Re: [AMC-list] Mileage with AMC/Jeep 4 Cyl 2.5 EFI or 4.0 in an 80's AMC

[Frank Swygert <farna@xxxxxxxxxxx>]

Date: Wed, 20 Mar 2013 08:21:23 -0700 (PDT)
From: Jesse<j2sax@xxxxxxxxx>

So I am looking at a getting a 2nd vehicle for my son to commute in. ?He LOVES his 87 Chero 2 door (4.0 Auto) but he has to drive a lot of miles now and I have a feeling gas is about to go up again and beyond where we have seen it in the past. ?I had considered an Escort or Mazda 3 when I stumbled upon a 4 Cyl Spirit. ?It has the Iron Duke that has puked and I could easily redo that motor.. and of course, adding EFI would not be difficult as the S trucks from GM had an EFI'd Duke. ?

I really like the idea of an AMC econo car the way AMC might have done it and found a 2WD Comanche 2.5/4 speed wrecked. ?Has anyone ever swapped an AMC 4 Cyl with the EFI into a RWD AMC Car? ?What kind of mileage did you get? ?

Also, if you have swapped a 4.0 into a RWD AMC car, I would be interested to know that number as well. ?

Not interested in speed so no stroker recommendations necessary. ?This is looking to mod for mileage. ?Would it be easier to buy an Escort.. YUP. ?Regardless, I just gotta be me!?

Thank you for your experienced opinions,?

=================================

I have a hopped up 4.0L and get about 22 mpg cruising at 70 mph. I've got 3.55 gears and an AW4 auto trans from a 2WD Cherokee. I feel it would do great with 3.31 gears, but don't want to pony up the dough to change the gears just for a couple more mpg. Mark Price is running a 4.0L in an American with a five speed. I don't recall his rear axle ratio, but he's reported getting around 24 mpg cruising. Both are about in line with a typical Cherokee that's been kept in top condition... maybe a couple mpg more in both cases. A dogged out Chero won't get that much, of course!

You should be about in line with a four cylinder Cherokee in a Spirit, maybe 2-3 mpg better, so you're talking mid to upper 20s as far as mpg, with 20-24 as an all around average. I'd use a five speed and something like a 3.55 axle. That should be about right for the four, a little taller than the 4.10 used in Cherokees with the four. A 3.73 might be better. Do get the direct port injection four -- 1991 or later (120 hp). The TBI model (117 hp) is the next best one and the intake is a bit narrower, but it was only used in 87-90 models. The carbed model (105 hp, 83-86) isn't worth messing with unless you throw the feedback carb away put something better on it. Then you have to get rid of the computer and do something with the ignition also. The ignition might be fine without the computer, I don't know enough about them to say, but most feedback carb systems have the computer controlling ignition somewhat as well.

--
Frank Swygert
Editor - American Motors Cars Magazine
www.amc-mag.com


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