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Single Exhaust?

2K views 30 replies 14 participants last post by  justinschmidt1 
#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
 
#2 ·
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
 
#8 ·
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!
 
#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?
 
#11 ·
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:
 
#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.
 
#13 ·
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:
 
#14 ·
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.
 
#17 ·
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?
 
#23 ·
Its a comp billet wheel 67....I really dont even know how to give an impression since I have nothing to compare it to.

Im still running 4.10s in the car and its only tuned on like 9 psi....its headed back to the dyno for 3.27s and hopefully to bump the boost up to 15-16 pounds.

Hard to really say when its under full boost since 4.10s are retarded...it seems to come on hard around 4k though in 2nd gear but I can definitely see boost way before that in 3rd gear with more load on the motor.

Ill give you some better info when I get the 3.27s in there and on the dyno, should give me some good solid info on when its spooling with that setup.

Im not sure why my car made such low power but seems like something is off with my setup, maybe the cams are just awful for a turbo setup or maybe I have a weak shortblock...not sure, gonna have to see what happens on more boost here.
 
#19 ·
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
 
#20 ·
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.
 
#26 ·
Based on what?

Wheres your proof that a straight through muffler will outperform a mac flowpath?

I have proof for my side of the argument.....

Check this out: http://forums.corral.net/forums/superchargers/1324858-mac-flowpath-vs-magnaflow-dyno-results.html

The guys making nearly 800 rwhp but still, he has numerous dyno runs showing that he lost a good bit of power with the straight through magnaflow design vs the mac flowpaths.

"Now conventional thinking would make you believe that a straight thru design muffler would be less resetrictive vs a MAC Flowpath. See pics of the Magnaflow muffler:"

"But that was not the case:

With no other changes we lost 45rwhp @ 5300rpms. "

Yea, he is making 800 rwhp but who is to say a 600 rwhp wont see gains of 20-30 rwhp?
 
#29 ·
Justin...

You referred a link to Mike Plummers facts or finding on mufflers/exhaust. 1st off your comparing apples to oranges. He is posting stuff thats directly related to the supercharger crowd. They mean nothing to us turbo guys ( his info )

The exhaust deal......he went from a 21/2 setup to a 3 inch set, then he went from a non chambered muffler to a chambered muffler....all this is blower related.

You ever notice Mike never post in turbo section.....plus he's biased to some degree, especially when you discuss e85 vs methanol. So his thread dealing with exhaust means nothing to me nor should it mean anything to you....since your doing a turbo setup

Any time you lengthen a 3 inch pipe, where you would have had two 21/2 you are creating backpressure...
 
#30 ·
3inch will be fine for 550. I wouldnt even worry about it. i have a single 3inch setup on mine with a 3inch straight though magnaflow and havent had any issues. i was having converter issues on the dyno but when i took the exhaust off from the downpipe under the car i gained 7hp on the dyno.
 
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