Removal of the rear cats...

I live in VA and I deleted my rear cats and put on flowmasters and everybody says my car is way louder than other MM's that's how they know its me! I did this about two years ago and no check engine light or nothing. I still have stock tips with the resonators and it still sounds like a beast. Even more when I get into it!
 
im not doubting you guys but i just called another muffler shop and he said my car wouldnt pass inspection and that it would use more gas just saying.. but im going with yalls word anyways..
 
If your worried about gas mileage, do as I did and get a Honda civic..and drive the MARAUDER on the weekends and on special occasions.. But it's kinda hard to stay out of the MARAUDER when u have a 97hp civic.. MARAUDERS(aka Ms. Betty Black) are to fun to not drive them for a while, then get back in them.. It feels like a new car. But it might just be me..
 
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airjordan2k8 said:
im not doubting you guys but i just called another muffler shop and he said my car wouldnt pass inspection and that it would use more gas just saying.. but im going with yalls word anyways..
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Ok. I'm going to go against my own advice...lol

My opinion regarding the above and do what you will with it: in texas (not sure of other states...and this may even be a federal emissions law), it is "technically" not legal to remove any part of the OEM catalytic convertor system unless the system FAILED/is failing. So, if someone removes the rear cats, which is part of the emissions system, the car will "technically" fail inspection because it does not have the entire OEM emissions system. If a part failed, and it was replaced, the shop that replaced it is required to give you a ticket/write-up thingy explaining what failed and what was replaced, etc. You then would take this to inspection if ever questioned about it. IN THE REAL WORLD, none of the above matters. As long as the car has at least 2 cats and isn't throwing emissions codes, it should pass. I've only had one inspector look under the car in the 15+ registrations on vehicles of mine (all ford mod motor vehicles) with rear cats removed and he didn't say anything because THE CAR STILL HAD 2 CATS. 5 of those inspections was with no EGR setup on a boosted motor and everytime the inspector opened the hood all they would say is "bet she runs like a champ."

If you want to be technical regarding inspections, any car with an aftermarket CAI like the JLT (I think the exception may be the K&N) would "technically" an inspection....just saying.

Now, regarding gas mileage...how much did this muffler guy say you would lose? 1mpg? 5mpg? If removing the rear cats had a large effect on gas mileage, there would be threads galore on every mod motor website on the mighty internet....I have yet to find one. Could it happen, sure, why not, but the fact of the matter remains there are too many variables in gas mileage and removing one set of cats to free up exhaust flow doesn't come to the forefront for me. This is just my opinion. I am not an engineer but I base my answers on research and experience.
 
PonyUP said:
This happened to me when I bought my first Marauder, took it for inspection not knowing the Cats were deleted, they checked and I failed.

Went to the shop, installed Hi-Flow Cats for a few hundred bucks, passed and din't notice a huge difference in the performance for the car or the sound.

I'd say he can do it, worst case scenario it will cost a few hundred dollars to get it back as a lesson learned
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Were all the cats deleted or just the rear cats?
 
I tell you what...I will be removing part of my exhaust from the engine block to the mufflers in a couple weeks (I hope). The parts being removed are the stock manifolds, front cats, straight pipe (i.e., rear cat delete) to 2.5 inch X-pipe to mufflers. If you are concerned about the consequences, get that and if there is a problem you can bolt your old system right back up.
 
Bingo, just keep your cats that are cut off, and if you have problems, have the same shop put them back on. You could also take your car in and get a new inspection done and see if they check the cats visibly. If they do, you could have the cats taken out, put in a replacement pipe, and have bolt-in flanges put on your exhaust and on both the cats and the replacement pipes. That way you can bolt the cats in each year before inspection time.

I don't really have a desire to take my cats off, but I will say the two best sounding MMs I have heard in person both had only 1 pair of cats.

It could be worse. Some of the 96-98 4.6 Mustangs had 3 PAIRS of cats!

Do any of you other old farts out there remember back in the late 70s and early 80s when JC Whitney sold "test pipes"? Replaces the catalyctic converter "for test purposes only"!!! Hardeeharhar!
 
mrjones said:
Bingo, just keep your cats that are cut off, and if you have problems, have the same shop put them back on. You could also take your car in and get a new inspection done and see if they check the cats visibly. If they do, you could have the cats taken out, put in a replacement pipe, and have bolt-in flanges put on your exhaust and on both the cats and the replacement pipes. That way you can bolt the cats in each year before inspection time.

I don't really have a desire to take my cats off, but I will say the two best sounding MMs I have heard in person both had only 1 pair of cats.

It could be worse. Some of the 96-98 4.6 Mustangs had 3 PAIRS of cats!

Do any of you other old farts out there remember back in the late 70s and early 80s when JC Whitney sold "test pipes"? Replaces the catalyctic converter "for test purposes only"!!! Hardeeharhar!
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Are you sure there were a third pair of cats? I know the mid-90's Ford was putting resonators in-line before the mufflers.
 
airjordan2k8 said:
im not doubting you guys but i just called another muffler shop and he said my car wouldnt pass inspection and that it would use more gas just saying.. but im going with yalls word anyways..
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Are you going to believe some dork at Midas, or people that own these cars and drive them everyday?:confused:
 
I still don't get how someone would argue a noticeable negative impact on fuel economy from removing a secondary unmonitored set of cats. I'm thinking either he doesn't understand this car, he doesn't understand how emissions control systems work, or he's just feeding you a line to try to make you not want to attempt the modifications of your own mind instead of him having to refuse you.
 
Has anyone tried running with 4 cats and no mufflers? If the cats eat up a good proportion of the engine noise, maybe the mufflers aren't needed.

That might come off as ridiculous, but I really am curious. If the main reason people remove cats is for more sound, wouldn't removing or swapping the mufflers also work?
 
Thanks everybody for yalls input on all this.. got it done sounds a hellofalot better and its true i do give it a lil more pedal to hear it... thanks again.. very impressed with the results....
 
airjordan2k8 said:
im not doubting you guys but i just called another muffler shop and he said my car wouldnt pass inspection and that it would use more gas just saying.. but im going with yalls word anyways..
Click to expand...

I just did this very thing... removed rear cats this week... I have looked at my mileage and your mechanic is 100% accurate... does he sell tires too???? reason being, with the change in the sound, not only have my mileage went down, I am also loosing more tread from my tires.... cant make the connection though....

Wait, I think I get it, my car sounds so much better that I give it more gas (AKA HEAVY RIGHT FOOT) which A: means worse gas mileage and B: leaves my rubber on the road......

So, there... the mystery is solved....

Tux!
 
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