would a turbo help with mpg

[slopdogg250]

I have a 04 F250 with a 5.4 would like to put a turbo is it worth it how much more power would it give it will it inprove the mpg about how much

[Freightrain]

Can't say you'll get much better mileage, and power wise is up to you how much boost you want to apply. Being all stock, I'd say about 6# max. Remember, adding boost requires added FUEL. So mileage isn't going to increase if you have your foot into it!

[frederic]

If you take an engine, add a turbo and the necessary fuel to maintain the increased air/fuel consumption (which is the norm) the answer is absolutely not - you will get worse mileage but you will in fact get more power.

Where turbocharging can give you better mileage, is to replace a larger, naturally aspirated engine with a notibly smaller engine, with a turbo. This way, you have the boost which brings the smaller engine's power level to the bigger engine, but when you're not hammering the throttle the smaller engine (with little to no boost) will give you better mileage.

Now, this is just the concept. If you build a larger engine for lower RPM use only, then boost it, you'll achieve almost the same effect as using a smaller engine, because fuel consumption (and air cfm requirements) is based on displacement AND RPM. So by cutting the RPMs in half, you've effectively cut the air/fuel requirements in half (more or less - it's not quite linear but I'm illustrating a point here).

But not everyone wants a gas engine with a 900-2800 usable RPM range. Those folks typically run towards a diesel engine. This by the way is why diesels very often get better mileage as compared to a gas engine - it's the significantly lower RPMs they turn in order to achieve maximum power/torque.

[thosfsull]

I found these referenced on mpgresearch, so I figured I would share. I don;t have the technical ability to claim a yes or a no, but any additional info can only help.

Mike Holler columns

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[85e150six4mtod]

More power yes, more gas yes.

A diesel will take all the air you can give it, and a turbo always is welcome. Gas needs approx. 14.7 : 1 air to fuel, so if you give it more air, more fuel has to follow.

The links posted above are interesting, but might as well be on another planet. The 2.2L Chrysler engines are factory turbo'd, he was just improving that, I think, as I couldn't really wade through the whole thing. The slant 6 "for power and economy" is farther out. Often touted as "...the best engine ever made..." by various people of sound but limited judgement, it is so woefully under performing in stock tune that pushing more air into it and keeping it below 3000 rpm (again, I couldn't really wade through much more...) would certainly improve it's pathetic stock performance.

Your 5.4 is in a pretty good state of tune. Improving will require serious work and money. A backyard turbo job is not the way to go.

Scroll down and see a frontyard turbo job...

5.4 Ford Lightning engine - GT40s.com


Ooops, looked at it again, even though they are talking 5.4 and supercharging on that site, the turbo motor is a 331, 302 based motor. My bad....

[frederic]

Backyard/junkyard/monkeygrade turbocharging is doable for almost any engine, but many who venture down this road seem to forget that you can't just slap a turbo on with some bolts and call it a day... there's a fair amount of fabrication involved, but more importantly, a lot of attention needs to be applied to the math involved.

Since one cannot run 45psi into a stock 10:1 c/r engine and expect it to run on 87 octane, some re-engineering is necessary.

[thosfsull]

The MpgMike that I showed you is really big into headwork by this foreign guy, who has bar none the worst webpage outside of geocities. It might be of interest, however, I would only experiment on my old stuff I have laying around first.
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