Fuel Savings??? - The Hull Truth

BadAttitude · 06-02-2004, 10:09 AM

Recently on a Paul Harvey broadcast, we were told that most all vehicles would experience a 9 mile per gallon fuel increase if the fuel/air mix were changed from the standard "rich" factory setting to more "lean". It was also suggested that this would also require a timing adjustment. The message was that the rich factory setting was required for a breakin peroid, but after 5000 miles or so, the settings could be changed for better fuel economy.

This seems to be an extreme claim, but it does make sense to a point. Any thoughts?

Carl

Fubar512 · 06-02-2004, 10:25 AM

First off, most modern vehicles are "tuned" to run on regular fuel. You can purchase a repogrammer or a chip that advances the timing and modifies the fuel delivery curve, but usually at the cost of having to run premium fuel. Also, most people are intoxicated by the added throttle response and put their foot deeper into the throttle, killing any possible improvements in fuel economy (if any).

The cheapest thing you can do to improve your vehicle's milage is to keep it in tune, make sure its tires are properly inflated, and that the front end is properly aligned, followed by driving intelligently.

TraderVic · 06-02-2004, 12:44 PM

Driving naked increases fuel economy by 150%.

Really.

Try it.

Garett · 06-02-2004, 01:06 PM

With most vehicles now-a-days the on board computer WILL NOT allow these settings to be change - they are computer controlled settings.

With my old 88 Nissan King Cab V6 4x4 I could change any setting out into left field and the computer would bring it back in. When I scaled up the factory tires 31 1/2" x 10 1/2" to 32 1/2" x 11 1/2" the truck was sick for a day (no joke) - until the computer could figure out how to right what was wrong. I even went to 35' x 12" tires for a very short period, and once again the truck was sick for a 24 hr. period. And when I ended up going back to the factory sized tires on the truck, you guessed it, the truck was sick for a day again. I did more tinkering to that drive train to improve the mpg but nothing helped - the computer controlled all.

Oh yah, the mpg never changed with anything and everything I tried. 24 mpg combined driving.
Chipping it is the only way to go IMO.

Garett · 06-02-2004, 01:18 PM

TraderVic,

No it doesn't.

To the contrary, it gives you sh!tty mileage. The reasons why I say this is because every time I've been naked while driving it always leads to pulling over and getting lucky

- all the while the engine is still running.

Hence crappy fuel mileage......but a heck of a good time.

baypro21 · 06-03-2004, 02:52 AM

My thought is - If this is true, why don't the car makers program this into the onboard computer.

BadAttitude · 06-03-2004, 12:12 PM

Are there sources for replacement computer chips? I checked with my vehicle's manufacturer (Subaru) who says that they can't legally change what's been approved by EPA, but they didn't respond to the possibility that anything would improve.

My mileage goes down when naked, mostly because of added wind resistance from something "erect"!

Carl

The Alaskan · 06-03-2004, 01:03 PM

TraderVic,
That only works for females

wellcraft20 · 06-11-2004, 05:00 AM

Go to any "performance shop" or "speed shop" and they can give you the info for a high performance chip. Almost all of the hot rod type of magazines will have ads for them too. I'd considered one for my Grand Cherokee 5.2 V8 but it's $250.00

Fubar512 · 06-11-2004, 08:19 AM

Wellcraft20, your GC 5.2 takes an entire SBEC/PCM, or Single Board Engine Controller/Powertrain Control Module, as opposed to a simple chip. And $250 is a screaming deal for that puppy.

You want to gain about 1 mpg more at highway speeds (with your 5.2)? Remove the engine driven clutch-fan, and replace it with an electric fan (I recommend a Black Magic 150). The clutch fan on that rig soaks up almost 5 hp at 2000 RPM.

ReelWork · 06-11-2004, 08:37 AM

Wow - 5 HP!!!!

Just kidding... 5 HP ain't squat..

