Cat bypass with resonator

[Dave80GTSi]

Originally Posted by edc

If it helps my car is only road use and I've fitted the cheapy aftermarket manifolds to both my Boxsters with no issues and a slight improvement both times. I saw your pics and saw that you had already removed them. That is the one part that normally deters people. The labor cost to remove them is often more than the manifolds themselves.

I assume that the comment above refers to the often encountered difficulty in getting the 6 steel manifold bolts out of the aluminum cylinder heads without snapping them off?

If so, having the bolts out thus offers the perfect occasion to replace the lot of them with M8 x 42 mm long studs and matching SS flanged nuts

Years from now, whoever might have any need to remove these manifolds will thank you for your efforts to "stud" them today!

Cheers - DM

[gsy4771]

Do you still like the setup? I'm thinking about the circuit werks pipes you installed and wondered how they worked for you?

[ike84]

Originally Posted by gsy4771

Do you still like the setup? I'm thinking about the circuit werks pipes you installed and wondered how they worked for you?

Just so you know, those"resonators" are just glass packs. I've not heard them in person but if you're keeping your stock muffler I'd be shocked if they did anything at all in terms of sound.

Sent from my SM-G970U1 using Tapatalk

[Dave80GTSi]

Originally Posted by gsy4771

Do you still like the setup? I'm thinking about the circuit werks pipes you installed and wondered how they worked for you?

I'll assume that this is directed to me, since I posted the pictures?

If so, then yes, I've been very pleased with the stock non-cat manifolds and the Circuit Werks "resonators". Aside from the fact that all of the white insulation which was a part of the "resonator" portion of the Circuit Werks pipes was blown out after about the first 10 minutes of use, ending up in the muffler!

Fortunately I was able to fish out most of this insulation after removing the muffler - what I could not remove eventually blew out of the muffler's tips.

One difference between the older pictures that I posted and the car as it sits today is that I ceramic coated the manifolds, as you can see below:



The use of the non-cat OEM manifolds resulted in a notable performance boost as compared to the cat manifolds as shown in the second picture in Post no. 23, so I am well pleased.

DM

[gsy4771]

Originally Posted by Dave80GTSi

I'll assume that this is directed to me, since I posted the pictures?

If so, then yes, I've been very pleased with the stock non-cat manifolds and the Circuit Werks "resonators". Aside from the fact that all of the white insulation which was a part of the "resonator" portion of the Circuit Werks pipes was blown out after about the first 10 minutes of use, ending up in the muffler!

Fortunately I was able to fish out most of this insulation after removing the muffler - what I could not remove eventually blew out of the muffler's tips.

One difference between the older pictures that I posted and the car as it sits today is that I ceramic coated the manifolds, as you can see below:



The use of the non-cat OEM manifolds resulted in a notable performance boost as compared to the cat manifolds as shown in the second picture in Post no. 23, so I am well pleased.

DM

Thank you for the response. How you had issues with the car passing inspection? You do not have any cats with your setup? Also any warning lights?

[Dave80GTSi]

Originally Posted by gsy4771

Thank you for the response. How you had issues with the car passing inspection? You do not have any cats with your setup? Also any warning lights?

No inspections required in my county, no warning lights, no worries whatsoever!

[flmont]

Hmm , So for those of us who have to do emissions testing Via the plug under the dash,.and the 2002 manifolds have the 02 sensor B4 the cat, could you backdate to 1999 manifolds or header's and still pass emissions ,if you welded a bung into the Exhaust header,..?? for the 02 sensor..? Thanks frank

[Dave80GTSi]

Originally Posted by flmont

Hmm , So for those of us who have to do emissions testing Via the plug under the dash,.and the 2002 manifolds have the 02 sensor B4 the cat, could you backdate to 1999 manifolds or header's and still pass emissions ,if you welded a bung into the Exhaust header,..?? for the 02 sensor..? Thanks frank

Take a look at my second picture in Post no. 20 of this thread.

You can see that these manifolds do not contain an O2 bung, but there is one at the front of the Circuit Werks resonators.

You need to fab up a pair of cable extensions for the FRONT O2 sensor so that it can reach the shown CW bung. A 'Search' of this forum will bring forth discussions about how to make these extensions.

Finally, you need to do a ROW tune which ignores the presence of the REAR O2 sensor since this system does not require the use of these second sensors. Thus, no dashboard warning lights.

DM

[jbreak]

Originally Posted by gsy4771

Do you still like the setup? I'm thinking about the circuit werks pipes you installed and wondered how they worked for you?

I have the circuit werks resonated test pipes as well on my '99 and love them except the occasional catless smell when stationary w/ the windows down. I've had them on for about 2 months with the O2 sensors hooked up to them and still no CEL. Also running Soul Performance's valved muffler bypass w/ oem muffler so she can get rowdy with the press of a button!

[flmont]

ECU Doctors website show's 499.00 for a upgrade,..but my 2002' ( I forgot ) has 4 02 sensors 2 B4 the cat and 2 After..is there still a chance I could do the 99' header system on my 02' with a plug in test only,but with only two o2 sensor's ? Thanks Frank