Which Injectors, Throttle body?

[farna]

My stroker is officially worn out. Had 0.018" piston to sidewall clearance at the bottom of the cylinders (with pistons pushed to one side, 0.009" all around). Since I have it in my car and don't really need all the low end torque, I'm rebuilding it as a 0.060" over 4.0L (I'm guessing... don't think it will pass at 0.040" though, but depends on the pistons). So I'm using the 4.0L crank and rods. I'll build another stroker with carb for my Jeep truck this summer though.

My problem now is what injectors to use, and what throttle body. I have a bored out Renix TB that I had planned on using. The large TB shouldn't hurt anything, might make throttle response better and could lean out at WOT, but this cruiser should rarely see WOT. Opinions? Is using the bigger TB a mistake? I'm putting it on a 1999 intake, already made an adapter for the Renix TB.

Will the 24# injectors (Ford Motorsport) I was running with the stroker be too big though -- should I got back to the original 19# injectors? I also have a set of injectors from 96-99 model, which should be 23#. According to my Chilton's Jeep manual (84-96) the fuel pressure at the rail was the same from 87-96 for the 4.0L. The rail used no return line though (bought entire head with manifold and injectors from a motor with rod through the block). I thought those used 49 psi at the rail. If so, the 23# injector will flow 20.5# at 39 psi, just a little more than the 19# injectors. Or are the injectors all rated at the 43.5 psi standard most aftermarket injectors use?

[farna]

No advice on injectors? Can someone at least tell me when the fuel pressure increased from 39 psi to higher, and what the higher pressure is (I think 49 psi)??

An update on my engine: The machine shop called and said they found a crack or two on the deck into the water jacket. Most likely this wouldn't be a problem, as I've never had any water loss or oil in the water. The cracks were just in the deck well under the head sealing surface. Still, they (and I!) would rather use a different block since mine would need to be bored 0.060" to clean up nice. Takes a few days for them to get another block, and it was the week between Christmas and New Year. I MIGHT get the engine back tomorrow afternoon, but most likely won't be until the middle of next week.

In the mean time, I had to have something to drive! I'm still way behind on building my J-10, had to start Tuesday of this week. Spent a couple days looking for a good six cylinder Comanche, but nothing within a 2-3 hour drive. A couple four cylinder jobs which I briefly considered, but that was it. Didn't expect to have much luck there, or a decent J-10 with six. Looked at other small to mid size trucks good enough to drive until I get the J-10 rebuilt, but not much more than junk out there. Ended up buying a 2002 Ford Ranger. A lot nicer and twice what I was thinking about spending, but a good deal on a very nice little truck. Now I'll probably just keep the Ranger for a while and sell the J-10s. Called a guy who deals in Jeep parts and he's interested in giving me a fair price for both. If he doesn't get them I may just keep and build one anyway, then decide which truck to sell when done. Not sure. Will need to get a 4.0L block to build a stroker for it.. have everything else (even a 6130 head).

[Cheromaniac]

My problem now is what injectors to use, and what throttle body. I have a bored out Renix TB that I had planned on using. The large TB shouldn't hurt anything, might make throttle response better and could lean out at WOT, but this cruiser should rarely see WOT. Opinions? Is using the bigger TB a mistake? I'm putting it on a 1999 intake, already made an adapter for the Renix TB.

The bored Renix TB should work fine and give better throttle response than an unbored unit.

Will the 24# injectors (Ford Motorsport) I was running with the stroker be too big though -- should I got back to the original 19# injectors?

If you're running a 39psi fuel system, yes.

Can someone at least tell me when the fuel pressure increased from 39 psi to higher, and what the higher pressure is (I think 49 psi)??

The transition from 39pi to 49psi fuel pressure took place in 1996 with the introduction of OBD II. The '96+ fuel system is also returnless.

[amcinstaller]

i was gonna post but i woulda been wrong i was gonna say that it changed in 99, with the new intake, but i was also goin to mention the difference with the return/returnless part.