MRT Catted H-pipe / Magnaflow Install ?

ctstanger said:

I'm finishing up the install but still have LEAKS!

One is on, I think, the driver side midpipe to header. I "impact wrenched" it a second time and it wasn't fully seated (or atleast it turned a few more times). I'm guessing the RTV cured with a gap the first time, so I will remove, re-RTV and impact wrench the heck out of it the third time.

But I have a question on the U-Bolt clamps. Both tailpipe to muffler connections are dripping water, thus leak exists. The tailpipe is the "female" and has SLOTS that goes in probably midway through the ovelap with the muffler. WHERE is the ideal place to clamp down? I've been trying to clamp AFTER the slot, but it's obviously not working for me. Should it just be in the middle of the ovelap? Or nice and clost to the mufflers?

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Ok now wait a second, why are you using RTV on an exhaust mating surface? RTV doesn't hold up well to high pressures or extreme heat like that. Is this something new that is popular that I missed out on?

I have 2 potential answers for your second question.

1) If you insist on using those clamps, then get yourself a 2 or 3 inch long section of the next size up pipe, and slip it over both the muffler and the pipe side, and use the clamps over that piece. That'll act as a band clamp (which would be the preferred type of clamp if you really want to use clamps.)

2) My second and best advice would be to temporarily throw those u shaped clamps on, and drive yourself to an exhaust shop to have it all mig welded. Most shops will charge you ~30 bucks (some less if you just spend a few seconds chit-chatting the guy about cars or sports or jockstraps or something) and you won't ever have to worry about it leaking again. I weld crap myself, with a 100 dollar flux core welder I got from Harbor Freight tools, and it's probably the best investment tool-wise I've made in the last 10 years.

Are you sure they are leaks? Can you feel the exhaust pulses? Many times new pipes sound airy.

I don't know how to conclusively check for leaks but when my Prochamber was new, I swore it was leaking. A week or two later, it quit sounding hissy.

I wonder if you bent the flanges on the mid-pipe or the exhaust manifold using that impact.

One way to check for leaks is light up a cigar, and climb under the car... blow some of the smoke up where you suspect the leak, and if the smoke visibly blows in one direction, etc. Of course this doesn't work too well if it's windy outside.

You can also Seafoam through a vac line, then wait 5 mins or so and turn it back on then quickly crawl back under and check for smoke leaking around connections.

Soapy, or any water for that matter, just burns if the pipes are hot even in the slightest.. so you have a few seconds maybe to check for bubbles with that method.

As far as your question about welding, I would proably weld along the slots if there isn't enough to cut the "slotted" part off the pipe. Normally, it's just a matter of welding around the end of wherever one pipe overlaps another. Welding the top is obviously hard. I don't know how I would do that with a tig. With a Mig, or FCAW (what I use) you just find the best position you can get the gun in there, then use a longer stickout to get to it.

propellerhead said:

I don't know how to conclusively check for leaks but when my Prochamber was new, I swore it was leaking. A week or two later, it quit sounding hissy.

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Mine did the same thing.

propellerhead said:

I don't know how to conclusively check for leaks but when my Prochamber was new, I swore it was leaking. A week or two later, it quit sounding hissy.

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i concur.

i put a catless x on my car, and got that low end hiss whenever i put the motor under a load, and i was almost positive i needed to get under there when the weekend comes to re-tighten all the bolts.

once the weekend came and i put about 100 miles on the setup, that low end hiss was gone, and it sounds like a exhaust should, LOUD and PROUD!

so yeah, id give it a week, let it "break in" so to speak.

I put the mrt catted h on my mach I along with the magnapack catback. You don't need to really worry about welding the catback yet, especially if you plan on doing any major rear suspension work. The leak you describe is definitely for real, mine was pretty loud on the low end when I first installed mine. I never could track down the leak precisely (I tried everything - bubbles, notebook paper etc. except for the sea foam and I like that idea!) but I knew it was coming from the header/midpipe joints. All I can tell you to do is everyweekend get under there and tighten the bolts down as much as you can. Eventually you'll get the hiss under control. I can only faintly hear mine now when its really cold, I have the radio off, and I'm giving wot in 5th gear at 1500-2000rpms. I'm satisfied with the situation now, but after trying for so long I'm sure that my midpipe will never be completely leak free. Good Luck.

Oh yeah, the sea foam. sgarlic was referring to this: http://www.seafoamsales.com/motorTuneUpConsumer.htm
You can get at any autoparts store. The product is meant to help clean out carbon deposits from your engine. The reason you should try this is because one of the side effects of the process is that when you run the engine, a great amount of thick smoke comes pouring out of your exhaust pipes for a few minutes.

However, if you are going to try this I would suggest that you get some kind of protective breathing mask. I've heard of this smoke staining the side of buildings, so I can only imagine what it will do to your lungs. Just search for seafoam on the forums and you will find what you need to know. As far as downsides go, don't worry about a thing, and if your motor has seen some miles, you'll probably be doing it some good.