Pulsing exhaust sound after header install

Dr Jay · May 14, 2009

I installed tuned length headers this spring. I already had an MRT catted H and MAC catback. I have a lot more drown around 2000 rpms now and after several searches I guess the best way to get around this is with straight through mufflers but I guess I'll have to put up with it because I really like the sound of the MAC's 99% of the time, especially under hard acceleration.

I have a different sound that I can only describe as a pulsing exhaust sound when slightly below 2000 rpms. It almost sounds like its coming from the headers but I'm not sure. Could it be a leak at the headers? The car sounds great at idle and under acceleration, no complaints there This is my first experience with headers, any suggestions on what I'm hearing and how to get rid of it?

007 · May 14, 2009

Ever seafoamed your car? If not, thats a wonderful way of looking for exhaust leaks.

My BBK tuned lengths changed the sound a bit, but didnt cause any drone.

Dr Jay · May 14, 2009

I've never seafoamed it, a bit hesitant I guess after so many stories and methods that are inconsistent. I used percy gaskets so I wouldn't run into any leaks but anything is possible right.

32ValveRom · May 14, 2009

A pulsing sound? Idk what that is but btw your describing it that sounds like a good thing. i wish I had a pulsing sound to scare the crap out of my passengers.

LaserSVT · May 14, 2009

Record it and post it up

Spreadman · May 15, 2009

If it's a loud and low pulsing, you have a leak.

slayr281 · May 15, 2009

Is it an inconsistent gargling or popping? That too, would be an exhaust leak somewhere.

Nice bike Scottty!

Dr Jay · May 15, 2009

Thanks for the responses. It's not a popping or ticking sound. Low frequency for sure and noticeable (loud) enough to be annoying. If I drop a gear and run in a higher rpm range the sound is gone, would an exhaust leak do that?

Spreadman · May 16, 2009

Dr Jay said:
Thanks for the responses. It's not a popping or ticking sound. Low frequency for sure and noticeable (loud) enough to be annoying. If I drop a gear and run in a higher rpm range the sound is gone, would an exhaust leak do that?

Yes, because at low speeds your exhaust and engine noises aren't loud enough to drown out the leak like they can at higher speeds.

Thanks Slayr! Of the two, she's my fav.

Dr Jay · May 17, 2009

Thanks Spreadman, I had it out again last night and I think I may have a leak at the header on the drivers side.

I've been putting off a plug change and I finally did it today since it was raining out for most of the day anyways. I thought the plugs on the passenger side looked ok but man, something is going on on the drivers side for sure. Would a leak at the headers cause the plugs to look like this?

Passenger Side
The two on the right were replaced 3 yrs ago when two coils went south.
The dirty one (second from right) is what a plug looks like when it starts backing out and you keep driving for a few days because you think it's an exhaust leak. . I'm very lucky there.
View attachment 257615

Drivers Side, NEED ADVICE PLEASE
View attachment 257616

LaserSVT · May 17, 2009

I see detonation and whats up with the right most drivers plug? Is your intake leaking or valve cover mabey? I was thinking oil at first but it may just be coolant and dirt.
Your drivers side plugs have been getting to hot or they are just really old

Do you have a tuner? Looks like you are not spraying enough fuel. What mods do you have? If you have alot of exhaust work then thats enough to lean out the stock tune

Dr Jay · May 18, 2009

LaserSVT said:
I see detonation and whats up with the right most drivers plug? Is your intake leaking or valve cover mabey? I was thinking oil at first but it may just be coolant and dirt.
Your drivers side plugs have been getting to hot or they are just really old

Do you have a tuner? Looks like you are not spraying enough fuel. What mods do you have? If you have alot of exhaust work then thats enough to lean out the stock tune

There are no leaks anywhere but that plug is wet. The 6 plugs with the short threads were the oldest and they have 90,000 km on them (55,923 miles).

The mods I have are all exhaust mods (see sig). I got a Predator for Christmas and installed the Predator tune last week and I have only driven the car 3 times since.

I don't have any tuners in my area, need advice.

StangYellow · May 18, 2009

If you bog your car in 5th with the windows up, you can get a good idea what side its coming from... which you probably already knew. When the exhaust is cold, you can run your hand up to the collector and see if its coming from there. If its not, its by the cyl. head.

I always had leaking issues. Try loosening up the h to the headers, and the bolts by the transmission on the h pipe. Jack the exhaust up with a floor jack and re-tighten everything. Seems like everything lines up better if its close to the underside of the car.

Dr Jay · May 18, 2009

Thanks StangYellow

Can anyone else offer any opinions on what's happening with the plugs on the drivers side?

Dr Jay · May 19, 2009

Well since I'm on vacation this week I decided to drop the k member again and check the header bolts. I started on the drivers side and there were several that needed to be snugged down. I'm assuming this is normal after breaking in new headers and gaskets. I'll hit the passenger side tomorrow morning. It takes a bit longer with the locking header bolts but I insurance of them not backing out is worth it.

95Vert383AOD · May 19, 2009

Whats up with the 2 right plugs in the 1st pic? The threads are longer. I'm a Pushrod guy so i could be wrong.....But typically the long thread is for aluminum heads and shorter threads go on Iron heads.

I think your problem is that 2 of your plugs arent the same length thread as the other 6.

If you have aluminum head then 6 plugs weren't deep enough in the engine and if you had iron heads then 2 plugs were protruding too deep into the combustion chamber.

Chris

Pulsing exhaust sound after header install

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