Stock 2003 3.8L - gas mileage SUCKS and need more HP (mods) - HELP!! - Page 2 - Forums at Modded Mustangs
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post #21 of 43 Old April 16th, 2011, 10:06 AM
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I am not sure how to do this or if there is a special way to do it??
if i remember right, 1/3 in pcv 1/3 in oil 1/3 in gas tank on a warm engine, you start the car to get the last third in---pcv, after you get it all in, shut the car off, come back start it up 20 minutes later, rev it up, then go drive around WOT and get everything out.

theres a how to seafoam thread on here I couldn't find, but also youtube how to seafoam mustang

I can't speak first hand on tuning yet, im about to order my tuner, i only know because of what others have said

for exhaust imo there's two main setups for our car, catback with flows or thrush mufflers either divorced and with an h pipe

longtubes h pipe with either no cats or hi flow cats, and thrush or flow 40's

some people with bring up the prochamber idk much about it but it reduces a lot of rasp, it takes the place of the h
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post #22 of 43 Old April 16th, 2011, 01:31 PM
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Story time.

I recently did a new exhaust system head's all the way back to tips. The first week after getting my exhaust I noticed a drastic decrease in MPG. Turns out the new Header's had a gasket that was bad at the collector. I replaced it, noticed a small increase in MPG. Replaced plugs, wires, O2 sensors, and gave the ECU a refresher tune and let the car idle for awhile to relearn its internal settings. This brought my MPG back to 200 to the tank, not where I was before the exhaust, so I seafoamed the block, and did a super hot oil change (not a good idea now) replaced the oil filter and added high mileage oil. I'm at 215-230 per tank still not as high as it was before the exhaust but I'm replacing my thermostat today to hopefully bring the operating temperature of the block down.

Side note... K&N air filters (the red ones) should be recharged every 10-15k miles. If you recharge it to much you could lose the charge on the filter thus hurting fuel mileage. You may want to just replace yours and read the manual that comes with it. Also a CAI only helps fuel mileage if it is actually bringing in cold air. If the filter does not have the housing that blocks the motor heat out it isn't worth it. Another option is to custom pipe the air filter into the bumper away from the motor.

Did you check for a vacuum leak?
How's your EGR looking?
Is your check engine light on? If so what code's are you throwing?

Done so far:
windstar, port and polish lower, UDP, aluminum Drive shaft, 3.73lsd, and some other goodies.

Looking for a 4.2 next and maybe some spray.
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post #23 of 43 Old April 16th, 2011, 01:45 PM
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Story time.

I recently did a new exhaust system head's all the way back to tips. The first week after getting my exhaust I noticed a drastic decrease in MPG. Turns out the new Header's had a gasket that was bad at the collector. I replaced it, noticed a small increase in MPG. Replaced plugs, wires, O2 sensors, and gave the ECU a refresher tune and let the car idle for awhile to relearn its internal settings. This brought my MPG back to 200 to the tank, not where I was before the exhaust, so I seafoamed the block, and did a super hot oil change (not a good idea now) replaced the oil filter and added high mileage oil. I'm at 215-230 per tank still not as high as it was before the exhaust but I'm replacing my thermostat today to hopefully bring the operating temperature of the block down.

Side note... K&N air filters (the red ones) should be recharged every 10-15k miles. If you recharge it to much you could lose the charge on the filter thus hurting fuel mileage. You may want to just replace yours and read the manual that comes with it. Also a CAI only helps fuel mileage if it is actually bringing in cold air. If the filter does not have the housing that blocks the motor heat out it isn't worth it. Another option is to custom pipe the air filter into the bumper away from the motor.

