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O/R X-Pipe Problem

2K views 17 replies 7 participants last post by  Displacement 
#1 ·
Recently, I installed your average BBK Off road X-Pipe on my beloved 2v. These are, of course, attached to Flowmaster 40's that came installed on the car when I purchased it. From what I can tell, the Flows are just mufflers and tips on the stock cat-back. I'm not sure if they are welded in, which may be the root of my problem!

So, after installing the x-pipe (2 days worth of old rusty broken studs and bolts) I set out to hear my dinosaur roar to life. However, I was not greeted with the wonderful symphony I had expected. If I give the engine more than an inch of pedal, I get a metal slapping noise directly inder the front seats. The sound seems to be more pronounced when driving under 2000 rpms. Above that, the exhaust sounds perfect-unless I floor it. As long as I ease into it until I am in higher revs I am more than pleased with the sound of the car. But under strain, the engine sounds like it is throwing up bolts into the downpipes.

I am hoping someone has had a similar problem so that they can tell me that it is just a bad flange/gasket, a loose o2 sensor, exhaust hanger or welding in the mufflers type problem. I have checked and double checked everything under the car and I am out of ideas. The only problems I can think of is that I have a small leak where the x-pipe meets the cat back which I cannot seem to remedy and I do not have my MIL eliminators connected yet.

Any input is appreciated! I am on the verge of buying some m80's as a solution and I don't want the metal sound to persist once they have been welded on!!
 
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#2 ·
Recently, I installed your average BBK Off road X-Pipe on my beloved 2v. These are, of course, attached to Flowmaster 40's that came installed on the car when I purchased it. From what I can tell, the Flows are just mufflers and tips on the stock cat-back. I'm not sure if they are welded in, which may be the root of my problem!



So, after installing the x-pipe (2 days worth of old rusty broken studs and bolts) I set out to hear my dinosaur roar to life. However, I was not greeted with the wonderful symphony I had expected. If I give the engine more than an inch of pedal, I get a metal slapping noise directly inder the front seats. The sound seems to be more pronounced when driving under 2000 rpms. Above that, the exhaust sounds perfect-unless I floor it. As long as I ease into it until I am in higher revs I am more than pleased with the sound of the car. But under strain, the engine sounds like it is throwing up bolts into the downpipes.



I am hoping someone has had a similar problem so that they can tell me that it is just a bad flange/gasket, a loose o2 sensor, exhaust hanger or welding in the mufflers type problem. I have checked and double checked everything under the car and I am out of ideas. The only problems I can think of is that I have a small leak where the x-pipe meets the cat back which I cannot seem to remedy and I do not have my MIL eliminators connected yet.



Any input is appreciated! I am on the verge of buying some m80's as a solution and I don't want the metal sound to persist once they have been welded on!!


The easiest way to find an exhaust leak is to run sea-foam or brand x equivalent through the intake manifold. Start it up and see where the smoke comes out.


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#4 ·
The easiest way to find an exhaust leak is to run sea-foam or brand x equivalent through the intake manifold. Start it up and see where the smoke comes out.


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I'm sorry but I disagree....seafoam and other similar type products are hazardous not only to you lungs (Carcinogen) but to the vehicle components as well...including O2 sensors, & CATS.....


To find a leak, simply jack the car up (properly of course), start the engine, have someone place a towel over the end of the exhaust pipe blocking the flow....got a leak...you will hear it very fast.....
 
#3 ·
You might be hearing what most people experience with that X-Pipe....

Are all your bolts tight? Is the X-pipe hitting the chassis at all?

BBK X Pipe can tend to sound like this though.
 
#8 ·
Napthalene......which is dry cleaning fluid, an Aromatic which means it is a "toxin"affecting directly the liver, kidneys, spleen, etc....the (Fed) Immediately Dangerous to Life & Health (IDLH) max exposure is 250 ppm......and yes, if you assume your engine & cats combined are working at 98% efficiency (which they aren't), you are likely exposed to this these elevels. This is NOT TRUE!!:|


Isopropylalcohol......not good for an engine (as this is 10% alcohol - typically) andthe rest water Who told you this Beechie??:surprise:
 
#9 ·
Napthalene......which is dry cleaning fluid, an Aromatic which means it is a "toxin"affecting directly the liver, kidneys, spleen, etc....the (Fed) Immediately Dangerous to Life & Health (IDLH) max exposure is 250 ppm......and yes, if you assume your engine & cats combined are working at 98% efficiency (which they aren't), you are likely exposed to this these elevels. This is NOT TRUE!!:|





Isopropylalcohol......not good for an engine (as this is 10% alcohol - typically) andthe rest water Who told you this Beechie??:surprise:


His sisters' brother in-law golfs with the owner of the company's uncles friend.


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#12 ·
You should worry more about Benzene "Beechie"......the Feds allow oil companies to "dispose" of it in gasoline!!:surprise: The maximum they may blend is 30% and we unknowingly handle it EVERY DAY!!:|

https://www.cancer.org/cancer/cancer-causes/benzene.html

I agree with you about Seafoam......you can accomplish equivalent results with plain ole Diesel fuel!!:wink:

BTW...Industrial IPA is about 95% Alcohol since it azeotropes about 5% water!!:|

https://en.wikipedia.org/wiki/Azeotrope_tables

Seafoam would separate into separate phases with the amount of water you suggest!!:|
 
#13 · (Edited)
You should worry more about Benzene "Beechie"......the Feds allow oil companies to "dispose" of it in gasoline!!:surprise: The maximum they may blend is 30% and we unknowingly handle it EVERY DAY!!:|



https://www.cancer.org/cancer/cancer-causes/benzene.html



I agree with you about Seafoam......you can accomplish equivalent results with plain ole Diesel fuel!!:wink:



BTW...Industrial IPA is about 95% Alcohol since it azeotropes about 5% water!!:|



https://en.wikipedia.org/wiki/Azeotrope_tables



Seafoam would separate into separate phases with the amount of water you suggest!!:|


I smoke cigarettes and I like my mosquito repellant to contain DEET.


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#15 ·
So back on topic.. did you make sure the metal gasket on the passenger side manifold stayed intact with no bends or tears? Did you have all the joints lined up well and then tighten your bolts slowly in a pattern? If you don't have any actual leaks, then chalk it up to the X pipe just sounding "raspy". All the guys in my group have X pipes, and that's the reason I went with the H pipe on mine. I don't like the sound at all on the X. Just my $0.02.
 
#16 ·
FWIW, that gasket at the passenger side manifold flange should be replaced every time the midpipe is R&R'd. Only costs about $6.

The way the OP's exhaust sounds may very well be a (large) leak and I would certainly rule that out first, but in my experience with that exact same pipe it could also be the mufflers. When I first installed a BBK o/r X pipe I had it hooked up to an SLP LM1 catback. It sounded like an open header competition at any engine speed above idle, and even worse under load. When I ditched the LM1's for the SLP Powerflo mufflers (and then eventually LM2's) it quieted it right down. It was always loud with that pipe but different mufflers made it quite reasonable and got rid of the 50 Cal automatic rifle blasting in your face sound.
 
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