Z4 resonator delete

Kiashi123 · Post by **Kiashi123** » Sat Mar 05, 2022 8:30 pm

Hi guys, so i have z4 28i and am thinking about deleting resonator for a little louder exhaust with bubbles. Is it worth it? Any negative side effects?
Just want a little louder / stronger exhaust sound to fit my 300hp car

Jay-Jay · Post by **Jay-Jay** » Sat Mar 05, 2022 8:49 pm

I'm looking to do the same and have researched a bit, I was looking at mid box delete like this video:
https://www.youtube.com/watch?v=963Or1nGAcQ

From others that have done it you wont get drone on motorways and it is a little louder, I'm just trying to find a decent custom exhaust garage to do the work and save the £'s for it.

Deepseaskateboard · Post by **Deepseaskateboard** » Sat Mar 05, 2022 8:54 pm

Jay-Jay wrote: ↑Sat Mar 05, 2022 8:49 pm I'm looking to do the same and have researched a bit, I was looking at mid box delete like this video:
https://www.youtube.com/watch?v=963Or1nGAcQ

From others that have done it you wont get drone on motorways and it is a little louder, I'm just trying to find a decent custom exhaust garage to do the work and save the £'s for it.

Not sure where you are based, but you could try these:

https://www.powerflowexhausts.co.uk/Powerflow-Halifax

They have good reviews.

Kiashi123 · Post by **Kiashi123** » Sat Mar 05, 2022 9:15 pm

Yes i watched this video.. not sure if i like the metal sound he got with deleting resonator.. maybe it sounds better live. love the bubbles though. Not sure if the car got louder

Kiashi123 · Post by **Kiashi123** » Sat Mar 05, 2022 9:17 pm

Well i dont have to buy the pipe, my mechanic can make it for me.. so i dont have to spend 500dolars.. that is why i am considering deleting resonator and not switching muffler.

Jay-Jay · Post by **Jay-Jay** » Sat Mar 05, 2022 9:32 pm

Kiashi123 wrote: ↑Sat Mar 05, 2022 9:15 pm Yes i watched this video.. not sure if i like the metal sound he got with deleting resonator.. maybe it sounds better live. love the bubbles though. Not sure if the car got louder

Yea I know what you mean, I think some of that is to do with the recording of the sound but if it does get annoying for me then I'll just have to get the back-box done as well

B21 · Post by **B21** » Sat Mar 05, 2022 9:58 pm

Better off..imho..with a sports cat..still pas emissions but makes a nice baritone noise not a shot down zeppelin diesel..helps motor breather…another 5-10 BHP..not as cheap as destroying your silencer..

Kiashi123 · Post by **Kiashi123** » Sat Mar 05, 2022 10:06 pm

So you are saying i should get a sport cat ? Dont delete resonator?

Kiashi123 · Post by **Kiashi123** » Sat Mar 05, 2022 10:08 pm

That is 2000€

Felixlamb · Post by **Felixlamb** » Sun Mar 06, 2022 8:58 pm

Resonator delete is probably the best and cheapest way to get a decent sound increase. Res is built as an “open y-pipe” design with 2 baffle chambers meaning the air doesn’t have a completely direct flow. See pic.

By binning the res, and replacing it with a y-pipe, the air has a far more direct path out of the car, particularly through the valved exhaust pipe. Explanation below.

The muffler is cleverly designed. The pipe with the valve is actually straight through i.e. the pipe actually passes right through the muffler without opening. This means for a stock car, by doing the golf-tee mod, you’re effectively doing half of a muffler delete. That’s why you get such a noticeable difference. Therefore, by combining the resonator delete with the golf-tee mod, your valved pipe is effectively a straight pipe the whole way from the cat.

The other muffler pipe follows a more convoluted and indirect path. You’ll find the majority of the exhaust comes out of the valved pipe regardless of whatever exhaust mods you have done (especially if you have binned the resonator). See pic below for flow:

I’ve done a few exhaust mods, starting from welding up perforations etc in the resonator and muffler (absolute waste of time and made next-to-no difference). I’m now running a resonator delete with a slightly modified muffler (modified muffler makes no difference though, I might revisit that later on). If I was to advise on purely a sound basis, I’d probably bin the resonator first, and then either the muffler or get a sports cat (obviously a sports cat will give a small performance increase, but will be more expensive than binning the muffler).

B21 · Post by **B21** » Sun Mar 06, 2022 9:23 pm

Kiashi123 wrote: ↑Sat Mar 05, 2022 10:08 pm That is 2000€

1000 euros

Kiashi123 · Post by **Kiashi123** » Sun Mar 06, 2022 11:11 pm

Felixlamb great reply! Thank you!
So what you are saying.. easiest and cheapest way for me is resonator delete plus golf tee mode, to have valve always opened in muffler? Might actually do this!
But what about performance? Some people say exhaust needs back pressure.. so with golftee mode and resonator delete no more backpressure .. wouldnt want to lose 10-30hp because of this.

B21 · Post by **B21** » Sun Mar 06, 2022 11:35 pm

Kiashi123 wrote: ↑Sun Mar 06, 2022 11:11 pm Felixlamb great reply! Thank you!
So what you are saying.. easiest and cheapest way for me is resonator delete plus golf tee mode, to have valve always opened in muffler? Might actually do this!
But what about performance? Some people say exhaust needs back pressure.. so with golftee mode and resonator delete no more backpressure .. wouldnt want to lose 10-30hp because of this.

With a turbo engine the less back pressure the better…

Felixlamb · Post by **Felixlamb** » Mon Mar 07, 2022 1:00 am

^ What B21 said. With a turbo, the less restrictions in the exhaust, the better. You want that turbine up to speed as quick as possible. That being said, you probably won’t gain anything by removing the resonator. Perhaps you might get 1-2hp at a push? Main restriction in an exhaust is generally the cat, which is why B21 recommended the sports cat, as you’ll gain not just sound, but some power too. But it’s also more pricey.

Kiashi123 · Post by **Kiashi123** » Mon Mar 07, 2022 8:55 am

Can i expect any engine lights?

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