Did you check for a vacuum leak?
How's your EGR looking?
Is your check engine light on? If so what code's are you throwing?
how do you know if your egr is good/bad?

is a k&n drop in worth it? (over stock filter)
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post #24 of 43 Old April 16th, 2011, 02:33 PM
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Remove the EGR and look at it. If its coated in black soot like material it needs cleaned. I use throttle body cleaner on mine, and it usually does it good. To check if its done for good clean it then blow air throw it at different pressures and make sure the diaphragm inside is working. if its stuck open it'll kill your fuel mileage by allowing exhaust gas into the combustion chamber at an unmettered rate suffocating your combustion process.

I bought a complete kit, comes with the filter, air dam and intake tubing to replace the stock tube, and at first I noticed a increase in throttle response, then as i grew accustomed to the added air flow it added to my fuel economy.

My last tank of gas got me a 212 miles to the tank. But it also cost me nearly $60 to fill up

Done so far:
windstar, port and polish lower, UDP, aluminum Drive shaft, 3.73lsd, and some other goodies.

Looking for a 4.2 next and maybe some spray.
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post #25 of 43 Old April 16th, 2011, 03:25 PM
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I am not sure how to do this or if there is a special way to do it??
I did a write up on this:
Seafoaming Your Mustang | Mod Your Mustang
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post #26 of 43 Old April 16th, 2011, 06:12 PM
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Yeah, my v6 although it has a 20LB injector, i get 180 per tank, id be hella happy with 240 or 250 with the gas prices these day
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post #27 of 43 Old April 16th, 2011, 06:16 PM
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Yeah, my v6 although it has a 20LB injector, i get 180 per tank, id be hella happy with 240 or 250 with the gas prices these day
i don't mind you posting...but never type that again lol
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post #28 of 43 Old April 16th, 2011, 06:20 PM
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Yeah, my v6 although it has a 20LB injector, i get 180 per tank, id be hella happy with 240 or 250 with the gas prices these day
Wait, you have one 20lb injector? Why?

2000 Prochaged V6. T-lok, Mach 1 takeoff exhaust with H-pipe, 20% tint, OEM fogs and all HIDs.

SAE Corrected: 289HP/298TQ at 5100RPM(Pegged MAF).
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post #29 of 43 Old April 17th, 2011, 12:30 AM Thread Starter
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a tuner is worth it and can carry over to other vehicles
also i'd recommend a 87 tune. if you really care about mpg, you can get a tune specifically to get the most mpg out of your fuel

what kind of exhaust are you looking to do? just a catback or full exhaust including or excluding headers

the leak could definitely be hurting your mpg

i think you're recharging your air filter to often? not sure don't have a k&n

if it makes you feel better i used to get 280 then 250, then 200, then 180, now like 200-250 per tank

your o2 sensors could be bad

you changed your spark plugs? what plugs did you use? and did you change your wires along with your plugs?

you could possibly increase your mpg if you do the 1/3, 1/3, 1/3 seafoam
OK, HOW do you do the SeaFoam thing? I went to WalMart tonight and bought a bottle. I read the back and poured 1/3 in a fresh tank of gas, 1/3 in my crank case (then came home and changed my oil after driving it 45 minutes) and I still have 1/3 of the bottle left? Did I do it correctly so far? What do I do with the rest? Or did I waste it?

Also I have an update...I went to a muffler shop this morning to ask them about the possible exhaust leak and what the cost would be in getting a high performance exhaust put on. Needless to say the exhaust leak appears to be coming from the drivers side of my manifold. They told me unless it gets really loud to not worry with it right now becuase it can be a pain in the A$$ to get replaced.

However, they talked me in to putting a high performance muffler on and it cost me $100 plus tax. It was not a FlowMaster ...it was their brand. However, they had this one cut open and a FlowMaster so I could see the insides (they had them in the showroom) and there was literally no difference and it was a fraction of the cost. You should see the insides of the stock muffler...LOL. That IS the joke YOU CANT see the inside. It was sickening how restriced and packed full of crap that thing was and how heavy it was as compared to my new one. I am tickled. Like a kid in a toy store!! SO....I have a WHOLE LOT meaner sounding V6 and it "seems" to be a LOT less restrictive and the responsiveness seems to be a better as well!! I think a SCT tuner is next in my list if any of you know of anyone wanting to sell one for cheap?? I can give my email address if you want to message me directly.

