Cube Van?
 

I own a 1989 Chevy G30 Cube van. The motor is a 5.7 350 TBI with 24,000 km's (original) on the dial.

I am averaging about 27 liters per 100 km or 11MPG

What would be some of the "best" modifications to make to a vehicle such as this? I am very mechanically inclined and would like to know everything that may save fuel right down to spark plug gapping.....

The truck has a 14' box and tire pressure is at 58PSI on all six tires. Curb weight is about 3600KG's

Is there anyone else on here with cube vans and if so, what are you averaging per 100/km or MPG's?

There are no current modifications to this truck, everything is bone stock. No air dams etc.

Welcome, midnight rumbler.

There appear to be 3 other threads here that specifically address cube/conversion vans.

http://ecomodder.com/forum/showthrea...ents-5895.html
http://ecomodder.com/forum/showthrea...here-1291.html
http://ecomodder.com/forum/showthrea...-van-4006.html

Answers to the following questions might help in tailoring answers to your specific situation.

Automatic or Manual transmission? And how many forward speeds?
Does it have a block heater?
Where and how is it being driven? eg.

1. 60% city in 4-15 km one-way trips?
2. 90% highway 10-50 km one-way trips?
3. 80% highway 100 km loop with 12 stops?
4. 8,000 km per year?
5. ????????

Adjusting driving habits requires no capitol outlay and nets the quickest results.
So be sure to read 100+ hypermiling / ecodriving tips to increase gas mileage - EcoModder.com

Automatic or Manual transmission? Auto
how many forward speeds? 3Spd
Does it have a block heater? No
Where and how is it being driven? 100% business, Ontario, Canada (Toronto)

The truck is a 50-50 when it comes to highway and city

Assuming you'll be able to plug it into an AC outlet at least 50% of the time, a circulating tank heater ($40-$60) is probably in order. Based on your original post - "24,000 km's (original) on the dial." - you're only putting 1-3 thousand km's per year on it??? If that's the case, it may take a year or so to reach payback. Less time if you can plug it in near 100% of the time. Also less time if most all of your trips are very short.

Is your load consistent in size? weight? What's the maximum weight you carry? If you're hauling volume (not weight), a used differential with a better gear ratio might possibly be a consideration.

Does it have a tach? A vacuum gage?

I should have specified that I purchased the truck 4 months ago with 19,000 original km's and I have since put on 5,000.

What is the benefit of the circulating tank heater? My truck starts great in cold weather. Is this to have the rad fluid at normal operating temperature to prevent the truck from idling high to bring the vehicle up to normal operating temperature? Seems to me that there is a give or take on this, am I actually saving by plugging the truck in, here I will have electrical expenses versus leaving the truck running for 3 minutes, is there truly a savings to be had?

My loads are usually consistent in size as I am a contractor and carry all my materials and supplies give or take a few hundred pounds. Maximum weight would probobly be 4200kg's

No tach or vacuum gauge but they will be installed after reading this forum and the benefits they can have....Princess auto, here I come

One thing I found out on my Astro is that the gearing makes a lot less difference on a van than it does on a lot of other cars. I get better mileage at 70 than I do at 45mph. Also driving in 3rd gear drops me at most 1mpg but typically is just like 0.3mpg worse than 4th gear, so changing to a 4 speed or rear end gears might make the engine last longer if you don't haul heavy loads, but probably won't change the mileage enough to even be able to measure it.

A few things I have found so far that help is to get rid of the belt driven fan and set the ignition timing at the proper setting, advancing it won't really help anything but if it is retarded any at all it kills your mileage. I am next going to try a tbi spacer and advance the cam timing to increase bottom end power for towing and hopefully pick up some mileage. While I have the tbi off I will probably do the 'ultimate tbi mods' to it so it improves throttle response.

The biggest gains on a van seems to be aero modifications. The underside of a van is terrible so adding some panels to smooth the airflow will be worthwhile and otherwise be invisible. Doing something to improve the wake coming off the rear would be a huge gain in mileage but I am really not sure how to go about that without making the back doors useless.

I am just starting the experimenting with my Astro so there is a lot I haven't figured out yet. The best thing to do first is build a MPGuino and start actually getting some data about your mileage so you can tell what is working.

Ok, so only about 15,000 km / 9,000 miles per year. Given the miles per year and load, there is likely not much point to considering gearing changes.

Toronto is warmer than I'd have guessed. Even so, I find it difficult to believe the engine reaches full operating temperature (82*-88* C) in just three minutes of idling? But if 3 minutes is really the case, maybe not. FE is decidedly worse until engine reaches full operating temperature!

On the other hand, cold starts are dramatically hard on cylinder walls & piston rings (fuel condenses on the cold cylinder walls and washes away oil film - especially true for carbureted engines - don't know about TBI) and other engine parts. If you decide not to do a tank heater at this time, be sure to monitor next summers FE and compare it to the drop you'll see next winter and you may change your mind.

I have a G30 and when its running I get 15-20 mpg. Of course its diesel and not a box van (its a 15-passenger van). Some of the things that do or would help my mileage are:

• Panel the bottom - there are HUGE open areas under there and the underside is an aerodynamic nightmare. The van sits way high, so this will be very good for G30 mileage. Smoothing the underside is better than an air dam.
• P&G as much as you can. My van coasts twice as far as my Volvo and no one gets as mad at you in a van.
• Switch to smooth highway tires if possible. My mileage dropped 3-4 mpg when I switched to M&S tires.
• Inflate those tires to max sidewall pressure
• Some sort of aero mod to transition between the cab body and the box would be a big help I think. Not applicable to me.
• Replace the belt driven fan with electrics. No diesel G30 can do this but gassers can. That huge belt driven fan steals 15 to 20 HP.