Cats=torque?or no cats=topend?

5.0TailPipeHump · Jan 29, 2008

Going to be doing my exaust when it warms up and am wondering if i should throw some new cats on . i was going to go the offroad way but now its got me thinking , iv been doing abit of reading and herd that if i go without cats my topend would gain but my torque would suffer , is this true.
btw i have 2 cats on @ the moment.

I dont want to lose any torque but rather gain some.

tim_lemmy · Jan 29, 2008

split the difference and get rid of one and keep one lol

85_SS_302_Coupe · Jan 29, 2008

Cats = restriction

No cats = More Torque + Top End

87foxstang · Jan 29, 2008

To be honest but not to steer you away, I actually "thought" i lost some with the O/R h-pipe. I had to bring my car through emissions so I had a 2 1/4" original h-pipe with cats on. Once I passed I took them back off and threw the O/R H back on. Now the first ride with the off road pipe I thought I lost some low end and gained some top end. It seemed very minimal and nothing to cry over but I thought i noticed something. Either way, the O/R pipe is the way to go

Mustang5L5 · Jan 29, 2008

You lose a little low end torque.

Counter it with gears like 3.73's or 4.10's

ninety15.0 · Jan 29, 2008

It's not really like you actually loose any amount of torque, you just move the powerband up a few rpm. Well thats how i think of it anyways.

87foxstang · Jan 29, 2008

ninety15.0 said:
It's not really like you actually loose any amount of torque, you just move the powerband up a few rpm. Well thats how i think of it anyways.

exactly

GTA_V6_Mustang · Jan 29, 2008

I would just go with a set of high flow cats, like me I have no complaints here. Plus you dont get out of your car smelling like a gas station attendant.

Mustang5L5 · Jan 29, 2008

+1 on the high flow cats.

When i was a teen i thought off-road H-pipe cars were the balls. I loved riding around in my friends cars with them.

Now that i'm older, i just think it's way too obnoxious and smells. High flow cats for me.

Fast63 · Jan 30, 2008

cats do not make any significant change in power or characteristics, talking a couple of hp or torque. I would not factor any of those two things into choosing whether or not to use them. They change sound and smell and that's about it.

5.0TailPipeHump · Jan 30, 2008

Mustang5L5 said:
You lose a little low end torque.

Counter it with gears like 3.73's or 4.10's

Now why didnt i think of that ! , btw are most exaust kits just a straight bolt on or is there any welding involved, id like to tackle this myself if i can but thats if its just a bolt on a go. i cannot weld and the car has a previous exaust that the 1st owner put on .

Thanks for the replies
Garry

87foxstang · Jan 30, 2008

Their bolt and go

stykthyn · Jan 30, 2008

depends on the kit, some weld in and some bolt and go. IMHO the weld in kits are better quality.

87foxstang · Jan 30, 2008

I rarely see any weld in...but yea make sure the site where you buy it from tells you. Most are bolt in

LXstang5.0 · Jan 30, 2008

im goin thro the same delimma. plus im running dumps so i think im ganna go wit cats cuz my car smells already. prob an x pipe

5.0Torx · Jan 30, 2008

guys youre talking about a few hp and a few ft-lbs. You wont feel the difference on that mod alone. usually youll feel the difference if you go from the stock 4 cat H pipe to an OR H pipe because the OR H Pipe is probably 2 1/12 inches in diameter. the gains from exhaust compound. If you have just a catback, youll maybe feel a small difference. if you ahve full exhaust, itll be an animal compared to stock.

I went from a 2.5" OR Xpipe with dynomax super turbos to a catted 2.5" Xpipe with SLP loudmouths and it feels alot stronger on top end. i attribute that to the LMs, not the cats. Also, the stock H pipe has 4 cats, most aftermarket ones only have 2. Ironically, i passed smog with signifcantly better numbers with the brand new X Pipe than i did with the 100k mile stocker. If your car has to have emissions, do yourself a favor and take that 2 hp hit and save yourself the trouble of changing mid pipes every year or two years.

JMO

Sicarius428 · Jan 30, 2008

The stock cats are pretty restrictive and they don't get better with age. I suggest some hi flow cats and be done with it.
Kevin

v8only · Jan 31, 2008

5.0Torx said:
guys youre talking about a few hp and a few ft-lbs. You wont feel the difference on that mod alone. usually youll feel the difference if you go from the stock 4 cat H pipe to an OR H pipe because the OR H Pipe is probably 2 1/12 inches in diameter. the gains from exhaust compound. If you have just a catback, youll maybe feel a small difference. if you ahve full exhaust, itll be an animal compared to stock.

JMO

Fast63 said:
cats do not make any significant change in power or characteristics, talking a couple of hp or torque. I would not factor any of those two things into choosing whether or not to use them. They change sound and smell and that's about it.

on a stock motor, this is correct, you won't really gain anything.

However, on a full h/c/i bolt on 5.0, that's completely wrong. My friend runs a 5.0 with afr 165's, eddy 2 intake, custom cam, etc etc. He dyno'd it with the HI FLOW 2 catted h pipe, then switched it out for an offroad pipe and picked up 21 hp.

On an engine with mods, running no cats over hi flow cats make a BIG difference in power.

they do, however stink like hell with no cats...and imo is not worth running like that on a street car.

5spd GT · Jan 31, 2008

v8only - Was that dyno run on the same day, dyno, mileage? I would expect a gain, but that is more on the significant size, but not unbelieveable.

v8only · Jan 31, 2008

i'll hit him up, I'm curious too.

Cats=torque?or no cats=topend?

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