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Posted: 8/17/2007 5:48:33 AM EDT
How much improvement has anyone found from putting a Magnaflow exhause system, new chip and air cleaner on their truck.

I've got a 95 Chevy 350 V8 and wondered if there was anyway I could justify spending the $900 to $1000 I was told this would cost....(yes, not installed by me, but by a shop).

I know a lot of boaters have chipped their tow vehicles.

I figured $1000 is 350 gallons of gas.  If I increased my mileage by 4 mpg (from 10-11 around town to 14...and from 17 highway to 21) then the payoff would come in around 22,000 miles or so.  

Is this likely from your experience.
Link Posted: 8/17/2007 5:55:31 AM EDT
[#1]
You shouldn't have to spend that much for a good exhuast system.  Before you do that though you might change your plugs and wires if they need to be changed.  Your engine needs to be performing its best before you do the add-ons otherwise you'll be wasting money.  You will typically pic up about 2mph with quality exhaust and intake.  I don't think there would be any way you would gain 4mph.

Bill3508
Link Posted: 8/17/2007 5:58:15 AM EDT
[#2]
You wont see 4mpg. I recommend a good cat back, new o2 sensors, NEW catalytic converters, and a soft or hard tonneau cover, and maybe a CAI. With those mods, 2mpg, MAYBE 3 could be realized.
Link Posted: 8/17/2007 6:00:18 AM EDT
[#3]
Both Flowmaster and Gibson run about $400 and you can install it yourself, its very easy, should not take more than an hour.  I didn't check Magnaflow price.  If you wanted to do it cheaper and your current exhaust is in decent shape just change out the muffler to a free flowing one of your choice.  Also get a decent air filter or one of the intake systems(preferably one that would seal it from the heat of the engine bay).

Bill3508
Link Posted: 8/17/2007 6:04:45 AM EDT
[#4]
you will never see 4mpg improvement..

Really the best bet to to just saved that $1000 towards gas... The minimual gains wont offset their own costs for a long time.

However, the addition or an exhaust, tuner, CAI would make your truck much more fun to drive.. Defentally should wake your engine up a bit and give you some more power, but that comes at a price..
Link Posted: 8/17/2007 6:05:21 AM EDT
[#5]
All engines perform better with better air intake and freer flowing exhaust. I have a diesel right now. Thats the 1st 2 mods I installed on it.

I did some minor tuning on a 99 Elantra (4cyl, gas) I should have kept

I installed the best NGK plugs made for it and 8mm plug wires. a cold air intake, a free flowing header and larger diameter exhaust all the way back. Its still legal, has its 2 O2 sensors and OBDII cat.

No chip, ECM is stock, but the mods I did livened it up A LOT and helped the mileage.

No fart can....the muffler had a deep bass tone to it

Do the basics first, intake, plugs, wires, then a catback. then look at a chip
Link Posted: 8/17/2007 6:06:06 AM EDT
[#6]
You can affect your gas mileage by more than that by changing
your driving habbits.  

On a pickup, the optimum speed for maximum gas mileage is
probably less than 55mph.  

I know it was listed in the owners manual of my dad's 1981 Bronco
that the optimum speed was 45mph.

Any idea what it is for your truck?
Link Posted: 8/17/2007 6:09:59 AM EDT
[#7]
most pickups (even new ones today) will be most fuel efficient  with easy driving around 45-50mph.

Drags a bitch when driving a brick..
Link Posted: 8/17/2007 6:16:11 AM EDT
[#8]
You can put the air filter and the chip in yourself.  Come on.

Link Posted: 8/17/2007 6:19:08 AM EDT
[#9]

Quoted:
most pickups (even new ones today) will be most fuel efficient  with easy driving around 45-50mph.

Drags a bitch when driving a brick..



As the driver of a 99 Chevy Tahoe (brick with wheels) I agree, to a point. I actually get better mileage with mine on the interstate at 75-80 than I do driving to work(25 mile drive at 55-60 the whole way). I've got 4WD, 32 inch tires and 3.42 gearing.

