Doc

The combination of stock headers / free-flow cats / stock mufflers works on the 997S (there's a solid increase in pull across the rev band) but isn't the best sounding you're going to get. My evidence about the standard cans not being restrictive comes in-part from AWE's site (their mufflers alone only give very small gains compared to standard) and partly from my discussions with 2 different tuners here in the UK that both confirmed there is little to be gained from just swapping mufflers. All agree that the cats are where the power is. My personal experience of equal-length headers is a loss of mid range for a gain in top end.

One thing you might like to know. You will get a big change in sound with this combination (for the better) if you reset your DME once the new cats are installed. This will revert it completely to factory base maps (by removing any stored adaptation values) and ensure it adapts correctly to the new parts. Even though the DME is supposed to recaibrate itself automatically over time, my experience is it doesn't do so reliably when changes are made to the car. To reset the DME, simply disconnect the battery negative terminal.

Contrary to advice elsewhere, you need to do this for 4 hours minimum. I've no idea why, but the unit takes this long to fully reset. Less than this and the mixture calibration seems to reset, but not the previously-stored ignition mapping adaptation values. I've tried this several times with the same results - leave it for 4 or more hours and you have a different car that just starts getting better and better as it adapts. Less, and you effectively have what you had before.

When you put the terminal back on and fire up the engine, you will get system failure warnings on the dash (for ABS and PASM IIRC). This is quite normal after disconnection of the battery. All you need to do to clear them is drive a short distance.

Ian

 

Ian: Your logic is cogent. Forgive me, but what mods are you running right now?

thanks,

DOC

 

Last year I was running Fabspeed headers / AWE cats / standard cans. I also tried Tubis with the Fabs/AWEs but they were way too loud so I removed the AWEs. Didn't like the loss of performance but stuck with that setup for a while as it sounded amazing.

I then put the car back to stock (for a dealer service). Surprisingly this resulted in an increase in performance across almost all the rpm band bar the top couple of thousand rpm! This turned out to be down to the headers.

Now I've got the AWE cats back on with the standard headers and mufflers. I have AWE mufflers and an IPD plenum arriving next week and the Tubis up for sale!

Seems like I can't stop messing / experimenting!

The only thing I'm totally undecided about is what to do about headers after finding the Fabs seemed to lose power.

Ian

 

Ian:

That is the set up I was going for: Stock Headers/ AWE cats/ stock mufflers.

1. Any dyno numbers?
2. What's your opinion about Intakes? My EVO makes sound but I'm skeptical. Call me a victim of my old Honda days where everything made noise but no power!

Doc

 

I would like to see any dyno numbers also.
I have just installed the ipd plenum and softronic.
I'm looking at using the new awe cats with an otherwise standard exhaust.
I think it was steve (softronic) who said these ecu's have certain programming limitations to keep them in the correct (marketing )horsepower bracket.
If it wasn't Steve, I appologise.
It means the 997s doesn't approach the x51 and that doesn't approach gt3.
Software reprogramming can help take care of some of this.(obviously there are many hardware changes other than ecu, you can't beat an x51 with just software).
Regards
Simon

 

Johnsosn:

How does the plenum feel like? Any dyno planned?

regards,

DOC

 

anyone getting a CEL with the AWE cats?

 

Doc,
It feels like a little improvement in the midrange.I don't think it's psycoschematic.(spelling!).
I think the car needs a little running.
I've installed that and the softronic within a couple of days of each other but not driven the car more than 20miles.Both of these mods require adapting time.
one good thing about the softronic is that you wont get cel's for the cats.You can even bypass the cats alltogether.
Regards
Simon

 

thanks for the info.

 

Not on my car, works well.

 

There are as many different combinations as there are different tastes in the exhaust note. Here is what I went with and I am very happy with the results. https://www.6speedonline.com/forums/...hlight=swatdoc Hope this helps out, and good luck with whatever you choose.

 

Hi NorthVan997C2S:

Thanks for your reply.

I'm in Vancouver and from your handle, you are in the area. If you don't mind me asking:

1 Did you order from AWE or a local vendor?
2. Who did the install? MCL not so friendly from I heard.

Regards,

DOC

 

Cargraphic, i have one for sale for a 997 (s) PM if interested

 

if you do a search you should find a lot of resources

 

I went with Agency on my 997. I love the sound, much lighter than stock and the welds looked good. I can't say it is 'the best' not exactly sure what that means but for the price I'm happy.