Hi, I have purchased a IPE exhaust with decat pipes but I want to use it with stock cats but the problem is the diameter of the pipes exiting the muffler are 69mm whereas the ones from the cat are much smaller. I thought the parts were interchangeable? Can someone assist?
Install them as you received them imo and ask the oem F dealer to test the system and approve it! (to prevent later problems)
Hi, I have the IPE exhaust installed with IPE Decat pipes. The IPE backbox will not fit the stock Cats. Basically the only way you can get CATs with this set up is by buying the IPE cat pipes which come with 200 CEL cats. You see the pipe diameter on the IPE backbox/muffler is 70mm which is much larger than the stock cats so IPEs set up is not compatible with stock cats and is not a true cat back system. It is however compatible with the stock headers/manifolds which to be honest you do not need to change to get the F1 sound. The only thing is the smell and drone sound. Driving at 3000 rpm you will get a loud drone and resonance but above 4000 rpm that goes away and is less noisy inside the cabin. The scream comes at the end of the rev range only. I measured the CO inside the car and it gets up to 20ppm in traffic which will give you a headache eventually and your clothes will smell of fuel. Also it's pretty bad if you start the car up in a garage /carpark. I have decided to purchase the IPE race cats in tandem with the IPE backbox. To avoid the CEL light you do not need to flash the ECU or retune. Just buy these https://www.demon-tweeks.co.uk/performance/catalysts-replacement-pipes/redback-fault-correction-mini-catalytic-converter These prevent the CEL light coming on by bolting to the high flow cats or decat pipes and cleaning up the gases before they reach the O2 sensor. Car will not run rich as it thinks the Cats are still there. I hope this information helps
Interested to learn the difference in sound, particularly volume. I have test pipes, as well - no CEL despite no special software nor O2 sensor shenanigans. The smell at low speeds is a problem. As a result of my experience with an iPE header failing on my car, I've been able to directly compare OEM vs. iPE headers paired with the remainder of the iPE system (test pipes and mufflers). The iPE headers are critical. Not only is the sound more "F1" through a larger portion of the rev range, the power difference is very noticeable. The best way to describe the iPE sound with OEM headers is like a singer singing with hand over mouth. On the power front, putting on the iPE headers makes 7th gear feel like 5th. A good friend described the Fabspeed header effect in the same way, so these improvements don't appear to be exclusive to iPE's headers.
