expect such a good pull at high RPM.