CAI and Flowmaster -3 mpg

[MikeCallery]

I thought I was going in a positive direction. The CAI (Volant) improved my response and mph by about 1 to 1.5. I thought adding a Flowmaster 50SUV would improve upon that. It hasn't.

I've found that with the CAI alone, good. With the 50 SUV Flowmaster, a drop. The city drop was about 2mph, I'm running about 13 again and the highway, well, hard to say.

On one note, I ran from New Orleans up to Shreveport yesterday, back today, and she was cruising along at 85 quite nicely. If I had to back down to 70 for a truck, she would pick up very quickly, BUT, mpg was about 18.2 to 19. At 70mph prior to all this I would get just at 23, but I didn't slow enough to tell you how it runs at that speed now.

I'm just surprised. I would expect if I punched it, yet, I'd loose mpg but I would think in general, I would have stayed the same or improved.

Oh well.

 

[AZSCTACO]

I would give it some time to adjust.....you may also have a little heavier foot now that you have some good sounding exhaust/intake. You also posted this in the 07+ section

 

[bparker]

:iagree:

I would give it some time to adjust.....you may also have a little heavier foot now that you have some good sounding exhaust/intake. You also posted this in the 07+ section

 

[MikeCallery]

Adjust? I would assume the computers would adjust things somewhat, but if someone who knows more of this than me could explain, that would be great.

I know on my Goldwing you can cause the bike to re-calibrate, which is more important if, for example, you are at altitude. Is there a way to tell the Tahoe's computer to do the same, or is it just a natural thing it does?

 

[Yuke2K]

You could pull the negative battery cable for 30 minutes or so, which will kill all of the power to the ECM, forcing it to "reset" once you hook the battery back up. This will clear your clock and radio presets and whatnot, but should cause the computer to start with a blank slate, so to speak.

 

[WhiteHoeZ71]

My mileage went down 1 - 1.5 mpg when I added a Magnaflow muffler. Before anyone says it, my foot is Not heavier now. I bought the muffler b/c of the claims of improved gas mileage and Im probably driving slower now than I was before the muffler...

 

[Yuke2K]

Well, I was thinking about doing this, but I'd like to hear the other side of the coin on this issue. Has anyone seen an increase in mileage, or not noticed any change at all? I'm curious to see if this loss of MPG is the exception or the rule...

 

[MikeCallery]

Well, to be more accurate, I was running about 13.7 easily without any mods, and was going into the upper 14 range with the CAI.

now, with the volant CAI, Flowmaster 50 SUV, red top optima, big 3 wiring upgrade, I'm running anywhere from 10.2 to 12.7.

Even trying to run city, no a/c, and a light foot.

Now, that said, sounds wonderful and great when you step on it, hauled at 85 from Shreveport down to New Orleans, but just wish there was something I find I missed, or some trick to this.

 

[Yuke2K]

Well, to be more accurate, I was running about 13.7 easily without any mods, and was going into the upper 14 range with the CAI.

now, with the volant CAI, Flowmaster 50 SUV, red top optima, big 3 wiring upgrade, I'm running anywhere from 10.2 to 12.7.

Even trying to run city, no a/c, and a light foot.

Now, that said, sounds wonderful and great when you step on it, hauled at 85 from Shreveport down to New Orleans, but just wish there was something I find I missed, or some trick to this.

Maybe a blackbear or similar tune would tie everything together for you and boost you back up a bit. Thats some $$$ though if you rent the cables and everything too...

 

[screamin86]

ditch the flowmaster given i run the 10 series race mufflers on my trans ams but from most all forums im part of and from what ive read that flowmaster is one of the worst flowing/performing muffler. im getting 15-17mpg city driving in my 03 yukon xl its bone stock for now. its getting a intake lt headers o/r y with stock exhaust and cutout with a tune. im not looking for all out power but since i will be getting a trailer to pull my cars i want more towing power and some better mpg if i can. i spend about $100-115 every 1.5-2 weeks in gas where when i had my dodge dakota with 4x4 ecsb 4.7v8 intake and blowmaster exhaust i was getting 9-11mpg city and aobut $60-70 every 3-4days, shot i was gettin 17mpg in my 82 t/a with cammed sbc with carb non od tranny and a stall it had shorty headers with stock exhaust. ive noticed personaly everythign i put a blowmaster on the fuel mileage goes down some there restrictive but if i want the flowmaster sound i deal with it being really loud and run the 10 series they flow a lot better but are also a good bit louder

 

[screamin86]

oh and like was said sometimes the computers do have to adjust since now the vehicle is breathing a little better or a lil worse. time of year has an effect too. winter gas mileage always for me atleast goes down dramaticly colder denser air computer adjusts advances timing some adds a li more fuel and bam gas mpg goes down. i experianced it in my 86 t/a when i was in high school it was a stock computer controled carb 305 with 700r4 and 2.73 gears i got 21-22mpg city and it had 205k+ on it then i added a flowmaster exhaust and winter hit and gas mileage went to aorund 16-17mpg. sorry for all my ranting but just my experiance not trying to be a dick

 

[Polecat]

added a Flowmaster to mine, didn't change at all...15.7 average...