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 :D

[ar0ck]

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

[Squirrel]

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]

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= :barf:

[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]

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]

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]

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]

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]

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

:stupid: 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.
http://www.pypesexhaust.com/images/94must-dyno03.jpg

[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!!! :lol:

http://www.fstones.com/photos/2003/Maymont/TreeHugger.jpg

[JL8Jeff]

And I still have that tree!:grin:

[Savage_Messiah]

:lol:

[NJSPEEDER]

and on that mustang did they do anything else to compensate for not having the cat there any more? take out fuel? add timing?
maybe f-bodies just have a better response to getting rid of them since everyone seems to pick up enough power to add at least 1 full mph to their trap speeds, even with out tuning.

[camaro2you]

sounds great in person!!!

[Tru2Chevy]

sounds great in person!!!

:werd:

It sure did sound great, both in the parking lot, and on 55 heading to the meet.

- Justin

[JL8Jeff]

and on that mustang did they do anything else to compensate for not having the cat there any more? take out fuel? add timing?
maybe f-bodies just have a better response to getting rid of them since everyone seems to pick up enough power to add at least 1 full mph to their trap speeds, even with out tuning.

Tim, you keep comparing to stock cats and that's not the point I'm making. All your examples except for your car were people removing a stock cat. Every car will pick up power removing the stock cat, but a high flow cat will make almost the same power as no cat. You can lean it out and add timing to pick up 5 hp but your motor will not last very long as proven by all those guys who lost their motors. Your car was tuned for no cat so you added a high flow and damaged it with a too lean mixture, then you blame it on the cat. The Chevy High Performance test I quoted above was done to make maximum power so I would think they tuned it without the cats and with the cats and made the same power. There have been lots of tests done showing virtually no loss of power. Your car was not a real test because of the way it was tuned. A catalytic converter is a normal maintenance item and when it has high miles it won't function like it was new. So replace it with a high flow cat and stay legal. Tune the car for the high flow cat. You change plugs, wires, air filters so change the cat.

[WayFast84]

crap I guess I shoulda got a high flow cat then huh? well I have the cut out so...

[NJSPEEDER]

actually jeff, my car still had a stock chip in it. that means there was plenty of fuel and no timing, not to mention that the car was not daily driven in the few months teh cat was on. assuming the cat was damaged somehow is not an answer for disputing my claim. it was only about 3months old when removed, had stock fuel and timing tables fed to it, and was driven 2000 miles at most. it was a random tech"high flow" cat and i saw a huge gain from eliminating it. and that was after i saw no gain at all going from stock 2 1/2 to 3inch too.
the result of huge gains from going to cut outs and !cat has been proven time and time again. it takes a lot more than 5hp to see the gains i found by ditching a "high flow" cat, and it certainly shows much larger gains once you tune the engine since there is no longer the need to dump excess amounts of fuel into the engine just to protect the cat from overheating.
if anyone has lost a motor due to tuning after cat removal they messed something up pretty bad. i drove my camaro on the street, autocross, and drag strip for 3 years after i got rid of the cat and had no ill effects on the engine.
if you choose to believe a magazine test that was done to sell some parts instead of real world results, that is your mistake. look at all teh people you know who have gone !cat and every NHRA stock class car that has ditched them. if having a cat helped or didn't cost horsepower, there would be a national record holder somewhere on this planet with one, but there isn't, so that kind of settles that.

[Savage_Messiah]

Mien was going from a 3" carsound highflow as well, not stock

[coldkilla]

sounds great in person!!!

It sure did sound great, both in the parking lot, and on 55 heading to the meet.

Thanks guys!

[JL8Jeff]

Tim, you're still missing the point about these being street driven cars. NHRA cars are race cars. You keep recommending that people break the law and remove their cats. That is not wise advice. And most of the tests that I have seen and referred to were done by independent testers and had no association with one of the cat manufacturers. Your car must have had a bad cat. Does that make all of them bad? No. In the end, is it worth the risk of losing the car and paying a large fine because you removed the cats to pick up 5 hp? There is a big push going in CA right now and they're yanking cars off the street left and right and people have to pay a fine($1000-1500) and then make the repairs to be emission's legal before they can re-register and get the car back. Is it worth it for 5 hp? Not if you have to drive the car to get to work. If it's a race car then it doesn't apply since it won't be driven on the street. If you're gonna remove the cats you might as well yank the EFI and put a carb on since your setup is illegal.

[JL8Jeff]

Mien was going from a 3" carsound highflow as well, not stock

Your car has a lot more issues with it so blaming the cat won't do any good. Your battery hold down is costing you 10 hp!:laugh:

[NJSPEEDER]

i don't know anyone who has ever been pulled over and been busted for their exhaust. and when i say that i include the times that i was pulled over because of how loud my 91 was.
you may also have noticed that we don't live in the republic of california.
you seem to also STILL be missing the fact that it takes more than 5hp to see teh gains that are involved with removing the cats.

bascially jeff, run it in all the circles you want. !cats is a an easy and economical mod that has been proven to show huge gains in f-bodies and has little to no downside.

[JL8Jeff]

bascially jeff, run it in all the circles you want. !cats is a an easy and economical mod that has been proven to show huge gains in f-bodies and has little to no downside.

Other than being illegal. Times are changing and they are cracking down on illegal vehicles. Look at RyanFX who had his tint done last year and just got pulled over for it. He's going to get hasseled constantly for that. And the huge gains are acquired by removing the cat and adding tuning. Did you ever try tuning for the high flow cat? No. Tuning with a high flow cat will get you within 5 hp of no cat. But I honestly don't care if everyone removes their cats. I just don't think it's good advice to tell people to remove them since it's illegal. There better ways to pick up power and stay legal. If you're removing a cat then you better be removing the muffler as well since that's a bigger restriction than the cat. That usually means a cut-out. So put the cut-out in front of the cat(not that a cut-out is legal either).

[Savage_Messiah]

My car was originally tuned w/ the high flow on.

It's illegal don't do it... if I ever see you going more than 26 in a 25, 41 in a 40, 56 in a 55, etc i'm gonna bitch you out. :lol: