Which Steve Wong chip would work for me?
 

I have no cat, B&B Billy Boat headers and muffler kit
The heat exchangers boxes are just wrapped around the outside of the pipes and have no effect on the internal airflow.

SWCHIPS.com - Performance Chips for the Porsche 911 Carrera
A) 911 premuffler/cat bypass exhaust configuration
B) 911 headers/SSI configuration

What's the difference b.w these two?
A) still had original exhaust, just no cat?

I'd need B) right?

If ur running heat exchangers -A

B is for a twin inlet muffler 74" style

I have a single outlet muffler.

What effect do heat exchangers have?
They are just wrapped around the outside of the pipes, right?
Even if I just tore those boxes off, I think nothing would change, mechanically.
Headers connect right to muffler. See the link in my first post for pics.

I know and single inlet too
correct?

Because of the headers use the "B" option - - - BUT, IIWM I would call Steve and talk it over with him - particularly if you plan to do any other modifications.

We took our 3.8L race car for him to Dyno tune a 964 chip - turned out great !!

It helps him a lot to know exactly what engine and mods you have . . .

Regards,

Call Steve - he is a terrific guy and knows his stuff. That way you get the best chip for your particular application. http://www.911chips.com

No, it's twin inlet and single outlet.
Both header sides collect into each side of the muffler.

Ok, now I get the heat exchanger question.
You mean STOCK heat exchangers, implying the stock exhaust manifold.
I am running B&B headers, and yea, they have heat exchangers, but they are aftermarket.
So, the point is, I am not running stock exhaust manifolds and heat exchangers.

So, it sounds like option B works for me, right?

http://i63.tinypic.com/2dhtrvs.jpg http://i67.tinypic.com/2ryhlzs.jpg

Yes definitely need B.
Call Steve and tell him about your setup I'm sure he will hep you out.

I am buying a used one, that is why I am asking.

91 or 93 octane? As we live in the NE with 93 available everywhere, I went with the 93 version when I bought mine. I've read Steve say though that if you do go 93, using 91 even in a pinch is not highly reccomended. I wasn't expecting it to nor did it turn in to a rocket ship but it DID transform the drivability of the car. 3rd and 4th now have much more get up and go in lower RPMs, the idle is way smoother etc. It wasn't until I put it on the track that I really said wow, used to fall off of power at 6200-300, now it keeps pulling and screams till about 6700, can shift later now with more speed going in to 4th or in to a corner. Rant over.. ;)

I am buying this one used. 93 octane, headers, sport muffler

Seems to be the right fit for my car. Yea, there isn't even an option for 91 around here, so it seems a moot point.

Perfectly happy with my car as is, and it idles like butter. However, I never liked the idea of the Weltmeister chip in my car. Not sure why, maybe the association with the snake oil Strut Brace by the same vendor. Figured I'd swap in the Wong, as it's more accepted. If it keeps everything the same, or improves anything, cool. If it makes the car run worse, then I'll resell it.

My Weltmeister chip came on strong at the high end, got a Wong chip and it pulls strong and even through the whole power band

Anybody run a 3.2 SW chip designed for headers/sport muffler, on a motor with stock manifolds and cat bypass? I'm thinking about getting a chip, but I do plan to eventually install 1 5/8 headers and a 2/1 sport muffler at some time in the future (sitting in basement now). Just curious if there would be any drive-ability issues using the header chip with the stock manifold configuration. (BTW, I did shoot this question to SW via e-mail, just waiting for response.)

Roger

When I did my SW chip..I selected the 91 octane. Most gas stations have 93 octane here but as the 911 gets driven out of state (or if "times are a-changing" thing and 93 gets hard to find)..i wanted some comfort if 93 was not available. And I was not looking for the very last available HP number.

The 91 octane chip works beautifully.

Absolutely. If one even runs a chance of not having access to 93 getting a 91 chip would be the prudent thing to do. My experience/performance gains would probably be 99% the same regardless of which octane chip I went with.

I installed the Wong chip today.

The car idles higher when cold.
Instantly revs to 1100-1200, instead of hesitating for a second or two, and then going higher.

It is very hard to know how much is placebo effect when comparing the Weltmeister to Wong.
The car seems to pull better when in the wrong gear, like at 2000-3000 range. Seems like less hesitation, but who knows.

I will take it for a proper drive and report back.

You should consider doing some runs on a chassis dyno and measuring AF ratio at full throttle. I did this when I installed my SW chip and sent him the results. Then he sent me another chip that was tweaked to keep the mixture between 12.8 and 13.1 throughout the entire RPM range. As he explained it, every car is slightly different and this is the only way to make sure the full throttle map is correct for your engine.

SW chip & new exhaust
 

After I purchased my 87, I noticed a slight hesitation around 2700 rpm. After numerous checks-the cruise control had a vacuum leak. Removed cruise control actuator ( throttle lineage was broken) & plugged vacuum line, car ran much better. After market exhaust was too loud. Replaced CAT with MK premuffler & new 1 IN-2OUT Muffler (love the sound). I then had SW re chip DME, performance is much better.
Just completed my 2nd DE (Maverick region), love the handling & performance! Hers a pix of exhaust.http://forums.pelicanparts.com/uploa...1475635816.jpg