SwedeSpeed - Volvo Performance Forum banner

Passing along tech tips for better mileage in a 960

16K views 26 replies 13 participants last post by  falconbobb 
#1 ·
I have a hobby of trying to max out the gas mileage in my cars and the latest Ginnie Pig is my 97 960.

Well back in Nov I made a MPG run with my 97 Volvo 960. It was my usual base line route Pittsburgh to Erie and back I always take after making any kind of mpg mods to the car. Speed is held to 65 mph and tires are inflated to 40 psi.
My base mileage on this run is an even 28.0 mpg which was run in July.
Well to the meat of the facts. At the front I enclosed the openings between the bottom of the fenders to the edges of plastic splash pan with Aluminum. This is an open area under the battery and the corresponding passenger side.
Heading towards the rear I placed a steel air deflector plate attached to the bottom of the suspension cross member. This was done to keep the air from being pulled up into the IRS frame work while it is flowing under the car. From there I ran an aluminum plate all the way back to bottom of the rear bumper. I did leave the rear muffler exposed due to the heat.
All in all I got an astounding 3.0 mpg increase with this mod. This has been probably the best mpg increase from all the mods I have made. When I bought the car Feb 05 I got 25.3 mpg on the highway and today 31.0 mpg. 5.7 mpg or 18.4% increase is nothing to complain about. Plus I figure this spring I'll spend a little time cleaning up the rest of the under carriage. That should be worth another 1/2 to 1 mpg.
Pics: http://photos.yahoo.com/ajspgh@sbcglobal.net
For those that are interested in all the mods.
This RWD car weighs in at around 3500 lbs and has a Cd of .36
I started with an Auto-Rx engine cleaning. A clean engine is an efficient engine. That helped me get the car to 26.3 mpg, Then I swapped out all the fluids for synthetic and I saw 27.4 mpg. I then increased the tire pressure from 36 psi (factory) to 40 psi and saw 28 mpg. With the addition of the belly pan mods I now get 31 mpg.
My Scan Gauge matched the gas pump when I filled up with 8.238 gallons of gas for 255.7 miles.
At Christmas I drove down to Fl. to visit family a 1180 mile trip, even with winter gas, driving through the mountains of WVa. and the sub freezing temperatures I still got a respectable 29.3 mpg highway. At my fill up on I - 26 near the I-26/ I-95 split to Fort Myers Fl. I averaged 31.3 mpg.
On the way home I averaged 30.5 mpg the first tank filling up close to the I-95/I-26 split. From there I got 29.1 mpg on the way back through the mountains to Morgantown WVa. where I filled up again. Averaging 30.05 mpg in the winter isn't half bad in a 960
 
See less See more
1
#2 ·
Re: Passing along tech tips for better mileage in a 960 (pghvolvo)

Alfred;

What is your "self-employ"? Master metal craftsman?

Great work, man!

At 40psi do the tires wear inside?

Would be cool to find a site with rolling resistance listed for tires.

Best I ever got with my '96 965 was just under 27mpg.

Keep us posted as we want to see how far you can take this to include weight reduction and engine mods.

George Dill
 
#3 ·
From what I have read, there is a lot of increase in mpg that can be made from simply smoothing out the bottom of Volvos, particularly under the rear end. I've hear of some work being done with plastic sheet, others done with galvanized metals sheets like they build heating ducts from (it may have been a heating duct first), and even heavier metals.

To me, this says that I can sell putting a full body set of skid plates on my 964 to my wife as a way of increasing the mpg and not as a way of making sure the car comes home in one piece after I rally it.

- John
 
#5 ·
Re: (gdill2)

I had a guy here in town do the work. He came very recommended since he restores old Vettes and builds street rods for a living. He is in his mid to late fifties so he is old school when it comes to this kind of work. A lot of the drag racers use him for metal work on their cars.
 
#7 ·
Re: (volvo4vida)

Minimum range is 550 miles per tank on the highway. Usually it takes 19-20 gallons to fill. I just don't trust the gas gauge and the idiot light to take it any farther than 575 miles until I can get another 1 mpg or more out of her. After the light comes on I don't start looking for a gas station until 40 miles later.
 
#8 ·
Re: (pghvolvo)

IF the gas gauge/warning light are functioning correctly the tank has two gallons remaining when the light glows.

