Exhaust oppinion from mechanic

2004GT · April 3rd, 2007, 12:43 AM

I was recently told that the 2004 gt actually runs better with catted exhaust than it will without cats due to the backpressure difference, is this true or bs

thanks in advance

Gates

DrHolliday · April 3rd, 2007, 01:25 AM

HP is all about getting as mush air in and out of your engine as fast as possible. Cats slow that down.

Some one correct me if I'm wrong, but you will get HP gains if you get either an O/R mid pipe, or one with high flow cats. The stock mid pipe just doesn't flow enough air.

Hope this helps,
Doc

HMUSN · April 3rd, 2007, 01:44 AM

Originally Posted by 2004GT

I was recently told that the 2004 gt actually runs better with catted exhaust than it will without cats due to the backpressure difference, is this true or bs

thanks in advance

Gates

since when does your car need to run off back pressure? do you have a 4 banger? lol

drop the cats and you will see an improvment

EDIT: don't think i am being a dick... i didn't mean to come across that way.. i just saw your post count and realised that you don't know me quite yet..

i am in good intentions man

SWEET2KSTANG · April 3rd, 2007, 04:03 AM

the only negative about going with an o/r mid pipe is that you will lose bottom end torque but will gain top end power. high flow cat will give the best of both worlds and will keep vehicle leagal (if that matters to you)

matrixpuba · April 3rd, 2007, 06:40 AM

the difference in a close to stock car is only a pony or two. on a fi car the numbers are alot more.

barksdaleammo · April 3rd, 2007, 10:35 AM

think of a motor as a human. your car comes like a human breathing through a gas mask. if you take that gas mask off itll breath real easy.

2004GT · April 3rd, 2007, 11:53 AM

Originally Posted by HMUSN

Originally Posted by 2004GT

I was recently told that the 2004 gt actually runs better with catted exhaust than it will without cats due to the backpressure difference, is this true or bs

thanks in advance

Gates

since when does your car need to run off back pressure? do you have a 4 banger? lol

drop the cats and you will see an improvment

EDIT: don't think i am being a dick... i didn't mean to come across that way.. i just saw your post count and realised that you don't know me quite yet..

i am in good intentions man

its all good bro,

thanks for the advice. I thought it sounded strange when i was told that just double checkin

Gates

2004GT · April 3rd, 2007, 11:54 AM

thanks to all for the advice

Gates

CantDrv55 · April 3rd, 2007, 01:15 PM

Any engine needs the correct amount of backpressure to produce torque. Modern monolithic cats arent very restrictive at all, not like the cats from the 1980's, but they, along with the size and shape of the pipe do produce a little bit of backpressure. If you remove your cats you will lose a little bit of low end power, but the car will breathe more freely at high rpm's. If your drag racing and launching at 3,500 rpm and keeping the engine up in the power band down the whole track you will see a slight improvement with the cats removed. If your autocrossing or road racing where you constantly have to slow down for corners then speed back up, i would leave the cats on.

Jon

neckbonekat · April 3rd, 2007, 06:21 PM

Yeah, I'm getting my exhaust put on as I write this and I have a Bassani X that comes with O/R extentions and cats. The guy told me that the ony real difference that it makes is sound. The no cats is definitly louder than the cats.

02steedagt · April 3rd, 2007, 08:46 PM

how much low end power do you really loose? i had never heard that before, but i guess it makes sense.

DrHolliday · April 3rd, 2007, 09:25 PM

Bark posted a link to a site that said you lose like 2 HP on the bottom end but gain 8 hp on the top end.

barksdaleammo · April 3rd, 2007, 09:38 PM

im going to try to post good info on here every day. just look for "barks post of wisdom"

neckbonekat · April 3rd, 2007, 09:39 PM

Originally Posted by DrHolliday

Bark posted a link to a site that said you lose like 2 HP on the bottom end but gain 8 hp on the top end.

I don't know how true that is. I guess it may depend on how stock you are. I just got my car back with no cats and if anything it feels more lively than at a loss.

