How much power/sound will i lose with hi-flo cats?
11-13-2006, 01:30 AM
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How much power/sound will i lose with hi-flo cats? Hey I have LT's with an ORY and some sort of mufflet equivalent to a flowmaster 80 series, i think. Anyways, I will be changing my setup to 2.5 inch tru duals with hi flo cats and dynomax bullets. Will i lose alot of sound or power at all or gain sound/power? I love how loud my setup is and i dont want to sacrifice too much sound... Any input would be appreciated.
11-13-2006, 04:36 AM
#2
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Good CATS will cost next to nothing in flow, and thus will cost next to nothing in HP. They will affect the exhaust pressure wave and there's no way round it, this may loose some HP potential but for most it is minimal.
You need a CAT which can flow 2.2cfm per HP. On duals you can divide by 2 because one cat is only dealing with 4 cylinders and thus half the HP.
So if a bolt on LS1 is making 400bhp SAE Net then you will need CATS which can flow:
(400 x 2.2) / 2 = 440cfm per CAT.
Most CATS are ceramic CATS. The Magnaflow Carsound CATS are pretty decent for the price (check Ebay for best prices). And they will flow well enough for next to no HP loss on a full bolt on LS1 and will only be a minor restriction on a cammed LS1.
You WILL need the 3" core inlet/outlet ones.
For the ultimate CAT you will need metal matrix (Magnaflow or Random Technology 7000 Series). Again in 3". These out flow many mufflers and will not affect HP on upto 550bhp motors. They are however more expensive.
Yes CATS will affect db level of the exhuast, generally they will help tone and remove any rasp. If you are worried about it being too quiet just fit smaller shorter mufflers. Case diameter and amount of packing affects db level as does the length of the muffler.
You need a CAT which can flow 2.2cfm per HP. On duals you can divide by 2 because one cat is only dealing with 4 cylinders and thus half the HP.
So if a bolt on LS1 is making 400bhp SAE Net then you will need CATS which can flow:
(400 x 2.2) / 2 = 440cfm per CAT.
Most CATS are ceramic CATS. The Magnaflow Carsound CATS are pretty decent for the price (check Ebay for best prices). And they will flow well enough for next to no HP loss on a full bolt on LS1 and will only be a minor restriction on a cammed LS1.
You WILL need the 3" core inlet/outlet ones.
For the ultimate CAT you will need metal matrix (Magnaflow or Random Technology 7000 Series). Again in 3". These out flow many mufflers and will not affect HP on upto 550bhp motors. They are however more expensive.
Yes CATS will affect db level of the exhuast, generally they will help tone and remove any rasp. If you are worried about it being too quiet just fit smaller shorter mufflers. Case diameter and amount of packing affects db level as does the length of the muffler.
11-13-2006, 11:26 AM
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if your gonna go true duals.. why go cats?
Cats on a y pipe is a must due to rasp.. but there is no real rasp on true duals..
I say get some bullets and skip the cats.
I have LT x pipe 2.5 inch 4 magnaflow bullets over the axel mandrel bent exhaust with heads and ms4 cam and it is LOUD and SICK.
Anyone that hears my exhaust WANTS ONE IMMEDIATELY.
Cats on a y pipe is a must due to rasp.. but there is no real rasp on true duals..
I say get some bullets and skip the cats.
I have LT x pipe 2.5 inch 4 magnaflow bullets over the axel mandrel bent exhaust with heads and ms4 cam and it is LOUD and SICK.
Anyone that hears my exhaust WANTS ONE IMMEDIATELY.
11-13-2006, 01:24 PM
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Originally Posted by Wyckedcamaro
if your gonna go true duals.. why go cats?.
11-15-2006, 10:36 PM
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Yes it is for emissions... the tru dual system will be 2.5 inch over the axle... maybe 3. And i already have the dynomax bullets. Im hoping that the cats will just help the tone and not reduce sound by too much. Thanks for all ur input guys.
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11-16-2006, 04:01 AM
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I know... but i dont know of very many ways around it... Plus the shop that quoted me for the duals wont even do it w/o cats... which kinda turned me off. I might have another shop in MD do it instead w/o cats which would be ideal.
11-16-2006, 04:23 AM
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Originally Posted by BirdmanLS1
I know... but i dont know of very many ways around it... Plus the shop that quoted me for the duals wont even do it w/o cats... which kinda turned me off. I might have another shop in MD do it instead w/o cats which would be ideal.
Personally I think it would sound mean as f*ck with a real agressive tone
and still be plenty loud enough for all but the nutters out there.I'd get the shop to custom make the H (would be real easy) and have it placed far enough forward that there was room to fit a body mounted torque arm.
If I ever change my exhaust setup (FI reasons) then this is the setup I'll be running, accept I'll probably have the exhaust exit each side of the car just in front of the rear wheel using a dual 2.5" outlet exhaust tip.
11-16-2006, 08:57 AM
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I think Patrick G or someone tested high-flo cats with and without at the 450 rwhp level, and lost only 10 rwhp with. I believe they were Magnaflow ceramic cats. I ran those same cats on my duals and didn't pick up any rwhp compared to stock cats, but picked up over 20 lb/ft in the midrange from the duals with cats.
Lol, riiiiiiiiight. 
Originally Posted by orangeapeel
Cats in true duals? 
11-30-2006, 02:14 AM
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Dam... i just wish i could go without cats... ugh, emissions are such a PITA. Would a shop install an off road h-pipe setup? I dont care about the piping size as much as i do the dam cats...
Last edited by Ragtop 99; 11-30-2006 at 10:45 AM.
11-30-2006, 09:42 AM
#14
Originally Posted by orangeapeel
Cats in true duals?
I'd flange the cats and make them removable if I ever did it again. I put cats into my TSP duals and it tamed the sound quite a bit, and I felt no power loss even with 400rwhp and $50 ebay cats. Check link in sig.
11-30-2006, 01:37 PM
#15
If you do not want to reduce noise by going with cats, go with the Metallic Cats from Magnaflow. Dynomax bullets have a bigger reduction in noise then these cats do. These are the cats that everyone in the shop runs in their vehicles, and by far the most popular cat that we sell. Haven't received a single complaint about them yet.
We sell them for $179 shipped for a pair. We can also get you an excellent price on the standard high flow ceramic cats from Carsound.
We sell them for $179 shipped for a pair. We can also get you an excellent price on the standard high flow ceramic cats from Carsound.
11-30-2006, 05:55 PM
#16
Cats vs no cats sounded way different to me! No cats sounds better/louder. I have Flowmaster 1 chambers on my duals. It didn't have that flowmaster sound with the cats, till I gutted them.
With cats
No cats or balence pipe
BTW...since I have the H pipe in now, it sounds much nicer and equal sound from both pipes.
With cats
No cats or balence pipe
BTW...since I have the H pipe in now, it sounds much nicer and equal sound from both pipes.
11-30-2006, 10:20 PM
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Originally Posted by Tim @ EAD Performance
If you do not want to reduce noise by going with cats, go with the Metallic Cats from Magnaflow. Dynomax bullets have a bigger reduction in noise then these cats do. These are the cats that everyone in the shop runs in their vehicles, and by far the most popular cat that we sell. Haven't received a single complaint about them yet.
We sell them for $179 shipped for a pair. We can also get you an excellent price on the standard high flow ceramic cats from Carsound.
We sell them for $179 shipped for a pair. We can also get you an excellent price on the standard high flow ceramic cats from Carsound.
12-07-2006, 11:52 PM
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Originally Posted by CaMaRo67RS355
true duals aint true duals with cats
