[Lee Iaccoca]

Know that the Voltage you want to use on an adjustable MAP tends to rise with your modifications. Also know that monitoring the AF ratio via an O2 based AF monitor would go along ways towards helping an individual adjustable-MAP-user know what voltage is optimum for his setup.

However, I don't have any kind of 02-sensor based AF monitor on hand at the moment. But I'd still like to get an idea of what Voltage settings have worked well for people here given their respective engine modifications (especially if similar to my own) -- 4 or 6 cylinder, either way

Mine is a 4Banger 2.5 with a Borla Cat-Back, PDI ignition, 62mm TB, custom cold air intake, 19lb Ford Injectors, and an Adjustable FPR.

Over the weekend I installed an Adjustable MAP sensor from Turbo City (yeah, I know you can make your own for $20-$30, but time is money and all that and I personally came out way ahead just buying a completed unit).

My stock MAP Sensor measured at 4.63V. Turbo City directions suggested increasing the Voltage by .2V. So I did that and now I am measuring 4.82V (precise .01V increments are hard to do with the thing).

And it is running better. But I would like to find out from you guys what Voltages you are using given your respective mods. Thanks.

 

[jgorm]

I would play with the fuel pressure to dial in the AFR for those injectors. You can watch the stock o2 sensor volts to dial it in for part throttle operation. They really wont read much under 14:1 so you need a real wideband for wot tuning.

 

[Lee Iaccoca]

The adjustable FPR I have is set at 44psi.

 

[Unlimited04]

Mine is a 4Banger 2.5 with a Borla Cat-Back, PDI ignition, 62mm TB, custom cold air intake, 19lb Ford Injectors, and an Adjustable FPR.

the original fuel injectors for your 2.5L should have been #53007232, and while I can't find any info on the rate...I did find the TJ series 2.5L's used #53030778, 23.2 lb/hr @ 49psi from the factory.

And if you do the calculation, the factory engine needed a larger than 19lb injector to run below the 80% duty cycle recommended for injectors. TJ 2.5L's used 23.2 lb for 120 hp 2.5L, or a max of 65% duty cycle - plenty of room for play.

So to maintain the factory power specs & ~65% duty cycle you should have 25 lb injectors @ 44psi. 19 lb injectors won't meet 80% duty cycle with 44psi....

Here's the injector size calculator -
Injector Size Calculator

 

[Lee Iaccoca]

the original fuel injectors for your 2.5L should have been #53007232, and while I can't find any info on the rate...I did find the TJ series 2.5L's used #53030778, 23.2 lb/hr @ 49psi from the factory.

And if you do the calculation, the factory engine needed a larger than 19lb injector to run below the 80% duty cycle recommended for injectors. TJ 2.5L's used 23.2 lb for 120 hp 2.5L, or a max of 65% duty cycle - plenty of room for play.

So to maintain the factory power specs & ~65% duty cycle you should have 25 lb injectors @ 44psi. 19 lb injectors won't meet 80% duty cycle with 44psi....

Here's the injector size calculator -
Injector Size Calculator

I appreciate your analysis on the injectors, Unlimited 04.

I've been spending a lot of time at 4bangerjp.com in the last few years. Word there has long been that the oem injectors on the YJ 2.5s run less than 19lbs (if memory serves, 17lbs). But they confirm TJs are like you said, 23lbs.