How bad is your gas mileage?
#32
12-21-2005, 01:13 PM
Originally Posted by Lance
Just checked mine (05 with 3500k) and it converts to 15 Mpg which isn't too bad for new and city driving, what do you think makes those 280 horses go?
I guess you meant 3.5K.... you can expect your car to get better economy as it gains milleage up until about 8K. Mine leveled off at about 8K miles.
#33
12-21-2005, 01:16 PM
2004.5 AT (purchased 12/31/04) with 24,000 miles. In the summer with alot of A/C I get around 20 mpg with mixed driving. This winter with alot of heater usage and 17" wheels instead of the 18"s, I have been getting around 19 mpg. I usually get around 300 miles per 15 - 16 gallons. I usually don't let the tank get lower than that since it almost physically hurts to put more than $45 in at one time, especially with all the driving I do for work.
#34
12-22-2005, 03:52 AM
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#35
12-22-2005, 06:22 PM
Originally Posted by partyman66
If you've ever seen the stock G35 intake tube, it's extremely restrictive and has all these sound baffles in it. It's not really a tube.. it's more like a huge contraption and looks like a paintball gun.
That's a picture I took of my G's stock intake tube, while I was in the process of swapping it out with a Z-Tube. The Z-Tube, on the other hand, is basicly just a pipe with no extra stuff anywhere on it.
The high flow air filter(K&N or Amsoil) will also reduce your intake restriction even more when coupled with a Z-Tube.
I'm not sure what the impact on economy would be if you just got a Z-Tube, and kept your stock paper-element air filter(because I never ran that configuration), but I'd be willing to be that the stock G35 Intake tube would negate any gains that might have been given due to the K&N filter alone. For me, When I put in my K&N filter, I didn't see any real economy gains... but when I added my Z-Tube into the equation, my economy spiked up very noticeably by 1.8-2.2 MPG consistently over a 6+ month test period.
I even took my Z-Tube out for about 2 weeks(to bullet-proof test the economy gains), and the economy went back down for the time that I had my stock tube back in.
One of the many reasons that a restrictive intake affects your fuel economy, is that your engine creates a vacuum(through the intake path) as it works and it also expells pressure through the exhaust. If your intake path is restrictive, there is resistance against the motors natural motions because the engine has to work harder to overcome the resistance of pulling in more air to fill the space that it is displacing as it pushes the used air out through the exhaust system. That additional intake effort both robs your car of some power, and also of some fuel economy(anytime your engine has to work harder while under forward load, you'll get lower economy).
If you want an example, go grab a coffee stirrer or a real small straw and try to breathe through it. You'll notice that you have to suck noticeably harder on the straw to get the air that you need to survive than you would if you just breathed normally. Then try breathing without the straw, and notice how much less effort is involved. Increased effort means increased energy useage. It's the same way with your car and the intake, because a restrictive intake(the stock G35 Intake tube, in our case)makes your car operate like it's breathing through a straw.
If you want to increase your fuel economy a bit more too... try to use your cruise control whenever possible. I noticed that my car gets better fuel economy when I use the cruise control to cruise(even at speeds of like 35 or 40 MPH), than I can get by going the same speed and manually operating the accelerator pedal.
That's a picture I took of my G's stock intake tube, while I was in the process of swapping it out with a Z-Tube. The Z-Tube, on the other hand, is basicly just a pipe with no extra stuff anywhere on it.
The high flow air filter(K&N or Amsoil) will also reduce your intake restriction even more when coupled with a Z-Tube.
I'm not sure what the impact on economy would be if you just got a Z-Tube, and kept your stock paper-element air filter(because I never ran that configuration), but I'd be willing to be that the stock G35 Intake tube would negate any gains that might have been given due to the K&N filter alone. For me, When I put in my K&N filter, I didn't see any real economy gains... but when I added my Z-Tube into the equation, my economy spiked up very noticeably by 1.8-2.2 MPG consistently over a 6+ month test period.
I even took my Z-Tube out for about 2 weeks(to bullet-proof test the economy gains), and the economy went back down for the time that I had my stock tube back in.
One of the many reasons that a restrictive intake affects your fuel economy, is that your engine creates a vacuum(through the intake path) as it works and it also expells pressure through the exhaust. If your intake path is restrictive, there is resistance against the motors natural motions because the engine has to work harder to overcome the resistance of pulling in more air to fill the space that it is displacing as it pushes the used air out through the exhaust system. That additional intake effort both robs your car of some power, and also of some fuel economy(anytime your engine has to work harder while under forward load, you'll get lower economy).
If you want an example, go grab a coffee stirrer or a real small straw and try to breathe through it. You'll notice that you have to suck noticeably harder on the straw to get the air that you need to survive than you would if you just breathed normally. Then try breathing without the straw, and notice how much less effort is involved. Increased effort means increased energy useage. It's the same way with your car and the intake, because a restrictive intake(the stock G35 Intake tube, in our case)makes your car operate like it's breathing through a straw.
