[Rivi]

Originally Posted by SpoiledRotten

I'm glad I've got a Ford F-250 7.3 PSD. That thing gets great fuel mileage. My Jeep is just for fun anyway for me. I knew before I got it that they weren't built for gas mileage.

BTW, I have always heard that if you have to worry about the gas/fuel mileage, you don't need the vehicle.

insanity screw the environment and let big oil rape me because i don't believe a jeep should get 20 mpg....i think you are all mad!

[Rivi]

by the way setup properly there is NO decrease in performance.I can see none of you understand a thing i'm trying to share.

[halfmoonclip]

Originally Posted by Red Dragon

By heating up the air you are reducing its density. So lets say normally your ECU sees a mass of 147g of air coming in, so it injects 10g of fuel (14.7:1), but now that you have heated the air, whats coming in has a mass of 73.g so the eco only injects 5g of fuel. Thats where your mileage bump comes from. The catch is that a straight warm air setup trades a few more MPG for power.

BUT you can achieve the same performance (acceleration or cruise) with a smaller throttle opening with the colder intake charge, which in turn will call for less fuel.
We are assuming here that you are trying for mileage, not just running WFO. The woodblock under the skinny pedal would achieve the same thing; limiting performance to limit fuel usage.

Guys, I gotta tell you, if DC could pick up 15% better mileage with preheat, they'd be all over it like a cheap suit. This is essentially the same argument as getting more horsepower out of the I-6; DC has already cherry-picked the easy stuff. While gas mileage hasn't been a major consideration, it is still a selling point. Twenty two mpg on the EPA cycle would look good.
Now if DC really wanted to help us out, they'd put a taller overdrive in the transmission. I don't understand the shorter overall gearing of the new six-speed, at least from a mileage standpoint.
I recant my blasphemy about changing the barn shape; please forgive me, everyone. Mea culpa, mea culpa.
And Rivi, heat away. If you're happy, I'm happy.
Moon

[Red_]

True, my reasoning was assuming one used the same amount of throttle

The six speed might have just been something "taken off the shelf" that would fit

[halfmoonclip]

Originally Posted by Red Dragon

True, my reasoning was assuming one used the same amount of throttle

The six speed might have just been something "taken off the shelf" that would fit

Yep on both. While I was snowblowing the driveway, I noticed my 25 year old blower has an airbox over both the muffler and the carb intake, warming the air charge. My chainsaw works the same way. Both have an antediluvian contraption called a 'carburetor' , which isn't smart enough to adjust to too great a range in air temps. Modern fuel injection systems with their bazillion sensors do a great job adjusting to changing conditions of ambient air temps and engine load. Save gas? Don't step on the pedal so hard. By limiting available air density, Rivi is doing the same thing.
I'm guessing you are particularly right about the transmission. Now that mileage is a big deal again, it will be interesting to see if DC changes the tranny or the final drive in the JK or the Libby.
Moon

[Rivi]

Originally Posted by halfmoonclip

Yep on both. While I was snowblowing the driveway, I noticed my 25 year old blower has an airbox over both the muffler and the carb intake, warming the air charge. My chainsaw works the same way. Both have an antediluvian contraption called a 'carburetor' , which isn't smart enough to adjust to too great a range in air temps. Modern fuel injection systems with their bazillion sensors do a great job adjusting to changing conditions of ambient air temps and engine load. Save gas? Don't step on the pedal so hard. By limiting available air density, Rivi is doing the same thing.
I'm guessing you are particularly right about the transmission. Now that mileage is a big deal again, it will be interesting to see if DC changes the tranny or the final drive in the JK or the Libby.
Moon

i'm not limiting anything!you guyz still don't get it.I'm getting a bit frustrated discussing this.I'm using wasted heat and putting it to use.The engine has MORE power and better throttle response and better fuel mileage.The mod i showed on my jeep is NOT what i would do for year round use.The proper way to do this is to use the vacuum controled system from any gm car or truck.It will then preheat the intake air up properly and at lower manifold vacuum GIVE FULL COLD AIR.This setup gives you everything you had ++++++ the exhaust energy you were tossing away.This wasted exhaust energy is then used to heat the intake air at idle and part throttle.This makes the engine more efficient by adding WASTED ENERGY back into the system.


I HONESTLY DON"T KNOW WHY YOU CAN"T GRASP THIS IDEA. seeya in a different thread.

