DodgeTalk Forum banner
Status
Not open for further replies.
1 - 15 of 15 Posts

·
Banned
Joined
·
756 Posts
Discussion Starter · #1 ·
few exhaust questions
1-are there any negative effects on running straight headers at the collector?? im thinking about bolting 2 dmh cut outs right after the collectors!!
2-If i do a rear o2 delete and remove the cats can i pass a obd2 inspection??
 

·
Registered
Joined
·
1,513 Posts
You will lose some back pressure which may or may not hurt low end power or torque.

And I would only be guessing at what you laws are NC but I think you would fail on a visual for the obd2 inspection.
 

·
Banned
Joined
·
756 Posts
Discussion Starter · #3 ·
I'm wondering if the since the diablo can turn off the rear O2 sensors if It would tell the inspection test everyting is good and pass!! Not concerned with visual friend owns the shop!
 

·
Registered
Joined
·
2,510 Posts
I would assume by removing any O2 sensors you will NOT pass the OBDII sniffer test, but again as stated the laws in NC are unknown to us.

Also, you guys have REAR O2 sensors? On my truck, I just removed the entire exhaust up to the collector, and didn't have a single O2 sensor anywhere along the path. Did they change the location or remove a few of them in 08?
 

·
Registered
Joined
·
28,791 Posts
As long as you are not throwing a code, you will pass the OBDII test...I have done this for the past 3 years ;)

As for running open headers, dual 3" at the collector might be a little short for your mods and weight. I would try to run at least 12-18" of pipe before the cutouts.
 

·
I RECOMMEND FUKKEN WAX
Joined
·
13,989 Posts
You won't pass the OBDII test with the cats turned off via diablo. It doesn't really "turn them off," it sets them to not ready and turns off the light. It will flag on the test.
 

·
Registered
Joined
·
1,513 Posts
I would assume by removing any O2 sensors you will NOT pass the OBDII sniffer test, but again as stated the laws in NC are unknown to us.

Also, you guys have REAR O2 sensors? On my truck, I just removed the entire exhaust up to the collector, and didn't have a single O2 sensor anywhere along the path. Did they change the location or remove a few of them in 08?
You didn't remove the CATs did you ?? They are on the CATs and forward from there.
 

·
Banned
Joined
·
636 Posts
I would assume by removing any O2 sensors you will NOT pass the OBDII sniffer test, but again as stated the laws in NC are unknown to us.

Also, you guys have REAR O2 sensors? On my truck, I just removed the entire exhaust up to the collector, and didn't have a single O2 sensor anywhere along the path. Did they change the location or remove a few of them in 08?
On every 2004 and up Ram with a Hemi there are four o2 sensors. There are 2 upstream and 2 downstream(each cat has 2 and there are 2 cats). The upstream sensors read air/fuel ratio, and the downstream tell the ECM if the catalyst is doing its job.:teacher:

Johnnyk
 

·
Registered
Joined
·
958 Posts
You won't pass the OBDII test with the cats turned off via diablo. It doesn't really "turn them off," it sets them to not ready and turns off the light. It will flag on the test.
X2
 

·
Registered
Joined
·
2,510 Posts
There were no cats removed when I removed my exhaust, only the long mid-muffler and the muffler by the tailpipe, that's all there was. I believe the cats are prior to the collector pipe (in the headers), but after that there were no cats or O2 sensors at all...I am 100% sure of that.
 

·
Registered
Joined
·
958 Posts
I would assume by removing any O2 sensors you will NOT pass the OBDII sniffer test, but again as stated the laws in NC are unknown to us.

Also, you guys have REAR O2 sensors? On my truck, I just removed the entire exhaust up to the collector, and didn't have a single O2 sensor anywhere along the path. Did they change the location or remove a few of them in 08?
On your truck the rear O2 sensors are in the middle of the cats. The cats are right off the manifolds. 08's are different from previous years, because my truck the rear O2 sensors are after the cats.
 

·
Registered
Joined
·
3,052 Posts
As long as you are not throwing a code, you will pass the OBDII test...I have done this for the past 3 years ;)

As for running open headers, dual 3" at the collector might be a little short for your mods and weight. I would try to run at least 12-18" of pipe before the cutouts.
x2.
You will be loosing a lot of tq with dual 3inch,a hell of a lot.
Dual 3inch is way to big for your truck.
In 100% of cases,it is always better to run a slightly smaller pipe size than a slightly larger pipe size.
 

·
Banned
Joined
·
756 Posts
Discussion Starter · #14 · (Edited)
so since my collectors are 2 1/2 a true dual 2 1/2 system would be ideal? do i need a cross over H or X pipe somewhere in the system?
Im thinking running 15" of 2 1/2 off the header collector then dump each with a DMH cut out then get some mandrel bent 90s to make my turns under my transfer case and then have a H or X pipe when both join (if needed) then some magnaflow mufflers dumped!!
as far as the obdII instead of choping up my expensive dynatech ypipe and cats ill keep them and my OEM stock system and when its inspection time ill just bolt that crap on!!
 

·
COUNTRYBOY1
Joined
·
630 Posts
so since my collectors are 2 1/2 a true dual 2 1/2 system would be ideal? do i need a cross over H or X pipe somewhere in the system?
Im thinking running 15" of 2 1/2 off the header collector then dump each with a DMH cut out then get some mandrel bent 90s to make my turns under my transfer case and then have a H or X pipe when both join (if needed) then some magnaflow mufflers dumped!!
as far as the obdII instead of choping up my expensive dynatech ypipe and cats ill keep them and my OEM stock system and when its inspection time ill just bolt that crap on!!
i have true duals on mine with 44 FM and my low end is gone get a y are a x pipe.
 
1 - 15 of 15 Posts
Status
Not open for further replies.
Top