GTM Performance Engineering: MHI Twin Turbo Official Release

Chuck33079 · 05-31-2013, 11:39 AM

Quote:

Originally Posted by puckshaw

That was the only thing I could think of. I believe the FI 3" exhaust which is made for turbo applications even has HFCs in it but they're much farther down stream. I guess if someone is determined/required to run cats, that would be a good option. I may go that route later down the road if my inspections don't go as planned.

I've got the catted FI 3". The cats are several feet away from the turbos. They should hold up fine.

SAM@GTM · 06-03-2013, 12:54 PM

Quote:

Originally Posted by puckshaw

I was curious about this too. I ran HFCs on my old STi and never heard anyone having a failure or even being concerned about it. Either way, I'm going with test pipes but I'd still like to know why it's an issue on this platform.

Quote:

Originally Posted by Chuck33079

The cats on the STI are a lot further down stream from the turbo than on the Z. Heat is the issue, and the additional distance makes a huge difference.

The reason the aftermarket STi cats don't fail is quite simple. They are designed for the application. Mounting the cats farther away is actually a bad thing and shortens the life of the cat since it needs heat to do its job. The better Subaru Downpipes use correct cats and mount them in the factory location right after the turbo outlet. The HFC's currently on the market for this car are NOT designed to handle Forced Induction.

We will be offering high flow cats as part of our new modular downpipe design. These cats are designed specifically for high horsepower, forced induction applications. In fact, we are so confident in their performance that we will be offering a warranty against failure.

The HFC's we will be offering are for our 3" downpipes with external wastegates as an option. You can also swap to 3" test pipes for track days if you like since they are bolted pieces. This new option is a great way for people to go that want 500whp and still have clean exhaust. Also, these cats will keep emissions down just as well as the stock cats, but have more flow and stand up to higher exhaust temps with richer air/fuel mixtures.

Sam

Nixlimited · 06-03-2013, 12:58 PM

Quote:

Originally Posted by SAM@GTM

The reason the aftermarket STi cats don't fail is quite simple. They are designed for the application. Mounting the cats farther away is actually a bad thing and shortens the life of the cat since it needs heat to do its job. The better Subaru Downpipes use correct cats and mount them in the factory location right after the turbo outlet. The HFC's currently on the market for this car are NOT designed to handle Forced Induction.

We will be offering high flow cats as part of our new modular downpipe design. These cats are designed specifically for high horsepower, forced induction applications. In fact, we are so confident in their performance that we will be offering a warranty against failure.

The HFC's we will be offering are for our 3" downpipes with external wastegates as an option. You can also swap to 3" test pipes for track days if you like since they are bolted pieces. This new option is a great way for people to go that want 500whp and still have clean exhaust. Also, these cats will keep emissions down just as well as the stock cats, but have more flow and stand up to higher exhaust temps with richer air/fuel mixtures.

Sam

It makes sense to test these on my car

gbrettin · 06-03-2013, 03:48 PM

So... What you are saying is that everyone should run open dumps.

Quote:

Originally Posted by SAM@GTM

The reason the aftermarket STi cats don't fail is quite simple. They are designed for the application. Mounting the cats farther away is actually a bad thing and shortens the life of the cat since it needs heat to do its job. The better Subaru Downpipes use correct cats and mount them in the factory location right after the turbo outlet. The HFC's currently on the market for this car are NOT designed to handle Forced Induction.

We will be offering high flow cats as part of our new modular downpipe design. These cats are designed specifically for high horsepower, forced induction applications. In fact, we are so confident in their performance that we will be offering a warranty against failure.

The HFC's we will be offering are for our 3" downpipes with external wastegates as an option. You can also swap to 3" test pipes for track days if you like since they are bolted pieces. This new option is a great way for people to go that want 500whp and still have clean exhaust. Also, these cats will keep emissions down just as well as the stock cats, but have more flow and stand up to higher exhaust temps with richer air/fuel mixtures.

Sam

conmam · 06-06-2013, 01:33 AM

Quote:

Originally Posted by SAM@GTM

The reason the aftermarket STi cats don't fail is quite simple. They are designed for the application. Mounting the cats farther away is actually a bad thing and shortens the life of the cat since it needs heat to do its job. The better Subaru Downpipes use correct cats and mount them in the factory location right after the turbo outlet. The HFC's currently on the market for this car are NOT designed to handle Forced Induction.

We will be offering high flow cats as part of our new modular downpipe design. These cats are designed specifically for high horsepower, forced induction applications. In fact, we are so confident in their performance that we will be offering a warranty against failure.

The HFC's we will be offering are for our 3" downpipes with external wastegates as an option. You can also swap to 3" test pipes for track days if you like since they are bolted pieces. This new option is a great way for people to go that want 500whp and still have clean exhaust. Also, these cats will keep emissions down just as well as the stock cats, but have more flow and stand up to higher exhaust temps with richer air/fuel mixtures.

Sam

Sam,

When will you offer these high power forced induction cats ( Without external wastegate ) ? I hope very soon.

