Eagle Posted November 16, 2015 Posted November 16, 2015 The vehicle is a 1988 2.5L MJ, with the throttle body injection. If anyone has priced that injector, it's crazy what they cost. I'm starting to consider a backwards conversion, to a carburetor instead of TBI. Not sure, but I think I can leave all the injection wiring intact and unused, and continue running the factory Renix ignition setup. Does anyone know anything about sizing carburetors? My numbers indicate that at 5,000 RPM a 2.5L engine nominally flows 220 CFM. I'm accustomed to 4-barrel carbs on V8s, running in the 550 to 750 CFM range. I'm guessing for normal street driving and economy, I should be looking for a carb in the 250 to 300 CFM range. Does that sound about right? One barrel, or two barrels? Does anyone offer a small 2-barrel carb that's set up like half a 4-barrel, with a small primary venturi for economy and a larger secondary that opens when the engine needs more air?
HOrnbrod Posted November 16, 2015 Posted November 16, 2015 Wasn't the AMC 2.5L engine carbed until 1986 when they got TBI? Should be pretty easy to find an 85 or below 2.5L carbed engine or the carb/manifold parts you need that were removed when someone upgraded their CJ or something to fuel injection, si? As I recall, the 85 and below 2.5 carbed engines had a simple one barrel Rochester carb.
Eagle Posted November 16, 2015 Author Posted November 16, 2015 As I recall, the 85 and below 2.5 carbed engines had a simple one barrel Rochester carb. Yes, they did. And the carb was widely regarded as a piece of [bleep]. If I go ahead with a carb conversion, I may seek out an '84-'85 intake manifold, but that's one carburetor that's not under consideration.
zomeizter Posted November 17, 2015 Posted November 17, 2015 Reverse upgrade=Downgrade dude, no carb could be as accurate as FI. If you need a new part but it's too pricey, maybe try a used replacement for less?
Eagle Posted November 17, 2015 Author Posted November 17, 2015 Reverse upgrade=Downgrade dude, no carb could be as accurate as FI. If you need a new part but it's too pricey, maybe try a used replacement for less? Easy to say. What's the best fuel mileage you ever heard of from a 4.0L XJ or MJ? Low 20s -- maybe? I got 28 MPG on a road trip in my '88 XJ 5-speed when it was fairly new -- ONCE. Must have been a helluva tailwind, because I never got mileage like that again. Go back 20 years. I had a 1966 Rambler American, 3-speed, no overdrive. No fuel injection, just an old-fashioned 1-barrel carburetor. I routinely logged 28 MPG for highway mileage in that car. And a Rambler American wasn't any more aerodynamic than an XJ.
buckwheat Posted November 17, 2015 Posted November 17, 2015 Am I the only one who read the title of this thread and thought "How can you make the reverse gear any better? Maybe he has found a way to go faster in reverse . . . "?
Wiggilez Posted November 17, 2015 Posted November 17, 2015 Am I the only one who read the title of this thread and thought "How can you make the reverse gear any better? Maybe he has found a way to go faster in reverse . . . "? same
Eagle Posted November 17, 2015 Author Posted November 17, 2015 It's a good thing we all speak the same language, isn't it? Just think how confusing things could be if we didn't ... :)
shelbyluvv Posted November 17, 2015 Posted November 17, 2015 http://www.webercarbsdirect.com/product_p/wk552.htm
cruiser54 Posted November 17, 2015 Posted November 17, 2015 What's wrong with your throttle body/injector? Dirty? Have you tried using BG44K? I have a complete assembly that's almost brand new, minus the TPS and ISC. Been sitting for years. I also have a manifold with carb.......
Megadan Posted November 17, 2015 Posted November 17, 2015 http://www.webercarbsdirect.com/product_p/wk552.htm I was going to suggest this very same carb setup. the 32/36 DGEV is a good carb replacement for mid sized (2.3-2.6ish) 4 pots in truck applications. We just used one on a buddies old Nissan Pickup with a 2.4 because the factory carb (an overly complicated electro-smog thing that costs $1100 rebuilt) needed replacing. His truck runs great now and gets pretty decent mileage too. Honestly, I've considered reverting my 4.0L to a carb more than once. I have a wideband sensor and gauge sitting around and a bung in the exhaust for one, so I could really get that thing fine tuned.