DanishStallion · April 5th, 2007, 10:10 PM

might run into problems if you go with to big of pipes cause of exhaust gases sneaking back in before valves closes up and it will go bang and shit.

not good for the car.

best way i can put it in engrish!

cats should not have any negative effects when removing them.

mjkids · April 5th, 2007, 10:54 PM

taking the cats off is for really the sound of it on a stock engine you dont lose that much hp only if you put to big of pipes on it. the reason is that the car is tune and program to run that way with the cats on. but i dont work on car for a living

Smoothgrandmama · April 7th, 2007, 09:58 AM

http://www.magnaflow.com/02product/dynos/ford46.jpg

Here's a dyno sheet of what magnaflows are suposed to do for You But I think they had there performance cat's on that one too

April 3rd, 2007, 12:43 AM	#1
2004GT Newbie Join Date: Feb 2007 Posts: 23 iTrader: 0 reviews	Exhaust oppinion from mechanic I was recently told that the 2004 gt actually runs better with catted exhaust than it will without cats due to the backpressure difference, is this true or bs thanks in advance Gates

April 3rd, 2007, 01:25 AM	#2
DrHolliday Enthusiast Join Date: Mar 2007 Location: New Port, NC Posts: 717 iTrader: 0 reviews	HP is all about getting as mush air in and out of your engine as fast as possible. Cats slow that down. Some one correct me if I'm wrong, but you will get HP gains if you get either an O/R mid pipe, or one with high flow cats. The stock mid pipe just doesn't flow enough air. Hope this helps, Doc __________________ Mustangless atm 2006 2500 HD Diesel. Built allison trans and other goodies

April 3rd, 2007, 04:03 AM	#4
SWEET2KSTANG mm's nitrous mod 2000 mustang gt 11.79@115.83 (old set up) Join Date: Oct 2006 Location: N.W. AR Posts: 12,540 iTrader: 8 reviews	the only negative about going with an o/r mid pipe is that you will lose bottom end torque but will gain top end power. high flow cat will give the best of both worlds and will keep vehicle leagal (if that matters to you) __________________ project warhorse under construction wagon burner under construction as well (04 lightning) being built by MP2 Performance

April 3rd, 2007, 06:40 AM	#5
matrixpuba Hardcore Enthusiast Join Date: Sep 2006 Location: tennessee Posts: 2,364 iTrader: 0 reviews	the difference in a close to stock car is only a pony or two. on a fi car the numbers are alot more. __________________

April 3rd, 2007, 10:35 AM	#6
barksdaleammo Regular Join Date: Mar 2007 Posts: 324 iTrader: 0 reviews	think of a motor as a human. your car comes like a human breathing through a gas mask. if you take that gas mask off itll breath real easy. __________________

Exhaust oppinion from mechanic

Exhaust oppinion from mechanic

Re: Exhaust oppinion from mechanic

Re: Exhaust oppinion from mechanic

April 3rd, 2007, 11:54 AM	#8
2004GT Newbie Join Date: Feb 2007 Posts: 23 iTrader: 0 reviews	thanks to all for the advice Gates

April 3rd, 2007, 01:15 PM	#9
CantDrv55 Newbie Join Date: Feb 2007 Posts: 15 iTrader: 0 reviews	Any engine needs the correct amount of backpressure to produce torque. Modern monolithic cats arent very restrictive at all, not like the cats from the 1980's, but they, along with the size and shape of the pipe do produce a little bit of backpressure. If you remove your cats you will lose a little bit of low end power, but the car will breathe more freely at high rpm's. If your drag racing and launching at 3,500 rpm and keeping the engine up in the power band down the whole track you will see a slight improvement with the cats removed. If your autocrossing or road racing where you constantly have to slow down for corners then speed back up, i would leave the cats on. Jon

April 3rd, 2007, 06:21 PM	#10
neckbonekat I Post Entirely Way Too Much 2005 Cadillac STS V8 ???????????????? Join Date: Dec 2006 Location: Upstate NY Posts: 6,344 iTrader: 3 reviews	Yeah, I'm getting my exhaust put on as I write this and I have a Bassani X that comes with O/R extentions and cats. The guy told me that the ony real difference that it makes is sound. The no cats is definitly louder than the cats. __________________ ITEMS FOR SALE! 4.10 GEARS + BEARING KIT