If you want to do an intake, exhaust and chip purely for your own enjoyment, then do it. If you're doing it for gas mileage, then learn how to drive within the optimum range for your vehicle.
Link Posted: 8/17/2007 6:20:21 AM EDT
[#10]

Quoted:
most pickups (even new ones today) will be most fuel efficient  with easy driving around 45-50mph.

Drags a bitch when driving a brick..


Yep. When I was driving on the expressway to and from work every day, 70 mph or so, I was getting crappy mileage. I now drive longer but it's on smaller highways (the kind where the speed limit is 50 and there are lights), I'm getting 5mpg and better routinely.

Which still isn't great but oh well.
Link Posted: 8/17/2007 6:20:32 AM EDT
[#11]

Quoted:
You can affect your gas mileage by more than that by changing
your driving habbits
drafting an 18-wheeler.


Fixed it for you since IIRC there was a thread on this recently.

FWIW my Suburban gets 8-10% better gas mileage when I run 93 octane gas versus 87.  Since 93 octane is only 5% more in price in my area, I end up saving money (the cost per mile driven is lower) by using the more expensive gasoline.  Most of the route to work is on the interstates at 70-75 mph.  Just something else to try...
Link Posted: 8/17/2007 6:42:14 AM EDT
[#12]
Trade it in on a diesel p/u. Im not kidding.

I have an 03 F250 SC 4x4, shortbed. My worst mileage is still better than your best mileage. Not being a prick, just tellin you the truth. Im getting 16+ local and it goes up with highway driving at legal crusing speeds.

A newer diesel pickup is not smelly or dirty. diesel has more power output and better mileage than its equivelant gas motor.

They hold their value better as well. Taken care of a diesel will last outlast the truck its mounted in.
Link Posted: 8/17/2007 6:44:37 AM EDT
[#13]
I put all synthetic fluids, an intake, and 2.5" Dynomax exhaust with no cat on my 94 Ford Explorer and brought it from 16 mpg to 20. Results may vary depending on vehicle.
Link Posted: 8/17/2007 6:50:01 AM EDT
[#14]
Just keep your tires properly inflated.
Link Posted: 8/17/2007 6:52:31 AM EDT
[#15]

Quoted:
most pickups (even new ones today) will be most fuel efficient  with easy driving around 45-50mph.

Drags a bitch when driving a brick..


Try Drafting.  
Link Posted: 8/17/2007 6:53:12 AM EDT
[#16]

Quoted:
You can affect your gas mileage by more than that by changing
your driving habbits.  

On a pickup, the optimum speed for maximum gas mileage is
probably less than 55mph.  

I know it was listed in the owners manual of my dad's 1981 Bronco
that the optimum speed was 45mph.

Any idea what it is for your truck?


Not true with modern trucks.  I can get nearly 20MPG at 80 MPH going to Florida in my Titan.  Lower speed steady state, I get about 17 or 18.  Not bad, but....
Link Posted: 8/17/2007 8:34:26 AM EDT
[#17]
OK, I see a great variety of opinions and the same with personal experience.  I do check the tires and drive with the speed control when possible on trips.  I'm no lead foot around town but the comment about accelerating quickly to high gear is one I'll consider.

After some consideration I think I'll do as one person suggested, do the oil, the air filter, and then see about the exhaust and new computer chip if it looks like it's going anywhere.  If I got half the 4 mpg, or 2 mpg, and spent half, or less of the money then this still might be a viable effort.

Thanks for all the input.  I'd heard about 10-15% improvements claimed which would be more in line with 2-3 mpg rather than 4 mpg, so I'll accept that that's the more reasonable target.  I'm not considering getting a new truck as I'm still pretty happy with this one and we have a Honda Pilot we can use for trips also.

Link Posted: 8/17/2007 9:00:55 AM EDT
[#18]
From the equiptment you are thinking about putting on your truck, you might see 1%-2% imporvement, maybe (if you strech it) 1 MPG.

