Engine Mods Question

[4more]

Originally Posted by MadisonMPG

That's one of those vehicles, that you might as well not worry about mileage.

true will never get 40+ like a geo but alittle better mileage, a little less oil dependancy, alittle less pollution and still get to play the fun game of trying. oly time in 2 years i have kept track of FE i got over 14 pulling a car trailer w/ ac on at highway speeds. im guessing with better driving i will be knocking 20 which is over epa id be happy with that

[davyboy]

I do realise that it is one of those vehicles that you can never have amazing mileage with, however I do wish to attempt to get enough mileage to make it decent to drive. Perhaps somewhere about 15mpg city and 19 or 20mpg highway would be amazing...

And I currently get little over 12mpg city and little over 15mpg highway...

[nemesis]

i've recently switch from going fast to getting better Fe and all those mods that you listed is what I am used to, but some of them might not work. The thing that I don't get is all this pumping losses stuff, for some reason I don't think the car will get better gas mileage with 50% of throttle open than 25%. If it did than you'd want to port the heads, intake, bigger duration/lift cam, big exhaust to put on the car to kill bottom end torque and raise the hp, that would require you to push the pedal to the metal just to barely move at lower rpms and would be the least of pumping losses. The thing is, I've done all those mods before and guess what, I got worse gas mileage. So in my theory I am moving the other direction, put smaller than stock exhaust, long tube headers with small primary tubes, put longer runner intake manifold or even a spacer, cai or hai ( not sure about this one yet, but I'll find out in a week or 2), smaller tb, under drive crank pulley, higher gears, higher comp ( not sure about this one yet either), and all the aero mods should give you better gas mileage. Your high end power will suffer, but your bottom end torque will increase. That's my theory and I'll continue to work on it and get good or bad results.

[MadisonMPG]

Hey if you think you can do it, and still be able to go 60 on the highway more power to you. But I wouldn't waste my time. I bought my Geo for that reason, I have a truck that i'm lucky to get 18mpg out of.

[Frank Lee]

With my engineering background, I'd recommend all your contemplated mods and in addition, add a Tornado and HHO, but be sure to put the HHO outlet in front of the Tornado or it won't work. Also, you will only get piddle around results if you only piddle around, so forget the glasspack and go straight pipe. Straight dual pipes, exiting ahead of the rear wheels to avoid that restrictive over-the-axle hump. Pull that restrictive catalytic converter outta there while you're at it. Then put some Monster Mudders on it; these will do several things: they'll give a much desired gearing up, and they will get the body and chassis up and out of the dense layer of air that exists in close proximity to the ground. A lift kit will only improve it further.

Other must-have aero tweaks are fender flares (to guide air away from the wheelwells), air tabs (to promote the turbulent wake zone), and air deflectors for the hood and front doors.

Acetone must also be used but be careful, too much or too little will fail to give the promised results. I'd suggest using acetone only for every other tank, and alternate the acetone treatments with a fuel line magnet. DO NOT USE THEM BOTH AT THE SAME TIME!!!

On that note, once you achieve good cold air intake temps, you will then need the hottest fuel temps possible for better vaporization and atomization. Google the net; there are many fine plans for copper tube fuel line heat exchangers that the handy and clever can fab up at home for nominal cost.

I should add that those mods might move the BSFC curve upwards and the best economy is found in the meat of the BS FC band, so you may have to go 80 mph instead of 65-70 for best economy.

Good luck!

[RobertSmalls]

That's very helpful, Frank.

You could easily double your fuel economy by trading it in on something like a Subaru Outback or some other tall 4x4 wagon.

You could then double your fuel economy again by trading that in on a featherweight Honda with snow tires, but with some loss in wintertime performance. Performance you might not need.

However, if you insist on daily-driving a behemoth, you can improve your MPG from "abominable" to merely "awful".

Start with instrumentation, like the MPGuino. It'll give you immediate feedback on what you're doing wrong and right.

Then I'd work on the cooling system. Switch out the inefficient clutch-driven fan for electric, then block the grille as much as you can without the fan coming on. Definately get an engine block heater. It takes a huge amount of gas to warm up your absurdly large engine. Combine that with a hot air intake, and your ECU will think it's summer, which will improve your fuel economy.

