Firestarter,

I am not saying your car drives like poop, but I will say you have nothing to compare it to since, if I recall your post from before you received the car, this is your first experience with a 944 of any flavor.

To temper that last statement, I have not owned other 944's or 924S's, but I have driven several, stock and modified. I also have a baseline to compare my current car with a cat and without. Without kind of sucked to be frank. With the car set up as it is now, I get good grunt smoothly from well below 3000 (more like 2500) and on through to over 5000 or so. Without a cat it seemed kind of asthmatic until at least 4000 and fell off quickly as it got close to 5000.

I must say however, I have not run without a cat since "opening" up my intake with the MSDS adaptor and cone filter, though I suspect this makes little difference. I cannot really say without trying it though.

Edited to say "Oh yeah, well based on the chassis code so is mine"

Couldn't resist that either

Instigator,

What do you figure the problem is with the alloy Porsche used? A lot of makers are using stainless these day, are they doomed to cracked tubes? Is Inconel cost effective enough for them to have used on our cars. I do know it is generally pretty corrosion resistant

 

inconel is used mainly in the aviation arena and is very expensive to work with, but it can withstand very high temps without the cracking that some stainlesses do.

as far as the type of stainless that porsche use on the "header" i dont know that but it did crack on mine, maybe cause of the age and the heat cycles it went thru

 

Typical stainless is 304 alloy and doesn't have as good heat-resistance as 321 alloy. Although the manufacturing process has a lot to do with it as well. The part should be back-filled with argon and the joint annealed after welding.

 

Danno,

You answered my next question before I could even ask it. I had though I recalled something about welding stainless being a pain in the **** like welding titanium. So a purge gas is required for welding stainless then.

Based on that I am going to guess that the manifolds are cracking in the heat affected zone near the welds then? Again, I haven't seen this yet and want to know where and what to watch for.

 

just looked at the cracked stock header again, and it is cracked at the weld from the gussett on the no. 1&4 tubes and it goes almost completly around the tube.