Exhaust question

[Coolmaxt]

Is there an easy way to improve flow in my factory dual exhaust? I have a bone stock 5.7 in my 13 express. I plan on getting a vararam in the near future.

 

[SyN]

In my opinion the only way to Truely improve exhaust flow is too install Headers & a true dual exhaust.

I personally would not waste $$ on a expensive cat back system... Just do a simple muffler swap with a straight threw design performance muffler. The stock system is fairly efficient except for the small piece of pipe below the transmission pan. Get rid of that huge A$$ Tank they call a muffler.

You have hundreds of Muffler choices out there!

 

[Coolmaxt]

Ok, I like what I'm hearing. So what would you do about that small pipe below the trans pan?

 

[SyN]

I really have no idea how much that little bit of flattened pipe is actually hurting flow...
I have seen pics of owners who have just cut the piece of pipe out and replaced it with a new piece. They also installed a new y-pipe to join both pipes back into the stock 3".

I really don't think you will be able to feel any difference...just by replacing the small (some what) flattened piece.

Even with the muffler swap-->You will only hear a change in sound-->No real power gains will be felt.

Do you have plans on doing any major HP mods in the future? If so--you might consider doing the true duals and headers...

All of this is just my simple thoughts and opinions-->Nothing More

Just hearing your Hemi Getting to roar was worth it too me!! Didn't really expect any extra!

 

[YellowDUc]

Ok, I like what I'm hearing. So what would you do about that small pipe below the trans pan?

You want to replace that y-pipe. That smashed pipe does decrease the flow. It is a minor cost, I think Moe's sells the y-pipe for around $30.00. Plus, what ever the shop charges you if you do not install it yourself.

Also, you will want a tuner at some point. Best performance upgrade for the dollar.

 

[Hemi450hp]

While the factory y-pipe is restrictive, replacing it without headers really doesn't show much of a gain, if any. The Magnaflow Ypipe is only about $30, but most shops are going to use cheaper aluminized steel with crush bends anyway when making your new one. In the end, I would just leave the Y-pipe alone unless you are going to be adding headers. If going with longtubes, they all offer a mandrel bent stainless Y-pipe to go with the header...this is going to replace the majority of the restriction in that factory system.

As for the muffler, you may pick up 5-8hp with a free flowing muffler, but that is tough to feel in the seat of the pants. The muffler will be more for sound than it will actual performance gains. Longtube headers are where the power is at.

 

[stungeon]

How much of a HP gain with headers?

 

[Moss]

I just ordered an MBRP cat back complete system, also ordered black tips cause I hate the chrome... Getting installed Saturday morning, will post clips when I get a chance...


Sent from my iPhone using Tapatalk

 

[Hemi450hp]

Longtubes are showing 25-30hp/tq to the wheels as long as you can tune for them. Without tuning, most guys are seeing about 20hp/tq.

 

[SlowRoller]

If a 'mild' ellipse has the same perimeter as a circle, the flow through both, to a point, is virtually identical. (~Extreme~ ellipse's being the exception)

I think quite a few folks see a circle reshaped to an ellipse (or a "D" in the case of the OEM "Y") and feel that there has been a reduction in the perimeter.

Also saw some pics recently of a 'Y' replacement where non mandrel bent tubing with some rather significant bends (significantly reduced perimeter) were utilized,,,

It's entirely possible to end up worse than where you started with your exhaust.

Choose wisely.

 

[Coolmaxt]

Thank you for the input guys. I am very blown away by the long tubes giving so much horsepower! I will have to start looking into some long tubes..

I have been on the fence about getting a tuner because I like using the cheap 87-89 gas. Does a tuner do much good if I stick with the lower grade gas?

Also, my hemi gets about 14-15 mph on average.. Would these mods help with mpg or hurt it? (With the exception of actually having fun with it Of course). Being able to tell my wife that it improves gas mileage suddenly makes blowing money on my truck ok haha