If you want to take it to the obsessive level, consider this: I intend to improve the fuel economy of my Honda Insight by removing weight. When I find an opportunity to remove 1lb, I'm thrilled, and I take it. I've removed decorative panels that aren't often seen, and the glove box, whose door is heavy with sound-deadening material. I keep my washer fluid tank half full, thus saving 3lbs. Imagine what I could do to the interior of a full-size SUV. Gut it. You don't need more than one speaker, or any carpet rear of the front row of seats, etc. You may also find that your wing mirrors can be relocated to the interior of the car.

Originally Posted by MadisonMPG

That's one of those vehicles, that you might as well not worry about mileage.

I disagree. When I drive a (rented or borrowed) truck, I'm *very* worried about mileage.

[2000mc]

i know some might say that CAI is better for mileage, i'm in the HAI camp though... however as it applies to you, i think the stock air intake setup is already something of a cold air setup. actually, the aftermarket setups i think are actually more prone to drawing under hood air. i believe your intake is attached to the fender where it draws air from. the aftermarket air intakes do have a more direct path for the air near the TB, but i think thats the only benefit.

the replacement intake manifolds that are a direct fit i believe are made for a higher rpm than stock which i think would hurt economy. other manifolds are going to require an adapter for the TBI unit, which could interfere with how they were designed to work.

spacers with 2 individual holes i've heard help low end power and increase velocity, also supposedly hurts topend, not that it matters if youre worried about mileage, and these engines have flat top end power at best.... but i've heard little about mileage, seems like a good idea though

its hard to imagine good headers couldnt help, but its probably a matter of how fast it can pay for itself. same with using mandrel bends if you dont have a system with them already....glasspacks/mufflers.. i dont know, it seems i hear alot that engines dont need backpresure... but from personal experience it seems that quieter systems seem to have more low end power and louder have more topend.

something else to consider would be a chip, i know many claim mileage increases. that i never checked out first hand, however i would say that chips offer the best performance gains per dollar of any mod on alot of vehicles... so i'd give them some faith in working their magic.

another spot i think you could see definitely see gains is by replacing the mechanical fan with electric

as with anything, watch your return on investment. i have a truck with the same engine, but i havent sank any money into these mods myself because i dont drive it enough.

you might never see 20mpg, but don't get discouraged. gains look like they come slow when you have a baseline of 12mpg. watch the tenths of mpg, think as a percentage increase. if you could start with a smaller vehicle it would be better, but if you have to drive a larger one ecomods and hypermiling are alot more important to do. look at gallons per 100miles. if you go from 12 to 15mpg that's 8.3 to 6.6 gallons per 100 miles for someone already getting 40mpg to save that much fuel they'd have to increase to 125mpg

[JasonG]

Durn Frank, there goes another keyboard shorted out by coffee !

[davyboy]

Originally Posted by 2000mc

i know some might say that CAI is better for mileage, i'm in the HAI camp though... however as it applies to you, i think the stock air intake setup is already something of a cold air setup. actually, the aftermarket setups i think are actually more prone to drawing under hood air. i believe your intake is attached to the fender where it draws air from. the aftermarket air intakes do have a more direct path for the air near the TB, but i think thats the only benefit.

Its been cold as h*** here lately but I've taken a look at the intake and yes it is similar to a cold air setup, this leads me to think that something of an air charger might be best, it reduces/eliminates the restriction of sucking up air trough a path, and would probably take in slightly warmer air being as it sits open in the engine bay. However with this idea I've also noticed that my engine has a (i guess i'll call it a hole but it comes out to a hole) hole on the top of the one side of the exhaust manifold which has a metal hose attaching it to the bottom of the stock air intake. This leads be to believe it is somewhat of a WAI, what would I be required to do to that if i put an air charger on the vehicle.

It also seems like a lot of people are recommending changing the belt driven parts such as the cooling fan and the water pump, with with electric ones. I was wondering if anyone had done this and would have recommendations for installation, as these all seem to have 100% support. I was also wondering if a more efficient or more powerful alternator would be a good idea if I'm changing more parts to be electric?

[chuckm]

davyboy,
Have you read through the 65+ efficiency mods yet? If not, read them. A lot of work has gone into them. They are proven.
(FYI, Frank's post above is an example of his sarcastic humor. HHO is junk science. The Tornado is a snake oil product. Lift kits and other means of increasing your vehicle height increase your effective drag area. Acetone has anecdotal evidence for it, but little hard science.)
Let me repeat my first recommendation: Go visit the 65+ efficiency mods. Afterwards, restart this discussion.