April 3rd, 2007, 08:46 PM	#11
02steedagt Enthusiast Join Date: Jan 2007 Location: Solomons, MD Posts: 634 iTrader: 0 reviews	how much low end power do you really loose? i had never heard that before, but i guess it makes sense. __________________ "America is all about speed. Hot, nasty, bad ass speed." Eleanor Roosevelt, 1936

April 3rd, 2007, 09:25 PM	#12
DrHolliday Enthusiast Join Date: Mar 2007 Location: New Port, NC Posts: 717 iTrader: 0 reviews	Bark posted a link to a site that said you lose like 2 HP on the bottom end but gain 8 hp on the top end. __________________ Mustangless atm 2006 2500 HD Diesel. Built allison trans and other goodies

April 3rd, 2007, 09:38 PM	#13
barksdaleammo Regular Join Date: Mar 2007 Posts: 324 iTrader: 0 reviews	im going to try to post good info on here every day. just look for "barks post of wisdom" __________________

April 5th, 2007, 10:10 PM	#15
DanishStallion Enthusiast Join Date: Sep 2006 Posts: 670 iTrader: 0 reviews	might run into problems if you go with to big of pipes cause of exhaust gases sneaking back in before valves closes up and it will go bang and shit. not good for the car. best way i can put it in engrish! cats should not have any negative effects when removing them. __________________ www.irmfclub.com

April 5th, 2007, 10:54 PM	#16
mjkids Enthusiast Join Date: Oct 2006 Location: ct Posts: 845 iTrader: 0 reviews	taking the cats off is for really the sound of it on a stock engine you dont lose that much hp only if you put to big of pipes on it. the reason is that the car is tune and program to run that way with the cats on. but i dont work on car for a living __________________ 2000 ford mustang gt convertible 2004 ford lightning truck,,,,,sold 2001 ford mustang/cobra,,,,sold 2008 ford f-350 4x4 truck 1989 ford notch back 5.0 2006 custom build bobber

April 7th, 2007, 09:58 AM	#17
Smoothgrandmama Assistant to the Manager 12 GT 8.46@88 1/8 Join Date: Apr 2007 Location: Willis,Texas Posts: 7,157 iTrader: 6 reviews	http://www.magnaflow.com/02product/dynos/ford46.jpg Here's a dyno sheet of what magnaflows are suposed to do for You But I think they had there performance cat's on that one too __________________ Join The MM Facebook: Modded Mustangs Facebook Vote For Modded Mustangs Ride of the Month Eskimo Brothers To Smooth: Safi, Blitz34, Graystang01, WillTheThrill, Bwal, 101Fng

Remove Advertisements Sponsored Links
Ford Mustang Forum Advertisement

Threads Similar to: Exhaust oppinion from mechanic
Thread	Thread Starter	Forum	Replies	Last Post
Time to kill my mechanic?	99v6stang	V6 Mustangs	5	October 31st, 2007 01:23 PM
SERIOUS need of HELP. My Mechanic can't even Figure it out**	Clever Minx	5.0 Mustangs	20	September 25th, 2007 09:26 AM
Turning 16, Considering A 96 V6. Mechanic Said Needs Work	vince1128	V6 Mustangs	46	August 31st, 2007 07:46 AM
Looking for a good shop/mechanic in NorCal	Jeffs50	5.0 Mustangs	1	June 14th, 2007 07:29 AM
So i'm a tank mechanic	jonboy	94-95	0	March 2nd, 2007 08:21 PM

All times are GMT -4. The time now is 11:08 AM.
Contact Us - Modded Mustangs : Ford Mustang Forums - Privacy Statement - Top
Modded Mustangs is ©2005-2008, All Rights Reserved, And is Not Affiliated with Ford Motor Company. Forum is powered by vBulletin ©2000 - 2012, Jelsoft Ent. Ltd. & SEO by vBSEO 3.3.2 ©2009, Crawlability, Inc.