I have an idea to increase my fuel economy...

[DJones]

This idea is so crazy, it may actually work.

The sad part is that I drive a lot less highway miles than I had been - not in college anymore .

I want to remove the engine belt and all of the load associated with it. Should improve performance and fuel economy.

That will leave my without air conditioning and power steering which isn't a problem... but I got to be sure I keep the engine running at the optimal temperature.

Water Pump:
The most challenging part of the process. If I don't do something right, a horrible meltdown could occur.
Here's what I'm thinking:
1. The factory water pump is always moving water, both through the block and heater core.
2. The engine block has two outlets, one for the heater core and one for the radiator; and two inlets, one for the heater core and one for the radiator.
3. The LWB models have a secondary water pump for the rear heater core. I can find the electrical connector, but can't find the pump. Any part numbers or am I imagining things?
4. Remove impeller from factory pump, use LWB pump for block and heater core circulation, on 100% as long as the engine is running.
5. Install a electric water pump in lower radiator hose, possibly with a fancy controller. Another temperature probe? Where?
6. Keep e-fan temperature probe at the outlet of the radiator, possibly moved to the hose.

To be sure I have bases covered, what direction does the coolant flow through the heater core?

Power steering:
I've been trying to find a hydraulic valve so that I can bypass it or use it as needed but haven't had much luck. I have no idea what to look for in this department.

Alternator:
I'll bring extra batteries, a charger, and the belt with me.

Air Conditioning:
No plans for electric. If I want A/C, I'll put the belt on.

Overall, all pulleys will remain so that I can use A/C, power steering, or alternator when needed.

Thoughts? Opinions? Comments? Anything I'm missing?

 

[The_Roadie]

The LWB coolant assist pump is undersized for all real-world applications. And any electric power you consume from the battery has to be replaced SOMEHOW. And that all costs energy.

Realistically - you'll never get more than 1 MPG better economy out of this path. You'd be better off yanking all the unused seats out and the spare tire. And the interior body panels, and the bumper covers and all the useless crap like radios.

And you might get another 1 MPG and be hating life.

Easier to get a 5 hour a week second job and just pay for the fuel and be glad you're not in Europe where it costs $10/gallon equivalent. Count your blessings and do a bit more Googling for hypermileage.

 

[limequat]

A/C off is the same as no A/C. That's what the clutch is for.

Alternator/Water pump - net energy would be about the same.

The only promising thing would be the power steering. Used to work on electric power steering. We claimed you could save about 1 mpg.
You could try to adapt one out of a Camaro or Explorer. Would be a cool project, but you'd never make your money back.
I've had the best results by cranking my tire pressure to 40 psi and leaning out the fuel mixture. The next time you buy tires, get the smallest size you're comfortable with. Lowering and airdams will provide real results too.

 

[BlazingTrails]

I'll be honest i really thought the OP was a joke and was chuckling to myself while reading thru it. If it wasn't a joke i apologize but that's just what it seems to me.

Just get a good tune and you can get better mileage than deactivating all of your accessories.

 

[smt 59]

Owning a vehicle like this, worrying about gas mileage should not be an issue as the weight and size should have been an indicator that it would use a lot of fuel. Maybe you should be looking at something smaller that is more of an economy car, but you will not be happy!

 

[DJones]

It was more of an "I wonder what would happen if I did this" type thing than anything.

If my engine ever completely fails, I'll consider an all-electric conversion.

I got my tune in what seems like forever ago. I'm considering getting a new one.

I'll go work on anti-gravity.

 

[smt 59]

Okay

 

[BlazingTrails]

Anti gravity would be awesome, maybe some kind of thrust pressure fed from solar panels. also if you could just refine the teleportation process fuel wouldn't even matter at all.

food for thought

 

[gmcman]

I have pondered this and I think if you want to take a stab at increasing efficiency.....I would suggest reducing drag by lowering the vehicle, or adding some type of stiff, flexible, material and make a side skirt or valence along the sides. I would also try to add panels under the vehicle but keeping some airflow over the transfer case, trans, and rear axle.

The bottom panels would be tricky since you don't want them leaving the vehicle at highway speeds...perhaps some type of stiff canvas wrapped over the frame.

Another area I think really pulls some drag is the rear bumber cover, it's basically a large small parachute. Taking some expansion foam and making a mold of the cavity in the rear them covering with a material making a wedge from around the top of the spare tire to the bottom of the bumper cover would make a smoother path for the air...and likely not even visible.

Another area is the wheel well openings, this is a proven area to collect air and filling them or make something to close the gap from the top to the tire while allowing suspension travel is another tricky area.

All that with making a smooth front fascia and low front valence I would think may bring up the MPG's especially at highway speeds.

