Twin Turbo with Stock Cats?

DIGItonium

Is anyone keeping the stock cats with the twin turbo setup? Jason at Baker Tuning, who is working on my car, noticed higher than normal water temps. Other than that, the car is running fine. So I'm wondering if this is an EGT issue with the stock cats.

I used to have Berk HFC with my TDX exhaust, but the rasp and loudness was too much for my ears. If I end up needing a set of HFCs, it might be Fast Intentions this time around to match with the exhaust.

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superchargedg

I blew my stock cats out less then 2 months after putting the Greddy twins on so i just run test pipes.

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My car is bone stock...i promise.

LafitteZ

Im gonna run test pipes on mine but the build is in progress now. Supposedly the turbos tone the rasp down just like a cat would do plus you make more power. Well at least thats what z1 told me.

Dembflyr

I have the 3" down pipes and a berk exhaust. My car is very quiet and not raspy at all. Until the waste gates open. Then its obnoxious.
I don't have them recirculating into the exhaust just yet.

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GambitX

if you dont need to do smog inspections no need keeping them. If anything it will make the car sound deeper, zero rasp. So take them off or gut them

theDreamer

I would go with something like a RTP, also remember with a TT kit your exhaust will be a little bit quieter from the turbos.

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DIGItonium

Without cats, wouldn't the smell out of the exhaust become nauseous ? How about the cats from a gtr? I know it is limiting potential, but sorta making it feel like OEM with smooth power and sound without getting nauseous haha.

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GambitX

LOL the smell is the smell of a performance car. Its not that bad.

Red__Zed

best to just get used to it.

DIGItonium

I'll either settle for HFC or Resonated HFC from Fast Intentions... minimal rasp without making things too loud, and retain the smooth and deep tone. Not a bad sacrifice.

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Dembflyr

From what I've been told, HFC's will not hold up to the increased temperature and pressure. Go with the RTP's if you're not doing the down pipes.

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2012 G37S Sedan 6MT - Project Practicality

2009-6MT-Sport/Touring-Dembflyr's Journal-TT Build Thread-CAR IS SOLD

SharpByCoop

We're in the process of changing exhausts on my G37. I have dual GTM 2.5"s with GTM test pipes. For me, it's got just too much drone in the cockpit at low load, 2000 RPM.

I like quiet: I had Sam provide recirculation for the waste gate AND the blow-off valves. Got what I wanted.

That said, although the 2.5" duals perform well, I want it even quieter. We are going to cut the test pipes to add in a stubby resonator and change the exhaust to an ARK 'grip' system. I'm hoping the changes will be dramatic in sound, and not dramatic in power change (unless it's more... )

Back to cats: I have the stock cats, and when I need to get an emission inspection we can simply replace them, get the test, and return to this setup.

Without question the cats (either HFC or OEM) provide emission compliance. They also provide a restriction. It's your choice. This is mine.

Coop

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Jim Cooper - (Retired: '08 Infiniti G37 Sport • TheShopCT built • 11.13 @ 123 mph (click for vid) • GTM Stage II Twin Turbo • 5-speed A/T Level Ten built • 591whp @17 lbs boost)

DIGItonium

Agreed, Jim. I like the smooth deep sound, but the drone does get pretty loud at times even with the stock cats.

How about this: N/A it was 12" TDX and stock cats. This is as loud as I can handle, and it's a plus if the turbos attenuate the current sound. With Berk HFC, the drone was obnoxious and the rasp was terrible.

So with the said solutions, I don't want my exhaust getting any louder and I definitely don't want any ricey sounding rasp.

I don't mind RTP if it doesn't stink up the place and holds up well for daily driving (i.e., CEL).

[EDIT] I settled with HFCs from Fast Intentions since I want to avoid rasp and smell. Although there is no 100% guarantee (no warranty) of the life span of the HFC with the turbos, it is the quickest solution. F.I.'s recommendation is a test pipe and catted s-pipe combination, which will move the HFC further away from the turbos. Resonators are technically not needed because the turbos already subdue the sound, so it ends up saving me money.

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