Notice while driving in the "E" area with no light glowing then shutting down to do a sit-down latte that when you start the car the light will glow.

George Dill
 
#11 ·
Re: (volvo4vida)

Quote, originally posted by volvo4vida »
so on a full tank of gas how many miles can you get out of it?I think 95 and your year 960 are about the same. One major difference is I got a wagon.

92' - 95' 960 wagons and sedans had Motronic 1.8 after that it was Motronic 4.4. I don't know if the mileage was better from one system to the other.
 
#14 ·
#15 ·
Re: (1999s70)

I saw this thread and I had to find out from the members HOW do I get this level of fuel mileage???

My 96 960 with 166k miles has never gotten better than 22mpg, now (maybe due to ethanol at 10% of fuel) it is 19 mpg.

I always run tires at 40 psi (many tires spec to 44 now), and a local certified volvo mechanic maintains it.

I did take off my under engine plastic cover, it was about to fall off. The aerodynamic improvements seem to make sense.

How do I make this better?

Thanks,
Bill
 
#16 ·
Re: (Bill Smith)

Welcome to Swedespeed, Bill.

Your 22mpg ain't bad - my '96 965 got 19 in town and 26 at best hwy.

Most will say to keep the car as Volvo designed and just maintain/repair as needed.

I'll be right back with some mods (reversable) that will improve mpg in a 960.

George Dill
 
#17 ·
Re: (gdill2)

Free-flow (life-time) engine air filter - whose life I ain't sure but installing one of these at about $50 would pay back in the next two stock filter changes and all thereafter is money in the pocket to buy more gas.

Free-flow exhaust - you won't find one for your 960 but any competent muffler shop can weld one up.

Free-flow cat - again, nothing on the market fits your car and the original Volvo cat is a top-notch product but very $$$. If you go with an aftermarket cat be sure the Ox sensors/senders don't cause OBD codes to spit out. BTW, be sure the existing cat has no restrictions from damage or deterioration.

Low-friction oils and lubes - just be careful what you put in the trans and diff as some products can cause more harm than good.

Remove junk from the car - 'nuf said.

Use 3/4 gas pedal when driving from stop - not true for newer cars with direct injection but for cars with air intake regulated by gas pedal position this technique can improve mpg. Just lift slowly as you reach the desired speed.

OK, here is the government telling you what to do...

http://www.fueleconomy.gov/FEG/drive.shtml

...and now "civilians"...

http://newcarbuyingguide.com/i...=view

...then movies...

http://www.mahalo.com/How_to_G...leage

Try to fill the tank on level ground and at the same pump and time of day if possible. MPG calculated from a single fill-up is often skewed too high or too low so average the mpg over many refills unless you are on a long trip.

Once again, your 22mpg is pretty good for a 13 year-old 6-cylinder 3700lb Volvo.

"I did take off my under engine plastic cover, it was about to fall off. The aerodynamic improvements seem to make sense."

Consider installing a new one (Volvo original) as this item was designed to protect the engine and adjacent components from road splash/damage plus aids in controlling high temps under the hood. Be sure it is properly mounted as some folks in a hurry don't bother to position the splash shield as designed and also leave out two mounting bolts that are darn near impossible to get a wrench on.

Good luck.

George Dill
 
#19 ·
Re: Passing along tech tips for better mileage in a 960 (pghvolvo)

What about running premium fuel? i know that the knock sensor retards the timing when you run regular, so you dont necessarily have to run premium. but does it help with fuel mileage? with gas prices going down ive started running premium but haven't noticed a difference in my city mileage.
 
#20 ·
Re: Passing along tech tips for better mileage in a 960 (Breakfast07)

The engine management system can handle 87-proof just fine and will detect any knock and make adjustments. 92+ octane will go unrecognized by the system as there is (usually) no knock to detect.

Premium fuel will not in itself increase mpg unless the low-grade fuel causes the engine to run almost constantly in the "anti-knock" mode.

Some premium fuels have more additives than regular which may or may not be beneficial to mpg in the short run but could result in a "cleaner" engine over many miles/months which should benefit mpg.

Looking at just the dollar and driving an older car that can manage low octane fuels I would fill up with the cheapest panther pee available.

George Dill
 
#21 ·
Was looking for something on Google and ran across this old thread.

Sorry about the pictures falling by the wayside I went back and found a few to repost.