Drag from air under the vehicle is a major player in aerodynamics.

 

[IllogicTC]

Ah yes, air dams! An under-appreciated concept. That's why you can find semi trailers these days with those diagonal skirts on the sides.

 

[snowbear]

Try to get a job that will allow you to telecommute one or two days a week and leave the truck parked on those days.

 

[AtlWrk]

Sure, the gains of eliminating the accessory belt will never offset the upfront costs and engineering effort but it's a fun thought experiment.

Eliminating the alternator is a non-starter. It may not be intuitive but the amount of current it takes just to run the various crucial vehicle subsystems is substantial. Batteries are not at all cheap and a standard lead acid car battery is not designed to be deep cycled heavily and often. Haven't tried it in my trailblazer but my little S-10 pickup lasted about 4 minutes on battery only when the alternator gave out.

As has been stated: the A/C is clutched so it's out of the loop when it's not being used anyway--no gains to be had. I do understand it would just be a causality of losing the belt altogether.

Power steering: have you tried driving an SUV without it? --especially now that you're not doing mostly highway driving. I did investigate retrofitting in an electro-hydraulic pump like a handful of vehicles use. This would allow tailoring the pump effort (and energy used) based on vehicle speed and steering demand. Unfortunately EH pumps were never widely adopted so they're rare and somewhat expensive ($300-$600 and up). Not to mention the special-fab hydraulic lines it would take to connect everything.

The water pump is a bit of a mystery to me because I don't have a great idea of how much power it uses and how efficiently it does so. Water flow is directly related to pump speed (engine speed). Cooling needs will be based on the power the engine is generating which isn't necessarily related to RPM. At higher engine speeds with lower power (cruising) the pump is likely working more than it needs to. Gains to be had? TBD

See? Fun.

 

[The_Roadie]

 

[HARDTRAILZ]

I thought you had converted to LP or some shit and got 30 mpg already?

 

[bspurloc]

Everyone knows the ONLY way to gain speed and better mpg is to add more spoilers...

and as for that rear skirt... I never thought of that, but that is most likely why my daughters envoys back lights always have water in them... the highway speeds of pressure just forces it in no matter how hard I try to seal them! so the suggestion to block them off in the back would most likely gitter done...

 

[DJones]

I was working on alternative fuels a long time ago, but gave up after the overall unavailability of parts and fuel. There is a LPG station about 20 miles away that had it for $1.59.

 

[Shojoro]

I would think you'd gain more from a supercharger and bigger gears. Stay at lower rpm longer, but have the juice to move. That's if these things need more torque. That beats me.

 

[bspurloc]

I would think you'd gain more from a supercharger and bigger gears. Stay at lower rpm longer, but have the juice to move. That's if these things need more torque. That beats me.

doesnt super charging generally mean installing larger capacity fuel injectors?
How about Turbos? the more horsepower the less effort to move, less gas wasted?

 

[bspurloc]

If you really wanted to get rid of the AC, it just takes installing a bypass aka shorter belt. I did that on my daughters car when the AC Bearing went bad, until a replacement bearing arrived.

Roadies answer is best though... remove all the excess weight, back seats, spare tire, rear bumper skirt drag etc

 

[IllogicTC]

It should be noted that the alternator already has a "power-save" mode, the controller automatically attempts to make output match the current load.

This is also why in cold weather, you'll have low voltage for a while if you have a decently-used battery, and after five-ten seconds running she suddenly perks right up. This allows the engine to stabilize better in the cold weather, with less wear while oil is beginning circulation.

 

[Playsinsnow]

Try driving as much as possible under 2k rpms. Going is slow but the mpgs are consistently higher than stock at 139k. Tire psi and tread type help too, (Ltx m/s). Coasting will also help- in drive of course-between redlights and in traffic.

That's been the best way to maximize my fuel economy. K&N filter too

 

[lint]

Works better than all the above. golf ball dents http://www.discovery.com/tv-shows/mythbusters/videos/dimpled-car-minimyth.htm The cheapest way ,all you need is a torch and a ballpein hammer, heat and pound But it does work great. you have too watch the video

 

[bspurloc]

Works better than all the above. golf ball dents http://www.discovery.com/tv-shows/mythbusters/videos/dimpled-car-minimyth.htm The cheapest way ,all you need is a torch and a ballpein hammer, heat and pound But it does work great. you have too watch the video

wow 11% increase in gas mileage... that is quite a lot!

 

[Shojoro]

Works better than all the above. golf ball dents http://www.discovery.com/tv-shows/mythbusters/videos/dimpled-car-minimyth.htm The cheapest way ,all you need is a torch and a ballpein hammer, heat and pound But it does work great. you have too watch the video

Haha that's awesome. They should have wind tunnelled it so we can see what's going on.

