First off, I realize how unscientific this is, but I thought I would pass it along. I drive the same 37 miles from Baltimore to Washington everyday and track my mileage on my onboard computer thing. Driving gently, at a reasonable speed, in light traffic I have always gotten around 16.5 - 17.5 mpg on this highway commute. I put my flowmasters on a week ago and made the same drive unde the same basic conditions and I filled up the tank and reset the computer before leaving. Arrived at work with 21.2 mpg on the readout. I know there are a million other variables that I'm not thinking about, but the flowmasters are not hurting things by any means.

 

It will be very interesting to see what your mileage is after you have done this for several weeks.

Keep us posted.

Mark

 

I hope the Flowmaster is the source of the increased mileage. I could use a little boost in that department. Is that BW Parkway driving or 95? I would think the BW Parkway would be more of a stop & go commute.

 

BW Parkway, but I go in a 9 pm and go home at 7 am missing most traffic.

 

Hmmm... think I see a flowmaster in my future.

 

bigsherm- Have you had a chance to do a (so-to-speak) hand calculation on the mileage since your flowmaster? I know you likely know this, but the onboard computers on our rigs are notoriously wrong. I've tracked every tank since I got my truck last September and typically the computer shows my mileage to be .6 to .7 mpg HIGHER than my actual. In fact there has never been a tankful where the indicated mileage was at or below the "actual" mileage. I wish I knew why these things were so easily "fooled". If you mileage increase bears out over time and with your own calculations, I'll have one on my Lariat SOON. Thanks for the info.

 

I tracked my mileage by hand for the first couple of months I had the truck and my computer was always about .2-.3 higher that actual mileage. I thought this was an excetable margin of error so I stopped tracking. I have started tracking it again just to make sure it's not out of whack or something so I will let you know.

 

bigsherm77,
I see you have the Flowmaster super 40 series. How does it sound on the inside of the cab? Is it tolerable or louder than you exspected? I was interested in getting the 50 series because I have had that in the past, but alot of guys have been talking about this super 40 series. Whats your opinion?

 

The guy at the exhaust shop said mine was a 40 series. When I asked about the super 40 he said he had never heard about it. Whatever. Maybe they are the same, maybe not. I love mine (whatever it is), loud, deep rumble. It can be heard in the cab but it doesn't bother me at all. Conversation is no problem and the radio will drown it out easily. I have a video clip of the sound but I havn't figured out a way to post it yet.

 

I HAVE A GIBSON CAT BACK EXHAUST ON MY 04 LARIAT AND IM GETTING AT MOST EVEN ON THE HIGHWAY 14MPG
I ALSO AM NOT REALLY THRILLED WITH THE SOUND OF THE EXHAUST I THOUGHT IT WOULD HAVE BEEN LOUDER.....
I MIGHT BE SWITCHING TO FLOWMASTERS THIS WEEK

 

The Super 40 is the delta flow. If the part number for the exhaust starts with a 9 then its is the delta flow (Super 40) I have this installed on mine and I love it.

 

Just finished off a full tank of gas. Mixture of highway and city driving but mostly highway same as before the exhaust. The computer said 16.6 mpg. My calculations came to 16.4 mpg. I used to consistantly get around 14 mpg. I don't know if its the exhaust, the temps, the summer gas, or something else but it's a step in the right direction.

 

BigSherm-That's great. Hopefully it keeps up..........forever. How many miles do you have on your truck now? I've got 12K on mine, and noticed that in the last 2900 or so miles, my mileage has gone up from an average of 14.38 to 15.32. This has baffled me as I am now running the A/C 60 to 70%% of the time (I'm in Arizona) and driving the same route to work as I had in the past. The summer gas reformulation is also just starting to show up at the pumps and I'll be curious how that might affect this mileage. Being a a guy and an engineer, I like to think I can figure things like this out, but I haven't got a handle on this yet. The good thing is, I'm not losing sleep over the increase in mileage......especially with gas right at $2.00 per gallon!

 

I have 16K on mine. There are probably 100 other variables that will never cross my mind that effect fuel economy.