Injectors

[EIXVO]

Im lookin to buyin a SC soon and was wondering how much gas mileage would be affected with the bigger injectors? I was lookin at either 440 or 550cc all walbro 255 high flow fuel pump?

[2point4DSM]

It really all depends on how you drive the car. If you can manage to keep the car at stock hp levels then you shouldn't notice a difference.

HP is what eats gas. So if you are on boost (and WOT) all the time you can easily lose 4 to 5 mpg.

example: A well modded DSM is actually a lot more fuel efficient and will pick up 4-5 mpg on the highway on a 75-86 mph cruising speed cause stock tuning makes the car run rich. Still, I'm down 2-3 mpg in the city cause I have a tendency to use boost from one stop light to the next.

At the track I've gotten it down to about ~10 mpg.

My buddy averaged 2mpg for over 20 miles, autocrossing!

[2point4DSM]

Btw, this is assuming you get the car tuned for the 550s. Othewise, the 550s are about 20% bigger and therefore your gas mileage will drop about that much. Although your stock ecu should be able to tune it down so you are only losing about 10% efficiency.

[EIXVO]

So in other words if Im not driving it hard I wont boost as much, and therefor retain somewhat of the same mpg, its when you high rev, and beat on the car that youd lose gas mileage?

[2point4DSM]

Yes, Yes.

[highmilehatch]

You can run whatever injector size you want, as long as there is some sort of engine management behind it. For your application I'd recommend the TurboXS Utec. I think it's one of the best bang for your buck engine management systems for the Z. You can still maintain good fuel mileage under cruise conditions (as you would N/A), but the fuel is always on tap when you step into boost. If your looking for injectors for your VQ:

http://www.tristatetuners.com/forum/showthread.php?t=13945

$420 for a set of 650cc for your VQ.

If your looking for an installer for your SC and dyno tuning, contact me.

[EIXVO]

LOl Ialready have one in my N/A setup I just will have to get it retuned with the supercharger.

( great minds think alike )

[highmilehatch]

You already have the Utec? Godd stuff. Have you considered any of the turbo kits for the Z?

[US_R33]

you're basically going to be "in boost" from just about off the line b/c you're running a supercharger

but are you honestly concerned about your gas mileage when running larger injectors???:bigeek: that's like me being concerned about my gas mileage with my rb swap :rofl: (which is roughly 12mpg btw)

- Daniel

[EIXVO]

its my only car therefor its my daily driver so of course im concerned 20mpg is bad enough with gas prices lol. They are tryin to kill us at the pumps. Ass holes

[US_R33]

its my only car therefor its my daily driver so of course im concerned 20mpg is bad enough with gas prices lol. They are tryin to kill us at the pumps. Ass holes
if you're really that bothered by 20mpg then you should NEVER boost your car....its only going to decrease your gas mileage, nothing you can do about that

[2point4DSM]

Boost alone and moderate gas pedal input should actually increase the efficiency of the motor and therefore make the car run close to stock in terms of gas mileage. Although a supercharger is like an A/C unit and therefore will suck power all the time.

Boost also allows the motor to eat up more gas on demand, hence the need for bigger injectors.

[321Gone_]

For some reason I always thought supercharges increased gas mileage... I remember reading it somewhere. Oh well.

Ill stick to gas guzzling turbo's.:banana:

[Master Mitsubishi]

Boost alone and moderate gas pedal input should actually increase the efficiency of the motor and therefore make the car run close to stock in terms of gas mileage. Although a supercharger is like an A/C unit and therefore will suck power all the time.

Boost also allows the motor to eat up more gas on demand, hence the need for bigger injectors.
turbos decrease gas milage about 10% or more those are the facts..... obviously if you are in boost you will eat more gas, i think the gas milage on a supercharged car is around 20% maybe less

[US_R33]

Boost alone and moderate gas pedal input should actually increase the efficiency of the motor and therefore make the car run close to stock in terms of gas mileage
:bigeek: boost and moderate gas pedal won't do anything except maybe guzzle a little less gas than boost and WOT

when you upgrade injectors and throw a blower/turbo onto a car you can kiss your gas mileage goodbye :rofl:

[Master Mitsubishi]

yea well all i have is for a turbo, thought i had the supercharger stuff, but for a turbo you will lose around 10% in city miles and 5% highway, supercharger might be about 5% more....

[highmilehatch]

You can still maintain good gas mileage with a proper tune under cruising conditions. Especially on larger turbos where your not always in positive pressure. I used to be able to still get 30mpg by staying out of boost on my LS-turbo hatchback. With my Nissan and the little T28, it's harder to stay out of boost and maintain as good mpg.

[moorefire]

if you're really that bothered by 20mpg then you should NEVER boost your car

Boost alone and moderate gas pedal input should actually increase the efficiency of the motor and therefore make the car run close to stock in terms of gas mileage.

Mabey in a fantasy world where an aftermarket tuner wouldn't care about any saftey magins in their tune and tune to near stock A/F levels.

But shops have reps to uphold, and building cars with knife edge tunes that run dangerously lean will destroy their reputations when their owners screw up and cry about it all over the net.