Right side of the rear pan covering the area between the rear axle and the bumper.



This is a box that was built to close up the open area infront of the tire and the bumper



This plate was installed to keep the air flow away from the IRS.





This is the box that was built to direct the air flow away from the spare tire hump and the rear bumper.





I did some testing back in 2007 down in Florida with straight gas before the E10 gas became mandatory and here are some speed mileage numbers that might help you out. With all Volvo's as well as all cars speed kills your fuel mileage.

I did some speed testing with my 1997 Volvo 960 when I was down in Naples in July of 07.

The test road is Rt 41 between Naples and Miami. I like this road for testing because it is very flat and most of the traffic now takes I-75 across the state. My starting point was the turn off for Everglades City. I ran 10 miles east then turned around and ran west back to my starting point.

Scan gauge readings were as follows.
Sg is extremely accurate to the pump fill numbers.
As long as you stop at the next .25 after the first click of the nozzle.

The MPG of each 20 mile run is as follows.

50 mph 35.4 mpg
55 mph 33.9 mpg
60 mph 31.15 mpg
65 mph 28.5 mpg
 
#24 ·
I have had a few 960s. The first, a 1993 wagon, never got more than 24mpg on the highway, and lower, of course, in city driving. The second, a 1997 wagon, got the best mpg, at 28mpg on one run between gas stations on I-95; the last, a 1996, my DD now, is pure awful, and is lucky to get about 22mpg on the highway, for reasons I cannot solve.

The one interesting tidbit, at least relative to the 1993, is that speed had nothing to do with MPG. I know, I know, you say, that something must have thrown off those numbers. But, it is true, I got 23-24mpg in that car whether I was travelling 55mph or 85mph on a trip. I tested this many times, btw.
 
#25 ·
Now to bring this thread up from the dead I found more MPG's through the cheap.

A buddy of mine Wayne Gerdes does a lot of fuel mileage testing for the major automobile companies as well as the oil companies.
One recent test involved a specially built V6 Dodge Charger with two separate fuel tanks feeding their own bank of cylinders.
One side got exclusively Shell V Power with Nitro and the other a leading competitors premium fuel.
After 5,000 miles Shell tore the motor down and compared the results of both fuels. You can Youtube this one if you wish.

Wayne raves about the cleaning ability of the Shell V-Power because it has seven times the additives of EPA minimum requirements
and four times the cleaning additives of their top tier competitors. I'm pretty sure at least lately all his test vehicles are filled with Shell fuel.

Anyway it got me thinking with the old 960 (118K) would cleaning out the fuel system and using better fuel get my fuel mileage back up.

Earlier this summer I decided filled her up with a full tank of Shell V Power and a bottle of Techron. Before this I was running the cheapest premium I could find over the last decade of so. My fuel mileage over the last five years or so had dropped from mid 29 mpgs to high 26 mpgs on the highway at 65 mph which I was blaming on E10 gas. I don't drive this car over 65 mph due to wanting the best highway fuel mileage verses time. Slower than 65 mph means much better fuel mileage but the loss in travel time doesn't make it worth it. I drive the speed limit up to 65 mph no faster which means if you see an old guy in the right lane in a black Volvo 960 driving 65 mph on a 70-75 mph posted road it will probably be me.

After filling with 93 Shell V-Power and a bottle of Techron I took her out on a long Sunday drive. Around 200-250 miles I got a pleasant surprise, the motor had started to really smooth out, the slight roughness and hesitation was completely gone. The only down side was I hadn't seen the jump in fuel mileage I had expected. Well after about two and half tanks of the Shell V Power and the bottle of Techron I took a 400 mile trip in the car in September and got the surprise of my life. The fuel mileage had jumped back up into the low 29's at 65 mph with with a high of 29.5 mpg without AC and it dropped down to 29.2 with stops and hills. When I turned on the AC for the ride home the fuel mileage dropped to at the worst 28.5 mpg. I use a calibrated Scan Gauge to monitor my fuel mileage on the highway. Obviously you can agree I can't complain about the gas mileage I'm getting in a 20 year old 960.

Specs, tires are Michelin MXV Energy's set at 42 psi, Mobile One 10W30, Ansoil synthetics in both the transmission and rear end.

Around me Shell V-Power is selling for the same price as the off brands. I will never put anything but Shell or another top tier fuel in this car ever again.
 
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top