I bought Goldie this past summer - an '89 240 Wagon, with automatic.

A previous owner installed a turbo out of a 740. It was pretty well done, but not perfectly.

Anyway, I'm thinking about dropping the turbo and just going back to naturally aspirated. The main reason is that I'd like to have 4-5 mpg better mileage, more than I want extra power. I struggle to get 20 mpg on the highway - which is what the turbos seem to be rated at. I'd much rather get 25 mpg.

All the OEM parts came with the car, including the entire exhaust system.

I'm guessing I could probably eBay the turbo set-up for a couple hundred bucks.

What would you do?

 

I would keep the turbo, just because I would rather have the extra power, though, running a naturally aspirated feels nice. If you are more concerned on gas mileage and saving money, take the turbo and sell it, you'll save a few bucks at the pump every week and get some out of that turbo.

 

Google what the EPA gas mileage estimates were for the 240 BRAND NEW. You might not want to waste the time swapping out the turbo, manifold, ecu and icu. Turbo cars typically don't get much worse mileage when set up right...except when you're in boost. I firmly believe 90% of people extolling their 25-30 mpg out of a 240 are either incapable of calculating accurate mpg or are running too lean. The 240 was never designed as an economy car.

 

I would think that you should get better mileage, but not much. I get about 22 (with a turbo) in everyday driving. But yeah, I don't think that it will go up much more if you take it off.

 

I am currently getting 22-23 mpg on my 240 sedan in everyday driving. It isn't a turbo and I have been trying to get improved but haven't had much luck.

My understanding of turbos is that the mileage you get is totally dependent on how you drive it. Basically if you drive it hard, mileage will drop. If you are light on the pedal, you should get mileage almost approaching the normally aspirated engines.

 

Maybe we need to talk about realistic expectations for fuel economy.

On a good day I might get 20 mpg on the highway. More often, it's 18-19. Granted, most of that has been Interstate speed, but I am not an aggressive driver. With fill-to-fill driving, I'm generally around 15-16 mpg.

My son's '86 740 Wagon used to do 27-28 mpg on the Interstate. Granted, it was a NA 5-speed and my 240 is an automatic. But even with an automatic, I'd think I should get somewhere in the low 20s.


As a note of clarification... A previous owner installed the turbo from a 740 into my Goldie. I do not know if he installed the injectors out of the turbo and/or the ECU from the donor car. Would that make a significant difference in my mileage? What else could be causing my poor mileage?

 

Realistic? OK...




My experience has been that epa estimates were always optimistic. The single most beneficial thing you could do for mileage, other than ascertain that maintenance is spot on, would be to swap in a 3.31 axle.

 

I'm listening!

Is this axle apt to be found at a U-Pull-It Salvage Yard, or is it pretty rare? And what would my mileage increase likely be? 1 mpg? 3 mpg?

Thanks!

 

3.73 is by far the most common axle ratio. Following is a list of axle interchange info including the Hollander numbers that salvage yards use. Should make things easier.

The following rear differential information was supplied by Scott of HWY 79 Auto Sales & Salvage,Inc. Many thanks.

The first number is the ADP Hollander salvage interchange number. If the front number is the same (minus
alphabetic suffix), they will interchange, and have been grouped accordingly. This number can be used to order
the axles from more than 3000 salvage yards across North America.
435-58228A 740 88-92, 940 92-94, 960SW 92-94: locking 3.31
435-58228B 740 88-92, 940 92-94: locking 3.54
435-58228C 740 89-92, 940 91-94: locking 3.73
435-58228D 740 88-92: locking 3.91
435-58228E 740 89-92, 940 91-95: locking 4.10
435-58228F 740 88: non-lock w/abs: 3.54
435-58228G 740 88-92, 760 88-90, 780 87: non-lock w/ abs 3.73
435-58228H 740 88-92: non-lock 3.91
435-58228J 740 88: non-lock 3.31
435-58228K 740 88: non-lock w/o abs 3.54
435-58228M 740 88, 760 83-84: non-lock w/o abs 3.73
435-58228N 740 88: non-lock w/o abs 3.91
435-58228P 740 88: non-lock w/o abs 4.10
435-58228N 740 88, 740 89-92: non-lock w/ abs 3.31
435-58228S 740 89-92: non-lock 4.10
435-58228T 740 88: non-lock w/ abs 4.10