Chuck33079 · 05-31-2013, 11:04 AM

You learn something new every day. I still don't know why you would go through the effort of turboing the car and leave the stock cats unless you're in a state that requires it.

Baer383 · 05-31-2013, 11:09 AM

Quote:

Originally Posted by Chuck33079

You learn something new every day. I still don't know why you would go through the effort of turboing the car and leave the stock cats unless you're in a state that requires it.

I have stock cats on mine but I'm SC ,and need emissions but I wouldn't put any cats on a turbo car they will get burned up faster than mine.

SPOHN · 05-31-2013, 12:13 PM

Am I the only one going open dump?

Chuck33079 · 05-31-2013, 12:16 PM

Quote:

Originally Posted by SPOHN

Am I the only one going open dump?

I've done it on previous cars. It's kind of cool on a toy car. There's just no way in hell I'd run open dumps on a daily driver.

SPOHN · 05-31-2013, 01:02 PM

Quote:

Originally Posted by Chuck33079

I've done it on previous cars. It's kind of cool on a toy car. There's just no way in hell I'd run open dumps on a daily driver.

Just stay out of boost. Wait, what did I just say?

NitrousZ34 · 06-01-2013, 01:51 AM

Quote:

Originally Posted by SPOHN

Am I the only one going open dump?

I am too. I want that ish as loud as possible. No fûcks given by me

Chuck33079 · 05-31-2013, 01:46 PM

Good luck with that. I've got the small GT28s, and it spools very quickly. I'd imagine the 16gs and 18gs are even quicker.

Dzel · 05-31-2013, 05:54 PM

If I would of known that I would of just fine a custom exhaust

Sent from my SCH-I605 using Tapatalk 4 Beta

Dzel · 05-31-2013, 10:00 PM

So I did some research (talked to Mike) and high flow cats will fail and be catastrophic resonated test pipes if they fail the resonated part will just burn off over time. So in good!

Sent from my SCH-I605 using Tapatalk 4 Beta

1slow370 · 05-31-2013, 10:16 PM

stock cats = ceramic = better under high heat

high flow cats = metal foil = burned up

05-31-2013, 11:04 AM	#6 (permalink)
Chuck33079 A True Z Fanatic Join Date: Nov 2011 Location: Houston Posts: 12,265 Drives: 2011 370ztt Rep Power: 29540	You learn something new every day. I still don't know why you would go through the effort of turboing the car and leave the stock cats unless you're in a state that requires it. __________________ 2011 MB Touring-Sport-6sp-Nav/GTM TT/FI TT TDX/JTran/Kosmic/Eibach/Hotchkis/SPC/CSF/RPS/SoThatsWhereAllMyMoneyWent

05-31-2013, 12:13 PM	#8 (permalink)
SPOHN A True Z Fanatic Join Date: Feb 2010 Location: Covington, GA Age: 47 Posts: 14,844 Drives: Waiting on next Z Rep Power: 223	Am I the only one going open dump? __________________

05-31-2013, 01:46 PM	#12 (permalink)
Chuck33079 A True Z Fanatic Join Date: Nov 2011 Location: Houston Posts: 12,265 Drives: 2011 370ztt Rep Power: 29540	Good luck with that. I've got the small GT28s, and it spools very quickly. I'd imagine the 16gs and 18gs are even quicker. __________________ 2011 MB Touring-Sport-6sp-Nav/GTM TT/FI TT TDX/JTran/Kosmic/Eibach/Hotchkis/SPC/CSF/RPS/SoThatsWhereAllMyMoneyWent

05-31-2013, 05:54 PM	#13 (permalink)
Dzel A True Z Fanatic Join Date: May 2011 Location: Midland, TX Posts: 3,884 Drives: 11 370Z PW M6 Rep Power: 25	If I would of known that I would of just fine a custom exhaust Sent from my SCH-I605 using Tapatalk 4 Beta __________________ 10secWS6 IF YOU CAN'T SWING IT THEN DON'T BRING IT! Check out Domestic Performance C.C.

05-31-2013, 10:00 PM	#14 (permalink)
Dzel A True Z Fanatic Join Date: May 2011 Location: Midland, TX Posts: 3,884 Drives: 11 370Z PW M6 Rep Power: 25	So I did some research (talked to Mike) and high flow cats will fail and be catastrophic resonated test pipes if they fail the resonated part will just burn off over time. So in good! Sent from my SCH-I605 using Tapatalk 4 Beta __________________ 10secWS6 IF YOU CAN'T SWING IT THEN DON'T BRING IT! Check out Domestic Performance C.C.

05-31-2013, 10:16 PM	#15 (permalink)
1slow370 A True Z Fanatic Join Date: Aug 2009 Location: In the D Posts: 3,732 Drives: v8 74 260z ;) Rep Power: 7252	stock cats = ceramic = better under high heat high flow cats = metal foil = burned up __________________ ANSWER PRICE LIST Answers - - - - - - - - - - - - - - - - $0.75 Answers (requiring thought) - - - - $1.25 Answers (correct) - - - - - - - - - - $12.50

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