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Discussion Starter · #201 ·
Ok, StreetPower is in now. The result is nothing short of unbelieveable.

Here are some Dbx vs StreetPower comparisons:

30mph in 4th:
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40mph in 5th:
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50mph in 6th:
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🤯 I hear a lot of intake and not a ton of exhaust. I think it's mission accomplished.

--Matt
 

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Discussion Starter · #203 · (Edited)
So what is your exhaust now header gasket to tail pipe? Congratulations on finding something suitable for you!
Haha, it's been a long road but I'm glad it finally lead somewhere!

Here it is, in order:
K-Tuned KRH-41-500
Vibrant 1482S
Vibrant 2630
Mishimoto MMCLAMP-VS-3
Quick Time Performance AR3 12300
Thrush 24241
Mishimoto MMCLAMP-VS-3
Vibrant StreetPower 1147

Everything not above is bits and pieces of a KTeller PK-9200-CIVIC-300-SS pipe kit. I didn't use any of their provided hardware because it's all mild steel, so there are stainless hangers and the flanges listed above holding everything together. The exhaust moved around way too much with the OEM fit Bosal isolators I installed when I initially bought the car, so the front 3 are Walker 35119 and the rear 2 are Walker 35637. The trunk is treated with KILMAT 80mil from the back seat to the back wall on the floor only, plus up to the rear lip where the trim below the door is installed.

Overall, yeah, there's definitely some weight in there. I'd have to take the exhaust system off to weigh everything, but it's finally acceptably quiet. The mat on the floor is under 5lb. The AR3 is 8lb, the Thrush is 7lb, and the Vibrant is just under 10lb. K-Teller clocks their pipes at 31lb, but there's honestly not that much of it left. Overall, It can't be heavier than a Skunk2 Mega Power RR at its claimed 62lb but probably weights more than something on the thinner/lighter end like a Yonaka exhaust. Given that it's 3", it could be much worse. 🤷‍♂️

From the driver seat, the max noise level and drone characteristics are probably slightly better than a stock SRT4 (Neon model) came from the factory. Not the quietest of cars, sure, but a factory street legal car...and this is from a 3" straight through exhaust on a cammed K20 with 4-1 headers.

--Matt
 

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Arouse the DAMPFHAMMER!
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The result is nothing short of unbelieveable.
Congratulations to your finding, that was an amazing road to success with a lot of information about noise canceling. Thanks for sharing so much details, from which everyone who want to reduce the exhaust noise level can profit of.

A video of it would be great too :).
 

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Discussion Starter · #205 ·
Congratulations to your finding, that was an amazing road to success with a lot of information about noise canceling. Thanks for sharing so much details, from which everyone who want to reduce the exhaust noise level can profit of.

A video of it would be great too :).
I'll have to circle back to make some with overlays including spectrum data, and still haven't determined how to record on my device without gain adjustment, but here are some clips:

~50mph in 6:

~60mph in 6:

50-60 flat foot in 6:

These were my most punishing spots, and they're all acceptable now. Yes, it is still a touch droney under heavy load at low RPMs (see last video) but it's way better and gone at cruising speeds. No issues going up most grades at speed or anything like that anymore.

--Matt
 

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Arouse the DAMPFHAMMER!
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These were my most punishing spots,
Is this still a K-series engine ;)? That's pretty silent and I've seen no drone vibrations in the cockpit! That's great!
 

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Yes, I'm quite pleased. Doesn't look half bad either.

View attachment 109373

DBX was just a really bad choice, I guess.

--Matt
Can we see a picture of what it looks like under the car?

I have an EG with K20a swap and the droning between 2k-4k is horrible! I do have a vibrant ultra quiet resonator waiting to be installed.

I currently have the Greddy Supreme catback exhaust.

So if I understand correctly, you have three mufflers? Running a header, connected to the QT, connected to thrush, connected to Vibrant?

EDIT:

Nevermind, I read through the entire thread for the past hour and learned a lot!

My set up will be as follows:

K-tuned header: 4-2-1 --> Vibrant Ultra Quiet Resonator --> Thrush 24241 --> Greddy Supreme SP axle back. Hopefully, that'll minimize the drone drastically as I struggle with the same ranges as you.

My ride is 92 Civic SI with K20a from a DC5 Type R.
 

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Discussion Starter · #209 · (Edited)
Can we see a picture of what it looks like under the car?

I have an EG with K20a swap and the droning between 2k-4k is horrible! I do have a vibrant ultra quiet resonator waiting to be installed.

I currently have the Greddy Supreme catback exhaust.

So if I understand correctly, you have three mufflers? Running a header, connected to the QT, connected to thrush, connected to Vibrant?

EDIT:

Nevermind, I read through the entire thread for the past hour and learned a lot!

My set up will be as follows:

K-tuned header: 4-2-1 --> Vibrant Ultra Quiet Resonator --> Thrush 24241 --> Greddy Supreme SP axle back. Hopefully, that'll minimize the drone drastically as I struggle with the same ranges as you.

