24lb or 30lb injectors??

[USAFEXPLORER]

I have noticed some aftermarket companies selling larger injectors, has anyone had any experience they would like to share. Are they worth changing or do you just waste more gas. Thanks.

 

[sprsvt]

Usually larger injectors are only used to provide additional fuel to an increased amount of air intake, i.e. a supercharger. If you have an intake, MAF sensor, throttle body, headers, and a catback, you could probably get a larger fuelpump and injectors, and get a custom chip to utilize the additional breathing capabilities of the engine. On a stock explorer, the stock fuel injectors should provide enough fuel to the chambers.

 

[Extreme4x4]

You do not want to change injectors unless you have maxed out the capacity of the stock ones. Injectors are their most efficient when running at a full duty cycle. If you run a larger injector without needing it, you will have poor idle quality and poorer fuel economy. Stock injectors should support at least 225 hp in the 4.0.

 

[JAY]

I have upgraded the injectors in my Explorer. It did make a noticable differance in the performance of my "modified" 4.0, but it also killed the gas mileage, down to about 6 on the interstate.

 

[Extreme4x4]

When you changed injector size, did you also have the MAF recalibrated? If not, then this could be a major cause of the fuel economy problem. If this is not fixed, you will end up burning up your cat from the unburned fuel that is being dumped into the exhaust. You will also end up fuel fouling the plugs. I don't care how much power you make with a 4.0, or how heavy a load you tow, you should NEVER get 6mpg.

 

[JAY]

Yes, I did have the MAF recalibrated, actually I have the Pro Flow 75mm unit. I really don't have to worry about burning up the cat because I don't run one. The mileage didn't just drop from the injectors, it slowly went down as the power went up, but the injectors made a big dent in it. If I keep my foot out of it and shift at about 2000 rpm I can get about 9 mpg out of it, but I didn't build my truck so I could drive it like grandma drives her car.

 

[scott]

Jay,
Just out of curiousity, what mods have you made? Unless you have a supercharger, hi-po heads, cam, exhaust etc... I can't figure out why you'd want to put a huge mass air, large throttle body and injectors on an Explorer. I have a supercharger, custom Superchip, Flowmaster cat-back, Jacobs' wires, 4.10 gears etc... and still run the stock injectors, mass air and throttle body with no problems. I know larger mass air and t.b. would help but it runs great now.

 

[Extreme4x4]

Yes, do please let us know the mods. I ran a Vortech, with the smallest custom pulley I could have made, headers, cat-back, throttle body, mass air, jacobs wires....... and my truck weighs 5500lbs, and I got 14mpg on the interstate. This is with stock injectors and the cat. Now, without the Vortech, but all the same mods, plus my Superchip,it gets 13mpg. Even off-road, in low range (I run 4.56 gears), I cannot get below 10. Have you tried running the cat with your combo. The 4.0 does not like having NO backpressure.

 

[JAY]

Scott,
I don't want to go into all the mods right now, I have done it a few times befor on some different threads. My truck should be one the site sometime soon, it depends on how soon I can get all the info to Rick. I'll give you a quick rundown though. I DO NOT have a supercharger, but I do have all the other mods listed above (in one form or another) plus some.
I actually don't recomend the injectors to most people, the overall cost doesn't justify the incease in performance. I also think that the larger MAF is a waste of money. The last run on the Dyno showed only 2hp increase over the stock MAF, calibrated for the the stock injectors. I haven't had a problem runnung the larger injectors with the stock MAF, I do however run the larger MAF now because I paid $250 for it.

 

[Rick]

6mpg OUCH! Especially with the little 18 gallon fuel tank.

My best tank on the way to Colorado this weekend was 18.2 while I was driving up to 70 mph on the back roads of New Mexico and Colorado.

My worst was 14 and that was while I was doing 85mph on the Interstate Fwy's and pedal to the metal climbing hills.

Engine mods include Vanir MAS and throttle body, and a cat back exahust. I'm also running 4:56 gears and 33x12.50's. My Exploder is also 5500lbs, it's been weighed on the local garbage dumps scale.

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Rick Horwitz
Editor
explorer@4x4central.com
Editor
www.4x4central.com