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V8 exhaust resonance help


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Ok, the ~1900-2300 resonance inside my Z is driving me crazy and making me deaf. The exhaust sounds great outside of the car, but inside is like having a lion roar directly in my ear. My exhaust is currently Sanderson headers dumping to dual 2.5" pipes which join into a single 3" pipe that runs through a Magnaflow out the back. I remember reading on here awhile back from a few people that had the same problem and fixed it using inline resonantors up front, but they didn't give many specifics. I was hoping someone here could point me in a more specific direction of how to fix this. I don't have a lot of areas of straight pipes where I can cut in a resonator.

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I have the same issue, running a twin 2.5" to single 3" with a super delta flowmaster at the very end of the system. Mine is due to the chamber design of the muffler combined with it being at the end of my exhaust system. Since I don't have any room to move it further upstream, I'll have to install a different muffler if I want to fix the problem. A resonator could help fix the problem...never tried that so I can't chime in on that one.

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Just had my exhaust done. 2.5 off of block huggers around trans dual resonators, 2-1 merge collector, 3 inch pipe to dynomax superturbo muffler in stock position. The exhaust is a bit subdued, but definitely v8. The exhaust shop apptly described it as "your grandma's lincoln meets nascar." No drone at all.

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I haven't changed mine out yet, but our exhaust guy says that he's heard the exact same noise that my exhaust was making on two different cars, both with similar setups (and both had the exact same muffler I was running at the end of the system), and a muffler with a simpler chamber design or straight-through design fixed the problem. Mine is more of a raspy resonance that's made during 1500-1900 rpms, not load dependent. It'll make the noise cruising down the highway or at idle. That's really the only advice I have towards it. Otherwise, keep looking into resonators.

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I built an exhaust system just like yours for a friend's V8 conversion and got the same results. The car was very hard to drive in.

 

So this is what I did to fix it.

 

1. Installed a short H pipe right after the transmission.

2. Installed two 2-1/2" x 12" long Dynomax Bullets (one on each side, after the H-pipe).

3. Moved the Y-pipe all the way back to the diff. (as far back as possible).

 

Now the car is very quiet while driving normally, but sounds really nice when driven more aggressively.

 

Note: I'm not sure if the H pipe was required or not, as I did all the changes at the same time.

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  • 2 weeks later...

vt_footer.png

 

Dynomax VT Click on the VT video and watch it.

 

When these came out, I was very intrigued by them. I'm going to purchase one for the next muffler I replace on my vehicles. That said, the system I bought for the Z from another HBZ member is supposedely "quiet" and "without drone" and consists of a Y pipe to a single 3" to a stainless Borla muffler in the stock location, to a 3" Dynomax (not a VT) in the rear. I don't have the system installed yet, but it should be good.

 

From various threads on this subject over the past decade, it has been stated that the Z system needs a "resonator" of some type in the middle of the system to kill drone. This is why the VT muffler is so interesting--I wonder if it alone would do the job without a "resonator" in the middle of the system.

 

 

Davy

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vt_footer.png

 

Dynomax VT Click on the VT video and watch it.

 

When these came out, I was very intrigued by them. I'm going to purchase one for the next muffler I replace on my vehicles. That said, the system I bought for the Z from another HBZ member is supposedely "quiet" and "without drone" and consists of a Y pipe to a single 3" to a stainless Borla muffler in the stock location, to a 3" Dynomax (not a VT) in the rear. I don't have the system installed yet, but it should be good.

 

From various threads on this subject over the past decade, it has been stated that the Z system needs a "resonator" of some type in the middle of the system to kill drone. This is why the VT muffler is so interesting--I wonder if it alone would do the job without a "resonator" in the middle of the system.

 

 

Davy

 

Hmm, only $100 too....I think I might have to give it a shot.

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  • 5 months later...

I'm thinking that I spent waaay too much on exhaust until I finally got on this thread and bought the Dynomax VT's That fixed the damn drone, Highway speeds are quiet as a mouse, step on it and it sounds very nice.   I have 2 1/2 pipes coming off of Sanderson block huggers, then an X pipe and generic glass packs just behind the rear axle then over to two Dynomax VT's. I had to cut a chunk out of the spare tire well to do this, but a donut still fits in the well. I found a donut that fit at the wrecking yard, and they gave it to me free. I have to have wheel spacers for the donut to work in the front to clear the calipers, but oh well, it'll get me home. I am here to tell you the Dynomax Vt's are the way to go if you want a quiet car in normal driving, and aggressive when you stand on it.

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  • 2 months later...

I just installed the Dynomax VT and it had a huge effect, completely eliminated the drone. 

 

The one caveat on these is that they need to be installed as close to horizontal (so the oval is laid down) as possible, otherwise the valve will make a large banging sound.  Mine is installed at about 45 degrees and it makes a sound when the car first turns on (although I think with the build-up of soot, it is slowly going away).

 

Anyway, this muffler is awesome!  I have no resonators/other mufflers or anything and there is no drone.

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I was going to bring this banging up, just kept forgetting, my mufflers are installed two side by side on the vertical and they do bang when the car first starts up, I have no clue why the banging stops after the muffs warm. I look at it as just an anomaly to a great fix!

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I called their help line, and it's from the valve hitting the side of the muffler body.  It goes away when warm because the expansion snugs it in there.  Apparently if they are installed flat this doesn't happen.

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I have 3" dual to 3" single and out an Aspec Fart can currently. Its loud but sounds good. I dont have any major drone thankfully.  Im about to install a single chamber flow knockoff in the center to act as a resonator. Im hoping to get some flowmaster sound but also quiet the exhaust a bit.

Ill be posting up some videos this weekend as Frank280zx was interested in hearing it.

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  • 1 month later...

Little late, but the vt muffler, Is clickitty clack even when installled flat. Mine is even only on a  2.0 (sr20det). But other than that, awsome.... Mine I would describe as the sound of a lifter that collapsed, only in the rear, And is constant until its been driven for a while (10-15 minutes of normal driving)....

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Little late, but the vt muffler, Is clickitty clack even when installled flat. Mine is even only on a  2.0 (sr20det). But other than that, awsome.... Mine I would describe as the sound of a lifter that collapsed, only in the rear, And is constant until its been driven for a while (10-15 minutes of normal driving)....

Which part number of muffler did you install?  Some of them are designed for larger engines than others. 

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