Is there any performance to be gained from X51 headers on an otherwise stock 997s 3.8? Lots of them on ebay. Seems like some people like the X51 headers with AWE cats and cans. Are the X51 tubes larger diameter? If so it seems that they would maybe provide a little extra high end grunt at the expense of low end power.

 

No one has ever 'quantified' any performance increase w/ just X51 headers. I suspect it takes headers, mufflers & less restrictive Cats to get any performance gain. And just possibly a change to your intake system as well.

I changed over to X51 headers when I put on my PSE. It seemed like the right thing to do. X51 headers just look like they have a smoother flow and yes they are a bit larger in diameter.

I too have seen the X51 headers on eBay. I bought mine from Sunset Porsche w/ gaskets & bolts for $550. I've seen a set(s) on Ebay in the $300 to $400 range making them a 'bargin' compared to Porsche dealer prices.

The plus regarding X51 headers is that they fit perfect. No tweaking is needed as I've heard is the case w/ aftermarket (cheap) headers.

 

No noted increase, or change in low end throttle response, slightly deeper and pleasant tone with PSE.

 

Exactly. You want to buy headers that give you power, has to be equal length spaghetti style. X-51 headers total waste of money.


Theo

 

I don't know if I totally agree w/ your assessment of the X51 header design. The Porsche Engineering Team must have felt they were adequate to accompany the intake system for the X51 Option. The tuning of headers (ie. equal length) is part science and part art form.

According to what I've read headers by themselves (what ever type) won't buy you zilch w/ respect to HP or torque improvements so your 'waste of money' in that respect is true.

 

Note that they only fit PSE exhaust which, in my opinion, adds significant weight in the worst place for no good reason.

 

I don't believe this is quite correct.

X51 headers will fit any and all 997 muffler systems (standard and PSE). The header-to-muffler flange type and relative physical location is the constant.

You're absolutely correct regarding weight!

 

Hi, In regards to header design the collector is were the majority of the power increase takes place. Hope this helps.
Tim

 

There are a number of companies that post dyno charts for headers, so I wouldn't say that all headers fail to generate power. In fact, some of them appear to generate quite a bit of "usable" power throughout a broad range of RPMs.

I'm not following the whole weight comment. Are the X51s heavier?

 

I'd be skeptical regarding header only dyno charts.

Weight comment referred to the PSE mufflers (not X51 headers)

 

Thank you for correcting the information. Gerry

 

Headers themselves are probably worth zip..as far as doing them as a complete system with the 200cpi cats then they fatten the midrange up some but as far as peak hp not really that much. I know the non S headers look like hell but they really aren't that bad. It's the 200cpi or less cats in which you are going to notice the biggest gains.

Dave

 

The other issue with the Stock "S" headers is; I believe they are the sole cause of the resonance I experienced in my coupe at Highway speeds in 6th gear. This went away when I put on the Ebay/suncoast headers. I know have the AWE headers and Cats with the Stock exhaust and am very happy with the results.

I think the stock headers are trash.

 

Just how much heavier is each PSE muffler compared to stock?