 

[DJones]

Dimples are a genius solution... I could at least start on the roof.

 

[IllogicTC]

Shifting to 3rd or 2nd and letting off the gas for a few seconds will enable fuel cut-off if the engine speed is above a certain level (1700 RPM?) very handy for going down a hill, also takes some strain off the brakes.

 

[Playsinsnow]

Shifting to 3rd or 2nd and letting off the gas for a few seconds will enable fuel cut-off if the engine speed is above a certain level (1700 RPM?) very handy for going down a hill, also takes some strain off the brakes.

I notice mine around 1700rpms ( jimmyjam posted/quoted the exact tables before) Over 70mph down a hill skyrockets the DIC reading in Drive!

 

[IllogicTC]

What's really interesting is sometimes the average economy counter won't update until another input is had - either from a tap to the gas or the brake. Sometimes it may update. I go down a very, very long hill five days a week. Then it'll fire up a few points outta nowhere.

 

[cynicalmj]

just folding the mirrors in, or removing them will get you close to 1 mpg...

 

[Mounce]

I find that nearly impossible to believe. No offense.

 

[The_Roadie]

Please cite urls with the research, or show your own math. Thanks from the GMTN Subcommittee on Scientific Verification.

 

[AtlWrk]

Let's not dismiss the mirrors so quickly:

Assuming:
V = 55mph (81ft/s) cruise
Cd = .42 (hemisphere shape) for mirror
Frontal Area = (6inx10in)x(2 mirrors) = 120 in^2 (.83 ft^2) (guess-timating here)
Air Density = .0023769 slug/ft^3

Drag Force = 1/2 x (.0023769) x (81x81) x (.42) x (.83) = 2.71 lbf
Power = F x v = 2.71 x 81 = 220 ft-lbf/s = .40hp

Granted folding them in isn't the same as them not being there at all. And converting horsepower to MPG is far more convoluted. AND of course this is back-of-the-envelope level of accuracy but the point remains...

Give or take, you're in the neighborhood of 1/3 to half a horsepower JUST to carry your mirrors along on the highway

 

[HARDTRAILZ]

I use my mirrors so not safe option....

 

[IllogicTC]

I require one center-mount mirror and one side-mount mirror on the driver's side, minimum, to meet federal law, so not legal option...

 

[808_LS_EXT]

This idea is so crazy, it may actually work.

.......

I want to remove the engine belt and all of the load associated with it. Should improve performance and fuel economy.

........

Thoughts? Opinions? Comments? Anything I'm missing?

I like the way you think and I believe it could be accomplished (to a certain degree).
More to fuel your desire:

Water Pump:

I used this Electric Water Pump on a street-rod project. The intent wasn't to improve MPGs, but to increase coolant flow while idling through traffic, which it did.

There are no aftermarket electric pumps specifically available for the 4.2L I6, so you'd have to utilize a Remote Electric Water Pump. I'm not sure what the 4.2L demands, but if the 20gpm is not enough, up to 42gpm is available.

Power Steering Pump:

The only option to belt driven power steering I would consider is the Toyota MR-2 style Electric Pump.

Air Conditioning:

As suggested above, leave it switched off... because when the clutch is disengaged, there is no load on the belt.
However, ALL of the HVAC components combined have some weight to it, so there might be mpg benefit in removing the entire system.

Alternator:

I've actually thought about this before. There are several ways to go about it.
First, you need to calculate your watt-hour usage used on a roundtrip from home.
Your usage will be much more with the electric fans and water / power steering pumps, so make sure you include those in the calculations.
You could either build a (very heavy) battery pack, large enough to sustain those watt hours while away from home, and recharge at home...
and/or mount PV Panels or Wind Turbine on the roof to replenish some of those watt-hours while on the road...
and/or remove the grille and mount the electric cooling fans outside of the condenser, so when you're traveling at high speed, the fans will actually charge the batteries instead of discharge...
and/or convert a A/C Compressor type Clutch to the Alternator, switching on when the battery voltage gets low.
and/or a Clutched Alternator belt driven from the driveshaft, programmed to switch on whenever you press the brakes, which will charge the battery on de-accels and help slow the vehicle down.

That all sounds like fun, and I would probably do some of it just for sh!ts and giggles...
BUT, I don't see much practicality in doing all of it to improve mpgs.
To solely increase mpgs while driving a comparably comfortable vehicle, I'll continue on my quest to find a nice V8 Tahoe.
I drove one for a few weeks that easily maintained 20mpg city/hwy...

AND it had functional A/C & Power Steering