However, if you change your driving habits (below) and keep your tires 4-8 PSI above recommended) you can save as much as 10%. When leaving a stop light, accelerate moderately and smoothly with as little throttle as you can get by with; When driving on the freeway, engauge cruise control or otherwise stick to a +/- 1 MPH speed band; when driving on the freeways, set cruise control no higher than 65 MPH; get o toneau cover for the bed; leave the bed EMPTY; Keep up with service intervals on your vehicle.
Link Posted: 8/17/2007 10:00:49 AM EDT
[#19]
In my 94' Chevy 1/2 ton 350 with 3.44 gears I get 21mpg highway w/o AC. I have a K&N filter, headers, dual exhaust, chip, TBI spacer, multi spark ignition box & plug wires.

ETA: I originally got around 17 to 18mpg.
Link Posted: 8/17/2007 10:03:06 AM EDT
[#20]
I guess I assumed the factory chip was already programmed to give the
best mileage, and that modding the chip was usually done to increase performance.

Link Posted: 8/17/2007 10:05:57 AM EDT
[#21]

Quoted:
Just keep your tires properly inflated.
+5 MPG.

This will affect your mileage more than any exhaust system or air filter EVER will.
Link Posted: 8/17/2007 10:08:52 AM EDT
[#22]

Quoted:
I guess I assumed the factory chip was already programmed to give the
best mileage, and that modding the chip was usually done to increase performance.



Most of what I have seen will improve your mileage as long as you can keep your foot off of the gas. Which is not usually the case when putting on a performance chip.
Link Posted: 8/17/2007 10:09:25 AM EDT
[#23]

Quoted:
I guess I assumed the factory chip was already programmed to give the
best mileage, and that modding the chip was usually done to increase performance.

No. The factory computer is programmed for the most consistent baseline performance, not necessarily the "best" in any particular category. Altering the shift points in the transmission, for example, could drastically change the overall fuel economy. From the factory, the shift points are set to be a compromise for empty, full and towing conditions. If you drive your truck empty 99% of the time, changing the shift points to correspond to your style of driving can have a very beneficial effect.
Link Posted: 8/17/2007 10:13:30 AM EDT
[#24]

Quoted:
I guess I assumed the factory chip was already programmed to give the
best mileage, and that modding the chip was usually done to increase performance.



Not neccessarily true. The PCM is calibrated to function with a wide variety of different engine outputs due to manufacturing tolerances. When the factory mass produces engines with a design goal of say 300 hp, some may put out 280, some 310. The PCM has to run with all of them. That's why a dyno tune can be so beneficial, the PCM can be retuned to perform most efficiently with your particular engine trans. combo. Gains of 10% more hp on a dyno tune done by good tuners are not uncommon on stock motors.

Link Posted: 8/17/2007 10:37:13 AM EDT
[#25]

Quoted:

Quoted:
I guess I assumed the factory chip was already programmed to give the
best mileage, and that modding the chip was usually done to increase performance.



Not neccessarily true. The PCM is calibrated to function with a wide variety of different engine outputs due to manufacturing tolerances. When the factory mass produces engines with a design goal of say 300 hp, some may put out 280, some 310. The PCM has to run with all of them. That's why a dyno tune can be so beneficial, the PCM can be retuned to perform most efficiently with your particular engine trans. combo. Gains of 10% more hp on a dyno tune done by good tuners are not uncommon on stock motors.




+1 on the last 2 replies.

ECM factory programs are based on across the board average driving of the masses.  

If you find the right balance of mods and more engine/useage specific tunes then performance and MPG will increase. but there is the point of diminishing returns if the mods and tunes are too extreme.

Back to diesels tuning (which I have been researching since I bought my F250), I was surprised to find out that with a cold air intake, turbo back 4" minimum exhaust and mild tunes, the HP/TQ and MPG goes up together. Usually with  more efficient tunes between 60-80HP. depends on who wrote the programs. But most important is prudent usage of the right foot pedal.

anything higher then your getting into pure shit n git YEEHAW, with diminishing MPG.


