Injector upgrade thoughts.

[Deezelweazel]

Sorry but how can you claim power gains with a self adjusting electronic injection?
Duty cycles are only getting shorter with a bigger fuel flow.
Provide a lot more airflow to gain any benefits.

Power= fuel + air

[rainman]

Sorry but how can you claim power gains with a self adjusting electronic injection?
Duty cycles are only getting shorter with a bigger fuel flow.
Provide a lot more airflow to gain any benefits.

Power= fuel + air

Power not so much,(wee bit maybe) more about throttle response, easier start, smother idle & fuel economy, also I was getting leaner than ideal at WOT. Since putting in injectors however have lifted jeep and changed axle ratios. So economy comparison numbers will not be coming from me, hope to do another run (with wide band oxy sensor) to see if air fuel ratios are better @ WOT soon. It is not a daily driver and it is taking time to get the kilometers/ starts up for the computer to relearn.

[Deezelweazel]

Ah ok, I see the idea behind- just was wondering a bit.
Have been at an injectur guru named Russ Collins (RC engineering).
Are Lucas plate disc injectors available? I would use them Those plates have a very quick slew rate.
Much better than those Bosch or Nippon pintle style injectors.

[rainman]

Not to sure about lucas plates, currently using Bosch director plates. to get away from the OEM pintal type injectors. Mostly because of cost, the idea was to get something that was better than stock, but also affordable for stock-ish jeep engines , like; $200 AUD @ your door for 6 injectors. Which any of the above mentioned injectors can be had for, or even less in some cases.
Rather than "the best & hang the expense" approach. Which might be be the path for someone who has just spend big bucks on a stroker rebuild.
The limited phone calls I made in Australia about injectors lead me to believe that $200 was not going to go very far and that importing from the states would be more cost effective.
That being said vt commodore injectors on post 96 XJs is prolly the cheapest ( 6 reconditioned injectors on ebay for $100) upgrade option out there.

[rainman]

So just a bit of an update since the Injector replacement, I have done about 1300km and no way have I done 50 starts yet. It is not a daily driver.

So with the wide band.
Warm idle AF=13.9
Warm coast AF=13.9
warm Cruse af=14.1
warm acceleration=14.3
warm WOT AF=11.7

So it has not realy changed that much from the initial run.

Now the real story here is the fuel consumption.
I was getting 16.2l /100km with the stock injectors.
I put the new injectors in then about two weeks later I lifted the jeep 4.5" and changed the diff ratios to 4.10 from 3.55. Still have same tires 29". New radiator and 90*c Thermostat to replace the 80*C that was in there.
Town and highway driving I am now getting around 12.3l/100km.
******YEAH BOLLOCKS! 14.8 L/100km After you adjust for the diff re-gearing**********


Now I do not know where exactly the 4l/100km improvement came from;
new Injectors, new Ratios, new hotter thermostat,
but I'm very happy with it.

I'm not worried about the slightly rich condition at WOT because even driving like a twerp you realy don't spend that much time at WOT. and look at the fuel figures.

Will do another run in a couple of months see if anything changes.

[Deezelweazel]

Thats a whopping 25% increase in fuel efficiency.
It seems that the changed diff ratio does good.
Same driving style?

[rainman]

Same driving style except the "driving like a twerp" phase to realy pin down the WOT AFR numbers.

[bruggz351]

That is a massive increase in economy. Has the ratio change been taken into account. eg. distance measured is no longer accurate. Or are you using some other method for distance measurement? (GPS etc.)

Excellent info by the way. Extremely thorough. Good job there rainman.

cheers