captainbob

Just curious how it sounds in the mild mode?? Still pretty quiet? I'm thinking about installing so AR longtubes cat delete.. I have an Eforce.

FloydSummerOf68

It'll be very quiet when they're closed and very loud when they're open.

TRINIC5

I think it sound good open and very quiet when closed, but I don't think the OP car will sound the same like mine because I am running a F1A with 2" primaries and 3" pipes through Z06 mufflers.

FloydSummerOf68

I think it sounds great....very loud is a good thing as far as I'm concerned

Detoxx03

Just picked my car up from the shop after getting the catless headers installed. It sounds great opened and closed. Very aggressive when open and tame when closed. I absolutely love it!!!

captainbob

Nice!! Did you dyno and see hp gains??

j_digi454

Sounds like we have a similar setup. I have the E-Force, ARHeaders with Hi-Flow Cats and NPP Exhaust. I know you asked about no cats.

The addition of the headers greatly increased the volume over my stock exhaust setup. The closed position is louder but a great sound and comfortable. The open position is unbelievably loud with a lot of drone, great for aggressive driving but not cruising any length of time. I have an A6 and get a small amount of drone with the valves closed but it is tolerable. Hope this helps.

captainbob

Just curious what hp gains you saw? I was going to go with cats, but It seems like on my blower cars, I always blow the cats out, and that sucks. You loose power, and it can be hard to detect sometimes.. I hope the drone isn't to bad.. Thanks..

lt1z

I run catless headers with a ZR1 X pipe and ZR1 mufflers and it sounds really good. Real quiet for a cammed and supercharged motor with the valves closed and a nice sound open but not as loud as some aftermarket axles backs would be.

captainbob

Cool. hoping to have it fairly quiet w/ valves closed, and killer sound w/ open..
How much hp gains are you guys seeing with the cat less headers addition??
Before, and after?? I'm guessing I will see at least 15hp, and maybe 20lbs torque..

j_digi454

I can't answer what the increase in hp was as the header install was done at the same time as the E-Force.

I installed the NPP Exhaust a couple of years before. It was almost whisper quiet, quieter than the stock exhaust it replaced with the valves closed and a great aggressive sound with them open. After the header install, the closed sound is now more aggressive but as I mentioned, very comfortable and the way a Vette should sound, IMHO. Open the valves, that's another story. The good news, you can always close the valves.

White_Lightning

sounds like this..

http://www.youtube.com/watch?v=X3y0eSx472I

ashanson

I have catless headers, and I had a Corsa exhaust and it was too much drone on a highway road trip for me. Switched to the Z06 bi-mode exhaust, and it's super quiet at 1700 rpms when closed, and very loud when open.