Exhaust Last Exhaust Related Question Before The Install

Venom351R

Founding Member
Apr 27, 2002
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Ive posted a lot of exhaust questions this year but only b/c I want to do this once and get it right so here is my last concern.

I want to make sure everything lines up with the hangers correctly so of course the over all length of the exhaust system comes into play. For a quick rundown I'm running Long tubes, Mac 3" prochamber and soon to be bought Borla catback.

I'll be installing cats on this system as well which is where my concern is. Should I band clamp the cats to the end of the prochamber and then band clamp them to the collectors or should I have a section of the prochamber cut out and have the cats welded in place. So I guess what it comes down to is should I make the cats part of the length of the prochamber or should I add the cats to the over all length of the whole system by band clamping them between the prochamber and the collectors?

These are what I will be using.

http://www.summitracing.com/parts/MPE-54959/

Thanks.
 
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I'd cut the pipe behind the box of the prochamber and weld in the cats. You could always remove the cats and weld pipe back in down the road. Sucks you have emissions, it's been over 13 years since emissions was cancelled in Florida.
 
The cats should go in front of the chamber. They really need to be a little closer to the engine to get more heat. Remove a straight section of pipe and weld them in.

Kurt
 
I know they go in front lol . Just didnt know if I had to make them part of the mid pipe or extend the length by having them be between the prochamber and collectors and clamped to both.

Its not for emission purpose's its to keep it more quiet. I've heard this car w/ an O/R H pipe and its f'ing annoying
 
I'm not for super certain but if you extend the prochamber it will not fit with long tube headers.
Im going to run long tubes and doing the reserch on them you must have a specific "shorty"
H pipe/prochamber So I cant imagine how you could extend them and still fit behind the long tubes. Gotta cut and weld. Just my .02 and I am by far not an expert.
 
I know they go in front lol . Just didnt know if I had to make them part of the mid pipe or extend the length by having them be between the prochamber and collectors and clamped to both.

Its not for emission purpose's its to keep it more quiet. I've heard this car w/ an O/R H pipe and its f'ing annoying

Yeah, the chamber has to go in a particular location. You will have to remove a section of straight pipe, and place them in that location. It is best to do this with them on the car. It is very hard to guess what kind of things will interfere with the catalytic fitment.

Kurt
 
There is only a small section of straight pipe on the front of the prochamber that can be cut out and the cat welded in place so it will either work or it wont as far as fitment. There's no room for adjustment or possible other places to put the cat on the front pipe. The pipe bends before it goes into the prochamber and there is only about 9" of straight pipe to cut and I believe that is an 8" cat. I can go over a little bit length wise but I dont think I could get away with putting at 12" cat and have it still line up w/ the hangers b/c it would increase the over all length of the mid pipe

I called summit and the overall length of the cat I listed is 9 3/4 which will add a total of 1" to the pipe over all but I dont think that will be an issue. There is another one that is 8" but it costs $103 so it would be $44 extra.
 
That's a toughy. You might have to change the shape of the pipe a little bit. Are you going to have these welded in at an exhaust shop? At this point I think you are better off holding out on the catalytic converters until after the car is running. Then maybe take it to whomever ends up doing the installation for recommendations.

Kurt
 
That causes more problems.

1. The inspection sticker is 2 years old and I cant get a new one with no cats. I dont really want to be driving around with no cats on it a lot and having not driven the car since sept of 2010 I want to drive it a lot as soon as I can

2. Its going to be loud as hell w/ out any cats on it.

The very end of the pipe is going to have to be cut off anyway since I am band clamping it to the collector. When I go into the exhaust shop to have this done I'll have to ask them about it.

What if I just sprung for the extra $44 and got the cats that were 8" since the amount of pipe that is going to be cut off is 8 3/4 to the point where it starts to bend before entering the prochamber
 
Not sure I know the answer to that one. If it goes to an exhaust shop, they will be able to move the pipe around to make it fit, so long as there is room under there. My instinct is to spend the extra money on the 8" cat, because that will lead to less manhandling of the pipes to get them fit. The prochamber is mandrel bent from the factory. Most exhaust shops don't have the equipment do do a mandrel bend farther down the pipe. If they had to buy a pipe pre bent, it will end up costing more than $44/side. That's really my best guess not having it to look at. I think that will lead to less headache later on.

Kurt
 
They dont I checked. No Mid pipes for long tubes come with cats in 3" and there are not many options for 3" to begin with . I usually try to take the easy route and if buying 3" catted mid pipe was an option would have been all over it. BBK is one of the few that actually makes a catted X pipe for long tubes but its in 2.5" and I heard the flow of that mid pipe was not the best anyway.
 
Well, you pretty much have 2 choices, good flow, or good cats. Most of those really high flow cats like the ones you are getting don't burn off too well. They usually won't get a car to pass emissions.

Kurt
 
Yeah, I mentioned it knowing that you didn't have to pass emissions. I know you are just putting them on for sound quality. I was just more responding to the possibility of the BBK X-pipe that doesn't flow well anyway.

Kurt
 
I can tell you that MAC parts are terrible to fit together. Getting the prochamber and cat-back setup perfectly aligned is one of the worst jobs I've done on my car, and I've done it about 6 times.

If I'm not mistaken, aren't the prochamber hangers on that small 9" straight section of pipe? Not like you really even need them on the pro chamber anyway, but just something to take into consideration. To me, it sounds like you're in custom territory and probably better off just heading to an exhaust shop and saying "put this together".

Unless you have exhaust fab skills?
 
I dont undestand why it would need to be brougt to a shop and have them do it. If the Prochamber connects to the long tubes (b/c its meant for a set of long tubes) and if I cut off the exact same section of pipe for the length of the cat and band clamp it to the collector then throw on the catback system I dont see why I would have a ton of issues? No the hangers are not on the same section of pipe that would be cut off. The hangers are after the bend before it enters the chamber.

Its not like I have an exhaust shop across the street so driving this thing with nothing but long tubes on it to try and get somwhere is not going to be the smartest thing to try and do. Not only is it illegal it will be a huge fine if I get pulled over which will happen if I go by any cops and the chance of not going by any cops in my area is slim to none.