No, I took great care with the O2 sensors down there and have had zero CEL's. That was a big concern for me too but it seems Berk got the design just right (as did Stillen for that matter). Once I find the cause of this sound and fix it, I will be beyond happy with this setup.

Well, I'm 99% sure it isn't the intakes at this point - I checked those out today and they seem quite snug in there. After that I took her out for a spin and the sound is still there. It seems to come from the passenger side rear. Doesn't make alot of sense because the exhaust has been on the car for months and I haven't heard anything like that before.

Is it possilbe this is some sort of break-in period thing with the HFC's? I guess that doesn't make sense either because the sound only happens when the car is in motion. Guess I'll spend some time underneath the rear this weekend and see if I can see anything that might have shifted while installing the cats.

Not really interested in starting to swap old parts back in to see what makes the sound go away but it may come to that. :(

Howdy.

I had Berk HFCs installed about a month back (there is a thread in here somewhere that I posted w/ dyno results). I also have that hiss and ping noise under hard acceleration. Sounds totally normal all other times.

I was worried that I had an exhaust leak from one of the joints with the HFCs and took it back to my local shop. They put it back up in the air, and checked all the joints for signs of leaks and checked the torque on everything from the oxygen sensors to the bracing. Everything was tight and there was no sign on a exhaust leak. He also examined the HFCs (as best he could while they were installed) for signs of broken or loose honeycomb. Everything checked out okay.

Finally, we took the car out for another test drive, this time with the data reader hooked up. Everything looked fine; no problem codes, no timing being pulled, nothing. Just that same sound anytime you flog it.

I'm still love to know what is making that sound and get rid of it if I could, but at least everything seems to be working fine. If you have any more luck then I, please post it here or send me a PM.

Bump.

I recently got these two put in. Hks and berk and am having the same sounds


It sounds like air rushing, almost like a turbine whine.