26.2 mpg Toyota Previa. Go Golden Egg!
 

Just got a record mpg run to Seattle and back with some city driving as well. Was doing average 70mph on the highway as well.

Mods so far:

1) No alternator, running on 2 deep cycle batteries.
2) Electric cooling fan
3) All accessory belts off (no p/s, a/c, fan, alt.)
4) All passenger seats out.

That's it.

Driving habits:

1) Coasting when possible.
2) Drafting at a safe distance
3) Side mirrors in.
4) Windshield wipers vertical when possible.

Lots more mods to come.

I use this van for business. I need a van to move my furniture and supplies.
My alternate transports are the electric motorcycles.

Added: EPA is 20mpg highway giving me 31% over EPA so far.

That's pretty solid. Just wondering... this no-alternator business has me a little skeptical... spark plugs are supposed to work with a 14v feed and you're only giving them 12... do you think maybe if you drop the alt you should re-gap your plugs? I would think the spark is much cooler and it should be adjusted.

Yeah, That's probably right. The spark may be cooler. I have not been able to find out how much difference it makes but my ultimate plan is to have 2 8v deep cycle golf cart batteries in series for 16v (cars are designed to be able to handle a wide voltage range)

The alternator disconnect savings is real though.

"Even more to the point, the U.S. Corporate Average Fleet Efficiency (CAFE) standard prescribes a maximum fuel consumption rate for cars sold in the United States. The Federal government assesses a penalty of US $5 for every 0.1 mile per gallon (0.04 kilometer per liter) below 27.5 mi/gal (8.55 L/100 km) on every car the manufacturer sells. A 200-W electrical load accounts for about 0.4 km/L in the FTP 75 cycle test; so, if a manufacturer is delivering 25-mi/gal (9.41 L/100 km) cars, for example, it can justify spending more per vehicle on components to improve electrical efficiency."

IEEE Spectrum: Automotive Electrical Systems Circa 2005

I could also install a higher voltage aftermarket coil which would take care of the problem right there.

Congratulations! You might need that radiator fan though, eh? Why not convert to electric?

I already got rid of the old clutched fan and installed an electric fan from an 88 Sable V6. It's overkill though. I need to find a speed control or a temperature switch or both. I was hoping to track them down in the sable parts car but no luck so far.

Your Previa mods are awesome to read about. What kind of range do you get with running your electrical off the deep cycle batteries?

I've been thinking of doing a straight EV conversion on my Previa, but removing all the accessories that depend on the SAD shaft seems like an obvious first step. I'm thinking about trying part of what you did and seeing how things work out by just disconnecting the accessories.

Do you still have the SAD shaft connected to the engine or have you been able to remove that too since you're not powering anything off of it?

From my doorstep to downtown Seattle one way is 212km or 132 miles according to google maps. This included about 45 minutes at the border with about 20 starts to avoid idling and some use of the electric fan. when I got there the batts were at about 60% depth of discharge. 50% is about as low as I can go with these batts. Lower shortens the life too much. I guess you could go quite a bit farther with new batts, more batts, or true deep cycle batts like trojans.

I'm itching to take the SAD beast out with all it's cast iron. There must be a couple hundred lbs there. Good bye inertial mass, hello Ferrarevia!

It already revs up quicker now.

It's relatively easy to pop off the belts to try it. Make sure your tires are fully pumped as well as your arms for any parallel parking. Steering is a little harder so be ready.

I'm also hoping to do a conversion or hybrid on mine. This is a stop gap measure in the mean time. Until the right batteries are cheap enough or I win the lottery. The easiest would be an assist motor attached to the accessory drive shaft but of course a lot of losses there through the motor.

Have you heard of any other EV Previas? We are lighter than an S10, can take a bigger payload and are much more aero. There are hundreds of S10 EV's.

My wish list includes a set of LRR tires. Do you know what the OEM tires were? I bet they were LRR.

You should put a diesel engine into your previa.
eBay Motors: JDM Used Toyota Previa Turbo Diesel Engine w/Auto (item 190246359383 end time Aug-29-08 15:28:36 PDT)

132 miles sounds like plenty of range for experimenting with. The only times I usually need my van anymore is on short trips to Home Depot or to move furniture. Although I will be eventually wanting to add back electric A/C since I'm in AZ and that'll be another power drain.

I've got a couple old SAD assemblies that were taken off my van and was able to weigh one of them, and the SAD itself looks like it's only about 20 pounds. I don't know about all its mounting hardware though.

It does seem like this mod would be excellent even for just adding performance to the Previa.

No, You're the first other person I've found who's thinking about it. There don't seem to be a lot of minivan conversions in general. The best minivan conversion I've found online is this guy's Voyager, which he claims can do at least 90mph: Bob Gruenwald's 1987 Plymouth Voyager Speed's going to be important to me when I do my conversion because of all the 75mph speed limits around here.

I used to have another Previa too, and that one still had the original Toyo spare (I always had them check it when I got new tires, and it was still in good condition 15 years later). I'll have to check if my other does and see what type it is.

I can highly recommend switching the fan via the brake light circuit. Someone on a Volvo board recommended that for my e-fan project and I'm very happy with it. It's true there are still ways the coolant can heat up aside from braking events so you'll still need a temp switch or a manual control, but at least for my setup I'm keeping the brake switch circuit installed.

I added a time delay relay to the circuit so when I just tap the brakes the fan stays off. There's a delay again after I come off the brake - fan continues for about 10 sec. That saves a lot of on-off cycling of the fan motor.

You'd have to scope out your brake light circuit and see how you want to tie it in, but I think you can handle that.