4-cylinder engines: upgrades through the years

xj92

xj92

NAXJA Forum User
Location
Junction City, KS
I just bought a major piece of junk '88 MJ with a 4-banger and plan on fixing it up and using it as a work truck for my business. I want the 4-banger for the little extra gas mileage, but I want to upgrade it as much as possible with the upgrades from later years, such as multi-port injection if it's available (I realize this will mean a head swap & probably a computer also), etc. I have lots of experience with the inline 6, but none with the 4-banger, so please help me. Are there upgraded intake or exhaust manifolds? How about cylinder head? It didn't even come with power steering so I'll be installing that soon. If necessary, I'll swap out the entire drivetrain, but if the engine blocks were the same throughout the years and they just updated the head & manifolds, then I'll go that route.
 
I did some googling and found out that the highest horsepower rating these engines ever had was from '91-'95 @ 130hp.

In '91 they got multi-port injection.

In '92 they got sequential multi-port injection
 
What's with the stupid thing that sucks air off of the exhaust manifold? Help it warm up quicker? Is that necessary or can I take it off? My '93 doesn't have anything like that.
 
I got 28mpg with my 2.5L. It was a tbi injection, a purple cam, and headers.
 
xj92 said:
What's with the stupid thing that sucks air off of the exhaust manifold? Help it warm up quicker? Is that necessary or can I take it off? My '93 doesn't have anything like that.
Click to expand...

Sounds like smog. It is meant to keep combustion temperature down to reduce NOX emissions.

~Alex
 
I put the 4.0's throttle body on and a tbs (spacer) if you also add some stickers you get more hp:viking:. There might be a piece of plastic covering the area where the air goes into the intake, take that off.
 
u can by my stock srt4 manifold and turbo and see if it bolts up and get a fuel controller and bigger injectors and a wastegate spring to run 6psi of boost and raise hell with it.
 
I have bin wanting to see if someone with a 4banger jeep build a low compression engine like 8:5:1 or 10:1 with forged pistons and internals, ported polished heads to the max, run a 60 trim or a 50 trim and run 25psi of boost and probably put out a mild 400hp and 450lbs a torque.(5spd) on 33's with 488's and 0 to 60mph in 4seconds. Be able to daily drive, pull trailer or camper, and rock crawl and mud bog all in one package. To do all this u would need a built tranny and transfer case to handle the power. Probably a nv3500 tranny and billet transfer case with rock jock axles. I know im talking alot of money but wouldnt that be a dream?
 
projectTK said:
I have bin wanting to see if someone with a 4banger jeep build a low compression engine like 8:5:1 or 10:1 with forged pistons and internals, ported polished heads to the max, run a 60 trim or a 50 trim and run 25psi of boost and probably put out a mild 400hp and 450lbs a torque.(5spd) on 33's with 488's and 0 to 60mph in 4seconds. Be able to daily drive, pull trailer or camper, and rock crawl and mud bog all in one package. To do all this u would need a built tranny and transfer case to handle the power. Probably a nv3500 tranny and billet transfer case with rock jock axles. I know im talking alot of money but wouldnt that be a dream?
Click to expand...

Wouldnt that defeat the purpouse of buying a 4 banger for gas mileage? I would say that you are best off with the newer fuel injection and manifold, AmsOil filter and a full tune up.
don't forget to top off the headlight fluid:gee:

~Alex
 
Building a work truck out of a 2.5 seems kinda useless if you just want milage. I mean, that is if your planing on pulling trailers adn having your bed full of wood and heavy loads of hay, etc. But if your just wanting a simple work truck for light duty stuff then I think its a great idea. Just find a newer 2.5(Mine is a 93) so you can get the most power. I personally love mine. My brother has a I-6 and sure the power is way more but honestly I am just fine with mine(That is after I rebuilt the motor)
 
The 2.5 MPI swap is easy compared to other swaps you could get into. I did it in my 84 with a carb. You do not need to swap the head. You will need the intake and mpi fuel rail, the harnes and computer and you will need to update your body harness. The connectors are different and its a lot easyer to pull the dash and swap the harness imho then to try and splice the two together. The fuel sending unit is different too. I may have missed some thing but those are the basics. I have all of it if you are intrested pm me.
 
you guys must of never owned a turbo car. Ive owned a 89 ford probe gt turbo, and a 2005 srt 4 with stage 3 turbo. With boosting i still got around 25mpg. Now with a jeep and all the stuff i listed probably a little over 20mpg. Youll have to replace the muffler bearings too.:gee:
 
projectTK said:
and a 2005 srt 4 with stage 3 turbo. With boosting i still got around 25mpg. Now with a jeep and all the stuff i listed probably a little over 20mpg. Youll have to replace the muffler bearings too.:gee:
Click to expand...

The SRT4 is a Chrysler engine and not anything like the 2.5 amc one he has. He could put a turbo on the 2.5 there are kits out there but yours would not bolt up at all from what I have read. Now the wrangler 2.46 is that motor minus the turbo.
 
Ghost said:
The SRT4 is a Chrysler engine and not anything like the 2.5 amc one he has. He could put a turbo on the 2.5 there are kits out there but yours would not bolt up at all from what I have read. Now the wrangler 2.46 is that motor minus the turbo.
Click to expand...
Doesnt the SRT4 have forged internals and all that jazz?
 
I spent all day at the junkyard on Wednesday, and got the following for $220:

'93 Cylinder Head, Intake Manifold, Throttle Body, Fuel Rail, & Injectors
'93 Computer & Wiring Harness (took me forever to figure out how to disconnect it from the fuse block at the firewall :))
I pretty much took all the sensors at the end of the wiring harness just in case my electric plugs don't match up with the new one, I won't have to splice a bunch of wires.
Power Steering pump, reservoir, & gear box (mine didn't have ps)
A/C Compressor & engine brackets
'93 coolant overflow tank & brackets
Gray interior pieces (it's currently burgandy interior and I hate it)
RE 1600 Track Bar
RE front coil springs
Dakota Rear Springs
Swaybar Disconnects
Braided steel rear brake line
RE lower control arms (RE joint one end, rubber the other end)
Extended front bumpstops
New fender, flare, & inner fender
There might be more, I can't remember

Here are my plans:
Have a local machine shop rebuild & port the new head for better torque & gas mileage ($210 is what he quoted me)
Rip out the burgandy dash and get a gray one, while replacing all the interior wiring with that of a '93 vintage also. Nothing works, so it all needs to be fixed anyways (not working: turn signals, dome light, dash lights, heater controls, radio, windshield wipers, etc. Somebody hacked it all up in the past)
Replace the AX-4 with an NV3550
Convert to 4wd (I'll get the 231 when I get the 3550)
Replace the worn out bench seat with buckets
Replace the rubber floor with gray carpet
Figure out how to add cruise control
and probably much more I'm not thinking of at the moment.

I did buy it as a work truck for the sign installation business I started, installing posts for Real Estate listings, so all I do is carry around signs & sign posts, nothing too heavy. Sorry to be long-winded, comments or suggestions are welcome.
 
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