Well that sucks, and I know the feeling. I was told by a Porsche tech at a dealership that hi flow cats can't be relied on in the long term. You know my fix for the issue, which seems to be working but I do have the occasional thing after installing the Dundon headers where it won't let me use PDK Sport mode. I think it's related to the O2 sensors, still trying to figure out that one.

 

Dundon does have a lifetime warranty on the cats. I’ve got 10k miles and a ton of track days on my street headers. No issues.

And to add to this thread, the Ti muffler with street headers is perfect. A bit quieter than their loud muffler (I had that before) less low end sound given the material difference. The sweet spot in terms of sound, worth the money for sure.

 

I have Dundon Street headers to fit, and am in teh UK, so interested to know if this is common fault or not, as could do without these issues.

Anyone else had these issues or is it a one off?

Thanks,

Mark

 

Yep, unless you bought a used exhaust system...

 

My Porsche tech says this is very common. He actually said he’s not a fan of the Dundon headers purely because they like to market it as CEL-proof and he said that is absolutely not the case.

Dundon uses the same HJS cats as all the other manufacturers. It’s the nature of aftermarket headers.

 

Odd that this didn't come up when I was researching. All the people who have fitted the street headers and commented, said no CEL. Very confusing!!!

 

How long have you had the system installed for? I have about 500 miles on mine so far without any issue and I've never had an issue with high flow cats on past vehicles, at least not HJS 200 or 300 cats.

 

And this is how rumors get started and mis-information spreads...

Our cats are not HJS. They are built to our specs to have next-to-zero pressure drop (which is why our street and race systems make very similar power) and excellent mixing characteristics for emissions. Any system that is properly installed (no leaks) will not have a check engine light.

If you are the original purchaser of one of our Street systems and you are experiencing issues, please reach out to me and I can assist in troubleshooting. We will of course, warranty any parts that need replacement once we've ensured that the install is 100%.

As a general FYI, the most common cause of a 420/430 CEL is an air leak. When a new system is installed, it's recommended to tighten all connections after a few good heat cycles.

We have hundreds of these systems out in the world, and many thousands of CEL-free miles. If your car has a CEL, please look at it and don't just assume it is because of the headers.

 

Thanks for clarifying on the cats. I can’t remember the specific thread but I read that somewhere here on RL.

Good to know on the CELs. I’ve considered the street headers but have been put off by potential CELs - just not something I want to deal with. Very happy owner of a Crack Pipe

 

I think I know what part I'm upgrading next.

A little over 6,000 miles.

Thanks for the reply. I'll nut and bolt it. It was installed and torqued to spec. What does the warranty look like for a refurbished unit purchased from Dundon?

 

Ted can confirm but if you bought refurbished I am pretty damn confident the warranty applies. The issue for them on used stuff is not knowing the installation and use history of the part, so hard to warranty it just because it is a Dundon bit.

I’m serious. The Ti muffler is that good. Had it out on the track and everyone agreed it was perfect. Not overly loud on the street, but loud enough for that emotional connection to the car. And the perfect scream on track.

Also the tips are a work of art, especially all blued up after heat. And the Nurburgring tips they have for them are also Ti and slip inside the tips and lock in place with a really ingenious approach.

Oh, and when we unpacked them they felt noticeably lighter after we took the bubble wrap off, that was a significant part of the weight of the package.

 

Thanks for the post Ted, makes me feel more comfortable fitting your system

 

I took off the Dundon headers and will sell them. I'm staying with the OEM headers, Soul valved side muffler delete, and the Dundon loud center muffler. I won't likely be making any more changes. The car's in a good spot for the balance between street and track (for me). I'm not getting into details here on why I made the change.

The new setup is:

• Only a little quieter (honestly a positive; too much drone when using the car in normal conditions);
• More different between exhaust valves being closed vs. open, which I enjoy;
• Down on additional peak HP (I'll miss it);
• Doesn't have the torque flat spot between 5-6K RPM (I really won't miss that, as it made the car much less enjoyable on the street);
• Doesn't have the CEL from the properly-installed headers (didn't really bother me but a nuisance when I had to get the car inspected); and
• Other reasons.

Bottom line: don't track the car with the headers.

 

Well sorry to hear the headers didn’t work out… still have mine on, but I agree the CEL phantom does linger around. Going for an inspection next month and it does make me a little nervous.

 

In general no you don't have cat codes with our parts. Need to check for air leaks, loose clamps etc. If the car has lots of track time on it, doing new O2 sensors at the same time as install is wise...

If you purchased the refurbished headers from Dundon then they carry a lifetime warranty. Anyone that purchased a new system from us has a lifetime warranty. Many many track miles driven, without issues on our own cars, local cars, international cars etc... O2 sensors don't last forever, they too can contribute to issues. Best way to handle these situations is to reach out to us via email or phone. a Rennlist comment isn't likely to be seen by us, nor do we know who you are or how to help...