94 Volvo 940, trying to break the 27 mpg barrier

[SmellyCat]

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

[orangustang]

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.

[SmellyCat]

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

[tjts1]

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?

[SmellyCat]

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

[SmellyCat]

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

[tjts1]

Originally Posted by SmellyCat

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 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

[SmellyCat]

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

[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

[SmellyCat]

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