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  #16  
Old May 8th, 2014, 22:24
G2WANIT G2WANIT is offline
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Re: 0280156007 VS. 784 Injectors

Quote:
Originally Posted by smiley View Post
Thirty miles to a tank is a pretty big difference in the long run... at least from my perspective.
Really?? Lets do the math.

Assumptions:
  • Driving 12,000 miles per year
  • Averaging 13 miles per gallon (that's what I get )
  • Paying $4.00 per gallon for regular unleaded
  • Averaging 18 gallons to fill the tank
With these numbers you will save 5.83 gallons per year, which is $23.31.
If you're getting 16 MPG then the savings shrinks to $15.72 in a year.
If it's a worst case scenario and you are driving 15,000 miles per year and averaging 13 MPG you would save a whopping $29.14 per year.

I did a quick search and found an eBay auction for 6 remanufactured 0280156007 injectors for $97.99. So I suppose if you fit the worst case scenario you would start to save money in year 4... But how many miles per year do YOU actually put on your XJ?

Personally, I put less than 1,000 in a year. I would drop the $100 in a heartbeat if there was a performance gain in it, but without that...

But it's an XJ and meant to be modded, so rock on. (I am interested to see your mileage difference after your trip.)
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  #17  
Old May 9th, 2014, 07:29
SolarBell SolarBell is offline
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Re: 0280156007 VS. 784 Injectors

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Originally Posted by Talyn View Post
Really I would expect 0 performance gain unless the stock injectors are dirty. The PCM will maintain 14.7:1 AFR in closed loop (most of the driving). Sure you are getting a finer spray, but you also have to take into consideration that the stock injector is firing on the back of a very hot closed intake valve.
Truth. I only replaced mine because my injectors were failing and needed to be replaced anyway. I wanted to try out a set with the finer spray for the heck of it since the price was comparable.
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  #18  
Old May 9th, 2014, 07:44
smiley smiley is offline
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Re: 0280156007 VS. 784 Injectors

I'm what you will call a "unique person." This jeep is the first and only car I have ever owned. I have had it for 12 years and its 14 years old. I plan on putting at least 300,000 more miles on it before it probably will break in half. So a 4 year ROI is worth it to me because I know I will have it for 25 more. No scientific data yet but, I am seeing 25mpg highway on my overhead console when I used to get 19-20 max. Thats crusing at 65 MPH on flat road. Not saying that there is any benefit yet because I have only put around 60 miles on it so far.

BTW IDK if the guy was lying but I had someone come up to me yesterday admiring my jeep. He said he got 500,000 miles on his origional engine before he sold it.... it didn't blow up... he sold it and he told me he regretted his decision.... gosh you gotta love a Jeep.
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  #19  
Old May 9th, 2014, 10:12
thatxjguy's Avatar
thatxjguy thatxjguy is offline
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Re: 0280156007 VS. 784 Injectors

Yeah in all honestly, they're not much different from the stock injectors. So I can agree with everything being said here.

I haven't noticed any major gains.
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  #20  
Old May 9th, 2014, 10:18
SolarBell SolarBell is offline
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Re: 0280156007 VS. 784 Injectors

Glad you have the long term outlook.

Something to keep in mind though. If I recall correctly (and I may be wrong), the fuel mileage on that display is based on injector pulse widths computed against the stock injector flow rate. Assuming that is right, then an injector with a different flow rate with make that display inaccurate since the computer will adjust fuel trims (and pulse width) to reach a correct fuel ratio. Your most accurate numbers will come from fill up to fill up mileage.
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  #21  
Old May 9th, 2014, 10:26
smiley smiley is offline
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Re: 0280156007 VS. 784 Injectors

Thats great information to know... I will start to do it the old fashioned way, with Pen and Paper
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  #22  
Old May 9th, 2014, 18:13
Talyn Talyn is offline
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Re: 0280156007 VS. 784 Injectors

Quote:
Originally Posted by thatxjguy View Post
Yeah in all honestly, they're not much different from the stock injectors.
They are a good fit. Anything different from the stock injectors(a good working set) won't show gains anyways.

Quote:
Originally Posted by SolarBell View Post
the fuel mileage on that display is based on injector pulse widths computed against the stock injector flow rate. Assuming that is right, then an injector with a different flow rate with make that display inaccurate since the computer will adjust fuel trims (and pulse width) to reach a correct fuel ratio. Your most accurate numbers will come from fill up to fill up mileage.
You are correct.
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  #23  
Old March 2nd, 2017, 21:33
ANZAC_1915 ANZAC_1915 is offline
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Re: 0280156007 VS. 784 Injectors

Quote:
Originally Posted by G2WANIT View Post
Really?? Lets do the math.

Assumptions:
  • Driving 12,000 miles per year
  • Averaging 13 miles per gallon (that's what I get )
  • Paying $4.00 per gallon for regular unleaded
  • Averaging 18 gallons to fill the tank
With these numbers you will save 5.83 gallons per year, which is $23.31.
If you're getting 16 MPG then the savings shrinks to $15.72 in a year.
If it's a worst case scenario and you are driving 15,000 miles per year and averaging 13 MPG you would save a whopping $29.14 per year.
Kicking a necrothread here, but I had to take a poke at the math.

If he was getting 13MPG on an 18gal tank, that's 234 miles per tank. If he gets 30 extra miles, that's 264 miles per tank, or 14.7 MPG - basically a 12% saving. If he was getting 16MPG on an 18gal tank, an extra 30 miles would mean he is getting 17.7 MPG about a 10% saving.

If you drive 12000 miles per year, lets say at 16MPG and $4/gal, that's $3,000 a year in gas. A 10% saving would be $300. At 13MPG, that's $3700 a year, a 12% saving would be $443/year.
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