94 Volvo 940, trying to break the 27 mpg barrier
 

Hey Everyone. Really like all the info and discussions. You have inspired me. This Volvo tank was getting 15 mpg and I was about have it crushed.
I got 26 mpg last week. I've been working on the engine and adding some aerodynamic mods. This week end added the rear wheel skirts. Cheers SC

Looks good, and congrats on the improvement! Are those aluminum sheet? Did you have to fabricate a brace of any sort under the wheel skirt?

I crave more information. Is that the turbo version or N/A? If no turbo, your EPA rating is 27 MPG highway/ 19 city (old standard), so just fixing what's broken and having a light foot should (from my experience) get you to your goal on the open road. If your commute is more stop-and-go, though, you're doing really well with an old auto trans. What have you had to do in the way of repairs to get it to run right?

A side story: Those things will run forever. I had a friend in high school who drove a 740, and he had diagnosed a bent valve. I located the tick and disabled the fuel injector on that cylinder, and the car ran the same as it had, but without wasting that fuel. He said it noticeably improved his gas mileage, though I don't think he ever measured it. I had another friend with a 1970 Mercedes 300D, and they raced one time. Even though it was on the street, I don't think they could have been pulled for anything beyond a noise violation. Neither car got up to the speed limit or was able to spin tires.

Thx Orangustang.
its a automatic no turbo. I do a city/ Highway mix of driving. All the EPA things I've read seemed to say it would only do 24 mpg high way. My Brother has a 91 brick SW he always smokes me with 25 + mpg

The Aluminum is pretty thick maybe 1/8 think or something. Ate up all my metal jigsaw blades. Got it at the Joes recycling for 15 bucks when I was trading in cans. No braces on the back wheel just sheet metal screws. Its gonna be a bad time undoing it when I get a flat .

The Exhaust was rusty and the 02 sensor was bad. Got that fixed. for about 80 bucks

Rigged up the air filter box so it sucks hot air all the time off the exhaust
Added slack to AT kick down cable so it stays in gear longer

Removed the Ac compressor, removed all the wood boards inside that cover the spare tire

Trimming the under side with black plastic garden trim to get that Nascar look
Blocked of the front radiator grill.


Things I plan do. disconnect Power steering. Rig up altenator so I can switch it off. Get some solar panels to charge the battery. Figure out how to make it go into overdrive under 45 mph. Rip out carpet and insulation. Replace the tires when these one wear out, Take out the back seat.. SC

You need to rig the airbox to get cold air ONLY not hot air. The hot air is murdering your fuel economy and soon it will also kill your MAF sensor.

My 94 965 with its B6304 can squeeze out 28 highway. You should be able to do even better with your B230 and a cold air intake.

Have you considered a rear belly pan?
http://img.photobucket.com/albums/v2...o/1dc86ee6.jpg

tjts1, I really like that cover you have under your car. I'll add that to my list

Here is what I read about hot air cold air

The hot air intake functions by drawing in air from near the engine, which has been heated due to internal combustion. This warm air causes the fuel mixture in the car to drop, thereby lessening how much fuel is used and increasing mileage.



The Volvo already has hot air intake with a thermal flap in the air box that goes to exhaust Manifold. (Mines rigged to open all the time) Once the car heats up it switches to out side air to increase HP.
Cold air = More O2 More fuel more power lower mpg
Hot air less O2, less fuel, less power Better MPG

It works with MAFs but not cars with MAPs

You can un hook the hot water lines to the intake manifold to get even more HP but less MPG. Turbos' have intercoolers to cool the air before the throttle body. again more HP. SC

The 940 sedan is rated 27 highway. the wagen highway mpg is 24

4 cyl, 2.3 L
Automatic 4-spd
Regular Gasoline
EPA Fuel Economy
Miles per Gallon
Regular Gasoline
20
Combined
17
City

24
Highway

Fuel Economics
Regular Gasoline
Cost to Drive 25 Miles $4.69
Fuel to Drive 25 Miles 1.25 gal
Cost to Fill the Tank -
Miles on a Tank -
Tank Size -
Annual Fuel Cost* $2800
Vehicle Specification Data
EPA Size Class Midsize-Large Station Wagons
Drive Rear-Wheel Drive
Gas Guzzler no
Turbocharger no
Supercharger no
Passenger Volume 95ft3 (Hatchback)
Luggage Volume 39ft3 (Hatchback)
Engine Descriptor (FFS)
Transmission Descriptor

The theory is all well and good but it doesn't work on these engines. Your MAF sensor will die an early death because it can't handle the extreme heat you're throwing at it. It wasn't designed for this. The thermostatic flap as it leaves the factory is designed to maintain a minimum of 70f in extreme cold temps. When it fails, it always goes into the hot air only side and it quickly murders the MAF sensor. The MAF also has a temp sensor built into it and it will cause the engine to delay ignition timing which kills economy, increases HC and NOx emissions. Switch it back to all cold air and you'll see an immediate increase in mileage. With all the other modifications you've done, you should be in the low 30s by now. Your car has AW70L transmission with a lockup torque converter which is a big advantage over older 740s, 240s and 940 turbos.

