Cats or no cats?

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Race96Red

New Member

Feb 11, 2009

5

0

0

Durham, North Carolina

Mar 29, 2009

#1

• Mar 29, 2009

• #1

First post... been coming to this site for years and have never posted anything I hope this don't sound stupid.

I have a Brother in-law that worked for Summit Racing for years and now runs a local branch of a national car parts store. He is usually the go to guy for car questions. I asked him last night about which non-catted or catted x or h to put on my 07 GT. He said that no cats will hurt the car and is for off road use only. I understand that it will not pass the sniffer test and I was under the impression that it will not hurt the car. He also said that I will only gain 2-3 more HP from the O/R compared to high flow cats and/or over the stock H. He said high flow are almost the same as the factory cats.
What do you guys have installed and have you had any problems? Is their a difference in HP between the three (catted, non-catted and high flows). Is it worth the money to go with high flows....?
Need help to complete the system. Can't put my headers on without going with a different x or h.
Also, are the delete plates worth it?
This is what I have on my car now...
C&L Racer CAI, SCT X3 93 tune and Pypes MM system.
I have these parts but not yet installed... MAC LT Headers coated, 4.10 gears (ordered), UDP and throttle body spacer. I am waiting to install the rest of the part after I make the decision on which X or H pipe to put on the car. I want to get all the parts installed and have one more tune done and be done with it.

Please help...

Thanks.

 

300

New Member

Feb 25, 2009

38

0

0

New York

Mar 29, 2009

#2

• Mar 29, 2009

• #2

Keep the cats and go with suspension mods.

 

NastyStang113

New Member

Sep 12, 2008

1,567

1

0

Florida

Mar 29, 2009

#3

• Mar 29, 2009

• #3

Losing the cats is worth ~4-5 rwhp. It will not hurt the car, either. As far as the delete plates. The economy plates are worth it. They will net you around ~6 rwhp peak and about ~9 in the mid range. They do require a custom mail order tune at the minimum. I'd highly recommend getting a tune from VMP Tuning.

 

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Race96Red

New Member

Feb 11, 2009

5

0

0

Durham, North Carolina

Mar 29, 2009

#4

• Mar 29, 2009

• #4

I guess my question should be, do I go with a catted or non-catted X or H with the Mac LT headers? And do I have to go with a mid pipe from MAC? Are their Headers true LT's or are they shorter then true LT's. I can't tell by looking at them. That's another reason I stopped installing parts because I didn't order the Headers with the mid pipe like an idiot. And I didn't know if I should go with cats or not and h or x. Can't find a good video with Mac LT's, Catted H and Pypes MM System.
And I will get a re-tune from Brenspeed when everything is installed. That's who I bought my tuner from. Then after the HP Mods are complete I will then focus on the suspension.
I've only had this car for a month or so. My last one was a 04 GT that was easier to work on without having all these tunes done. I'm getting to the point with the Mods that I felt I can't do this without doing that. With my old car I could bolt and play. I have everyone (local) now saying you can'y do this without doing that so I just stopped. Now I'm coming to you guys and I thank everyone in advance for the help.

Thanks...

 

ufnavy06

Member

May 23, 2006

292

0

16

Jacksonville, Florida

Mar 29, 2009

#5

• Mar 29, 2009

• #5

I have the MAC LT. I went with the O/R Prochambers as well and no problems. I mean if you go with MAC LT, it'll probably be easier to match pieces up if you go with one of their setups. However, you don't have to use theirs. I went with theirs because it was a package deal from Brenspeed and I've been very happy.

 

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Race96Red

New Member

Feb 11, 2009

5

0

0

Durham, North Carolina

Mar 29, 2009

#6

• Mar 29, 2009

• #6

Thanks for the chamber idea, and by the way I have the same Vista blue with the white stripes. I never thought or considered the Pro Chambers....hhhmm. Do you have or do you know where their are any sound clips?
Also are these Mac LT's full length headers? and do you need O2 extensions?

 

06bluegt

New Member

Mar 20, 2009

46

0

0

Circleville, Ohio

Mar 29, 2009

#7

• Mar 29, 2009

• #7

pro chamber and hpipes have more restriction then an xpipe so try to stick with an xpipe if possible better flowing exhaust

 

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Race96Red

New Member

Feb 11, 2009

5

0

0

Durham, North Carolina

Mar 31, 2009

#8

• Mar 31, 2009

• #8

I ordered the O/R x pipe to go with the MAC LT's. I don't know if their is enough room to put in high flow cats if I want to install them later. So I think i'm going to buy the catted x pipe next week as well. I just installed pypes o/r x I got from a friend (he's waiting on more parts to install his exhaust), just wanted to see how loud that was going to be. I think im going to use his set up for a while, a week or two till his parts come in, and see if my neighbors and "the wife" get mad about the noise level before installing the LT's with o/r x. Better to ask for forgiveness then permission sometimes.
BTW... it sound great with the pypes o/r x now, I can't wait to install the LT's! He may not get these back, i may sell him the MAC's and the mid pipes...