FrankTheDog Posted November 19, 2015 Posted November 19, 2015 Eagle I have an 87 TBI that seemed to work good when I ran the motor. You're welcome to it if you want it. I need to stop down sometime anyways. Any 2.5 parts you need let me know. I have no use for them and nobody seems to want them.
outlaw star Posted November 19, 2015 Posted November 19, 2015 It's a Chevrolet injector, same one used in their TBI trucks. Shouldn't be more than 40 bucks.
Eagle Posted November 19, 2015 Author Posted November 19, 2015 It's a Chevrolet injector, same one used in their TBI trucks. Shouldn't be more than 40 bucks. http://www.autozone.com/fuel-delivery/fuel-injector/jeep/comanche-4wd/1988/4-cylinders-h-2-5l-tbi
outlaw star Posted November 19, 2015 Posted November 19, 2015 It's a Chevrolet injector, same one used in their TBI trucks. Shouldn't be more than 40 bucks. http://www.autozone.com/fuel-delivery/fuel-injector/jeep/comanche-4wd/1988/4-cylinders-h-2-5l-tbi Its just going to a home screen. Here's the reman ones. www.partsgeek.com/gbproducts/MC/3126-07142055.html?utm_content=MC&utm_term=1989-1993+Chevrolet+Caprice+Fuel+Injectors+GB+Remanufacturing+831-14114+89-93+Chevrolet+Fuel+Injector+1991+1992&fp=pp&gbm=a&utm_source=google&utm_medium=ff&utm_campaign=PartsGeek+Google+Base&gclid=Cj0KEQiAg7ayBRD8qqSGt-fj6uYBEiQAucjOwWOJvK0dN-ktu9AvReZdy2XsXR3Eei-yddu2-WS6BlEaAvCq8P8HAQ
outlaw star Posted November 19, 2015 Posted November 19, 2015 Morris 4x4 has them for 99 new from Crown. Free shipping on orders 99 dollars and up.
HOrnbrod Posted November 19, 2015 Posted November 19, 2015 New, not rebuilt junk - $86.99: http://www.sbcoffroad.net/oscommerce/product_info.php?cPath=44_174_1393_1852&products_id=9399 Rebuilt junk $31.63 + $15.00 Core: http://www.partsgeek.com/catalog/1989/jeep/cherokee/fuel_injection/fuel_injector.html
outlaw star Posted November 20, 2015 Posted November 20, 2015 Either choice was better priced than AutoZones ones.
Eagle Posted November 20, 2015 Author Posted November 20, 2015 Either choice was better priced than AutoZones ones. Yes, the AutoZone listings ran from $115 to $150.
CSchumm88 Posted November 21, 2015 Posted November 21, 2015 i just did a injector replacement and it cost me aboiut 130 for a brand new one ut it was well worth it carbs are great but there is a reason they are not put in vehicles now days.
cruiser54 Posted November 21, 2015 Posted November 21, 2015 Eagle, you're being offered one for free and delivered.......by Frank the dog.
Minuit Posted November 21, 2015 Posted November 21, 2015 Dunno about anyone else, but I'd gladly pay $150 to keep fuel injection.
HOrnbrod Posted November 21, 2015 Posted November 21, 2015 I'd sure love to see how a 4.7 Hesco built stroker would perform with dual Webers. There was a member, Stacks I think, who was building a stroker with Clifford go-fast stuff. Anyone know what happened to him? I was very interested in his build.
cruiser54 Posted November 21, 2015 Posted November 21, 2015 I'd sure love to see how a 4.7 Hesco built stroker would perform with dual Webers. Triple Webers or Mikunis. Sidedrafts.
cruiser54 Posted November 21, 2015 Posted November 21, 2015 http://www.google.com/imgres?imgurl=http://www.torosite.com.ar/imagenes/originales/grandes/71.gif&imgrefurl=http://www.ifsja.org/forums/vb/archive/index.php/t-92906.html&h=350&w=450&tbnid=XTqycS4Po5Bj1M:&docid=yacNUNxFf9FmYM&ei=dudPVpqULInQoASU2K_QBQ&tbm=isch&ved=0ahUKEwiap-3sy6DJAhUJKIgKHRTsC1oQMwhPKCgwKA
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