SO...LOng story short, I have a newer/meaner sounding car, new muffler (non dualed out), and a fresh oil change with "some" SeaFoam....I just need to know what to do with the SeaFoam for the 1/3, 1/3, 1/3 you all mention.

Gerald
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post #30 of 43 Old April 17th, 2011, 12:41 AM
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Originally Posted by ggipson79 View Post
OK, HOW do you do the SeaFoam thing? I went to WalMart tonight and bought a bottle. I read the back and poured 1/3 in a fresh tank of gas, 1/3 in my crank case (then came home and changed my oil after driving it 45 minutes) and I still have 1/3 of the bottle left? Did I do it correctly so far? What do I do with the rest? Or did I waste it?

Also I have an update...I went to a muffler shop this morning to ask them about the possible exhaust leak and what the cost would be in getting a high performance exhaust put on. Needless to say the exhaust leak appears to be coming from the drivers side of my manifold. They told me unless it gets really loud to not worry with it right now becuase it can be a pain in the A$$ to get replaced.

However, they talked me in to putting a high performance muffler on and it cost me $100 plus tax. It was not a FlowMaster ...it was their brand. However, they had this one cut open and a FlowMaster so I could see the insides (they had them in the showroom) and there was literally no difference and it was a fraction of the cost. You should see the insides of the stock muffler...LOL. That IS the joke YOU CANT see the inside. It was sickening how restriced and packed full of crap that thing was and how heavy it was as compared to my new one. I am tickled. Like a kid in a toy store!! SO....I have a WHOLE LOT meaner sounding V6 and it "seems" to be a LOT less restrictive and the responsiveness seems to be a better as well!! I think a SCT tuner is next in my list if any of you know of anyone wanting to sell one for cheap?? I can give my email address if you want to message me directly.

SO...LOng story short, I have a newer/meaner sounding car, new muffler (non dualed out), and a fresh oil change with "some" SeaFoam....I just need to know what to do with the SeaFoam for the 1/3, 1/3, 1/3 you all mention.

Gerald
For the Seafoam, you need to run that last 1/3 can through the upper intake. Pour it into a cup, start the car, pull the PCV line off of the driver side valve cover, and let it slowly suck of the Seafoam (don't dunk it in or the engine will stall). When it's gone, shut the car off for 15 minutes then start it up and go for a nice drive. Don't be surprised if there's a lot of smoke.

And you should have gone dual exhaust. It's pricier but if you heard a single exhaust next to a dual exhaust, you'd want to shoot yourself for not going with the dual exhaust.
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post #31 of 43 Old April 17th, 2011, 12:42 AM
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first off...please stop posting in bold large letters...it's distracting and won't help your cause...

as for your exhaust trip...cracked manifolds are common on our cars. i'd just save for some headers since you'll probly end up having to replace it anyway...as for telling them you want a high performance exhaust...that's asking them to rape you in costs

LET ME DO YOU A FAVOR...

i know your in the buro which is only around 30 minutes from Gallatin...my exhaust shop is there and he does great work and is reasonable from my experiences in his pricing. if you'd like to get his number and address just let me know

from the sounds of it you got ripped on your exhaust and spent way to much for a muffler swap with an off brand muffler

also if you're ever bored on one of my days off i'll let you hear how much louder a duel setup is
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post #32 of 43 Old April 17th, 2011, 12:46 AM Thread Starter
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My apologies....

I just now saw the post from McQueen on the "SeaFoam Writeup" he did. I just did not see that earlier when I asked bout it.

Well, since I did the SeaFoam kinda bass ackwards (I poured 1/3 into a full tank of gas while at walmart and also 1/3 into my crankcase and drove it home and changed my oil tonight) I still have 1/3 left. Is it still ok to pull a PCV valve from my valve cover and have it slowly suck it up even though I have already changed my oil?

