Catless Downpipe + DiabLew Tune = More Power & Better Mileage!
01-24-2011, 01:26 PM
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Catless Downpipe + DiabLew Tune = More Power & Better Mileage! Learned something new today!
After being shocked beyond belief at the 31.45 MPG (calculated, not DIC!) I got in the Impala on a 300 mile trip, I talked to Lew (06MonteSS) this morning about what kind of wizardry he worked to get my car to do this.
What he told me was surprising: Apparently, our cars dump a ton of fuel into the engine trying to keep the catalytic converter from overheating. The extra side-effect to all this fuel, according to Lew, is extra load on the engine, which causes knock and, ultimately, KR. By removing the cat and getting Lew's matching custom tune, which omits the Cat Over-Temp routine, this extra fuel is not needed or used. The result is a huge increase in fuel economy. For me, the difference was about 5 MPG on the highway for this particular trip, as I was happy to see 26 MPG on that drive in previous attempts.
I was a bit skeptical of the catless DP when I bought it, but I got such a great deal on it, I couldn't pass it up. I had heard that our cats are very high-flowing from the factory, but it never occurred to me that I'd see a mileage improvement simply because the cat was physically gone, and the COT was programmed out.
Anyone else have similar results?
After being shocked beyond belief at the 31.45 MPG (calculated, not DIC!) I got in the Impala on a 300 mile trip, I talked to Lew (06MonteSS) this morning about what kind of wizardry he worked to get my car to do this.
What he told me was surprising: Apparently, our cars dump a ton of fuel into the engine trying to keep the catalytic converter from overheating. The extra side-effect to all this fuel, according to Lew, is extra load on the engine, which causes knock and, ultimately, KR. By removing the cat and getting Lew's matching custom tune, which omits the Cat Over-Temp routine, this extra fuel is not needed or used. The result is a huge increase in fuel economy. For me, the difference was about 5 MPG on the highway for this particular trip, as I was happy to see 26 MPG on that drive in previous attempts.
I was a bit skeptical of the catless DP when I bought it, but I got such a great deal on it, I couldn't pass it up. I had heard that our cats are very high-flowing from the factory, but it never occurred to me that I'd see a mileage improvement simply because the cat was physically gone, and the COT was programmed out.
Anyone else have similar results?
01-24-2011, 02:20 PM
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I've searched past threads here and there but can't seem to figure out why I need one. I don't know anything about them but you can't pass e check without a cat on there. I live in Ohio maybe you don't have the e check. What is the benefit of a catless downpipe though. I see its a popular mod with the LS4
01-24-2011, 02:28 PM
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I've searched past threads here and there but can't seem to figure out why I need one. I don't know anything about them but you can't pass e check without a cat on there. I live in Ohio maybe you don't have the e check. What is the benefit of a catless downpipe though. I see its a popular mod with the LS4
For me, I'll just put the stock pipe back on when I need to go see the smog guy. Problem solved.
As for the benefit, well, you'll get small bump in power due to increased exhaust flow. But the main benefit comes when you go catless and get a tune that also turns off the Cat Over Temp routine. It's really has a positive impact on fuel mileage.
01-24-2011, 02:34 PM
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I appreciate the info. I want to grab some DT headers here soon, hopefully in the summer. Maybe I'll just do the whole thing. Still debating how much more money I want to put into my car because I want a Camaro probably next summer. I know one thing: This Toyota is making me hate winter even more.
01-24-2011, 03:42 PM
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I so wish Diablo would make one for 07+ Imapala SS', so I could get one for my 09. The Diablo tune in my 07 Escalade made it into an absolute animal (by large SUV standards).
I am sure I am not alone among 07+ SS owners in this desire.
I am sure I am not alone among 07+ SS owners in this desire.
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02-04-2011, 05:06 PM
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You can find used DS Predator tuners for under $200. A tune from Lew is $100, and I got my catless DP for $75 used.
As for the noise, I went from no mufflers WITH the cat, to a pair of Magnaflows with NO cat. My car obviously got much quieter!
As for the noise, I went from no mufflers WITH the cat, to a pair of Magnaflows with NO cat. My car obviously got much quieter!
02-04-2011, 05:49 PM
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06MonteSS / DiabLew Tune
2014 Camaro 2SS/RS - LS3, 6-speed manual, short-throw performance shifter, NPP dual-mode performance exhaust, 1LE front splitter, ZL1 rockers, Z28 Rear Spoiler, all paint-matched Red Rock Metallic, BMR strut tower brace, Cold Air Inductions cold air intake, Apex Motorsports, Inc. catch-can, Custom DiabLew Tune
www.diablewtune.com -- www.diablocustomtune.com -- www.diablocustomtunegm.com
06MonteSS / DiabLew Tune
2014 Camaro 2SS/RS - LS3, 6-speed manual, short-throw performance shifter, NPP dual-mode performance exhaust, 1LE front splitter, ZL1 rockers, Z28 Rear Spoiler, all paint-matched Red Rock Metallic, BMR strut tower brace, Cold Air Inductions cold air intake, Apex Motorsports, Inc. catch-can, Custom DiabLew Tune
www.diablewtune.com -- www.diablocustomtune.com -- www.diablocustomtunegm.com
02-04-2011, 05:51 PM
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06MonteSS / DiabLew Tune
2014 Camaro 2SS/RS - LS3, 6-speed manual, short-throw performance shifter, NPP dual-mode performance exhaust, 1LE front splitter, ZL1 rockers, Z28 Rear Spoiler, all paint-matched Red Rock Metallic, BMR strut tower brace, Cold Air Inductions cold air intake, Apex Motorsports, Inc. catch-can, Custom DiabLew Tune
www.diablewtune.com -- www.diablocustomtune.com -- www.diablocustomtunegm.com
06MonteSS / DiabLew Tune
2014 Camaro 2SS/RS - LS3, 6-speed manual, short-throw performance shifter, NPP dual-mode performance exhaust, 1LE front splitter, ZL1 rockers, Z28 Rear Spoiler, all paint-matched Red Rock Metallic, BMR strut tower brace, Cold Air Inductions cold air intake, Apex Motorsports, Inc. catch-can, Custom DiabLew Tune
www.diablewtune.com -- www.diablocustomtune.com -- www.diablocustomtunegm.com