ETA.....If you can watch a few episodes of POWERBLOCKTV on the Spike channel. Sometimes they go apeshit with mods but they also do basic mild hp/mpg mods for the real world daily drivers.
Link Posted: 8/17/2007 10:43:34 AM EDT
[#26]
Install underdrive pulleys on the engine.  They should net you 1-2.0 mpg improvement on the highway alone and they run around 250 bucks or less.


See if March Performance or ASP Racing sells a set.  Plus you will pick up about 10rwhp or more from them.  
Link Posted: 8/17/2007 11:04:50 AM EDT
[#27]
Just put the parts on if you want them.  You can hardly justify the expense to save in gas mileage.

FlowMasters made zero difference in MPG on the Wife's Hemi, but that isn't the reason I bought them.  

She gets 15 to 16.5 mpg in the city driving stoplights and 45mph roads for about 30 miles a day.   It only takes a few minutes for me to drop her gas mileage down to 12mpg.

Link Posted: 8/17/2007 11:07:29 AM EDT
[#28]

Quoted:
Install underdrive pulleys on the engine.  They should net you 1-2.0 mpg improvement on the highway alone and they run around 250 bucks or less.


See if March Performance or ASP Racing sells a set.  Plus you will pick up about 10rwhp or more from them.  


With a lock-up torque converter and overdrive that most vehicles have and the low cruising rpm, I bet this won't be very noticeable in mpg, either.  

Maybe buy a bicycle?  

My 94 Dodge 4x4 w/ a 318 gets 10mpg city, which is about as good as my 454 Chevy Dually.  FlowMasters and air cleaners didn't make any difference in MPg either, but, again, that isn't why I bought them.

I almost think that MPG discussions should be in the religion forum.  
Link Posted: 8/17/2007 12:23:04 PM EDT
[#29]

Quoted:

With a lock-up torque converter and overdrive that most vehicles have and the low cruising rpm, I bet this won't be very noticeable in mpg, either.  

Maybe buy a bicycle?  

My 94 Dodge 4x4 w/ a 318 gets 10mpg city, which is about as good as my 454 Chevy Dually.  FlowMasters and air cleaners didn't make any difference in MPg either, but, again, that isn't why I bought them.

I almost think that MPG discussions should be in the religion forum.  


What is in red is oversimplifying what we are discussing.

Its not just adding Flowmasters or changing air filters.

It is opening up the OVERLY RESTRICTIVE factory air intakes and rerouting where the engine draws air to a "cooler" area.
Cooler=denser=more efficient fuel burn

The exhaust is a "Cat-back" or even replacement headers, larger diameter pipes along with a freer flowing CAT and mufflers to stay "smog legal".

Making sure gas engines have a hotter more efficient spark (plugs, wires, and even hotter coil packs) with improved airflow increases economy and power.

You cant just do 1 thing half ass. You change 1 thing even a tad then you need to change something else to match/compliment the 1st change. That includes (possibly) switching to synthetic lubricants, making sure your running the correct tire pressure and controlling your right foot. Running higher octane gas, if your car runs better on it and shows an MPG increase than that will offset the higher pump price.

Link Posted: 8/17/2007 12:27:55 PM EDT
[#30]

Quoted:

Quoted:
Install underdrive pulleys on the engine.  They should net you 1-2.0 mpg improvement on the highway alone and they run around 250 bucks or less.


See if March Performance or ASP Racing sells a set.  Plus you will pick up about 10rwhp or more from them.  


With a lock-up torque converter and overdrive that most vehicles have and the low cruising rpm, I bet this won't be very noticeable in mpg, either.  

Maybe buy a bicycle?  

My 94 Dodge 4x4 w/ a 318 gets 10mpg city, which is about as good as my 454 Chevy Dually.  FlowMasters and air cleaners didn't make any difference in MPg either, but, again, that isn't why I bought them.

I almost think that MPG discussions should be in the religion forum.  



Wrong, but what do i know, I only build 850 hp mustangs.  


My 04 Lincoln Aviator got a 1.5 mpg improvement with nothing but a pulley change.  
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