I have worked on many volvo red block and white blocks, replaced more failed MAFs and thermostatic intakes than I care to remember.

http://www.matthewsvolvosite.com/for...48301&p=239490

http://www.volvoclub.org.uk/faq/Engi...ermostatChange

Yikes. I better quit doing the hot air thing. Thanks TJTs1

Try cold air for a while and see how the FE changes. I suspect you'll see a marked improvement. I like some of the aero modifications you've done to that car. Another thing you might consider is BOSCH EV6 aka Design 3 injectors. These have the same flow rate as your existing EV1 injectors but much better fuel atomization. You can find these all over the JYs in the same 19# flow rate in late 90s Ford V8s and 96+ non turbo Volvo 850s. They are all bright yellow and drop right in.
PN
0280155700 ford
0280155710 ford
0280155746 Volvo

Pintle type EV1 left (what you have right now), EV6 4 hole right.
http://farm3.static.flickr.com/2319/...79b3f801_o.jpg
http://i664.photobucket.com/albums/v...r/IMG_1206.jpg

I swapped my 960 over about 5 years ago without any problems. The FE improvement is marginal but it idles and starts much more smoothly.
http://www.youtube.com/watch?v=oxImoYMRUCA

I had a tuna jalapeno subway at walmart on my lunch hour... Which was Great!!!. . I was gonna just buy some more 4 buck garden edging for the Volvo. But I had a Stroke..... Of genius. Today is the day!!!!. Drove the POS..I mean Volvo... to the Autocenter. Bought a 60 buck marine battery. Had Stanley the Battery changer guy, Unstick the old battery out while I used his wrenches to take the altonator belt off. Had to do some SC rigging since marine batteries all have the plus terminal on the wrong side of the battery. any way.. drove back to work. got gas drove back to Ringgold. started 4 times. filled up the tank.. 25 mpg (I blame the drop to the overdrive solenoid is acting up I'm driving around a lot at 3k rpm cause it wont shift up) .... went the 20 miles home. Just showed off'ed the Volvo to the UPS guy that delivered a box and he thought is was cool. Not a bad day. I Rock!...SC

A good mod. Well done!

If you disconnect the alternator - then:
Just be sure to keep that lead acid battery charged up as much as possible via a battery charger. Yes it has xx Amp Hours capacity but the further down you drain it and the more often you do that, the shorter the overall lifespan of the battery. California98Civic had one that died after about a half year of heavy discharge use. He just got a bigger one so he won't have to drain it down so far.

My thread on my EPES project:
http://ecomodder.com/forum/showthrea...highlight=EPES
I had a few additional challenges to deal with due to a 55 mile commute, each way. So my installation is a bit more complex...

I am running with out an alternator. I drove about 40 miles today. the battery had 12.6 volts left in it when I got home tonite. Is there a rule to how low the battery can get before it wont keep the car going? SC

As voltage drops the ecu will compensate with longer injector PW and afr goes haywire. Not worth it.

Ok tjts1, that makes sense. is there a certain voltage that the afr and pw stay stable.? I had to lookup what they are..just now.

I need to fake out the ecu so all the dash light go Off. Do I need to hook a 2nd battery across the out put wire from the alternator?

if I don't use the deep cycle to start the car. That might be better for it. Is that logical? Sc

Today drove 50miles and started engine. 5 times. With car running , battery read 12.4 volts. What percent charge on the battery is left? sc

Actually, what tests here by myself and Sentra-SER have shown is that the warm air intake works with MAP cars and not with MAF cars (the opposite descirbed above). Also, most guys have insisted that its not changes in AFR that result in savings, since the ECU will detect less oxygen and adjust fuel. Rather it is that you will open the throttle further to get the same power, thus reducing losses from the effort to pump air past the throttle body. But at any rate, Sentra-SER showed pretty convincingly that it does not work with a MAF. And I wouldn't argue with anyone who has experience with these Volvo engines. I just know that my MAP equipped car has been running a WAI for a year, the last 14000 miles or so, without trouble from it.