If you want to increase your fuel economy a bit more too... try to use your cruise control whenever possible. I noticed that my car gets better fuel economy when I use the cruise control to cruise(even at speeds of like 35 or 40 MPH), than I can get by going the same speed and manually operating the accelerator pedal.
#36
12-22-2005, 06:23 PM
Originally Posted by gthirtyfizzle
i know it sounds crazy but i shift at 3 thousand rpm, i dont really race the car at all, and i get around 210 miles per gallon. Maybe i should get it checked out? Plus I use 93 octane, only the best for my baby 
However i have noticed that if i do 50% highway and 50% city i can maybe bang out about 270 miles per gallon
However i have noticed that if i do 50% highway and 50% city i can maybe bang out about 270 miles per gallonThe only way my G breaks 30mpg is when it's being towed by another car.
#38
12-22-2005, 06:37 PM
I average right arount 18-20 mpg driving the crap out of it.
How about looking at it this way.....
What is the lowest amt. of miles you put on a tank before the light came on?
When I first installed my Vortech and was boosting every min. of the day, I only got about 145 miles before the light on a few tanks.
Normally....around 300.
How about looking at it this way.....
What is the lowest amt. of miles you put on a tank before the light came on?
When I first installed my Vortech and was boosting every min. of the day, I only got about 145 miles before the light on a few tanks.
Normally....around 300.
#39
12-22-2005, 06:50 PM
you guys must be very conservative... I'm a young driver so I don't shift below 3k..it's always 3k or up.. but lately I haven't pushed the G due to winter weather.
I never really look at the gas tank but always fill up before it comes close to touching the light and normally throw in 20-25 bucks and it fills it up, 93 octane ofcourse... the guys in cali I wonder if you guys are running 91?..
I notice the G eating some gas but I wouldn't call it a lot.
I never really look at the gas tank but always fill up before it comes close to touching the light and normally throw in 20-25 bucks and it fills it up, 93 octane ofcourse... the guys in cali I wonder if you guys are running 91?..
I notice the G eating some gas but I wouldn't call it a lot.
#40
12-22-2005, 07:18 PM
The VQ engine is strange to me. Sometimes I can hardly get above 20mpg and sometimes it gets much better gas milage than I expected. Right now I am averaging around 21-22mpg mixed city/highway drive. It doesn't really help that I like to accelerate faster than normal. The most I've ever gotten was around 420 miles to a tank highway driving.
I drove on PCH from San Francisco to LA and it averaged 25mpg, the same as when I drove on 5 freeway the same trip. Strange how highway milage is the same as curvy road w/ elevation change milage.
Mods I noticed that have changed my gas milage history:
K&N, Z-Tube - Slight increase, maybe around 1 mpg.
Motordyne Plenum spacer - Improvement by around 2mpg on average.
Borla Exhaust - Gas milage got worse by around 2-3mpg.
So now I am right back where I started at 21-22 mpg.
I drove on PCH from San Francisco to LA and it averaged 25mpg, the same as when I drove on 5 freeway the same trip. Strange how highway milage is the same as curvy road w/ elevation change milage.
Mods I noticed that have changed my gas milage history:
K&N, Z-Tube - Slight increase, maybe around 1 mpg.
Motordyne Plenum spacer - Improvement by around 2mpg on average.
Borla Exhaust - Gas milage got worse by around 2-3mpg.
So now I am right back where I started at 21-22 mpg.
#41
12-22-2005, 07:23 PM
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#42
12-22-2005, 07:24 PM
Assuming there is a slight decrease in intake resistance, I can see a slightly increase in mileage. But 5-10% as you claim? If that was truly the case, surely Infiniti would have used that intake piece and been able to claim the much higher mileage numbers to increase sales of the car, unless the intake makes the car REALLY loud (does it?).
Last edited by MechEE; 12-22-2005 at 07:43 PM.
#43
12-22-2005, 08:22 PM
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#44
12-22-2005, 11:18 PM
Originally Posted by MechEE
Assuming there is a slight decrease in intake resistance, I can see a slightly increase in mileage. But 5-10% as you claim? If that was truly the case, surely Infiniti would have used that intake piece and been able to claim the much higher mileage numbers to increase sales of the car, unless the intake makes the car REALLY loud (does it?).
It also sacrifices a claimed 7 crank HP(3%) with the stock intake tube, over the Z-Tube and aftermarket air filter. Nobody will argue that a high-flow air-filter gives a vehicle increased fuel economy, but I can't think of many production vehicles that come with these filters in them from the factory(just to illustrate a point that car manufacturers don't normally engineer a vehicle to have the ultimate efficiency possible out of the factory). Paper element filters tend to be the way most manufacturers go(possibly in part due to the quality of dirt filtration inherent with a paper filter, at the cost of air-flow efficiency traditionally associated with aftermarket filters)
#45
12-22-2005, 11:40 PM
I don't know about other G's but the VQ in mine seems to really dislike stop and go, but really like highway driving. By that I mean in the city I rarely get over 20km/g (~14mpg), however if I do 100% highway driving on a tank I will routiney get well over 600km to a tank, which averages out to 23-24mpg.
I drive it pretty hard regardless.
I drive it pretty hard regardless.