Dual Exhaust MPG gains

[95busa]

Originally Posted By: Colt45ws
Oh, one thing I noticed with duals is it downshifts less often. I have the same gears you do. There are a couple hills Ive tested this on. One on a 50mph highway would normally take a TC unlock in order to pull it. No longer.
On the interstate (75mph) a particular hill used to cause a unlock, then shortly after a kickdown to 3rd. Now it will just unlock but remain in OD.
This is all with cruise control on.
I call that a win in my book.

Sounds pretty sweet. The Walker system is 2" pipe with a regular H pipe much like the stock system. I will be doing some long drives in this beast about 1000 miles at a lick. If it is holding gears longer, it couldn't be killing torque. It sounds like it is pulling stronger. I value your analysis very much since we have essentially the same vehicle. I did a 21mm Ford sway bar with Moog end links. Its like a different vehicle. I am thinking about some Moog progressive coils in the back also. I think that would help the way it likes to squat with even a small load in the back. For $60 you can't beat that!

 

[Colt45ws]

I actually put airlift bags in the factory rear coils for the same reason. I run 10-15 psi normally and max (35psi) under load. Worked really well with 500lbs in the trunk.

 

[dwcopple]

I went to junkyard and got a H-pipe from a wrecked crown vic and threw it on my MGM that had factory Y-pipe single on it. I installed some Edelbrock mufflers and dumped after them before the axle. I gained and lost nothing as far as MPG. Not worth it. The drone from 40-45 MPH was horrid. I used the O/D override button to avoid the drone around town.

 

[fisher83]

Dual exhaust would be a nice modification and will probably pick up a little power but I don't think it would make a noticeable difference in MPG. I agree with mpvue. I always got WORSE mileage from romping on it to hear the dual exhaust!

 

[Colt45ws]

Originally Posted By: dwcopple
I went to junkyard and got a H-pipe from a wrecked crown vic and threw it on my MGM that had factory Y-pipe single on it. I installed some Edelbrock mufflers and dumped after them before the axle. I gained and lost nothing as far as MPG. Not worth it. The drone from 40-45 MPH was horrid. I used the O/D override button to avoid the drone around town.

Thats because you dumped it. If it was done properly it wouldnt drone.
My a/m system drones. I think half of it is because of the tips. They are 18" long IIRC and 3.5" in diameter. Like a loud speaker. When I get around to getting my long tube headers, Im going to have a shop make me up a set of factory style turn downs to replace them. That'll quiet it. If that isnt enough, a resonator can be added and wont add any restriction.

 

[95busa]

Yeah, I am going to run a Walker factory style system without resonators. Resonators are $75 more and I drove CVPIs without resonators on factory systems for eight years with no droning or anything else untoward.

 

[Cujet]

I installed a Gibson system w/JBA shorty headers on my 98 F150. My MPG's went down a bit. When I gave the truck to my brother, I re-installed the stock exhaust. MPG's went back up. Hmmm.

 

[95busa]

That performance exhaust might be a case of throttle application. I am working with an OEM style exhaust, so it wont really sound inspiring. It will just free up about 15 horsepower (as rated by Ford) and hopefully about 1-1.5 MPG!

 

[SteveSRT8]

Thank God it won't just be another noisy car! They are a dime a dozen.

A quiet sleeper is always better.

 

[rpn453]

Once you get it installed and the savings start pouring in you could become a consultant for the auto manufacturers. I bet they'd pay a lot of money for the knowledge to improve power and fuel economy across the board for an extra $10 per vehicle in exhaust piping materials!

 

[95busa]

Originally Posted By: rpn453
Once you get it installed and the savings start pouring in you could become a consultant for the auto manufacturers. I bet they'd pay a lot of money for the knowledge to improve power and fuel economy across the board for an extra $10 per vehicle in exhaust piping materials!


