Mods to improve mpg?
01-12-2012, 03:05 AM
#42
Member
Join Date: 09-22-2007
Location: USA
Posts: 86
As far as engine mods: If you can increase hp and torque without increasing fuel consumption, you raise mpg because less pedal is needed to achieve the same results. I bought mine for a 110 mile daily commute. Engine mods are header with exhaust manifold port matched to exhaust manifold(ported and polished), down pipe, K&N cai, shift kit to reduce clutches slipping, bored out throttle body and straight through muffler.
The cai has a hole in the front where the tube comes out to go to the tb. I made a panel to cover the space in front of the engine. The air shield under the hood was cut out directly in line with the hole. It also uses the factory duct. So quite a bit more cold air than stock. Thermal insulation was put on the bottom of the panel. Header and dp are wrapped to reduce under hood temp as well.
I honestly don't remember what they are called but there is a term used for making an under car shield to do away with wind resistance. Even if the car is not aerodynamic there are somewhat smooth lines or at least flat surfaces for the body. Underneath there are big hunks of metal to catch air, oil pans, cross members and so on. Nothing is really smooth or flat. I used a large political sign and screwed it to the bottom. That helps quite a bit if you run at highway speeds. Also narrow tires help with resistance but I have wider than stock currently.
Mine averaged around 24 mpg stock with interstate driving. Most likely that was with pure gas as 10% ethanol has taken over locally and we never had it before. I live on a mountain which kills 4 mpg off of my average. Current runs 28 to 32 depending on my foot. I drive aggressively. Plus as noted only ethanol blend is available now and the steep mountain kills my mileage. Taking it easy with acceleration, coasting to red lights and down hills I was getting 43-44 for a while but I was concerned that it would end up shortening the life of the auto tranny coasting for several miles a day in neutral. Plus I get bored easily. :)
The cai has a hole in the front where the tube comes out to go to the tb. I made a panel to cover the space in front of the engine. The air shield under the hood was cut out directly in line with the hole. It also uses the factory duct. So quite a bit more cold air than stock. Thermal insulation was put on the bottom of the panel. Header and dp are wrapped to reduce under hood temp as well.
I honestly don't remember what they are called but there is a term used for making an under car shield to do away with wind resistance. Even if the car is not aerodynamic there are somewhat smooth lines or at least flat surfaces for the body. Underneath there are big hunks of metal to catch air, oil pans, cross members and so on. Nothing is really smooth or flat. I used a large political sign and screwed it to the bottom. That helps quite a bit if you run at highway speeds. Also narrow tires help with resistance but I have wider than stock currently.
Mine averaged around 24 mpg stock with interstate driving. Most likely that was with pure gas as 10% ethanol has taken over locally and we never had it before. I live on a mountain which kills 4 mpg off of my average. Current runs 28 to 32 depending on my foot. I drive aggressively. Plus as noted only ethanol blend is available now and the steep mountain kills my mileage. Taking it easy with acceleration, coasting to red lights and down hills I was getting 43-44 for a while but I was concerned that it would end up shortening the life of the auto tranny coasting for several miles a day in neutral. Plus I get bored easily. :)
01-13-2012, 05:57 PM
#45
Platinum Member
Join Date: 05-09-2006
Location: "Upland" Mesa, Arizona
Posts: 6,805
sleeper, you got me chuckling on that.
One of GM's former engineers weight in at about 400 lbs at about 6-8 in height.....he was a big sucker. He always complained about the uncomfortable seats and poor mileage.......well, duh. AND he always drove full size Cadillacs.
One of GM's former engineers weight in at about 400 lbs at about 6-8 in height.....he was a big sucker. He always complained about the uncomfortable seats and poor mileage.......well, duh. AND he always drove full size Cadillacs.
01-13-2012, 07:52 PM
#46
Senior Member
Join Date: 11-19-2011
Location: Alabama
Posts: 227
After about a month and a half, Herman's getting just a smidge under 30 with mixed driving. I've spent a lot of time developing a light right foot, though, and pay close attention to energy conservation, like letting up on the gas just before cresting a hill... letting the downhill accelerate me back up rather than using the throttle, that sort of thing. Instead of driving up on a stop and using the brakes, I'll coast for a bit instead. How long I allow the car to coast depends on terrain and concern for anyone who might be behind me. If they're following too closely I don't feel so bad about coasting down. Gives 'em time to slow down themselves.
01-14-2012, 01:24 AM
#47
Platinum Member
Join Date: 01-09-2007
Location: SE USA
Posts: 15,870
"rubics cube" said that a couple years ago. Made me chuckle also.. Never forgot it..
That was a Big dude at 400lbs & 6' 8" guess maybe he only fit in Big Caddys..
I feel bad for the seats he 'broke in'...
04-11-2012, 05:07 PM
#50
Senior Member
Join Date: 04-04-2012
Location: Sarasota, FL
Posts: 1,307
My 09 ls gets about 26mpg in town and at 68mph on the interstate I get right at 33mpg. Its all stock for now. I agree with an earlier post if you can keep a steady foot at 40-45 mph you will get around 45 miles per gallon. My wife only gets about 25 mpg average when she drives it with a mix of city and highway. I have a good feel for it and I get about 28 to 30 mpg average over the same routes. A lot of it is in the driver, actually most of it.