New GT liberty wagon.

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craash
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Re: New GT liberty wagon.

Postby craash » Wed Aug 31, 2011 5:23 pm

What's everybody's thoughts on cat back exhausts? I got the car a couple of weeks ago, and I can't hear the thing.

I don't what loud, I just want to be able too hear it. I plan on getting a reflash done, when I decide on a muffler. Not sure how restrictive the standard mufflers are? I know on my old Sti, the restricter was in the dump pipe. Not sure if the GT's are the same? I really don't want too go that far though.

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cpitts
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Re: New GT liberty wagon.

Postby cpitts » Wed Aug 31, 2011 9:50 pm

Cat back will give you rumble depending on the tip you use. Stock mufflers are restrictive for initial pressure loading, so you will improve throttle response. Dump pipe will further improve throttle response and spool time.

Understand though that you'll also start to run richer.
'07 Lib GT Spec B <- adjusting
Done: Intake, Brakes, Stereo 90%, bars, AVO TMIC
To fit: Sil intake, ECU, 3 Port, Walbro
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The STiG
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Re: New GT liberty wagon.

Postby The STiG » Thu Sep 01, 2011 8:15 am

Craig,

For the n00b in us all, what does running richer mean and what does this mean over say a tank of fuel?
Ada///M.

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craash
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Re: New GT liberty wagon.

Postby craash » Thu Sep 01, 2011 6:29 pm

I plan on getting a reflash, as soon as I work out what exhaust is going on. So that should fix up any issues with running rich.

I was guessing that the new Lib's were the same as my old Sti, in that a new dump pipe would also help - but I really didn't want to go down that path. I wasn't even going to put a catback on, until I heard it.

I spoke to a guy at Hallam Performance Exhausts today, and might go that way with a catback. I still need to do a bit more research.

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cpitts
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Re: New GT liberty wagon.

Postby cpitts » Thu Sep 01, 2011 8:44 pm

The STiG wrote:Craig,
For the n00b in us all, what does running richer mean and what does this mean over say a tank of fuel?


With just the mufflers/cat back done, you'll get (all info based on Shell VPwr 98):
- typically will drink a little more fuel per tank (less km's travelled)
- a bit of over-run and crackling in the exhaust under heavy acceleration and gearchange (manual)
- city cycle (little or no freeway/stop start) fuel economy as low as 400km from full fill to fuel light
- incl freeway cycle maybe up to ~450km from full to fuel light
- pure freeway cycle will actually show better stats up to 550km before fuel light comes on
- reduction in driveline shudder at low rpm (friction point take-off in traffic)
- improved speed accelerating through the rev range (hits redline faster/easier)

The car responds even better with the intake being openned up as well, but it really over-compensates and fuelling increases further due to the significant airflow increase. But the intake noise and crackling exhaust just brings a smile to the dial. ;-)

The ECU in these things is VERY much flagged with the new ECU sensitivity to airflow changes. Hence the need for a reflash, even from the factory super conservative rich setup.
'07 Lib GT Spec B <- adjusting
Done: Intake, Brakes, Stereo 90%, bars, AVO TMIC
To fit: Sil intake, ECU, 3 Port, Walbro
WWW (button below) for my Subaru/Audi dyno's, detailing, pics and mods!

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