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V10 primary cat

1098 Views 9 Replies 2 Participants Last post by  Vaughan Manders
Just wondering has anyone gutted the primary cats in a V10? i have deleted the secondary cats and was thinking about gutting the primary ones, if anyone has was there a change in sound,smoke,power or millage?
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I deleted the primary and secondary on mine. Couldn't really tell a difference, due to the fact that I was troubleshooting a turbo that wouldn't build boost like it should have at the time, and then changed both turbos afterwards...

One thing that I have noticed, and my wife hates, is that the car now smells like a diesel vehicle. Really badly. It now has a very acrid smell to the exhaust, and is much worse when the outside air temperature is colder. When hot, the smell isn't near as bad.

Did not change the sound of the exhaust at all.
I can't speak to the performance, or the smoke, unfortunately, and here's why:

When I deleted the cats, it was after I had put my engine back together with Colt Stage 2 Cam, bigger turbos, and a Malone Tuning custom tune. I developed a problem with the engine going into limp mode, after about 3500 miles due to one of the turbos not spooling properly compared to the other. One of my thoughts to all of this was maybe the catalytic converters were clogged on one side, so I gutted the cats hoping that would solve my problem, and unfortunately, it did not. So I took the big turbos out and put the stock turbos back in, and then the problem was solved. However, I still have a custom Malone Tune, and if you drive it hard, it will smoke. But I can't tell if gutting the cats made it smoke more, due to the tuning prior to gutting them. Also I can't attest to any performance gains of gutting the catalytic converters on the stock engine and tune, due to the tuning and Colt Cams. However, I have not seen a difference in mileage. I think that mileage is more directly associated with how much right pedal is being used. That seems to make the biggest difference in mileage to me.

So basically, I have no clue if it smokes more with the cats removed, or if there was any performance gain by doing so. Sorry I can't answer those two questions for you.
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Love the tune. Much more enjoyable to drive than stock. I would never want to go back to stock now that I've got it tuned.
The big turbos are not worth the hassle. The turbo lag is much greater, and requires more fueling to get them to spool up at lower RPM's, which equals much more smoke. I actually nicknamed the Tune that I had with the big turbos "Smokey Joe". It was not fun to drive around town with, because I had to be super careful not to black out an intersection.

The Malone tune makes the power keep pulling until much after 3000 RPM. It will pull pretty hard to 4000, and then starts to nose over at that point.
I didn't answer your question. Yes, there was a big difference between the 59mm turbos and stock. Once spooled, the big turbos made much more power, with the appropriate tune. But driveability suffered greatly. On the freeway, they were great. Around town, painful and very very smoky.
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