It's the way this engine is designed that makes the hissing noises. It's there stock but can't really be heard because of the restrictiveness of the exhaust. You can lessen/ pretty much eliminate the hissing with better exhaust designs. The x pipe design is going to make the hissing louder but there is a way around it. Again it's all in the design of the exhaust. For example. The fi exhaust comes out of the cats and goes straight into an x pipe. The fi x pipe crossover is very small and creates Alot of hissing through it. I switched over to the invidia exhaust and noticed that the hole in the x pipe is larger to allow more air to crossover and flow with less turbulence. Also there are resonators right before the x pipe on the invidia exhaust to quiet to hissing down. There is virtually no hissing from the invidia exhaust. The fi exhaust hissing was almost unbearable. If companies start to use invidias design or even better use resonated x pipes I believe everyone will be much happier as there will be little to no hiss. I tried telling Tony this at fi only to be told that the different x pipe design would make no difference and that it was a characteristic of this engine and that nothing could be done to change it yet when I switched it made all the difference in the world.

Yea, ARK told me the same about the HFC. If they can come up with one that fixes the hiss, I'm putting the Berk's up for sale.

same here. the eta for the prototype is apparently 8 weeks so I would hope some time during the summer. Either way, the car is making great power. And it sounds great at WOT.

I just listened to the sound clip and damn that sucks!
How don't you like that rasp when your car sounds amazing @ WOT.
That is sexy.

I'm telling you check my thread I have videos and the source of the hissing noise it the X-Pipe.




Dan

Oh yea, we know. It's just that ARK is supposedly working on an HFC design (resonated?) that should solve this issue. Either that or maybe they can offer a true dual replacement center section to replace the x-pipe.

I wonder how much the hiss will be decreased with the FI RESONATED HFC? It's kinda price though. I wonder if it would be better to just save the money and go back to the stock cats? I think i'd sacrifice a lot of power though.

Just out of curiosity, do you think an H pipe would help in all of this? I haven't seen many of them on the forums but I would think that it would help while also improving performance over the stock cats.

FWIW I don't have hiss with my HKS HI POWER TI. However, I have stock cats and stillen G3 intake.

The ARK also has no hiss with stock cats either. I'm trying to decide whether it's worth it to switch from my RTP to a resonated hfc or if I should just go back to stock cats. They're so restrictive though. The hfc itself will lessen the hiss but I don't know if adding a resonator to the pipe will eliminate it. Im doubting it. The HFC guys have hiss and I have it with an RTP.

the hiss supposedly comes from too much exhaust flow, so anything that is less restrictive than stock cats will hiss, i think :confused:

I THINK a Berk HFC/CBE combo doesn't hiss. Idk really. I'll either deal with it or re-install the oem cats. Not gonna pay another $500 plus install for a resonated cat pipe unless I'm sure it will eliminate the hiss. I'll just wait for ARK to release their pipe.

hm i think the berk cbe is designed differently tho, their X section in made by welding 2 pipes bend in a U shape, which would give more volume in the part where the pipes meet for the flow to cross over.

Same here, was looking at the ERZ/CNT HFC or RTP but im worried about the hissing, so i'll wait to see what ARK comes up with.

edit: you can see a pic of the berk cbe in this thread

Yes they were working on that months ago when I had their exhaust. I wouldn't hold my breath.



Dan

I've been trying to decide if I should just go with the Fast Intention resonated cat pipe ($600 plus install) or simply re-install the stock cats. There's no guarantee the FI pipe will eliminate the rasp. I feel the longer I wait I'll just end up getting used to the sound. Plus, starting in July I will be garaging the car for a year. So at some point in the next 16 months I'm sure ARK will come up with a fix for the rasp.

How is the rasp/whistle/hiss with your current set-up?