Cat delete pipes and driveshaft boots
 

After installing my dubois cat delete pipes this weekend, I was looking at the closeness of the pipes (+/- 50 mm) to the inner driveshaft rubber boots.
Has anyone that has fitted the pipes over a long period had any problems with the heat affecting the rubber boots due to the close proximity of the pipes ??

wrap them if you are worried.

sorry steve no experience with this but rubber is pretty heat resistant and 2" is not all that close, I doubt the rubber will get too hot. How does you car sound with the cats deleted? I assume that this is secondary cat delete. Did you get better exhaust note?

newt....
I fitted the header first a couple of weeks ago - no loss of torque @ lower revs and a definate pickup above 4,000rpm.
I then installed the secondary cat delete pipes last weekend - I'm still not convinced but I think there maybe a little bit less performance (less kick @ the 4,000rpm mark) but that is probably due to the pipes beng a larger diameter than the originals.
The sound is no different with the hood up but with it down there is a definate hard nosed "rasp" to the sound on acceleration.
Remember that we run ROW specs here in Australia, so the US results may differ.

i took a look at mine yesterday . the pipes are 2.5" from the boots it does not seem like it will be an issue.
i already had the charlie chan muffler which sounds decent but the raspy sound it makes with the delete pipes is more porsche sounding. under normal driving it does not seem like it made any difference in power but when i took it for a blast on the highway it gives the car more high end power and the motor revs more freely. i just ran through the gears getting on the highway and i looked down and i was doing 127 mph ! much better than before. seems like i removed one more piece of restriction in the 3.2 motor.

I had the same concerns as you, but after 3+ years in this configuration everything's fine

Thanks Chris and jacabean for your observations, you made me feel a little easier.
Changing out inner driveshaft boots @ 5 x the cost of the delete pipe doesn't add up to me, so caution was the best option...
I'm still not convinced that the larger bore of the pipes have given me any added performance - in fact they seem to have have robbed a little of the mid range torque. I may bite the bullet and re-fit the originals back on (ugh - my old bones will resist again) just to confirm my butt dyno....
Perhaps I should have bought Che's 2.5 engine delete pipes - I seem to remember they are the same diameter as the Porsche pipes.

have you taken a run at highway speed ? that is where you will see the improvements.

Yes,
I live in a fairly hilly part of eastern Australia where long highway 2 mile hills are quite common. At the speed limited 110 km/hr (70 mph), the engine is turning over @ less than 2,800 rpm - well off the peak torque or power curve. If I accelerate up the incline at those revs, there seem to be something lacking compared with the original pipes. Over 4,000 rpm it equates to the old original system of header / pipe combo.
Now I know this is a seat of the pants, non scientific appraisal, but I've owned this car for nearly 4 years so I have a reasonable understanding of its capabilities in these conditions.

I guess the only real way is to compare dyno data, but those things around here in Austalia are as rare as hobby horse droppings.....

There's an old racers story that if you give him more HP he never complains, but reduce the HP and he'll let you know big time - the missing neddies are obvious!!

Steve,
Have you disconnected the battery to reset the ECU (fuel maps) since making your changes to the exhaust?

No, I haven't - are you saying that a "reset' is going to change the trim level??
I thought that the ECU was self adjusting after xxx miles of driving.
Please explain.

Hi steve. The 2.5 and 3.2 pipes have different geometry; you can't change mid-pioes without changing headers.

I'm not sure how long it will take it to adjust.
I've observed long term fuel trim numbers seem to take more than a few hundred miles to adjust. I've reset my ECU by disconnecting the battery, then captured fuel trim info with my durametric after a few hundred miles. A few months later, when i check fuel trims again, they are different.

Just my experience.

On my 2000 S, I've had no ill effects from resetting the ECU. Any time I make a change to the exhaust or intake, I reset the ECU.

Thanks RK - I didn't know that the 2.5 pipes geometry differ from my 3.2 - I should have guessed, something else to go in the memory bank....

Tommy - I'll be checking the torque settings od the header bolts this weekend - I'll try disconnecting the battery then to see if there is any noticable change over the next few hundred clicks.

Tinker, I think the loss of low end torque is exactly what is to be expected from less back pressure. If you look at dyno results that is predictable, loss of low end torque but some gain in high RPM horsepower. Again, I am certainly no expert here, just have been reading a lot. If you want more power I think you will need to re-map the ECU to throw in more fuel, this combined with the more open exhaust should give some power gains. Check out this site: Products: Performance and Enhancement Products for your Porsche

Pedro makes a "techno power 2" kit which includes remapping the ECU, I have met Pedro and he is a really nice and trustworthy guy, highly respected everywhere. I don't have the power kit (yet) but am considering purchaing it along with deleting the secondary cats.