just wanted to see if any one knows the mm size of the throttle body on the 4L. is one year stock better then another? if so is it worth it. i read about the 99 and up intakes being better. but every one has answers that are diff from one another. any help would be great. i have a 97xj with simple bolt ons and wanted some more mpg. (tb spacer,stock air box with k&n filter, high flow cat with high flow muffler. is what i have done.) i am running stock coil with msd cap, taylor wires.

 

You could get a bored out tb, thats about it. They stayed the same throughout the years, just different configurations. Also, be careful with too much exhaust work, loss of back-pressure = loss of power & loss of mpg's.

The best MPG adder is a light pedal. Don't be the first one off a green light, and don't go above 2k rpm. These aren't Toyota Prius, not made for MPG supremacy. Regular maintance and upkeep, a light foot. I just topped my tank at 14 gallons, and got 341 miles before I had to refuel, = a hair over 24mpg.

 

Contact www.strokedjeep.com for the best deal on bored throttle bodies. He has a program where you order a bored TB, he sends it to you, and you then send your old one back. No downtime and he's very reasonably priced.

 

hey thanks for getting back to me. i do not know tho about what size to get that would work best. i have a rear bumper in the works with a hitch. i wanna tow a small pop up camper. i dont want to loose any bottom end by going to big.

 

If your mechanically inclined..not even its super easy to do
I say run that jeep until its empty..let it idle itself out of gas. And then drop the tank and clean it out. Mine was pretty dirty. And it was super easy to do.
I did that installed a new filter and my 703 injectors. Seafoamed her and it runs alot better!

So I say follow that..you'll need the 784 injectors..but its a good upgrade. Better throttle response and everyone claims better mpg as well...you can find the injectors for $50 bucks or so, constantly for sale on the forum.

Also you can relocated your IAT sensor..its located on the intake manifold by the 5th runner I believe. Obviously the intake manifold gets extremely hot, so its better to move it into the airbox, so it reads actual air temps instead of manifold temps.
Theres some really cheap stuff that helps out. Nothings extremely major, like OMG dude I gained mad power...but then again every little big helps! I have all this done on my jeep and it runs great! Alot snappier than it used to be!

 

You will lose NO bottom end at all with the larger TB. Jeff at www.strokedjeep.com can help you select the best TB for your needs. I would just get the biggst one that will fit without modifying the inlet of the stock manifold. I think that's 60mm for Renix Jeeps and 62mm for the HOs..

 

doing motor work is no biggie. but i can find no look up for the 784 injectors you speak of. i looked on ebay and see many stock/aftermarket ones. i need more info on this. like a comp name.

 

Try www.precisionautoinjectors.com. I've used 3 sets of his in my 3 Jeeps with good results. No guesswork in choosing the correct ones and they're 4 disc, flow-matched with new o-rings.

 

Ya precision is a good place to buy and its painless...literally plug and play!
I say relocated the IAT as well. its a cheap upgrade!
Also throw the stock filter back on there. It flows more than enough and filters out more dirt & such. You ever notice the dust particles in your intake filter? Thats cause the K&N isn't filtering it out!

You can also get a heat blanket for the intake manifold. It goes underneath it, and reflects the head from the header! It'll keep your incoming air cooler which will equal more power, effciency & mpg.
Again its not a OMG kind of difference but again every little bit helps. I have done all this and got my references from Dino Savva's website!
Which can be seen here.
http://www.jeep4.0performance.4mg.com/

I've done just about everything he has, plus a few things..I haven't done my head gasket or ported head just yet, but everything else is done!

 

Won't colder air decrease MPG? IIRC thats one of the reasons people usually get worse gas mileage in the winter. Cold air is great for power, not so great for economy.

 

Cold air will increase charge density and if everythings is functioning correctly increase mileage. However if you relocate the Iat sensor you will get worse mileage because it woo read much colder then it would in the intake and richen the mixture.

 

Like it. I found that website quite a while ago and have yet to gt the t.b. but I'm guessing he does high quality work?

 

Yes he does do quality work. He's a gunsmith, too!!

FWIW, I noticed no decrease in fuel economy on my 90 Comanche or my wife's 88 Cherokee when relocatign the IAT.

 

You live in a hot place? I thought about performing this mod when I build a cowl intake.... I was thinking its not worth it. Like to hear your input.

 

Central Arizona at 5500 ft elevation. Yes, it gets hot here but nothing like Phoenix. It also gets to zero in the winter.