Alright- I'll play your silly game. 1.) I find it interesting how much attitude you have on the internet. moving along. 2.) The OEM does not have to pay me a lot of money to prove a power difference, because they already did. In 2004 the Panther bodies were rated at 224hp with single exhaust and 239 for duals. The fact that the OEM documented a 15 horsepower increase with duals gave me cause to feel that there may be a economy benefit. Furthermore, the OEM did not publish an enhanced EPA rating, but the duals were only available with deeper gears from Ford, which probaby offset any MPG increase and leads me to believe there may be a fuel economy benefit. 3.) When is the last time you saw an OEM redo EPA mileage testing for an exhaust or gear option? There is one EPA rating for Ram 1500s with a 4.7 regardless of axle ratio be it 3:55s or 3:91s and we all know gears effect MPG right? 1980s Corvettes with the TPI engine had a performance muffler option that gave a documented HP increase (+5)- one EPA rating. 3.8 liter Camaro rally sports, same.
- So, maybe you should watch the sarcasm and educate yourself before you start bumping your gums together. Life will teach you these lessons in a much harder manner if this is the way you conduct yourself face to face (which I doubt).

 

[rpn453]

Originally Posted By: 95busa
So, maybe you should watch the sarcasm and educate yourself before you start bumping your gums together. Life will teach you these lessons in a much harder manner if this is the way you conduct yourself face to face (which I doubt).


This is exactly the way I conduct myself in person. I actually probably come across a bit milder on here than in real life, as I lack the self-control to decide whether I'm going to hit reply on what I've composed in real time, and I don't have any interest in this forum or any other sort of discourse when I'm feeling angry and violent. My father is the most offensive person I have ever known, and as they say, "I am my father's son". I'm not terribly fond of him or myself, so self-destruction comes naturally.

Of course, it's possible I'd never get to the point of using such sarcasm if everyone in this thread were discussing this in person because you may not have been as rude to user52165 for questioning your expected outcome. But if you had, I tend to rise to the challenge of being the biggest [censored] in the room, so I'd expect a similar response.

 

[95busa]

Originally Posted By: rpn453
Originally Posted By: 95busa
So, maybe you should watch the sarcasm and educate yourself before you start bumping your gums together. Life will teach you these lessons in a much harder manner if this is the way you conduct yourself face to face (which I doubt).


This is exactly the way I conduct myself in person. I actually probably come across a bit milder on here than in real life, as I lack the self-control to decide whether I'm going to hit reply on what I've composed in real time, and I don't have any interest in this forum or any other sort of discourse when I'm feeling angry and violent. My father is the most offensive person I have ever known, and as they say, "I am my father's son". I'm not terribly fond of him or myself, so self-destruction comes naturally.

Of course, it's possible I'd never get to the point of using such sarcasm if everyone in this thread were discussing this in person because you may not have been as rude to user52165 for questioning your expected outcome. But if you had, I tend to rise to the challenge of being the biggest [censored] in the room, so I'd expect a similar response.

As far as user's comment, I was not the least bit concerned about being questioned, I did not appreciate the way he went about it.
I am sure life has been and will continue to be kind to you. Best of luck.

 

[rpn453]

Originally Posted By: 95busa
As far as user's comment, I was not the least bit concerned about being questioned, I did not appreciate the way he went about it.
I am sure life has been and will continue to be kind to you. Best of luck.


The question was very direct. I'm glad you have an answer for his question within your own mind, because I'm not sure anybody else can figure out how you've determined that fuel economy improves proportionally to a gain in peak power resulting from an exhaust modification.

I admit I have lived an easy life, even by Western standards!

 

[TFB1]

Originally Posted By: rpn453


I'm glad you have an answer for his question within your own mind, because I'm not sure anybody else can figure out how you've determined that fuel economy improves proportionally to a gain in peak power resulting from an exhaust modification.
Dual exhaust won't give a increase in mileage unless the current system is creating a restriction at highway cruse speed... At this engine RPM(1500-1800) & vehicle speed, power required is usually around 30-40 HP, for a mid/large size sedan... Since the engine in question produces 224Hp at a far higher speed, likely there is nothing(a tenth or two at best) to be gained in fuel economy at the 1500-1800 RPM cruse speed...

At WOT & 4500RPM the single exhaust has enough restriction to choke out approx 15Hp vs the dual setup... Maybe, if you constantly cruse at 100MPH plus, the duals could have a slight edge vs the single system...

