Interesting. We can't remove the cats here in cow hampshire and get it through inspection though I'm sure there's ways around it. Keep us posted on how it works out with yours.

On another note, how warm does eveyone's V10 run? Mine never goes above 180. I wonder if the previous owner put in a cooler thermostat to help performance.

 

mine had 2 pre cat O2 sensors that went into 2 cats, from there 1 muffler and a 3" tailpipe, mine ran sluggish as well, but i removed the exhaust manifolds and put headers on and replaced the cats with hi-flow cats from flowmaster and i had a magnaflow dual in dual out muffler, sounded mean at idle but once you stepped on the gas it sounded like a 4 cyl. with a glass pack, but back to the subject, i'd be willing to bet your cats are clogged, as i said before mine ran sluggish as well, when i used my truck to haul trailers i never got 5mpg from an 8k lb trailer i was getting 10.

 

Well, I called the Utah Hwy Patrols main office over vehicle safety and asked them about it. They said, it was installed because of the year from the factory so the CAT's must be in place for it to pass vehicle and emissions inspection (moreover the exhaust part of it). So just installing a pipe across where they were is out of the question.......

On a better note however, one could just gut em and leave the shell there to look like they are installed and working! ........ Which brings me to a question, how the hell do you gut one?


Vehicle temp is 190-195 F.



I plan on removing the O2 sensors if the weather holds out today.

 

Cut the pipe off just after the CAT and REMOVE your O2 Sensor. Then take a broomstick or metal rod and jam it in there to break it all up. Start your truck and blow it all out. When it's good and clear, reinstall the O2 sensor and reattach the pipe.

 

Mine runs at 180 also, but I also don't know what the previous owner has done to it.

 

Well I removed the O2's and I removed the air pump hose so as to get as much exhaust out as possible. I hooked up to the trailer and was off. I noticed a small improvement but not much.............And it smelled like **** and rotten eggs......LOL


Still can't run on the interstate at 70 mph in Over Drive. If on flat ground I keep the speed but slowly loose it. So now I'm wondering about the O2 sensors???? While there out I'm going to clean them up with a little emery cloth and propane torch the ends and reinstall. Maybe I'm just dammed to run in 3rd gear at 3000 RPM @ 65 and eat the fuel costs. She will run just fine with about 1/4 throttle that way on flat ground, just eats my wallet out of my pants. Maybe after 141K miles the motors worn.

Any other ideas or comments???

 

Rotten egg smell???? Wonder if your cats ARE bad? If you saw a bit of an improvement... might indeed be the case. You aren't opening up much of a hole for the exhaust to get out..... and you have a bunch of cylinders contributing to the cause there.

 

i removed the cats, and installed true duals with an H-pipe and 40 series flows on my 98, pulling a 26ft enclosed trailer @ 14,000 lbs and truck weighs in at 8,000 lbs, 3.37 gears 35in tires... ran 10 mpg's from wyoming to cali @ 75 mph in OD (5-spd manual tho)...

if you want to "delete the cats" hollow them out and run a pipe through them, it will pass the visual that way, and mine passed cali emmissions with out the cats, just not the visual, but that was easy enough to take care of...

 

Forget about the trailer for now, drive on the highway about 60MPH then floor it like you have to pass someone.
See how it performs when it kicks down from 4 to 3. Listen for PING as well as other noises.
I could feel the performance drop when my CATs were going, (and could hear it PING but only when It was punched).

 

Is that a "typo"?

3.37 gears and 35" tires??????


Anyway when I stomp on it and get the RPM's up it seems to lack like it's holding back. That 3k-4k rpm area is slow. It feels like it has more power when takin off but again lags, (in comparison to my old custom built Durango 5.9L) but that was to expected from what I read the V10's can't keep up like that.

When hooked up on a hill lets say 4-5% grade it down shifts into 3rd and barely holds if not slows down. It makes you feel like it should have more. In comparison, my old Durango 5.9L pulled almost as good but you can feel a little more torque in the truck. My Druango had 3.92's and 31"s.

For that matter, unless I am turning I can't spin the tires. I do have the LS but still, I would have thought with a stock V10 with new 4.10"s should be at least able to light em up without being floored. The truck runs smooth and shifts great?

*EDIT* Maybe I need to take some video.