MY thoughts are "Yes, it should not be a problem since I am not pouring anymore in my crankcase" and since it is going through my vacuum lines only. I just want to double check with you experts and make sure??
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post #33 of 43 Old April 17th, 2011, 12:48 AM
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My apologies....

I just now saw the post from McQueen on the "SeaFoam Writeup" he did. I just did not see that earlier when I asked bout it.

Well, since I did the SeaFoam kinda bass ackwards (I poured 1/3 into a full tank of gas while at walmart and also 1/3 into my crankcase and drove it home and changed my oil tonight) I still have 1/3 left. Is it still ok to pull a PCV valve from my valve cover and have it slowly suck it up even though I have already changed my oil?

MY thoughts are "Yes, it should not be a problem since I am not pouring anymore in my crankcase" and since it is going through my vacuum lines only. I just want to double check with you experts and make sure??
you can put it through the vacuum lines...just don't let it suck it up too quickly or you'll foul a plug.

btw....we do enjoy the buro

Last edited by 6ER THEN I 8ER!; April 17th, 2011 at 12:55 AM.
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post #34 of 43 Old April 17th, 2011, 12:53 AM
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OK, HOW do you do the SeaFoam thing? I went to WalMart tonight and bought a bottle. I read the back and poured 1/3 in a fresh tank of gas, 1/3 in my crank case (then came home and changed my oil after driving it 45 minutes) and I still have 1/3 of the bottle left? Did I do it correctly so far? What do I do with the rest? Or did I waste it?

Also I have an update...I went to a muffler shop this morning to ask them about the possible exhaust leak and what the cost would be in getting a high performance exhaust put on. Needless to say the exhaust leak appears to be coming from the drivers side of my manifold. They told me unless it gets really loud to not worry with it right now becuase it can be a pain in the A$$ to get replaced.

However, they talked me in to putting a high performance muffler on and it cost me $100 plus tax. It was not a FlowMaster ...it was their brand. However, they had this one cut open and a FlowMaster so I could see the insides (they had them in the showroom) and there was literally no difference and it was a fraction of the cost. You should see the insides of the stock muffler...LOL. That IS the joke YOU CANT see the inside. It was sickening how restriced and packed full of crap that thing was and how heavy it was as compared to my new one. I am tickled. Like a kid in a toy store!! SO....I have a WHOLE LOT meaner sounding V6 and it "seems" to be a LOT less restrictive and the responsiveness seems to be a better as well!! I think a SCT tuner is next in my list if any of you know of anyone wanting to sell one for cheap?? I can give my email address if you want to message me directly.

SO...LOng story short, I have a newer/meaner sounding car, new muffler (non dualed out), and a fresh oil change with "some" SeaFoam....I just need to know what to do with the SeaFoam for the 1/3, 1/3, 1/3 you all mention.

Gerald
Definately got ripped off. And as far as it is more responsive to a muffler swap, that is called an "ass dyno" because it is louder so your ass thinks its going faster. As far as the diablo, I keep it on 93 octane race tune, and it did not affect my mpg at all. And I have a heavy foot. Call around to your local or nearest dyno shop and see which tuner platform they use to decide which one you go with.
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post #35 of 43 Old April 17th, 2011, 10:30 AM
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my advice is to listen to what everyone has to say on here and wait to do it until you know exactly what and how to do it, for example the seafoam you got too excited with it and just started using it, instead of doing it once the complete proper way lol

and with the muffler, now you basically paid 100 for a muffler, instead of 200-400 for a true dual setup which blows singles away
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post #36 of 43 Old April 17th, 2011, 02:25 PM Thread Starter
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For the Seafoam, you need to run that last 1/3 can through the upper intake. Pour it into a cup, start the car, pull the PCV line off of the driver side valve cover, and let it slowly suck of the Seafoam (don't dunk it in or the engine will stall). When it's gone, shut the car off for 15 minutes then start it up and go for a nice drive. Don't be surprised if there's a lot of smoke.