Update, TJTS1 is right. I was squeezing 25 mpg out of this pig with the alternator and 25mpg with out. I am so Bummed. It really seemed like a good Idea. I will try a switch on the Alt hot wire to see if that does anything next. Cheers. SC

Without really controlled ABA testing, you really can't know for sure the results. You'll want weather, road, temp, throttle, speed, and route conditions all to be the same at minimum. Then there is the state of how warm the engine and tires are... the slightest changes in your throttling--imperceptible to the driver--will alter results. I hope by "the hot wire" you don't mean the alt's output wire to the battery... somebody here wrecked an alt that way, fried it, IIRC.

Sorry for the bummer... keep up the efforts... some work some don't, you know? Good luck!

james

Thanks California Civic, A read a bunch of posts and never figured out exactly how to delete the alt correctly. On this Volvo..

One Big hot wires go to Plus battery side and and a 2nd small hot wire goes to the ignition switch.

For the last week I just had the the belt off the alternator. Do you have to disconnect the all the hot wires or just the little hot wire , or just the big hot wire? SC

I'm not sure why you want to disconnect wires. If you're considering switching the charge function on and off, see my very last paragraph below.

Do you not want the red "Battery/Alt" light glowing on your dash? If so, you could remove the cluster and then remove that one bulb. However that will somewhat compromise your ability to run the alternator, if you ever do want to. On the Volvo 240's we drove for 15 years, that indicator bulb and a few others provided the "exciter" current to the alt's small red wire. If enough of those 4-5 bulbs are dead or removed, the alternator doesn't put out any charge.

A related concern -
If your alt belt is removed, I'd say it doesn't matter what else is going on - that alternator isn't going to put out any current. So it's presenting no mechanical load to the engine. In fact that setup will save your more energy than disabling it electrically, because you're also saving the mechanical effort of spinning the alternator, it's bearing friction, belt friction, etc.

You might not detect the mpg improvement due to all the other factors in play - weather, traffic, etc etc etc. But you're taking a load off the engine. You'll likely notice some increase in power available for acceleration or hill climbing.

Definitely charge your deep cycle battery as often as possible. Daily would be nice. The more time it spends fully charged, the longer it will last. That's the basic behavior of a lead-acid battery. And of course charging it off wall current is the way to go, otherwise you're back to buying gasoline to provide a charge to the battery.

Aww... I wanted to play redblock ecotuning, but the best tricks are already out. I gained... maybe 3-4 mpg replacing (well it wasn't there originally) the airdam with a curve sheet of aluminum that used to be a sign. Electric fan... is that on a 94?

I guess the red block is the Volvo engine. it is a great big station wagon with a little bity red engine. It has an electric radiator fan. . I like the idea of the Alt switch. I have ran the battery down to critical 3 times that the tach and speedo start getting wiggy and I die at the roadside. I have maybe a minute to hook the jumper cables under the hood and connect to the 2nd battery on passenger floor board, The Summer sun takes the fun out of conking out on the side of the road.

Will it hurt anything it I hook the marine battery and the start battery in parallel and charge them together. pResently the Marine battery is on the 10 amp charger and and the starter battery is on the 2 amp trickle ... SC

First time I've seen this thread. I have been running an mpguino in a 940 for a few years now. ( figure in imperial gallons)

Car: 1995 B230FT estate
Modifications: Mainly none, lowered to sport levels, Bosch super 4 plugs, stainless exhaust.
Max average: 40mpg using pulse and glide, 60-80mph
Max flat: 46mpg at 30mph

No alternator - the lower/dropping voltage will screw up the mpg readings, as well as reduce the efficiency and calibration of everything in the fuel and ignition. You need to use additional batteries and/or solar cells to keep the voltage stable at 14V.
It should be worth something, typical min load is 300W. Hightbeams add about 0.03 gal/hr to the fuel flow at tickover. so that is about 0.03 gal/hr per 100W, which means fuel flow should drop by 0.09, which is about a 30% drop at tickover. The benefit is less the faster you go, say 15% reduction at 30mph, but would be a 4-5mpg improvement.

I must try that, need a good 2V battery.

I think you could fit 600W of solar, but you don't need that amount. 100W would be plenty with suitable batteries depending on your daily milage.
It might be worth increasing the amount of electricity used say with a electric water pump, steering, turbo etc to make use of solar.

Another thing I've notice is gearbox, engine and diff oil. MPG takes a while to get up there in cold mornings even after engine has warmed up. Maybe benefits with thinner oil or heater pads.