[spyderbyte]

Originally Posted by Rivi

The engine has MORE power and better throttle response and better fuel mileage.

I'm sure you'd get a lot more response to your idea if you actually dyno tested your Jeep. Post some concrete numbers, not just butt dyno, and we'll all take you a lot more seriously. At the moment, your claims are violating a few different laws of physics:

You've established that the mpg gains come from the engine requiring less fuel to reach the stoichiometric ratio when the air is less dense. Makes sense. However, you go on to claim this smaller mass of air and fuel makes a more powerful explosion? Doesn't add up.

Second, according to carnot and the second law of thermodynamics, an engine will become less efficient the closer the air intake and exhaust temperatures become. The theoretically perfect engine can still only achieve a carnot efficiency of 1-(Intake temperature)/(Exhaust temperature). Therefore increasing the starting temperature of the air will actually decrease the efficiency of the engine. A less efficient engine burning less fuel is still going to produce more power?

I'm sure there are other laws I'm not thinking of right now, but go ahead and post some dyno numbers to make me a believer.

Funny how you need to find a junkyard GM car to get the supplies. If they had it figured out back in the seventies, why would they stop? Did the oil companies get to them too, or did the 1973 oil crisis end and it stopped being worth it to trade power for gas milage? You're making a trade off, you're just too excited by your new mileage to admit it to yourself.

Spyderbyte

[XabuJr]

Originally Posted by Rivi

I HONESTLY DON"T KNOW WHY YOU CAN"T GRASP THIS IDEA.

Because there is a difference in OPINION since there is nothing that shows any FACT other than GM used something back in the day (How come they still don't use it if it works so well??). Show facts or your opinion gets put in the same place as all those Tornado ebay auctions..

[The Mean Fish]

Rivi, better watch out... the government and big oil will be watching you from here on out after putting that kind of info out to the general public.









Old paranoid people are funny.

[halfmoonclip]

Attempting to capture waste engine heat is not a bad idea in itself, and there is a very effective way to do it. It's called a turbocharger.
I seem to remember an article about a WWII British bomber engine that actually used power from the turbo shaft as well as the crankshaft to deliver power to the prop.
External combustion engines do this is well; on steam engines there were feedwater heaters that used waste heat from the stack.
Before someone says , Jeep technology reaches back to steam days, at least in some respects.
Moon

[MichMarine78]

Seafoam...you can buy it any parts store. Great for not only fuel, but also crankcase, and cleaning carbon out. I actually noticed an additonal improvement in mpg (only 2-3), and a slight increase in power.

[SuperBTZ]

I just do my best not to worry about my mileage. I knew before I bought my jeep that I would be getting low numbers in the mpg category. I get anywhere from 8-15mpg, just really depends.
To me its worth the extra $300 or so per year in gas to not drive like a granny.

[hoseclamp]

Run an AT or AS tire, ditch the MTR's. You'll gain milage with the smoother tread, less rolling resistance. Run 30-35psi, will be a bit stiff but will increase milage and power.

I read a writeup in a 4WD mag years back, they took a 460CID ford, ran a system like the FIPK, gained the most power but lost milage, excess heat under the hood effecting intake air temps.

Best combo they found for milage increase, they used a drop-in K&N, wrapped the whole intake up in heat reflectant tape, from the snorkle on the air box, right to the throttle body. They did gain slight power, not as much as the FIPK, but gained milage, enouogh so there was a projected payback within a reasonable time frame.

Keep added weight to a minimum, run a smoother tire with 30-35psi, don't let it idle for extended periods, draft behind big trucks (if you like living in dangerous blind spots, LOL), a drop in K&N or equivalent high flow filter with "cool wrap" tape, not much else to do. I'll also add, be light on the skinny pedal, heheh!

[XabuJr]

Originally Posted by hoseclamp

I read a writeup in a 4WD mag years back, they took a 460CID ford, ran a system like the FIPK, gained the most power but lost milage, excess heat under the hood effecting intake air temps.

What works with V8's will not work with your Jeep.

If you really want better MPG, the best mod you can do is this one:

[hoseclamp]

Originally Posted by XabuJr

What works with V8's will not work with your Jeep.

Says Who? Since when has there been a standardized format of what works with one motor cannot apply to a Jeep, or any other motor for that matter? Will they all respond the same, of course not, but does that mean there are no gains to be had? Until it's done, how can we call the results without it being tried and tested?