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-   -   Quietest Boosted Exhaust? (http://www.the370z.com/forced-induction/121197-quietest-boosted-exhaust.html)

Kzonts 04-26-2017 03:44 PM

Quote:

Originally Posted by TopgunZ (Post 3645784)
That is why it sounds so good. The best sound I ever heard coming from a Z was when I had the stock cats with FI exhaust. Take those cats off (because boost) and its a total game changer. They act as 2 giant mufflers.

Your cats will eventually blow out on you.



Because it has cats.

Cats that were designed for forced induction.

Ok... That's the point I'm trying to understand. I take it there's no aftermarket cats he could throw in there that would help?

TopgunZ 04-26-2017 03:59 PM

Not in the stock location if he is going to boost. They dont hold up very well.

Jayhovah 04-26-2017 04:10 PM

Quote:

Originally Posted by Kzonts (Post 3645806)
Ok... That's the point I'm trying to understand. I take it there's no aftermarket cats he could throw in there that would help?

Quote:

Originally Posted by TopgunZ (Post 3645816)
Not in the stock location if he is going to boost. They dont hold up very well.

I feel like there must be something that can hold up to it. I have seen on the Scoobie forums folks have used Magnaflows with good success.. Z1 sells a "Thunderbolt" cat that they believe will hold up to the abuse. (They use them for Z32, but I posted a question to the product page about using on a boosted 370z and they think it will work)

I'd like to see some other boosted platforms in terms of how far upstream they mount the cats... It may be as Topz says and the stock location is just too hot.

I suspect, however, that the data we have in this forum is probably related to the bolt on options we have available, and I am pretty sure none of those are up to the task to dealing with FI. I feel like there must be some weld-in options that will work... just based on other platforms having options.

ChaseZ 04-26-2017 04:30 PM

Quote:

Originally Posted by Hotrodz (Post 3645648)
Also, I think it would be a good idea for the OP to give Sebastian a call regarding a solution as a 3" down pipe and exhaust could potentially impact performance negatively because a SC doese need some back pressure to make optimum power so it's a catch 22!

Sent from my SM-N910P using Tapatalk

Sebastian recommends ART pipes ten out of ten times, which are 2.5" same as the FI resonated pipes I have on right now. We've chatted about this several times.

I love the ART/Shockwave combo. But from experience it can be varied in noise level a LOT based on air going into the engine. NA example it was actually pretty quiet last summer when I had the Stillen G3 intakes on, whereas it was pretty damn loud with the Injens. That's changing nothing except the intakes.

Knowing that I really couldn't say how loud or quiet it would be with the blower and air to air setup. I suspect given the shear volume of air coming in it would tend to be on the loud side with reasonable certainty. That said, I also don't know exactly how loud the FI res pipes and shockwave combo will be with the air to air yet either. I do know that with my current setup (modified Stillen piping) it is damn loud. Much too loud.

I emailed Mariella at Motordyne a few days ago and haven't heard back yet. There are mid-pipes between the X and tailbacks that are straight with nothing more than a hangar on them. They do offer individual components like resonators and various cats but I'm not sure if any of them are a direct replacement for these mid-pipes. I'll update with her response when I receive it.

That's also the same spot I've been considering for downstream cats that I could just cut and weld in. Somebody a whole back had posted a link to some 200/300 rated aftermarket HFC (think it was jayhova) so those might be worth trying out.

With the current setup, the motordyne exhaust and OEM cats are a great sound sound and basically what I'm after when it's all said and done. So basically the goal here is something along those lines.

I did look into the CNT exhaust and it is backordered all over the place. I found one set with the blues tips (which I don't like but can change easily enough) but he wants about $200 more than CNT does for it so that's not going to happen.

In short, no resolution yet but there's some good suggestions floating around now that the conversation has been started and I'm sure something will come of it.

ChaseZ 04-26-2017 04:33 PM

Quote:

Originally Posted by Jayhovah (Post 3645818)
I'd like to see some other boosted platforms in terms of how far upstream they mount the cats... It may be as Topz says and the stock location is just too hot.

That's the issue for sure. Though your comment reminds me of something else Sebastian mentioned to me over the winter that you can weld in some metal substrate before the OEM cats to absorb and dissipate the heat to a degree before it gets to the cats. Like welding in a metal X or something inside the pipe.

ChaseZ 04-26-2017 04:35 PM

For reference here is the shockwave exhaust, and the straight sections I mentioned for the cats circled
http://www.the370z.com/members/chase...5-img-3785.jpg

Hotrodz 04-26-2017 04:56 PM

Yo Chase, you may want to check out ssfirehawk's old build thread as he is the one I was talking about that had the gtm twin SC setup along with the motordyne exhaust system. He had ppe long tube headers so I think would be as loud as it would get. He is still active on the forum and I know he did some videos. I know it hard to tell but can give you some indication.

Sent from my SM-N910P using Tapatalk

ChaseZ 04-26-2017 05:14 PM

Thanks, I found it and it's a biggy so dropping a link here so I can read it later

http://www.the370z.com/members-370z-...a-project.html

future370zzz 04-26-2017 05:30 PM

Who cares about your neighbors? I have neighbors with mustangs and corvettes and harleys with loud exhausts. It's part of the city noise.

When you see cops, just keep it below 3K rpms.

I'm looking to switch over to motordyne to eliminate all the drone from my FI exhaust setup. Have side branches resonators but still has some drone at highway rpms. A lot better than before though.

ChaseZ 04-26-2017 09:09 PM

Anyone try the CNT ART/HKS style test pipes?

MoulaZ 04-27-2017 01:31 AM

1 Attachment(s)
Quote:

Originally Posted by ChaseZ (Post 3645824)
For reference here is the shockwave exhaust, and the straight sections I mentioned for the cats circled
http://www.the370z.com/members/chase...5-img-3785.jpg

This is exactly what I did. Made little difference.

I installed a pair of these:

ChaseZ 04-27-2017 03:25 AM

Quote:

Originally Posted by MoulaZ (Post 3646029)
This is exactly what I did. Made little difference.

I installed a pair of these:

Considered these HFC in that spot, and they are supposed to be good but I'm not sure I want to drop $250 usd plus install to find out.

http://www.ebay.com/itm/110847989857...torefresh=true

MoulaZ 04-27-2017 04:19 AM

Trust me, they'll be even worse. Take a look at the dimensions of that one, and then these:

Magnaflow 3" 200 CPI Metal Core Stainless Steel Cat Catalytic Converter Oval New

These are exact one I bought. They're longer & wider, and like I said they didn't have too much of an effect.

bcfromfl 04-27-2017 11:28 AM

Quote:

Originally Posted by MoulaZ (Post 3646041)
Trust me, they'll be even worse. Take a look at the dimensions of that one, and then these:

Magnaflow 3" 200 CPI Metal Core Stainless Steel Cat Catalytic Converter Oval New

These are exact one I bought. They're longer & wider, and like I said they didn't have too much of an effect.

When you say that "they didn't have too much of an effect," do you mean on boost pressures (i.e. restricting the exhaust and increasing boost), or on sound levels, or both?

jmroy6 04-27-2017 11:49 AM

GESI makes a nice high quality drop in cat that will withstand the high egts from boost. i know Seb tuned a nismo 370z with these cats on a stillen sc and had good results.

link https://www.vibrantperformance.com/c...Path=1527_1326


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