 

[95busa]

Originally Posted By: TFB1
Originally Posted By: rpn453


I'm glad you have an answer for his question within your own mind, because I'm not sure anybody else can figure out how you've determined that fuel economy improves proportionally to a gain in peak power resulting from an exhaust modification.
Dual exhaust won't give a increase in mileage unless the current system is creating a restriction at highway cruse speed... At this engine RPM(1500-1800) & vehicle speed, power required is usually around 30-40 HP, for a mid/large size sedan... Since the engine in question produces 224Hp at a far higher speed, likely there is nothing(a tenth or two at best) to be gained in fuel economy at the 1500-1800 RPM cruse speed...

At WOT & 4500RPM the single exhaust has enough restriction to choke out approx 15Hp vs the dual setup... Maybe, if you constantly cruse at 100MPH plus, the duals could have a slight edge vs the single system...


RPN453- you continue to fail to read accurately. Reading is fundamental. Thank you for your contributions, but your sarcasm and antagonism add no value to the discussion. Clearly I don't KNOW- if I KNEW I would never have posted this thread, I would have executed my plan with no input requested. Your statement is redundant and designed to illicit a response and illicit support for your comments, not to contribute knowledge. Yes, I am speculating, much like the rest of you. I did not speculate that economy improved proportionally with HP, I speculated 5% gain in economy off of a 7% HP improvement. I appreciate the well thought out response TFB1, however also of note is that the engine will suffer less pumping loss with 2" duals and the H pipe will prevent some exhaust backflow. You may be correct that gains will be less than a MPG, no telling but to do it I imagine. I won't have my feelings hurt too badly if MPG improvements are insignificant I guess since duals are cool and 15HP is nothing to sneeze at.

 

[ltslimjim]

Duals + long-tubes got my friend a good 2 MPG gain on the interstate with his Titan. 2006(IIRC). Makes about 23-24 on the interstate, will report back.

 

[rpn453]

Originally Posted By: 95busa
I did not speculate that economy improved proportionally with HP, I speculated 5% gain in economy off of a 7% HP improvement.


Not directly proportional, but an assumption of proportionality couldn't be ruled out with the limited data points proposed.

There's simply no reason to assume they will move in a positive direction together. With respect to exhaust sizing only, these two properties have an inverse relationship. When exhaust flow velocity is optimized toward higher output, it will be too slow to be ideal for the minimal output that most driving involves.

I apologize for polluting your thread with my negativity. I perceived an air of general disrespect that may not have existed. Even if it had, there is nothing to be gained by nurturing such an environment. For that, I am ashamed.

 

[95busa]

I hear you. Accepted. Better flowing exhausts within certain constraints are more efficient. We are talking about 2" duals. They really aren't excessive. Plus I do not believe an OEM would install an exhaust that reduces efficiency by virtue of being too big- I think everyone can agree on that. OEM systems virtually without fail lean towards constriction. The system I am doing is an OEM equivalent system.

 

[1999nick]

I am an old man. The only car I ever put a dual exhaust system on was a 1954 Ford V-8, the first year of the OHV V-8 for Ford. Back in those days, exhaust systems (stock) were much more restricted than now. I got this car brand new in 1954, a present from my dad for graduating high school. It had the overdrive manual transmission.

Naturally, being 18 years old, I had to find out how fast it would go. This turned out to be 95 to 97 mph. In 1956, I already had 40,000 miles on it, and I took a look at the exhaust manifolding. It was really terrible: the left side exhaust manifold emptied into a collector pipe that passed around the front of the engine and emptied into the right side exhaust manifold. From there, it all went out to the rear in one pipe.

I installed manifold and pipes so that each side's exhaust went out its own pipe. Now, I knew that speedometers of the day were usually wildly optomistic, but after this modification, my car went from indicating a 97 mph top speed to an indicated 108.

Now, as far as better fuel economy, I am not certain. However, it made sense to me that, with less power required to push the exhaust gasses out, less throttle would be required to maintain any given speed. Less throttle opening for any given speed should, to my way of thinking, translate to less fuel burned.

Where did my 20 year old thinking go wrong? By the way, that was my second car. My first was a 1940 Ford. I have since owned 26 other cars and trucks. I am now 75 years old.