Removing Cats or Not

[Annu Kumar]

Guys I Had to start this thread because of so much Controversy on this subject. The owner of a Good exhaust shop told me this about deleting cats:
You lose power by removing the cat because there is a lack of back pressure-the enigne needs a little back pressure to create torque. So my question is it worth it to remove the cats on our Viper trucks or not. Your Input would be appreciated.

 

[Sharpimage]

Guys I Had to start this thread because of so much Controversy on this subject. The owner of a Good exhaust shop told me this about deleting cats:
You lose power by removing the cat because there is a lack of back pressure-the enigne needs a little back pressure to create torque. So my question is it worth it to remove the cats on our Viper trucks or not. Your Input would be appreciated.

Brother Annu, i can tell you first hand that's a load... when i took my
stock cats off and put Boomers catless mid pipes on.. i clearly felt a difference
in power.. unbiased opinion right tha' :rock:

Sharpi

 

[VNM PWRD]

Brother Annu, i can tell you first hand that's a load... when i took my
stock cats off and put Boomers catless mid pipes on.. i clearly felt a difference
in power.. unbiased opinion right tha' :rock:

Sharpi

:withstupid: :withstupid: :withstupid: :withstupid: :withstupid: :withstupid:

 

[stick]

I deleated my cats and felt a big difference,,,,,,,,best mod I ever did besides caltracs...And makes my borla sound alot better

 

[hunter_angler]

Dyno evidence has demonstrated that losing the cats or going to high-flows will gain you 15+ HP. This is not theory.

I chuckle whenever I hear the backpressure argument. It's not backpressure that effects power/torque, it's the velocity of your exhaust flow, and 2 1/2-3" tubing behind your manifolds or headers will maintain plenty of that, even if you remove your cats and/or muffler.

Your exhaust will get a lot louder, though...

 

[TheMoparConnection]

it doesnt sound like that guy know's what he's talking about with this truck. That is clearly the single most horsepower gain for the price.

 

[Rockin Ronnie]

I deleted my rear cats and kept the fronts because of the anal state we live in but I felt a serious boost with the catback exhaust!

 

[Prof]

Friend you need to never go back...I ran a dyno before and after the cat delete...38 hp increase.

I do think that 2 cycle engines do need back pressure...ask Stinker or some others that race motorcycles...

Your source is wrong about our trucks in my opinion.

 

[JTS VENOM PERFORMANCE]

Annu if you cut the cats apart and you have two on each side, one is almost like a high flow cat, not too restrictive, but the other is a very tightly wound aluminum, and very very restrictive.

You will gain at least 20 RWHP by removing

 

[Chuck B]

Here's an article thats just scratching the surface of exhaust design. My race background is with motorcycles and trust me there are well designed systems and poor designed systems. Put them side by side and most can't tell the difference but differences there are.

To your exhaust buddy's defense....in his experiences this may be true (loss of power) but deleting cats changes much more than possible 'loss of back pressure' Read below....

http://www.burnsstainless.com/TechArticles/Theory/theory.html

 

[hehateme/1Fast400]

It will pick up power. After this I would hold off on adding headers if you enjoy a semi quiet cabin. My truck had headers, no cats and magnaflow. To say it was loud was an understatement. It wasn't to bad driving around, but on the interstate, it had a BAD drone around 80. Just make sure you can pass emissions when needed.

 

[Prof]

Annu, I had the same set up as stated above, so I added Magnaflow resonators in front of the Magnaflow muffler...the resonators got rid of the cab noise...still set up that way and it sounds very deep and is loud but that is what I like...the question about emissions checking and passing state tests is still an open one for me...I may just clamp in some high flow resonators for the inspection and from that point forward just exchange the resonators for high flow cats each time I have to be inspected...don't know if that will pass or not but it is a plan.

 

[mauiSRT/10]

Your exhaust guy is not a Viper motor expert.......Cat delete is the single best bang for your buck mod out there!!!!! I dropped mine and felt a nice increase in power...............but also felt a big difference in throttle sensitivity.

patrick

 

[nycstev]

I am going to try the stock exhaust and leave it as is. At most adda catback.
I realize this will hinder perf with Roe unit, but ill experiment. I happen to like the sound of it.

 

[Prof]

Careful Steve, any cats may get clogged very quickly with the Roe Blower...that might cause some sever problems...we need some experts to opine here...a blower with cats is not what I would recommend, but I am no expert by any means.

 

[eddie102870]

he was probably giving you the runaround, most exhaust shops dont like to remove the cats cause it aint legal.

 

[fast fred]

if you do a cat-delete, make sure you keep them as later on when you go for smog you can cut them back in...........here in calif. no cats no pass smog....

 

[JTS VENOM PERFORMANCE]

Annu my QC has long tubes , no cats, and magnaflow and we pull a 10,000 lb trailor with it.

As long as the exhaust is properly hung on the rubber insulators there should be no interior noise at cruise, under full throttle it sounds very strong.

Just get you a set of hi flow cats to have around for inspection time, other than that you will be fine, ours in making around the 470 mark to the ground and pulls like a bull

 

[sleeper]

Hi flow cats won't do it here in California. You will need to put all four cats on to pass smog test.

 

[Annu Kumar]

Sleeper According to Ted May Of Valaya Racing In San Jose, Ca (Master Viper Tech) He said he guarantees That If I Delete my rear cats and get highflows in the front I will pass smog for sure. So Stinker Is right Saying that to make sure I have the High flows on During Inspection. :rock: :rock: :rock: