Oh, yes....

[coldkilla]

Well finally, today, I finished my exhaust system. For the past 4-5 months the retarded mystery catback that came on the car when I bought it has been rattling around like a penny jar. One of the tailpipe mounts snapped so it was wire hangered up, the flange that bolts to the catcon rotted away so guess what....wire hangers to the rescue. The car sounded like a farm tractor and when idling sounded like a busted washing machine! Well today in addition to the Mac midlength headers, Mac y pipe, and 3in hi flow cat I added an SLP Loudmouth! Man Ive been ****in clamorin for this for so long. No way I was gonna pay 750.00 for a Borla no matter what it sounds like. I heard a few Loudmouths on LS1 cars and didnt like how high pitched it was but believe you me...my dirty bird sounds like an A10 Warthog coming in for the kill with gatling guns blazin! **** yeah. Nice and deep, not too raspy, low highway drone and best of all...if you stand behind it when I get on it, your ears hurt and your nose burns.....just the way I like it.

[coldkilla]

Oh yeah, almost forgot, the mystery catback? It was a Vortex system, stamped on the top where I couldnt see it. Who the **** is Vortex anyways?

[JW]

Nice man I am glad you like it!

JW

[ar0ck]

Those Loud Mouths sure do sound purty on an LT1! Congrats on the new set up!

[Squirrel]

Originally Posted by coldkilla

Well finally, today, I finished my exhaust system. For the past 4-5 months the retarded mystery catback that came on the car when I bought it has been rattling around like a penny jar. One of the tailpipe mounts snapped so it was wire hangered up, the flange that bolts to the catcon rotted away so guess what....wire hangers to the rescue. The car sounded like a farm tractor and when idling sounded like a busted washing machine! Well today in addition to the Mac midlength headers, Mac y pipe, and 3in hi flow cat I added an SLP Loudmouth! Man Ive been ****in clamorin for this for so long. No way I was gonna pay 750.00 for a Borla no matter what it sounds like. I heard a few Loudmouths on LS1 cars and didnt like how high pitched it was but believe you me...my dirty bird sounds like an A10 Warthog coming in for the kill with gatling guns blazin! **** yeah. Nice and deep, not too raspy, low highway drone and best of all...if you stand behind it when I get on it, your ears hurt and your nose burns.....just the way I like it.

keep your cats FTW

[Savage_Messiah]

cats suck... !cats FTW

[coldkilla]

gotta keep the cat, itll prob be too loud without it and i know that itll be inevitable that ill be pulled over. and i just know he'll look under the car and see, no cat.

[Squirrel]

Originally Posted by Savage_Messiah

cats suck... !cats FTW

guess you never heard a loudmouth without (a) cat(s)?

[coldkilla]

no, i havent how does it sound!!??

[JL8Jeff]

Like crap! The original Loudmouth exhaust was too obnoxious on the LT1 cars but the newer version with the "muffler" might be a little better. Makes your car sound like a redneck pickup truck!

[slasherbarb]

LM - Cat + Bigger Cam=

[Savage_Messiah]

magnaflow FTW

[bokey]

your better off if you take off the muffler and keep the cat... Muffler is where most of your restriction is at

[enRo]

Originally Posted by coldkilla

Oh yeah, almost forgot, the mystery catback? It was a Vortex system, stamped on the top where I couldnt see it. Who the **** is Vortex anyways?

Its a Meineke brand... so in other words, Meineke installed that exhaust. It actually had pretty good gains in my 86 TA.

[NJSPEEDER]

Originally Posted by bokey

your better off if you take off the muffler and keep the cat... Muffler is where most of your restriction is at

actually the cat is about 5times as restritive as a muffler.

[JL8Jeff]

Originally Posted by NJSPEEDER

actually the cat is about 5times as restritive as a muffler.

Wrong Tim. How many times do we have to discuss this! High flow cats flow just as well if not better than most mufflers. If you have a stock cat or a clogged cat or a damaged cat, then you'll see gains by removing it. If you put a high flow cat in it's place, you will still see gains. Craig probably saw his gains because his cat was not working properly.

[Savage_Messiah]

"muffler" is a very broad term... you talking stock, flowmaster, magnaflow, borla, loudmouth, what??? think about that

[JL8Jeff]

A high flow cat will outflow most of those brand mufflers until you get into their "race" mufflers which most likely won't pass noise inspection. Tests have shown that running dual high flow cats will actually make more torque than no cats at all and only cost around 2-5 hp vs no cats.

Here's from a test:

Chevy High Performance Magazine
LT1 Power Play covered a series of dyno tests using a 460-horsepower 396 cubic inch LT1 engine. With open exhaust, the engine produced 457 lbs/ft of torque and 455 horsepower. With Random Technology Super High Flow catalytic converters, the engine cranked out 455 lbs/ft of torque and 458 horsepower.

[V]

my monte with LT's and true dual exhaust with dual 3" cats ran like crap and had horrible bottom end. I finally switched to a new header back system with a single 3" cat, and runs great. Before i had too much flow, and some engines need the backpressure. so even if you have 100% flow with !CAT, its probably hurting the performance more than anything. I'd liek to hollow otut he cat in that car just to get the sound a little louder but i dont wanna risk messing with the flow again.

[NJSPEEDER]

Originally Posted by JL8Jeff

Wrong Tim. How many times do we have to discuss this! High flow cats flow just as well if not better than most mufflers. If you have a stock cat or a clogged cat or a damaged cat, then you'll see gains by removing it. If you put a high flow cat in it's place, you will still see gains. Craig probably saw his gains because his cat was not working properly.

i don't know where you got this.
i took a 3 month old "high flow" random tech cat off my 91 rs and picked up 1.5 mph of trap speed. it wasn't bad or clogged, it was jsut a POS cat.
you wil also note that the "high flow models all flow with in 5% of the stock replacement units. not very high flow.
last time i saw a test of cat flows a stock cat was even the highest flowing one. so much for the "high flow" aftermarket.
the flip side is that most "performance" replacement mufflers outflow stock units by 40% or more. a stock muffler wil show similar resistance to a cat, change the muffler and that problem goes away quickly.
also, an obstruction closer to the engine is more damaging to hp than an obstruction that is 7 ft further down the tubing.
the gains of ditching the cat can be further seen by taking advantage of retuning fuel tables since you no longer have tocompendate for the power robbing cat.
catalitic covertors hurt performance on every level. they cost power, gas mileage, and throttle response. there is no denying it, they just suck.

[Savage_Messiah]

Originally Posted by NJSPEEDER

they cost power, gas mileage, and throttle response. there is no denying it, they just suck.

based on personal experiance

[JL8Jeff]

You guys must have had damaged cats or damaged them with tuning. I've gone through a bunch of tests that show that high flow cats will not affect performance. Tim, your example is a single incident and you can't use it as a standard. With all the mods you were doing to the car I'm sure you somehow damaged the cat. And since removing cats is illegal it's not really an argument on a street driven car. For a track only car, no, you don't need cats obviously. I would like to see some real test numbers that show a high flow cat is robbing more than 2-5 hp.

This test result shows that the TTS Bullet cats were poor flowing but the others flowed very well and better that most mufflers. And the passenger side cat was modified to a 2.5" opening to make it an equal test and it flowed better because of the increased opening size.

Table 1
Inlet Diameter (in.) Outlet Diameter (in.) CFM @ 20.4” H2O CFM @ 28” H2O
Passenger Side
Catalytic
Converter 2.5 2.5 299.5 350.9

Driver's Side
Catalytic
Converter 2.5 2.5 268.3 314.4

TTS Bullet Catalytic
Converter 2.5 2.5 277.1 324.6

Carsound Catalytic
Converter 2.5 2.5 372.7 436.7

FLP Catalytic
Converter 2.5 2.5 376.0 440.5



Another test done on a Mustang.

[NJSPEEDER]

ok, i won't use my car as the standard. i will use the hundreds of other cars, including all the thousands of cars in NHRA stock classes that had cats from the factory.
if cats didn't cost or didn't cost more power than a muffler someone would have noticed by now and the standard would be to ditch the muffler and not the cat.
my example was a cat that was bought brand new and only use for maybe 2000 miles before being deleted. at the time it was the cat on the market claiming the highest flow of any unit available. my results are a perfect example of what a cat does to performance. a brand new part that the car improved a ton after it was removed.
it is also the same result that little g, foff667, evil90ss, projectz28, and god knows how many more people we both know saw.

[JL8Jeff]

And how many of you guys had "tuning" done which leaned the car out and destroyed the engine? So that tells you that your cat was most likely damaged by your own tuning. High flow cats will not affect power levels up to around 500 hp. When you get above that level you could still run some 3.5 or 4" cats and have minimal losses. But at that level the car is most likely not a street vehicle so why bother with cats. Did you flow test your cat after you removed it to see if it was functioning properly? Most likely not. I know I picked up power when I put a 3" high flow cat on my 93 Pace Car. Tests prove that these cats flow enough to not restrict power. So there's no reason to be running around on the street without a cat(s).

[Savage_Messiah]

Look guys, it's Jeff as a little kid!!!