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3.5 inch turbo back exhaust to stock rear muffler


lulululululul

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  • Member For: 6y 8m 24d

Hi guys,

 

New to the forum, usually a lurker but I have a question which I have done some research about but I'm not 100% sure about. 

 

I have a fg xr6t with supporting mods making 470rwhp. However the car drones way too much at highway speeds even though I have a cat, mid muffler and rear muffler. Recently I replaced the rear muffler with the stock 3 inch muffler. I assume ive lost power but would this be a substantial loss?. Doing some research suggests that it shouldn't harm the engine. 

 

I prefer the quiet sound while cruising around. I have a varex on the way which ill probably install but if the stock muffler does the job is it worth putting a 3.5inch varex rear muffler?. 

 

Tl;dr - Is it okay to have an exhaust go from 3.5inch turbo back to 3 inch even with power upgrades. 

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  • Member For: 15y 11m 18d
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  • Location: Melbourne

It's fine to have it like that. You've probably lost a few ponies, though. Only one way to find out - before and after dyno runs in the same conditions.

 

:Welcome2FordXR6t:

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  • Member For: 6y 8m 24d

Hmm that is a good point. Might have to do that. I usually read that getting a turbo back exhaust would require a retune. But if im replacing the rear muffler to a 3 inch would that require a retune?. 

 

If I use the varex which is a 3.5 inch muffler I assume that I wouldnt need a tune again at all as its back to what it originally was?. 

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  • Member For: 15y 11m 18d
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changing the rear muffler (or the middle muffler) does NOT require a retune.

 

It's the cat that is the most restrictive part and if you free up that restriction it can overboost with the stock turbo setup.

 

A varex is totally fine to just install.

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  • 4 weeks later...
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  • Member For: 6y 8m 24d

Sorry for reviving this thread but hopefully someone answers. I just had a 3.5 inch varex installed onto my 3.5 inch exhaust with 4 inch dump. The exhaust shop however added some tips to the rear muffler that is only 3 inch in diameter. I am wondering will this hinder performance or be bad for the car?. The guy at the shop reckons it wouldnt make a difference but I am looking at getting more power soon.

 

Thanks in advance

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  • Member For: 9y 1m 27d
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42 minutes ago, lulululululul said:

The exhaust shop however added some tips to the rear muffler that is only 3 inch in diameter.

 

The grammar says muffler but the context says tips. Which is it?

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  • Member For: 9y 1m 27d
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  • Location: South Australia

Yep it makes sense. 

 

After the exhaust gas goes through the cat and various exhaust bends I doubt a 3 inch tip will be a restriction.

 

As hamster balls said the only way to know for sure will be a dyno comparison but that's a waste of money. 

 

If it bothers you then swap it.

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