1.5T Greddy exhaust interior noise / drone?

CIVICUK

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Yeah I feel the same when I start it definitely vibrates my front door from the street. It definitely is the 3" piping that makes it a little much and I feel like I get a bit of a throttle lag with it. However I have read on this forum people say 27won has the loudest exhaust when you compare the popular ones (greddy, 27won, borla). Let me know how the 27won compares when you get it as I was originally debating between the two myself but went with greddy due to the price and popularity. The sound rating on the greddy is just 90db which is just up 6 from stock. I guess everyone has different options on what's loud or not. I think in the meantime I may put some soundproofing in the area where the spare is housed and see if that helps. Good luck!
I have posted an update since this post and i am convinced its the backbox causing the vibration so i am booked in next week to have it removed and sleeve tested to see if this stops the vibrations.( I used an app on my phone to test the decibels outside and they were 68-70 and about 65 in the cabin on cruising and part throttle)

If this fails then i will try a smaller thin resonator to replace the big box type, this should hopefully work! I got the greddy cheap so dont mind spending money on it to create my perfect set up :)

I will re post once tests have been carried out.
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Aiirik

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Update *** ran some decibel testing today and on cold start near the dual pipes it was 68-70 decibels which isnt alot BUT the vibration from the cabin and stood a foot away from the car was horrid! So my understanding is thats the problem. Spoke to my exhaust guy and he recommends somehow by passing the back resonator by sleeving the piping to the exhaust tips and see if that stops the vibration. Then if this works he will then simply cut out the back box and replacing with 3" piping hoping that i may get more raspy noise at open throttle but no vibration in the car.

Any thoughts on this method? Have i got it all wrong ? Im a newbie to exhausts
thanks for the update! This is what I was guessing would happen. Which is probably why I’m going to use the stock exhaust and get a connector made to have just the greddy muffler as I like the look of the muffler and it may be enough noise to make it sound a bit better but none of the 3” piping. I already have my stock exhaust cut pretty much where the greddy muffler flange starts so I don’t think it would be that expensive. And this way I can sell the greddy exhaust without nodding it if ever I decide to sell it.

Thanks again for your input on this!
 

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*** update ** so i visited my local custom exhaust builders (powerflow) and once up on the lift he commented on how nice my Greddy exhaust is, the welding and the design he said is very well built.

So i mentioned to him that im getting alot of drone from the back end when on cold start and sometimes light cruising. He said that on any honda, as soon as you change the exhausts they immediatly become loud and drone a lot. So there was no point in him building me a full catback system, instead we focused mainly on the back resonator and muffler. He reckons that by having the 3" pipe go into a y bend and then the pipes loop inwards through a specialist chamber resonator in the centre, then the pipes come straight towards the bumper opening, then thats where we weld the tips on. ( i personally have gone off the tips on Greddy so i am opting for some new ones very simular to the 27won) anyway by fitting this system it should capture any drone inside the resonator.

Waiting on pricing and booking date.

He did say it will be very simular to the vw golf setup how theres a centre box with pipes coming out and round if you want to google thiers and will give you an idea.

He is super excited to get this build going so its nice to have someone whos passionate at getting results.

Will post when booked in :D
 

CIVICUK

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** update ** struggling to get the rear section built with chamber resonator as it is a bit of a fiddle and might not be enough room for 3" piping to the exit tips so looking at different options. However, he said that my vibrant resonator is only 9inch length and he can replace it with a 20" length oval box so has more sound padding and will atleast capture the drone before reaching the muffler box. So booked in to try this next week. Spoke to a guy with an fk8 with greddy who had bad drone too and he installed a 21" resonator and its prettty much killed the drone but kept the sound still nice and beefy.

Will post when fitted :)
 

CIVICUK

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*** update! *** so the 22 oval shaped " centre resonator has been fitted in replacement of the 9" vibrant one and it has significantly reduced the drone! My wife couldnt even hear me pull up on the drive! The cabin drone has reduced a hell of a lot. I am very very happy with the result AND it still pops crackles and sounds lovely at w.o.t. :D

Next thing i might look at is changing
The exhaust tips as im not a fan of the jap cut thin walled type anymore so looking for a custom tip design maybe hexagonal like the mugen just not as bold?

I will try get sound clip on cold start tomorrow morning and photos of the exhaust :)
 


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*** update! *** so the 22 oval shaped " centre resonator has been fitted in replacement of the 9" vibrant one and it has significantly reduced the drone! My wife couldnt even hear me pull up on the drive! The cabin drone has reduced a hell of a lot. I am very very happy with the result AND it still pops crackles and sounds lovely at w.o.t. :D

Next thing i might look at is changing
The exhaust tips as im not a fan of the jap cut thin walled type anymore so looking for a custom tip design maybe hexagonal like the mugen just not as bold?

I will try get sound clip on cold start tomorrow morning and photos of the exhaust :)
What resonator did you get? Or was it something the shop made you?
 

CIVICUK

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What resonator did you get? Or was it something the shop made you?
So sorry i never replied back to this thread! The resonator was a 22" powerflow version but again it was still too much on cold start and after i changed jobs i was in a more smaller car park, well.. it set car alarms off so i took it off and went back to stock.

But im missing the extra sound again so im thinking of joining my stock piping to the greddy back muffler box and seeing how this sounds!

Also im back on stock downpipe and frontpipe so be interesting to see how it will sound!

I imagine someone here has done the same?
 
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I have the greddy exhaust with stock down pipe. It’s a very quiet exhaust and gives off mild crackles and pops in 1st and 2nd gear. Recently I’ve been driving with my back seats down to make it a little louder. You will have zero drone. I personally love it.

Are you referrign to the DDR or the Supreme SP?
 


 


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