My ride is 92 Civic SI with K20a from a DC5 Type R.
So you'll replace the midpipe stuff with a Vibrant Ultra Quiet and a long glasspack? It seems worth a shot, but I don't have any data on that Greddy muffler so only time will tell.

The glasspack did cut down on overall sound level a good bit, but its contribution to reducing drone seems to really only come into play once the exhaust it all the way warm so be patient if you're not immediately satisfied on your first drive. The QTP I added didn't seem to help that frequency range much at all, but did quiet the top end a lot, so maybe the Vibrant Ultra Quiet will help more in the problem area. When I picked that part out I was aiming for the biggest resonator I could fit in that space, but I know the Ultra Quiet is built to help with 4-cylinder-specific noises so it may accel there more.

If it were me at this point, and you're not opposed to multiple round trips of exhaust work, I might just try the ultra quiet and see how it does with the resonator you already have on there. Depending on how that went, I think the choice on whether to replace the muffler at the rear or the tube resonator would be a clearer one.

--Matt
 

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So you'll replace the midpipe stuff with a Vibrant Ultra Quiet and a long glasspack? It seems worth a shot, but I don't have any data on that Greddy muffler so only time will tell.

The glasspack did cut down on overall sound level a good bit, but its contribution to reducing drone seems to really only come into play once the exhaust it all the way warm so be patient if you're not immediately satisfied on your first drive. The QTP I added didn't seem to help that frequency range much at all, but did quiet the top end a lot, so maybe the Vibrant Ultra Quiet will help more in the problem area. When I picked that part out I was aiming for the biggest resonator I could fit in that space, but I know the Ultra Quiet is built to help with 4-cylinder-specific noises so it may accel there more.

If it were me at this point, and you're not opposed to multiple round trips of exhaust work, I might just try the ultra quiet and see how it does with the resonator you already have on there. Depending on how that went, I think the choice on whether to replace the muffler at the rear or the tube resonator would be a clearer one.

--Matt
 

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Discussion Starter · #212 ·
what do you think the biggest improvement was? The power street muffler? I’d rather do everything in one shot.

My wife drove in the car for the first time and was very embarrassed to say the least.
For the bad frequency range? Definitely the StreetPower. I'd think the res you have on there plus an Ultra Quiet and StreetPower should be pretty close to what I've got.
 

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For the bad frequency range? Definitely the StreetPower. I'd think the res you have on there plus an Ultra Quiet and StreetPower should be pretty close to what I've got.
Perfect.

Do you happen to know the DB rating for the Street Power? This is my current exhaust and it states 92DB with a turbo application. So I assume NA would be a tad louder?
 

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Discussion Starter · #215 ·
Perfect.

Do you happen to know the DB rating for the Street Power? This is my current exhaust and it states 92DB with a turbo application. So I assume NA would be a tad louder?
It's not that simple. Some muffler manufacturers do quote DB reduction numbers, but I don't think Vibrant does. At the end of the day it's very implementation and frequency dependent. That 92dB is for a while system, assuming some engine/turbo setup, and any numbers for anything else would be equally dependent on variables holding constant.

At the worst frequencies, the StreetPower is somehow cutting a whole 20dB or more when compared to the Flowmaster I had there. At other frequencies it is much less different, or even slightly louder. The Thrush glasspack cut about 6dB off at the worst spots but, again, it really varies based on the frequency you're comparing.

Those numbers are reductions too. From what with no mufflers at all? I cannot say.

--Matt
 

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Discussion Starter · #218 ·
Hey Guys,

Have my resonator and mufflers installed. Certainly a lot more quiet. As the mufflers break in, will it get quieter?

Thanks.
Nice! Glad to hear it helped!

The glasspack and Vibrant muffler definitely got quieter over the first couple hundred miles. More noticeable than that, though, the Vibrant does its best work once warm. I find the drone only to be completely gone when the car has been running for at least 10-15 minutes.

--Matt
 

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Nice! Glad to hear it helped!

The glasspack and Vibrant muffler definitely got quieter over the first couple hundred miles. More noticeable than that, though, the Vibrant does its best work once warm. I find the drone only to be completely gone when the car has been running for at least 10-15 minutes.

--Matt
Gonna be honest. Still kind of loud. Gonna give it a few weeks. Last resort is going to stock exhaust as well as replacing the header to stock if possible.
 

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Discussion Starter · #220 ·
Gonna be honest. Still kind of loud. Gonna give it a few weeks. Last resort is going to stock exhaust as well as replacing the header to stock if possible.
Ouch. Mine consistently reaches civil once warm every time. I guess we have different headers and I've got the QTP instead of the Vibrant up front, but I'm not sure what might account for the difference if you're not seeing the same. Are you experiencing drone or is it just louder than you want?

There's a real huge gap between a 3" exhaust and stock, lol! I'd sure as heck be trying a cat, 2.75", or even 2.5" exhaust long before considering anything anywhere near stock unless you want it to be OEM quiet.

How quiet are you looking for it to be? A 3" straight through exhaust on an NA Honda can only be so quiet, no matter what you do, but dropping down to something like a 2.5" WS2 or something is probably the next step if you need a lot quieter...but you're likely to drop close to 10hp making a jump like that.

--Matt
 
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