Quiet Headers?

[DAEMANO]

Originally Posted by Donbrz

NOB Q. If gut cat from stock header, does that trigger a CEL code ?

Probably will. You can reset it with any OBD II tool, but it will pop up again eventually. Better to get a tune because you won't get the most out of a catless header without one. OpenFlashTablets (that include free lifetime tunes) go for about $400 on the board used or $500 brand new the mfg.

[churchx]

And if one decides to pay for ecu tune (be it ecutek or OFT), and go catless .. why not change to some even more efficient catless aftermarket header, so that if needed, one still has normal stock header that one can bolt back for MOT exhaust checks or prior car sale, but have more power (and it will weight less) then what gutted cats in stock header may bring?

[mad_sb]

You will be fine IF you keep the Q300

I did all the other bits first (2 x headers, 2x front / over pipe) and then changed catbacks several times trying to find the right blend of power and low volume.... the Q300 keeps any setup bearable on the twins.

And no, the catted headers do not keep the car quiet, necessarily. Depends on the cat density, placement, header material, material thickness, etc etc. My first header was catted the second was not. with the Q300 it won't make much difference if any at all.

Originally Posted by OnionTou

I'm thinking on buying a header for my car, but all of my friends with headers have particularly loud cars. I like loud cars for the track or whenever I go full throttle. But I don't like a loud car the rest of the time.

As a backstory, I used to have an invidia N1 on my car, without the silencer caps on it, it would wake up every car alarm in the apartment building's garage. With the silencer caps only 2 or 3. I managed to reduce it to 0 when I changed my N1 for the Q300.

Afterwards I changed my OEM frontpipe to a invidia catted frontpipe (noise didn't change much), and same with the overpipe, not much of a difference in sound. Even after I added ECUTek and the car's warm up idle is up at 2000+ rpm

Now I'm looking into getting a header, and I want a quiet one. I've heard that if I stick to catted headers the car will still be quiet. Is this true? Anyone have speedfactory's catted header?

Any suggestions for headers? I would prefer UEL because it delivers more torque at lower rpm, but I'm willing to go EL if it means a quieter exhaust at idle and low rpms.

[DAEMANO]

Originally Posted by churchx

And if one decides to pay for ecu tune (be it ecutek or OFT), and go catless .. why not change to some even more efficient catless aftermarket header, so that if needed, one still has normal stock header that one can bolt back for MOT exhaust checks or prior car sale, but have more power (and it will weight less) then what gutted cats in stock header may bring?

Benefits of a OEM header with gutted cat and straight pipe are:

1. Price. A take-off OEM header sells for $75-$125. Buy it, gut it and keep your orginal header for smog check swaps.
2. Power. The WHP difference between OEM header with gutted cat OEM vs aftermarket is minimal (less than 3 WHP compared to the RevWorks header in NickFRS dyno)
3. Compliance. An OEM header with gutted cat will pass a roadside visual inspection
4. Heat. An OEM header retains the factory heat shields. Heat in the oil pan and on the coilpacks is a well documented issue
5. Noise. An OEM header is quieter because of the aformentioned heat shields.

Undoubtedly a highly optimized aftermarket header can produce a few more WHP and shave some weight, but the above benefits are pretty compelling. Also welding in a straight-pipe makes the OEM header roughly equivalent in power to most of the sub $1000 aftermarket headers.

[churchx]

To me only 1. & 3. seems important enough. 2. - there are several providing much more gains. Not 3, not 5, but +20 above gutted stock i believe (of course PTuning's or Ace's cost accordingly higher). Why compare with least performing? 4. - even with stock header for track use i'd think about oil cooler. 5. many intentionally go for noise increase with aftermarket parts, don't see it as issue. Get extra loudness from header swap, get less agressive/not too loud rest of exhaust upgrades (or even leave stock).

[Vmax911]

Originally Posted by DAEMANO

5. Noise. An OEM header is quieter because of the aformentioned heat shields.

How does a heat shield make it quieter?

[DAEMANO]

Originally Posted by Vmax911

How does a heat shield make it quieter?

Insulation. Essentially the clamshell of formed metal plates that is the stock heat shield acts as a vibration damper that reduces certain sound waves.

Top is stock bottom is Borla UEL.

[Vmax911]

Hmm, I thought the loudness associated with headers was due to the sound coming out of the tail pipe, not the vibration of the header mounted to the engine. I guess you could add some Dynamat to your header and if it's too loud, lol!

[Chad11491]

I have an uncatted JDL UEL and a q300. It is maybe 10% louder than all stock, and sounds amazing and deep. No drone. Perfect for a DD.

[OnionTou]

Originally Posted by mad_sb

You will be fine IF you keep the Q300

I did all the other bits first (2 x headers, 2x front / over pipe) and then changed catbacks several times trying to find the right blend of power and low volume.... the Q300 keeps any setup bearable on the twins.

And no, the catted headers do not keep the car quiet, necessarily. Depends on the cat density, placement, header material, material thickness, etc etc. My first header was catted the second was not. with the Q300 it won't make much difference if any at all.

Can you tell me what brand of headers you had? thank you!

[mad_sb]

Originally Posted by OnionTou

Can you tell me what brand of headers you had? thank you!

namless coated both before the revision and after (i had to rma mine due to fitment issues)
fa20club long tube catted, also tried the catless version.

[Turdinator]

Originally Posted by DAEMANO

@OnionTou & @akash_

Sooo... The stock header only sucks vs. aftermarket because it has a standard cat. And we know that the stock EL header is quieter than an aftermarket one, but why? Well it's because...

1. The stock cat is denser than an aftermarket high-flow cat
2. The stock header is made from thicker metal than an aftermarket header
3. The stock header retains both top and bottom heat shields

Easiest way to get the best of both worlds would be to either:
1. Gut the cat in the stock header and optionally have a muffler shop weld in a straight pipe
2. Cut off the stock cat and have a muffler shop weld in a straight pipe

The stock EL header is actually a pretty decent piece. People that have removed the stock cat from the stock header report equal gains to an aftermarket catless header.

The other benefit of doing this is that you can't tell any modifications have been done afterwards (because the stock heat shield is covering everything). So you don't have to worry about passing a visual inspection.

Read here:
http://www.ft86club.com/forums/showthread.php?t=55770

I am not saying you are wrong but the linked thread is a bad example as it is a supercharged car and swapping headers is quite different to doing so on an NA car.

[Mr.Impreza]

Originally Posted by OnionTou

Afterwards I changed my OEM frontpipe to a invidia catted frontpipe (noise didn't change much), and same with the overpipe, not much of a difference in sound. Even after I added ECUTek and the car's warm up idle is up at 2000+ rpm

Just want to point out that I love your setup and exactly what I'm planning to do.

I want to leave the header last because of noise. Maybe work on audio a bit and then do header last cause I don't go to the track or anything so won't matter much. Maybe in a few years they will make a quieter header haha.

What overpipe brand did you use
Cause i also want the invidia catted frontpipe and want an overpipe that ill match it well

Also how did the gains feel after the front pipe, over pipe and tune for a daily driver car?

[chas3wba0]

Just switched back to stock catback and this is what it sounds like. The rest of the exhaust is aftermarket, cats in both the header and front pipe:

[ame="https://www.youtube.com/watch?v=zuZhV7MZ3_g&list=PL-yYtv6mizg6LnXijtKs3sLeSdnZpF2qV&index=13"]Catted UEL header + Berk catted FP + stock catback + E85 - YouTube[/ame]