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Discussion Starter #1
So I've been debating hacking the y pipe and just running a 3 inch single pipe to a muffler and dumping it over the axle.

Is this gonna sound like ass or what?


It a 4.6 mod motor with a 67mm single
 

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Should sound the same. All the exhaust is already brought into one while going through the turbo. I've heard plenty single exhaust cars, liked them all

My f150 has a single exhaust from the turbo and the sound is perfect IMO
 

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Put a cut out in place of the Y-pipe pipe that you don't use, more power for when you want it, quiet when you don't need it.
 

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So you want to take two 2 1/2 tailpipes (which is 5 inches of total exhaust pipe) and reduce it down to a 3 inch exhaust? Your going to increase backpressure!
 

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So you want to take two 2 1/2 tailpipes (which is 5 inches of total exhaust pipe) and reduce it down to a 3 inch exhaust? Your going to increase backpressure!
His down pipe is 3" y piped to the stock tailpipes, he wants to remove the y pipe and run 3" all the way from turbo back.
 

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Discussion Starter #10
That is correct, its a 3 inch down pipe out of the turbo and runs back past the transmission and has a y pipe which splits off into the twin 2.5 inch pipes to the mufflers and out the stock tips.

I just want to hack the y pipe and extend the 3 inch diameter pipe through a single 3 inch in.out muffler and dump it over the axle most likely.

I have a few reasons.

1) the y pipe hangs low and scrapes ####
2) weight saving
3) simplicity
4) want to get the passenger tail pipe away from my fuel lines
5) Ive always wanted to have no tail pipes on my sn95 cause I think it looks cleaner

Considering it runs a 3 inch pipe for 75% of the exhaust length I dont see how this would increase back pressure but maybe I am wrong?
 

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Your Y pipe problem ("Hanging Like ####") more than likely is caused by bad mounts....i.e. engine and trans. Found that out the hard way!

Your other reasons 2 through 5 are valid. On the other hand you have to consider backpressure issues. The minumum for a turbo system is a 3 inch exhaust...which is what you want and will be down sizing to.

I was just wondering why you would to subtract from your build rather than add.

good luck on your build:salute:
 

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Discussion Starter #12
As far as scraping, the car is just low...and the way the y pipe is designed the one side drops down lower than the other for some reason and literally scrapes coming out of my driveway.

As far as back pressure, I would think that the only way to decrease backpressure would be to have larger exhaust coming off the turbo?

The exhaust is still going to be 3 inch for 50-75% of the exhaust total length no matter what.

Anyone have any real input on this? Real data?

Its kinda like breathing through a straw.

If you connect a garden hose to a straw your still restricted by the straw correct?

Same concept as connecting 5 inches of pipe to the 3 inch pipe.

I would think the backpressure would be the same or very similar.
 

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As far as scraping, the car is just low...and the way the y pipe is designed the one side drops down lower than the other for some reason and literally scrapes coming out of my driveway.

As far as back pressure, I would think that the only way to decrease backpressure would be to have larger exhaust coming off the turbo?

The exhaust is still going to be 3 inch for 50-75% of the exhaust total length no matter what.

Anyone have any real input on this? Real data?

Its kinda like breathing through a straw.

If you connect a garden hose to a straw your still restricted by the straw correct?

Same concept as connecting 5 inches of pipe to the 3 inch pipe.

I would think the backpressure would be the same or very similar.
you are correct. if the exhaust is a restriction due to being 3", your not changing that by ditching the dual 2.5" because the exhaust is already a single 3" up stream. youll have no hp change, enjoy the new exhaust. post pics when your done:salute:
 

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When you add both 2.5"-pipes together and get 5" that is incorrect yes it will be 5" wide total but you need to look at cicumference and surface area not width of the pipe. The single 3" pipe will outflow the dual 2.5" pipes because the 3" pipe has more surface area. The total surface area of TWO 2.5" pipes is 7.85". The total surface are of ONE 3" pipe is 9.42". So Justin you WILl gain power with a single exhaust over the dual 2.5" pipes.
 

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Discussion Starter #15
When you add both 2.5"-pipes together and get 5" that is incorrect yes it will be 5" wide total but you need to look at cicumference and surface area not width of the pipe. The single 3" pipe will outflow the dual 2.5" pipes because the 3" pipe has more surface area. The total surface area of TWO 2.5" pipes is 7.85". The total surface are of ONE 3" pipe is 9.42". So Justin you WILl gain power with a single exhaust over the dual 2.5" pipes.
Lol thanks for the info...i was thinking the same thing after I thought about it but didn't care to get into it.

Sent from my DROID RAZR using Tapatalk 2
 

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So I've been debating hacking the y pipe and just running a 3 inch single pipe to a muffler and dumping it over the axle.

Is this gonna sound like ass or what?


It a 4.6 mod motor with a 67mm single
how does that 67mm work for ya? what brand is it? what kind of boost and # are you seening? when is it underf full boost?
 

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When you add both 2.5"-pipes together and get 5" that is incorrect yes it will be 5" wide total but you need to look at cicumference and surface area not width of the pipe. The single 3" pipe will outflow the dual 2.5" pipes because the 3" pipe has more surface area. The total surface area of TWO 2.5" pipes is 7.85". The total surface are of ONE 3" pipe is 9.42". So Justin you WILl gain power with a single exhaust over the dual 2.5" pipes.
WHAT? You mean to tell me your applying mathematics and logic? Noooo. Glad you posted this. A lot of misinformation out there about flow characteristics of exhaust and turbo piping.
 

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There is a book out there called street turbocharging with a yellow supra on the front in this book they have a simple flow chart of single exhaust vs dual exhaust on a turbocharged car and the single exhaust is aways outflowing the dual exhaust at least up until a substantial amount of horse power then you have to up the size if i knew how to post a pic on here i would post it for you all to see. I run 3 in. all the way back through a dynomax race bullet and dump before the axle and like it a lot
 

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So did u go single 3" yet? I think I'm going to do the same thing. The Y-pipe and awkward dual exhaust piping is more a pain to keep than just replace. Especially since I want to put a catalytic back in.
 
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