Thanks to all of you for the advise.

 

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o0Dan0o

Founding Member

Feb 8, 2001

485

1

0

Mar 31, 2009

#9

• Mar 31, 2009

• #9

The Macs are mid length headers. I personally would have gone with the prochamber, but I don't believe it really makes any difference, power wise. You can always have cats welded in to you setup, though they will be lower than stock which shouldn't be an issue.
Dan

 

69mach1-409

Member

Apr 21, 2004

81

0

16

South Jersey

Mar 31, 2009

#10

• Mar 31, 2009

• #10

On a Dynojet Dyno I gained 8rwhp and 10rwtrq going from a stock H-pipe to an 'offroad' Prochamber. They were done within a month or so of eachother and were done on the same dyno... because of the time gap I ask that you take the results 'with a grain of salt'.

*I'm not promoting MAC in anyway, just giving the op some dyno numbers*

 

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blbrchnk

New Member

Oct 16, 2006

268

0

0

Bridgeport, WV

Mar 31, 2009

#11

• Mar 31, 2009

• #11

69mach1-409 said:

On a Dynojet Dyno I gained 8rwhp and 10rwtrq going from a stock H-pipe to an 'offroad' Prochamber. They were done within a month or so of eachother and were done on the same dyno... because of the time gap I ask that you take the results 'with a grain of salt'.

*I'm not promoting MAC in anyway, just giving the op some dyno numbers*

Click to expand...

Back when I ordered my Pypes O/R H-pipe from Brenspeed, those are the exact numbers that they had posted on their website that they got from testing. 8rwhp, 10rwtrq.

 

UrbanRedneck

New Member

Mar 27, 2008

173

0

0

Apr 8, 2009

#12

• Apr 8, 2009

• #12

Well your only options for your MAC headers are either an offroad prochamber or the offroad X pipe that Brenspeed sells. Noone makes an H pipe for them, and midpipes for stock cars will not work. To answer your other questions, the MAC headers are mid-lenth long tubes, so to speak. Longer than a mid lenth, shorter than a long tube. BUT The mid-lenth longtubes like Mac and Kooks make more power than full-lenth long tubes. As far as cats, there is enough room to add high flow cats if you so desire.

 

gmantheman

Member

Dec 30, 2007

483

1

16

Escondido, CA

Apr 10, 2009

#13

• Apr 10, 2009

• #13

With the stock H, Steeda UDP, JLT and Bama 91 tq tune I was at 298 RWHP, 309 RWTQ
Off Road Prochamber 302 RWHP, 305 RWTQ
With Magnaflow hi-flow cats 302 RWHP, 312 RWTQ.

This was on the same dyno, but on different days. IMO, hi-flow cats are worth the money.

 

69mach1-409

Member

Apr 21, 2004

81

0

16

South Jersey

Apr 10, 2009

#14

• Apr 10, 2009

• #14

How did adding restriction to your exhaust add power? ..was your car tuned for the off-road pipes?

 

chad9350

New Member

Jan 13, 2007

248

0

0

Lake Charles, LA

Apr 10, 2009

#15

• Apr 10, 2009

• #15

cut em out, gut em... get rid of em!

 

gmantheman

Member

Dec 30, 2007

483

1

16

Escondido, CA

Apr 10, 2009

#16

• Apr 10, 2009

• #16

W/O cats there is no backpressure. I could feel a loss of power down low, but an increase around 2500-3000 RPMs.

 

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Race96Red

New Member

Feb 11, 2009

5

0

0

Durham, North Carolina

Apr 10, 2009

#17

• Apr 10, 2009

• #17

Thanks for all the information and opinions. My laptop went down after posting this so I didn't get a chance to read anything or post back.
I still have the pypes o/r x with the mm on my car. I really don't like the tone. It's ok but not what I want.
I just seen a clip on youtube with a 07 GT with the Kooks LT, catted x and mm system. WOOOW! That's the sound I'm looking for. I also like the Magnapack that i heard as well.
I ordered the catted x and i hope to get everything installed this weekend.
BTW my wife hated the o/r x for the first couple of rides now she said she "kinda likes it". I think I'm going to be happy with the catted x...

Thanks guys...

 

jasonh328

Member

Mar 13, 2007

40

0

7

Apr 10, 2009

#18

• Apr 10, 2009

• #18

I am running an o/r h pipe with SLP Loud Mouths. I installed 18" resonators after the H pipe to keep it from being basically a "straight pipe" setup and to maintain some amount of backpressure. I have no cats and no mufflers and I have experienced no loss in hp or tq. I'm running a Brenspeed tune and the mods listed below.