Exhaust Dump Questions

[CALDWELL]

Whats up boys,

so i was reading Fedy's ( V8 mpg thread ), and posted my mileage from my previous 03' 4.0 - R.I.P </3, compared to my current 05' 4.0

03' 4.0 w/ K&N Intake + 2.5'' CBE = 15-16 MPG city drive only.

05' 4.0 w/ K&N Airbox Mod + Magnaflow Muffler = 13 MPG city drive only.

I really wanna get my exhaust done + get better MPG. I was thinking about dumping my exhaust for 2 reasons.

1. encourage me to get the exhaust done quicker...

2. see if I could achieve a little bump in mpg by eliminating 4 major bends from the factory exhaust, until i get a full 2.5'' system installed...

I dont mind having a loud exhaust, after having a FM 40, i dont think my magnaflow will ever be that loud. I am also aware of the " low end TQ loss ", but awesome top end pull lol What im really getting after is...

If i were to temporarily dump my exhaust before the rear axle, would it make my mpg worse than what it currently is ????????

 

[Ronin8002]

Doubt it would hurt your MPG. Pretty easy mod

 

[CALDWELL]

i dont think it would either, based on the fact that the exhaust flow is being free'd up majorly. again this wont be a perminant thing for me. cause i wanna get a 2.5'' exhaust again...

this could also benefit other members. I will i could turn my X into a tester, and compare MPG with 4 different stages of exhaust...

stock - muffler only - muffler w/ dump - true CBE...

 

[Ronin8002]

I'm not 100% sure but I think the stock muffler and piping are the same between the V-6 and V-8 models. If that is true then I don't think you'll see a huge improvement in mileage just from dumping the stock muffler. I suspect the stock muffler is the biggest restriction either way.

Since you're adding a full exhaust anyway it doesn't hurt to try though.

 

[CALDWELL]

you are correct about the stock pipe size...

but im not dumping the stock muffler, i currently have a 14'' magnaflow under my X right now lol. I lost the bulky stock keg of a muffler like 3 weeks after i bought the X hahaha...

exhaust flows best when it has minimal amount of bends. so by dumping prior to the rear axle, if you think about the factory pipe going over the axle. I will be eliminating 5 major bends in the exhaust...

 

[Ronin8002]

ah right on, I somehow missed you already had the magnaflow. Yeah dump that thing and see what you get!

Do you have any sound clips of what it sounds like now?

 

[CALDWELL]

i do not... heres the closest clip i can find to what mine sounds like currently. the quailty isnt good, but kind of an idea...

http://www.youtube.com/watch?v=NRgq-BEbT04

 

[zerodevil]

did you already do this? if your going to do it go ahead and kill it AFTER the Y pipe, there is not enough manifold to keep the engine from pulling cold air back in, the y pipe should ensure you dont burn valves. Other than that no you should see a serious increase in noise and power. lol i remember when i had an exhaust clamp fail on a friends mustang and half the exhaust came off and all of a sudden we were getting pulled back in the seats again, good times.

 

[CALDWELL]

nah im gonna cut the pipe into a turndown, right before the rear axle...

holy wow i mine as well run open headers if i were to turn down right after the Y-pipe lol...

im getting it done tommorrow morning, and they told me 50$. went to my exhaust shop to ask them if they would do it. they told me i wouldnt pass inspection, and i told him it would be temporary, and my inspection isnt up until febuary. pleanty of time to have the exhaust full finished.

then i asked if they knew of any negative effects. they compared my X to a 4.0 ranger, and said that we do turndowns on rangers atleast 5 to 6 times a month, and alot of people have no complains with the exhaust...

 

[kstrayhorn]

Man, I love living in Arkansas, no inspections or anything. I could cut mine off at the headers and no one would say anything. A cop might pull me over just to tell me it sounds good, though. lol.

 

[zerodevil]

my exhaust with headers, high flowing cats, and the muffler BARELY scrapes by here in alaska, cant wait to see what they have to say about cams and a supercharger....

 

[CALDWELL]

Zero the exhaust clip you made at night, in the snow...

your truck even then sounds like it has a supercharger. your X screams violence lol

 

[Turdle]

this could also benefit other members. I will i could turn my X into a tester, and compare MPG with 4 different stages of exhaust...

Under the car exhaust is a no no
CO causes brain damage--you cannot smell it or taste it and it will be blowing into your passenger compartment.

The tip must exit the undercarriage of the vehicle to be safe.

IMO this is setting a bad example, and should not even be considered.

 

[Squirrelmaster]

Under the car exhaust is a no no
CO causes brain damage--you cannot smell it or taste it and it will be blowing into your passenger compartment.

The tip must exit the undercarriage of the vehicle to be safe.

IMO this is setting a bad example, and should not even be considered.

I agree. Dumping the exhaust after the cab on trucks is one thing, but there is a reason why it won't pass inspection in any state that has inspections if it dumps under the passenger compartment. My friend dumped his exhaust on his full-size Bronco right before the rear axle, and not only was the drone RIDICULOUS from the open resonance chamber that is the empty back end of a SUV, but we would easily get fumed out when we would come to a stop at stoplight whether the windows were up (A/C on) or down.

I should also note he saw no gain in gas mileage, just noise.

Tom

 

[kstrayhorn]

But that wouldn't be much of a problem if you never idle, would it? I was planning on dumping mine after the muffler, but I never idle. I sometimes even turn off my truck at stop lights.

 

[IZwack]

I was planning on dumping mine after the muffler, but I never idle. I sometimes even turn off my truck at stop lights.

Doesnt that mean you still idle at other times?

 

[kstrayhorn]

not really, I find that idling is a waste of gas, lol.
But, I was really planning on dumping mine as caldwell was talking about. I know that it is dangerous, as turdle said, but lots of people have done it, right?

I guess I just don't really want to give up the option of dumping it because I really don't know what else to do with it. I don't want to run it normally because I don't like the way it is so low on the trucks with the body lift.

 

[IZwack]

What I meant to say was, you said you sometimes turn off the engine at light. So what is the engine doing at those other times when its running and you are at a light (taking into consideration that you only turn off the engine some of the time)? Is the engine not at idle?
Posted via Mobile Device

 

[kstrayhorn]

yeah, I guess I only turn it off when I saw that the light just turned red.

 

[CALDWELL]

Well let me update on my current status...

*** NEGATIVE on the EXHAUST DUMP ***

Turdle, and Squirremaster are correct...

So I had the exhaust dumped yesterday morning, and first i would like to say that the noise factor didnt even change for me, which i was kinda suprised. After reading about what Turdle, and Squirrelmaster stated. I went to the firehouse, and wanted to do a test on the X. I grabbed a CO meter out of the engineers locker. I took 2 trips with the X on a 3 mile round trip. one trip with windows up, and windows down. the CO meter was kept in the back seat.

short answer, the meter was going off... not good at all... so i called the exhaust shop, and explained to them what was happening. They said no problem, and for me to come back in the shop, and they will run pipe behind the driverside wheel, and exit the side for an extra 50$...

I was extremely nieve about this, and can say that i learned an extremely important lesson today...


DO NOT DUMP YOUR EXHAUST !!!!! BAD IDEA FOR YOU AND YOUR FAMILY/FRIENDS !!!!!!