435-58440A 240 84-85 locking: 3.31
435-58440B 240 84-91 non-lock w/o abs: 3.31
435-58440C 240 91-93 w/ abs: 3.31
435-58440D 240 84-91 locking w/o abs: 3.54
435-58440E 240 84-88 non-lock: 3.54
435-58440F 240 84-88 locking: 3.73
435-58440G 240 84-91 non-lock w/o abs: 3.73
435-58440H 240 91-93 w/ abs: 3.73
435-58440J 240 84-85 locking: 3.91
435-58440K 240 84-88 non-lock: 3.91
435-58440M 240 84-85 non-lock: 4.56

435-58023A 740 85-87,760 83-87: non-lock, w/o abs: 3.31
435-58023B 740 85-87,760 83-87: non-lock, w/o abs: 3.54
435-58023C 740 85-87,760 83-87: non-lock, w/o abs: 3.73
435-58023D 740 85-87,760 83-87: non-lock, w/o abs: 3.91
435-58023E 740 85-87,760 83-87: non-lock, w/o abs: 4.10
435-58023F 740 87,760 87: non-lock, w/ abs: 3.54
435-58023G 740 87,760 87: non-lock, w/ abs: 3.73
435-58023H 740 87,760 87: non-lock, w/ abs: 3.91
435-58023J 740 87: non-lock, w/ abs: 3.54

435-58040 760 83-84: 3.54
435-58029 760 83-84: 3.91
435-51680A 240 75-78, 260 75-78: locking 3.54
435-51680B 240 75-78, 260 75-78: locking 3.73
435-51680C 240 75-78, 260 75-78: locking 3.91
435-51680D 240 75-78, 260 75-78: locking 4.10
435-51680E 240 75-78, 260 75-78: locking 4.30
435-51680F 240 75-78, 260 75-78: non-lock 3.54
435-51680G 240 75-83, 260 75-82: non-lock 3.73
435-51680H 240 75-83, 260 75-82: non-lock 3.91
435-51680J 240 75-78, 260 75-78: non-lock 4.30
435-51680K 240 75-78, 260 75-78: non-lock 4.10
435-51680M 240 79-83, 260 79-82: locking 3.31
435-51680N 240 79-83, 260 79-82: non-lock 3.31
435-51680P 240 79-83, 260 79-82: locking 3.54
435-51680P 240 79-83, 260 79-82: non-lock 3.54
435-51680S 240 79-83, 260 79-82: locking 3.73
435-51680T 240 83: non-lock 4.56
435-51680U 240 79-83, 260 79-82: locking 3.91
435-94020A 140 69-72, 1800 69-72
435-50546A 140 67-69: 4.10
435-50546B 140 67-69: 4.30
435-50546C 140 67-69: 4.56
435-50547A 140 70-74: 3.91
435-50547B 140 70-74: 4.10
435-50547C 140 70-74: 4.30
435-50711 120 62-67, 1800 62-69: 4.10, 4.30, 4.56 drum (no distinction by p/n)
435-50943 1800 70-73: 3.91, 4.30 disc brake (no distinction by p/n)

Also, for anyone reading this and wondering where the label is on their car's axle, here's some pics to help...hopefully.
The first two pics are of an early (1980) 240 axle. There is no acknowledgement of axle type without looking up the stock numbers. It is a 1030 axle...

And...a 3.91 ratio

This photo is of a later axle (1991). The label has changed and has a bit more easily interpreted info. It's a 1041 w/ a 3.73 ratio from a turbo 740 w/ an automatic...