lucxy

Anyone running Dundon headers with center bypass like RSS, GMG, GRP? I see most header installs are paired with a center muffler (either stock or Dundon muffler). What are pros and cons? (like drone, etc).
I am thinking about getting headers but already have RSS bypass with stock headers and would rather keep my X pipe. Anyone? Also how bad is the smell with catless Dundon headers?
This mostly for street use and track a few times a year.

C2Spin

I've been thinking of this as well. I have RSS X pipe, too. The route I am considering is to get rid of side mufflers with Dundon headers and lifetime center. I was thinking of headers, side delete and X pipe, but then realized that was a straight exhaust. Neighbors might not like that. I will probably stay with cats. I've driven behind folks with catless and can only take it for so long. No experience what catless smell is like from driver's seat.

Akunob

From what I understand, there are a number of reasons why one wouldn't want to run Dundon headers, side bypass delete AND rear muffler bypass such as (i) very loud, essentially straight pipe, (ii) loss of torque, particularly down at rpms below 4K, (iii) toms of drone and (iv) won't pass emissions (if your state requires it). For added measure, I don't believe the Dundon street headers would mate with GMG or GRP/BBi rear center bypass as Dundon's attachment points are situated different from the OEM point (which the others use) to allow for the extra length required in their system to meet the power gain goals. Best bet is to get a side delete and put your OEM center muffler back on. This way you get weight reduction (~ 40lbs), less heat around the ignition coil and rear tires and improved sound (over stock) as benefits.

lucxy

Seems like Dundon muffler is the way to go with Dundon LTH.

Jamie@dundonmotorsports

We have had some customers use a center bypass on our headers and side deletes. They were looking for a straight piped solution.

Since our headers and side deletes fit the stock muffler, they in turn must fit with center deletes if the center delete only replaces the center muffler.
Our systems don't fit the side mufflers, those are eliminated.

That said, there are some draw backs:

1. Drone:2. Loud all the time, as you've discussed the car is essentially straight piped. Some have done this intentionally and loved it. We don't recommend it...

3. Loss of torque with center deleteWe designed our lifetime center muffler to cure the issues of split/broken oem mufflers. Making them from 321 Stainless steel, a full 3" flow path and in 2 version Loud and Quiet to suit most desires. The most popular combination is our Long Tube Street Headers with a Loud Muffler (especially on the 991.2).

If you're concerned about smell then get our catted headers, very similar power gains, no smell, lighter weight than stock.

When headers and mufflers are purchased together we do offer a discount of $850.00.

Jimmy-D

But if you are using Dundon w/Catts on a .2 why not use the OEM rear muffler. I thought some one mentioned less heat being used due to piping on the .2

lucxy

What is the difference in sound: 911.1 stock headers, stock sides + bypass delete (GMG, RSS, etc) vs Dundon street headers + Dundon Black muffler. Have you done sound measurements in db?

lucxy

Good point. Why not Dundon catted headers with OEM muffler even on a .1 GT3?

Jamie@dundonmotorsports

Black Muffler is equivalent of center delete volume wise at full throttle, but with better flow charachteristics.
The sound is better managed when moving in and out of the valves. Center deletes have a quiet then loud kinda sound. Black Muffler is more seamless, no drone, can be quiet if you keep your right foot tender on the loud pedal...

Catted headers are louder than stock. Best is to go to our blog section of our website and listen to some videos.

https://www.dundonmotorsports.com/bl...rgia-mountains

Catted headers/BlackMuffler will be more edgy a little more raw. Oem muffler is a little more subdued.

Quiet muffler is 10-12dB less than stock
Loud is about 10dB more than stock

Street System is louder than stock headers/cats/side mufflers

Like I said, hard to type what something sounds like...

Many run Catted headers and oem muffler on the 991.1 GT3. You can always upgrade to the Black Muffler later if you want more (you do lose the discount though...)

Jamie

SToronto

Any group buys? Deals for Canadians with a weak dollar?

Jamie@dundonmotorsports

I've run group buys in the past with little reward for doing it, chasing people for money etc... ends up being a mess.


How about if I get at least 5 guys to PM me asking for a discount and include "321Stainless" after the 5th guys PM I'll send a code for our web store for 10% off that's good for 2 weeks to all that replied...

Jamie

SToronto

Sounds good to me. However my car doesn't arrive until late December and will be in storage as it will be winter until late March. So a bit premature on the purchase. I'd be looking to buy closer to spring when it can actually be installed and tested.

Jamie@dundonmotorsports

So there are 2 others that requested the code, if you wanted it that would make 3. Understood on wanting to wait, but is the case with "group buys" have to strike while the iron's hot...

SToronto

Totally understand....maybe my initial question was premature. Guess I'm just excited and have been doing research on exhaust mods. Modded my 997.2 and thought my GT4 could've used some additional sound. So figure I will want something on the GT3 and going with headers, side deletes and lifetime makes sense to me for weight savings, sound and whatever performance gains may result.

Maybe we can get another one going in late Feb-March.

Jamie@dundonmotorsports

It really does wake the car up and add another dimension. And now you can likely understand why we don't do group buys...

Jamie