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forza italia
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Discussion Starter #1
Alright, I'm just full of questions today...

Inspired by 8 UR 2DR (;)) and his cutout (http://www.dmhperformance.com/ecutout.htm), I bring to you another question. Slap me if it's stupid.

Law enforcement officials can be an issue. It's actually getting pretty bad where I live. I'm sure there are problems in other areas.

Now, would it be possible to go turbo, and keep the entire exhaust system on the car stock (maybe gut the cat), with an electric exhaust cut-out located pretty much right at the end of the exhaust manifold?

Obviously having stock exhaust piping etc. is not ideal and will rob a ton of power, but you do have the advantage of a very quiet car and a car that appears quite stock. If you don't "display" your FMIC it would be pretty hard to tell, no?

And then, when you open that cut-out, the car will fly. Obviously it will be LOUD.

So the questions:

  • Is this possible?
  • How much power are you really losing with < 3" piping?
  • How quiet will the car be with the cut-out closed?
  • How loud is LOUD?

And then there's the obvious problem of tuning. The car will behave differently with the cut-out open vs. the cut-out closed.

How big of a deal is this?

Can any of the standalones be programmed such that when I hit the (electronic) button for the cut-out, a different map is loaded (or something to that effect)?

Thanks for any opinions. And I hope that this question isn't stupid ;)
 

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Hello World
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Just replace with an aftermarket exhaust instead of this hassle on stock. Some aftermarket exhausts(i.e. L-Tuned/CarsonTuned, Tanabe SMH) actually do look like stock exhausts and sound awesome, not to mention. But that is just for me :)
How loud is LOUD depends on a person's taste. For example, person A's loudness can be much louder than person B's thoughts. It is always good to hear in person :bigSmile:
 

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It is nigh impossible to keep the exhaust system 100% stock and install a turbo.

Even NA with the OEM header in the car... a cutout will still have to come after the 2 cats (you might fit it before the Ypipe cat)... I imagine you'd gain some power... but your ECU would probably freak and start chucking CEL's
 

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forza italia
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Discussion Starter #4
dasgalloway said:
It is nigh impossible to keep the exhaust system 100% stock and install a turbo.

Even NA with the OEM header in the car... a cutout will still have to come after the 2 cats (you might fit it before the Ypipe cat)... I imagine you'd gain some power... but your ECU would probably freak and start chucking CEL's
I meant keeping the exhaust system completely stock, after the appropriate (turbo-spec'd) exhaust manifold. Or did you understand what I meant? Either way, I'm still confused.
 

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There is a thread i seem to remember where the diff in tuning was discussed. Depending on how much boost you are pushing this could make a BIG diff in tuning or just a small diff in tuning.
 

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azzurro said:
I meant keeping the exhaust system completely stock, after the appropriate (turbo-spec'd) exhaust manifold. Or did you understand what I meant? Either way, I'm still confused.

"Completely stock" is irrelevant when talking turbos...

OEM takes a 6-into-2 header into a 2-into-1 ypipe... (6 tubes go in, one comes out, at the middle of the ypipe)

Turbo manifold/header takes 6 exhaust ports and turns them into 1 downpipe/midpipe... usually connecting directly to the bpipe (this means the header and Y are replaced in a turbo setup... header becomes turbo manifold/downpipe, y becomes midpipe)

Now, the only emissions control devices in the IS exhaust system are in the header and Y... you replace those when you go turbo... so you have 0% of your emissions devices and 50% of your stock exhaust.

So no... you can't keep it "completely stock" but you can keep it 50% stock (bpipe and exhaust)
 

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We had to tune my turbo setup with the cutout open. The A/F #'s were fine. Once you close the cutout, the A/F's go so rich that my wideband will not even register it. If we tuned with the cutout closed, it would run lean when open. Not good.

There is an option to run dual maps with the my Haltech E6X, but it's more of a hassle to wireup something to be triggered when the cutout is open/closed. Then, make the 2nd maps.

I added a hi-flow cat.
I added the cutout after the cat.
I have 3" piping from turbo to 1st stock resonator.
I have the L-Tuned exhaust out the back.

With the cutout closed, there is no drone or noise other than what the L-Tuned sounds like. With it open, it sounds like a drag car. Loud, but not ear breaking. When open...it sounds like no other IS I have heard. "Mean" comes to mind.

Open vs closed --> The power difference has to be 50+whp. It is nutz! It's like having 2 cars in 1.

So far...I do not have any exhaust leaks from the cutout.
 

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forza italia
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Discussion Starter #9
dasgalloway said:
"Completely stock" is irrelevant when talking turbos...

OEM takes a 6-into-2 header into a 2-into-1 ypipe... (6 tubes go in, one comes out, at the middle of the ypipe)

Turbo manifold/header takes 6 exhaust ports and turns them into 1 downpipe/midpipe... usually connecting directly to the bpipe (this means the header and Y are replaced in a turbo setup... header becomes turbo manifold/downpipe, y becomes midpipe)

Now, the only emissions control devices in the IS exhaust system are in the header and Y... you replace those when you go turbo... so you have 0% of your emissions devices and 50% of your stock exhaust.

So no... you can't keep it "completely stock" but you can keep it 50% stock (bpipe and exhaust)
Thank you very much for the explanation Das. Much appreciated.

Would it matter where the cut-out is placed? I would imagine that the downpipe isn't causing much resistance. Is anywhere before the B pipe OK, or will there be a noticeable performance gain if the cutout is pretty much right at the exhaust manifold, versus at the beginning of the B pipe?

In terms of sound: With the cutout closed, how will the car sound versus a completely stock car? The turbo itself cannot be ignored, but...: Will the new manifold and straight, thicker piping to the B pipe sound "drony" or noticeably different than stock?


redline814 said:
We had to tune my turbo setup with the cutout open. The A/F #'s were fine. Once you close the cutout, the A/F's go so rich that my wideband will not even register it. If we tuned with the cutout closed, it would run lean when open. Not good.

There is an option to run dual maps with the my Haltech E6X, but it's more of a hassle to wireup something to be triggered when the cutout is open/closed. Then, make the 2nd maps.

I added a hi-flow cat.
I added the cutout after the cat.
I have 3" piping from turbo to 1st stock resonator.
I have the L-Tuned exhaust out the back.

With the cutout closed, there is no drone or noise other than what the L-Tuned sounds like. With it open, it sounds like a drag car. Loud, but not ear breaking. When open...it sounds like no other IS I have heard. "Mean" comes to mind.

Open vs closed --> The power difference has to be 50+whp. It is nutz! It's like having 2 cars in 1.

So far...I do not have any exhaust leaks from the cutout.
Awesome... thank you for sharing, and for your other thread (with the pics and other details).

I do like the fact that you can have the switch trigger a new map. Not necessary, but it's nice having the option there. And the wiring is the fun part (but this is coming from a guy with a PC in his car ;)).

I really like the sleeper idea though. How do you think that the car would sound if the cutout were before the cat you added? Was that really necessary to pass safety inspections? I would figure you'd fail on the spot for "other" reasons.
 
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