That's only about 1.5% of the total power produced and isn't going to make that big of a difference once it hits the rear wheels for that 1% gain after driveline loss.. Add a chip and an exhaust with that fan, slap in a K&N. Now you're talking.. You could see as much as a 1-3 MPG real gain if you keep your foot out of it...

Want real power?

Add a supercharger...

Want economy, get a diesel...

I think Paul Harvey's comment are crap.. If you lean out an engine, you shorten piston life and can prematurely destroy an engine. Now, you can modify the compression and therefore reduce the fuel that way, but then you are going to possibly be running a higher octane and then what have you really gained?

Now, I do that factories could build a more efficient engine. When I am running a 5.4 (330 CI) that ONLY puts out 260+ HP, that is inneffecient. An efficient engine makes approximately 1 HP per Cubic Inch or better.. Like Honda, Nissan, BMW etc...

Fubar512 · 06-11-2004, 09:22 AM

Wellcraft20, that's 5 HP at the rear wheels. And that's all in by 2K rpm, which tranlates to about 65 mpg in your typical, 3:55 geared, 29 inch tall tired, 5.2 liter (318 cube) V8 powered Jeep Grand Cherokee.

That 1 mpg improvement at highway is nice for a free mod.

Also, the biggest improvement in performance on your 5.2 will come from: 1) 1.7:1 roller rockers, 15-20 HP for about $400. 2) A K&N FIPK, approx 10 HP for $220. 3) PCM, approx 8-10 HP and 30 (Yes, THIRTY) ft. lbs. of torque. 4) Ported, or billet throttle body, 5-7 HP for $200-400.

Now, if you really want crazy HP, go for an Mopar Performance M1 MPI manifold, about a 25 HP increase above 5000 RPM. You'll loose a bit of low end and mid-range torque (below 4K RPM), but from 4K on up....wow!

After you work on the intake tract, next up are a good cat-back (I suggest a Gibson 3" single), which will net you about 3-5 RPM, and then, headers (17 HP for full length tri-y system). Shorty style headers may gain you 5-7 HP, but the real bottle-neck is the crappy OEM Y-pipe that kinks down to 1-7/8, thanks to non-mandrel bent curves.

All the aforementioned HP figures are at the rear wheels.

My apologies for hi-jacking your post, BadAttitude.

Fubar512 · 06-11-2004, 10:44 AM

Quote:

Fubar512 - 6/11/2004 9:22 AM
"which tranlates to about 65 mpg in your typical, 3:55 geared, 29 inch tall tired, 5.2 liter (318 cube) V8 powered Jeep Grand Cherokee."

Oooops!

My bad. I meant (of course), 65 MPH, not 65 MPG.

Mako Slayer · 06-11-2004, 03:28 PM

Ride a bike!!!

GravyBoat · 06-11-2004, 03:37 PM

"An efficient engine makes approximately 1 HP per Cubic Inch or better."

More like 1 HP per Cubic Centimeter on my Honda/Acura

chalkguy · 06-11-2004, 05:18 PM

I changed out my mass airflow sensor and picked up 2 mpg

yachtjim · 06-11-2004, 06:05 PM

Quote:

BadAttitude - 6/3/2004 12:12 PM Are there sources for replacement computer chips? I checked with my vehicle's manufacturer (Subaru) who says that they can't legally change what's been approved by EPA, but they didn't respond to the possibility that anything would improve. My mileage goes down when naked, mostly because of added wind resistance from something "erect"! Carl

You drive with something erect????**

Whalehead · 06-11-2004, 07:55 PM

Gravy Boat, where can I get one of those Honda/Acuras with 1 hp per cc? I'd love to have a 2,000 horsepower Civic - yahoo!

Kamper · 06-18-2004, 09:37 PM

Once you get over about 45mph, *the drag caused by wind*really eats up your power output. Having your windows open disrupts the aerodynamics and*the wind*hitting against your interior is almost as bad as dragging a parachute.

The energy bled off by your a/c system is a lot less than that.

Or so I've been told...