Skip Talker Posted October 15, 2004 Report Share Posted October 15, 2004 Hello everyone, been following several threads but haven’t said much. I don’t have an SS, but a Z71. Most mods work on all trucks and this site has been the best I’ve found for such info. Hope you don’t hold the Z71 thing against me…..(or the long posts.) I average about 1,000 miles a week, so mileage is important to me. I have a Snug Top shell, carry a few hundred pounds of tools/materials and 90% of the time on the highway with the cruise control locked on 74 or 79 MPH. Finally had some time and had a Flowmaster 40 series with 3” pipe from the cat back installed. It was done at a local shop outside of San Diego. Price wasn’t bad but I didn’t research that much either. It’s louder but not annoying. The only problem I fell is that it is a bit loud when driving through a residential area at night. Some of the guys at work says it sounds sic, so I guess that is good. Like mentioned earlier, mileage is what I’m looking for. A lot of people mention mileage improvements but don’t state figures. I calculate the mileage by dividing the number of miles traveled since the last fill up by the number of gallons needed to fill up. The readout on the instrument cluster is way off and not even consistent. For the last 20 fillups before I had the exhaust done I averaged 16.09 MPG. The first couple of tankfulls afterwards the mileage went down, way down. I attributed that to flooring it more but someone else mentioned it may take time for the PCM to learn? After a few more tankfuls it seemed to rise and for the last 9 fill ups I average 17.5 MPG that is an increase of 1.41 MPG. I figured it out to be worth about $4 a fillup. It will pay for itself in a few weeks. I just added the Home Depot ram air system and will report back on that in a few weeks. I have a 160 degree thermostat and hope to find time to install that soon. Then a tune by PCM4Less. Also following a few electric fan threads. Will try that too. Link to comment Share on other sites More sharing options...
Dylan06SS Posted October 15, 2004 Report Share Posted October 15, 2004 NICE! I never actually took the time to calculate the mileage gain w/ my setup (probably cuz I had the exhaust on a week after I got the truck ) Thats some great information... thanks for takin the time to post it! Link to comment Share on other sites More sharing options...
BenKey Posted October 15, 2004 Report Share Posted October 15, 2004 Got the biggest gains from the electric fans. Wish I had the discipline to figure what kind of gas mileage. I do know that my 408 gets much better gas milage than my stock motor. Didn't figure it for a whole tank, but got 275 miles with still a little more than a 1/2 tank. Never got that good before. This was on the highway doing 72. Link to comment Share on other sites More sharing options...
ctrow Posted October 15, 2004 Report Share Posted October 15, 2004 That's roughly 21+ MPG Ben. Way to go How long would you have to drive to recoup the cost of the 408? Link to comment Share on other sites More sharing options...
rdss Posted October 15, 2004 Report Share Posted October 15, 2004 That's roughly 21+ MPG Ben. Way to go How long would you have to drive to recoup the cost of the 408? <{POST_SNAPBACK}> Link to comment Share on other sites More sharing options...
styleandspeed Posted October 15, 2004 Report Share Posted October 15, 2004 Thanks for doing the research for us on that. How much did you find that the avg mpg per the computer was off compared to the figures that you calculated? Like the computer said you got 14mpg when you were really getting 16. Thanks Aaron Link to comment Share on other sites More sharing options...
BenKey Posted October 16, 2004 Report Share Posted October 16, 2004 I don't ever trust the computer for mpg. I do my figuring at the pump. Link to comment Share on other sites More sharing options...
BenKey Posted October 16, 2004 Report Share Posted October 16, 2004 How long would you have to drive to recoup the cost of the 408? <{POST_SNAPBACK}> With the way gas prices have gone, in about 6 months. ;) Link to comment Share on other sites More sharing options...
SSMANIAC Posted October 16, 2004 Report Share Posted October 16, 2004 17 mpg's ooooh that is good, if i get 16.0 i am doing the way to go. Ben 21 mpg's with the 408 is really impressive, maybe when my warranty is over i should consider the 408. mind me asking what kind of mods did you have to do to your tranny to take the abuse of a 408? Also $$$$ spent for the whole set up would be great. Link to comment Share on other sites More sharing options...
rdss Posted October 16, 2004 Report Share Posted October 16, 2004 I'm happy getting 14 mpg with 6 miles highway, 6miles city driving one way to work. If I really baby it (but its really boring) I can get 14.5 to 15 mpg. Link to comment Share on other sites More sharing options...
haynss Posted October 16, 2004 Report Share Posted October 16, 2004 guess thats better than my 11.0-11.5 mpg to work and home, all 40 miles of it. Wait a minute...damn in the end looks like im paying to work Link to comment Share on other sites More sharing options...
Skip Talker Posted October 18, 2004 Author Report Share Posted October 18, 2004 Thanks for doing the research for us on that. How much did you find that the avg mpg per the computer was off compared to the figures that you calculated? Like the computer said you got 14mpg when you were really getting 16. Thanks Aaron <{POST_SNAPBACK}> The computer varied from .2 MPG to 1 MPG off. Most times the computer said I was getting better than I actually did except for one, then it said I got .2 worse. Link to comment Share on other sites More sharing options...
Skip Talker Posted October 18, 2004 Author Report Share Posted October 18, 2004 NICE! I never actually took the time to calculate the mileage gain w/ my setup (probably cuz I had the exhaust on a week after I got the truck ) Thats some great information... thanks for takin the time to post it! <{POST_SNAPBACK}> Electric fans are next on my list after a tune. Any ideas on how much gain with fans? I'm looking for that 20 MPG....... Link to comment Share on other sites More sharing options...
rdss Posted October 18, 2004 Report Share Posted October 18, 2004 Thanks for doing the research for us on that. How much did you find that the avg mpg per the computer was off compared to the figures that you calculated? Like the computer said you got 14mpg when you were really getting 16. Thanks Aaron <{POST_SNAPBACK}> The computer varied from .2 MPG to 1 MPG off. Most times the computer said I was getting better than I actually did except for one, then it said I got .2 worse. <{POST_SNAPBACK}> My MPG computer is always balls on. E-fans will help, if your gonna get a custom tune, I would tell the tuner that you plan on getting E-fans and purchase the module at the same time. Link to comment Share on other sites More sharing options...
styleandspeed Posted October 18, 2004 Report Share Posted October 18, 2004 E-fans are making a big difference on mine. I haven't calculated it yet, but my tanks last a couple days longer than they used to with no change in driving habits Aaron Link to comment Share on other sites More sharing options...
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