1987 ford idi and turbo

OT...if I install a turbo on a idi but not turn pump up, will my MPG improve? By the way, these trucsk are starting to increase in value.

Don't count on MPG improving..

It will just run cleaner. The pump is set
for the amount of air the stock NA engine
can move. So unless it is smoking heavily
now (which means something is wrong) there
will be no mpg improvement. You won't be
able run much boost, less than 10 psi,
unless you install an intercooler.

Adding a turbo to a gas engine with no fuel increase raises the effective compression ratio and can increase MPGs. Not usually so with a
diesel. Not unless you are trying to compensate for thin air at a high altitude. That is why they used to be called "altitude
compensators."

What kind of MPGs are you getting now? I have owned and driven IDI Fords for years. My current driver is a 1994 with 4WD, 4.10 gears,
overdrive trans, and 7.3 IDI turbo that runs a max of 7 PSI. If driven empty at 65 MPH it gets 17 MPG on the relatively flat highways in
northern Michigan. When I lived in the mountains of New York, it averaged 15 MPG doing the same.

Ford used two different types of dealer-installed turbos. Banks and ATS. The Banks ran more boost. ATS became adopted for factory
installs and that is what my 1994 has. The 7.3 engine with a factory turbo is not the same engine as a non-turbo 7.3. It got slightly
beefed up in some areas by International Harvester at Ford's request.

General rule of thumb is this. If you have a lot of black soot in your tailpipe now, and often see black smoke - and adding 7-8 PSI of
boost gets rid of it, then yes - you should get slightly better MPGs without touching the injection pump.

Here is my 1994 with the IDI turbo 445 cubic inch diesel from IH. Has the factory installed ATS turbo with a wastegate and runs 7 PSI boost.

In 92 or 93, Ford authorized dealer-installed turbo kits from Banks that were not wastegated and ran as high as 10 PSI. I still see a few of
those early Banks running and those 7.3s did not blow up.

My 1994 has 325,000 miles and still runs like new. Starting to use a little oil though. 1 quart every 1000 miles.

Adding a turbocharger will increase the volumetric efficiency of an engine whether it is gas or diesel. The also increases the effective compression ratio regardless of fuel. More air in means more compression.

Yes, but some gas engines respond with slightly better MPGs when the effective compression ratio is increase, while some diesels do not. I do not need to work on theory anyway. I have had many GM 379 cubic inch diesels and Ford-IH 445s with turbo kits added and done actual road testing with them. I am just posting my personal experiences after having owned and used many of them with many sorts of added turbo systems. I will note that I did the work solely trying to get better fuel mileage and NOT for more power.

I finally discovered the easy answer was - to buy a truck with a 12 valve Cummins.

(quoted from post at 21:06:18 05/08/20) OT...if I install a turbo on a idi but not turn pump up, will my MPG improve? By the way, these truck are starting to increase in value.

Click to expand...

On my idi, every time I changed the air filter, I notice it was much quicker and responsive. It WAS very sensitive to air charge in its performance. So... yes, you will notice more power, cleaner burn and slightly better mpg's in most cases... If your a heavy on the pedal, you will probably lose any increase while accelerating faster, If your easy on the pedal, you will see the gain.


Also rear end gears come into play... If your running 4.11s you will see less gain.. If your running 3.77s you will see much more gain. 3.55gears would see the most but were used less often on the fords iirc.....

The 12 valve cummins got better mpg than the first 24 valves?...because the pump was also turned up?...would 24 valve breath better so would get better mpg if everything else equal?