Legal disclaimer: Vehicle in question is for off road use only, not to be registered or driven on any road or highway in the USA, fine print - bla bla bla.

Now, with that out of the way, if my new 05 SD PSD was to have an exhaust system minus the cat, what would happen, I mean with the truck? Would I get "service engine soon" warnings or would the computer give me problems or what? Does anyone have any knowledge about this?

 

On the gassers many have a catalytic converter sensor. If it is clogged or has other problems the CEL will light up. I am not aware of any such sensor on the 6.0s. However, federal laws forbid you to mess with the environmental aspects.

 

I removed the cat converter on my 6.0L PSD to run new exhaust. Not a bit of a problem here in Canada. Would not have at any other way.

 

WELCOME to the site, please read the Guidelines… Check out the list of forums and make sure you read the headings and Read First: notices in each forum.

Be sure to check out the 6.0 Bible…..great reading
http://dan.prxy.org/Truck/6L_bible_html/html/TOC.html
http://www.backglass.org/duncan/ps60_manual/

…. In the upper right hand corner of your screen check this out PARTS SHOP for all your “trucking” needs

Must read
http://www.clubfte.com/users/monsta/SuperDutyFAQ.html
Enjoy FTE

 

There are no Cat Sensors on our trucks. Just FYI.

 

No cat no problems here.

 

As long as you are operating the vehicle on private property and not simply off road - i.e., not in state or national parks, then the cat delete might be OK.

But put it on public lands and you may be a candidate for the $10,000 federal fine.

A call to your state emissions board or web site would probably be prudent to get the real requirements for your area.

 

The most important part of this discussion, there is no shred of credible proof eliminating the CAT helps the 6.0…….so why do it?????

 

Most Diesels I know about work better with less exhaust back pressure. This has been proven on dynos many times. I know a cat has "some" back pressure.
Providing a cleaner flowing exhaust and getting rid of the "diesel run through a cat" smell is why I am pursuing answers on this subject.
Just one other note, for purposes of this discussion, please assume the truck is being operated outside the USA where there are no restirctions what-so-ever and no laws are being broken. Thanks

 

IF I were to have removed my Cat... not that I did, of course, wink, wink, nod, nod, it would run just fine. A piece of 3.5” heavy walled aluminized exhaust tubing would have slipped right in... put some anti-seize on the ends so it comes apart easy for cat re-installation if you need inspection. It will reduce backpressure some amount- sounds MUCH better on my truck. Oh, I mean it WOULD sound better.

I was worried about all the black sooty smoke my rig was putting out at WOT level 6- didn’t want to clog the thing up prematurely. Let me just say that the guy in the Pontiac GP GTP I blew away the other day is having the hearing checked in his left ear, and is scraping soot from his nostrils- I came from 4 car lengths behind to dust him on an on-ramp. He was WOT as well- could smell it and see the body language of the car- that’s what gave me a spasm in my left foot… from my hot rodding days. Not smart, but fun.

 

Most diesels yes, the 6.0 with the VGT, and higer RPM operating range, has not been proven that way...all others ...it helps

 

international designs their motors to operate with a certain amount of back pressure because it is necessary for the intake, exhaust, fuel flow, timing and mostly emissions and noise. Its like an equation, whatever pressure the cat provides add the correct amount to the muffler and you have the backpressure requirements fulfilled (for simplicity only: minus flow restrictions, turbos, etc.) Remove one of these devices and the motor operates on tilt. It will work, just not as it is designed to which is what you are after anyway!

 

But in Tekrep's case, he's added exhaust to flow out, meaning the removal of the exhaust "crimp" (Cat) made it alright.

Backpressure isn't wanted. Exhaust velocity is what you want. This is gained through the exhaust pipe diameter. Get a piece of 1" PVC pipe to breath through an shove something in it that reduces the crosssection to that of a .5" pipe...flow changes. Even if you have more then enough pipe diamter...having that little section hurts flow completely. and with Cat's being mounted right next to the header/manifold, its the worst it could be. The closer to the engine the restriction is, the worse it is.

 

Then why an Exhaust Pressure Sensor? Exhaust Pressure is needs to be measured for an input into the PCM to control the VGT actuator. Read the 6.0 Bible or the Service Manuals.

 

All the backpressure that is required for proper operation is provided by the uppipes and manifolds. Turbo-back systems absolutely, in no way whatsoever, affects the reading of the pre-turbo exhaust backpressure. I will probably have lots of spare time at work as soon as I start- if anyone is really that concerned about it, I will test my 04 with a 4 inch downpipe against a stock one (the EBPS reading) just to see...

The main reason we 6.0 guys don't notice the same lag reduction with an upgraded downpipe as the 7.3 guys is the fact that the VGT is slow to respond. It is NOT slow to build boost, however the time that the computer takes to process a sudden increase in throttle position (yes, the computer's brain in these vehicles is very overloaded, and is the cause of more problems with these trucks that most people realize) and the delay between the VGT valve's opening and the physical movement of the variable vanes causes what we feel as "turbo" lag, when it is a lapse in processing and movement.

To build boost, you have to have restriction in the uppipes, otherwise the exhaust would have very little velocity to turn the charger turbine. On many higher performance gas turbo cars, the *upgraded* uppipe assemblies are significantly smaller in diameter than stock, in order to increase the velocity. However, once it has left the turbo, you want it just as free as you can make it. After the air has left the turbine, there is no beneficial scavenging effect as with a naturally aspirated engine.