And you should have gone dual exhaust. It's pricier but if you heard a single exhaust next to a dual exhaust, you'd want to shoot yourself for not going with the dual exhaust.
Mcqueen, I did this exactly like you said. I got all the pretty white smoke and all. Since I changed my oil BEFORE I did this last part of my SeaFoam treatment do I need to chnage it again? I assume not since going throught he PCV valve did not go through the crankcase (at least I dont think it does). Please let me know asap. Thanks buddy
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post #37 of 43 Old April 17th, 2011, 02:28 PM Thread Starter
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my advice is to listen to what everyone has to say on here and wait to do it until you know exactly what and how to do it, for example the seafoam you got too excited with it and just started using it, instead of doing it once the complete proper way lol

and with the muffler, now you basically paid 100 for a muffler, instead of 200-400 for a true dual setup which blows singles away
Ok, just asking (not being a smart ass - I just dont know) but what does "dualed out" do for me besides be louder? What are the benefits?

Then, when you say dualed out does that mean that each side is coming straight off of each header and have 2 mufflers (1 on the left and 1 on the right)? Or are they both coming down from the headers into 1 muffler and then split off from there?
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post #38 of 43 Old April 17th, 2011, 04:03 PM
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Mcqueen, I did this exactly like you said. I got all the pretty white smoke and all. Since I changed my oil BEFORE I did this last part of my SeaFoam treatment do I need to chnage it again? I assume not since going throught he PCV valve did not go through the crankcase (at least I dont think it does). Please let me know asap. Thanks buddy
Nope, you're good to go. The Seafoam is sucked into the cylinders, burned up, and sent out through the exhaust
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post #39 of 43 Old April 17th, 2011, 04:15 PM
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Ok, just asking (not being a smart ass - I just dont know) but what does "dualed out" do for me besides be louder? What are the benefits?

Then, when you say dualed out does that mean that each side is coming straight off of each header and have 2 mufflers (1 on the left and 1 on the right)? Or are they both coming down from the headers into 1 muffler and then split off from there?
Right now you have a y-pipe. Basically, the pipe between your headers and your muffler looks like a big "y". One pipe runs off of each header then the pipe from the passenger side curves over and connects to the driver side pipe, making a y shape before connecting to the muffler and running out through a single pipe. Dual exhaust will run 1 pipe from each header. These two pipes can come together then split again in an "x" shape, making an x pipe. They can run straight back with another pipe going straight between the two in and "h" shape, making an h pipe. Or the two pipes can run straight back, with or without mufflers (I don't recommend no mufflers), which would be divorced duals or straight pipes.

Unfortunately our cars see little to no gains from exhaust. It's all about the sound. When I see a V6 Mustang with a single exhaust I think "eh, a Mustang." But when I see a V6 Mustang with dual exhaust and I can actually hear the car (my exhaust drowns out most vehicles I generally see) then I actually get interested in what else he's done to the car and I probably remember his car. I see Mustangs every day and I forget most of them within minutes unless they've done something that is memorable or gets my attention. A V6 with a loud, nice sounding exhaust is much more memorable than a V6 with a quite single mufflers. Not everything we do to our cars is about making them faster, some things are just for turning heads and getting attention. Plus when a ricer pulls up and starts revving up his weed-whacker, a nice dual exhaust can drown him out so nobody else has to listen to him
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post #40 of 43 Old April 18th, 2011, 12:58 PM Thread Starter
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delete your bottom two cats and replace your upper cats with some highflow cats. better gas mileage as well as power to
Did you cut those 2 cats off yourself? The muffler shop I went to Saturday told me by law they could not do it AND that it would throw codes if i did. I think that is horse crap. Why a car needs more than 2 cats is beyond me. If you have the 3.8, how is yours setup and did you do it yourself? I dont have a torch or welder so I may have a problem there.
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