Gas Milage Increase

Al · Oct 24, 2003

My 01 Nissan Sentra 2.0L consistantly gave 26.5 to 28.5 mpg in "Suburban Driving" I define this driving as maybe 25% highway. 60% driving in say 30 to 50 mph conditions. The rest is stop and go.

I recently changed oil from the 5W-30 Schaeffers Moly Pure Syn and switched to the 10W-30 Schaefffers Blend. I also changed plugs from the stock Platinums to the Bosch +4 Platinums (which are supposed to be inferior to the stock plugs). I changed plugs at 35 K miles.

In the last two tankfulls of what I would consider typical driving my milage was 30.1 and 30.4 mpg. Its not that I tried to get better milage bc I always drive to get good milage. And my wife puts on most of the milage on that car. It may too early to jump to conclusions. But if the milage is higher- Which gets the credit-plugs or oil or both.

Obviously-I wish I would have done things separately Plugs and oil changeout). I have a road trip planned for next month. The vehicle typically gets 33 to 36 mpg. Well have to wait until then

sbc350gearhead · Oct 24, 2003

I don't think the oil had anything to do with it.

Al · Oct 24, 2003

I would tend to agree except for the fact that I believe that Bob had mentioned that he had seen fleet milage go up dramatically with the Schaeffer's blend. I'm not saying that I believe it is the oil-but since the plugs were en excellent shape when I replaced them-its hard to give the plugs a lot of credit. I probably just need to put a few more tankfulls in. Two tankfulls is not a statstically valid number.

sbc350gearhead · Oct 24, 2003

Was he comparing the blend, to other oils, or to schaeffer's pure syn? I have a hard time believing that there would be much difference within the schaeffers line of oils.

[ October 25, 2003, 10:39 AM: Message edited by: sbc350gearhead ]

Pablo · Oct 24, 2003

First let's just say that is a HUGE delta. 2 mpg is big - just two tanks, we'll see??

I think it's a combo effect of the plugs 'n oil and just maybe a change of fuel blend at the station.

sbc350gearhead · Oct 24, 2003

I have never had a problem with the regular bosch platinums in any vehicle I have ever put them in. They always last 30-40k, which is longer than most of the cheaper plugs I have tried.

Gary Allan · Oct 25, 2003

I've used Bosch plats for the last 10 years. I first installed the regular plats on my mothers Cosica. I got 50k out of them (this is another vehicle where the fuel economy was perpetually calculated) with no drivability problems. Naturally when the PLUS+4 came out, I was in line to buy them. I truly noted no difference ...but have had the same 100% reliability from them for mega miles.

BUT!!!!

There is a growing consensus that the heat range of the platinums (note the outlandishly big insulator), although GREAT for extended plug life, is NOT SO GOOD for your engine. You'll also note that "one size fits many" is the application chart for the Bosch line ..while all the conventional plugs have a much wider variety.

Next time around, I'm going with the "truck plugs" that have a conventional tip ..with just a bigger conductive area.

Any thoughts from the rank and file???

...and getting back on topic "proper"....

I switched to Delvac 1 and experienced a 2 mpg increase in fuel economy. Some scoff at this ..but the increase lasted over 6k with no other mods to the vehicle. This leads me to believe that I have a 6k fatique time with my oil. The 10k UOA will tell if this is true.

So I say that it's "possible" to experience this increase. In your case it is NOT that big of a jump. For me, going from a solid 17.5 mpg ..to 19.5 is a much bigger jump.

[ October 25, 2003, 06:31 PM: Message edited by: Gary Allan ]

cousincletus · Oct 25, 2003

I honestly didn't notice any difference when switching over from dino to Amsoil synthetic, but did see a consistent 5% increase in mileage from using Lucas UCL in the gas tank. I mix it at the recommended ratio. Air pressure in the tires made the second biggest difference in fuel mileage for me. But if enough people say they're getting better mileage with a particular brand of oil, then I'm open minded to try it.

Al · Oct 25, 2003

quote:

Originally posted by Fastr1:
Beware! I am an ASE Mastertech in both Med/Heavy truck as well as Mastertech in Automotive and my advice is Pull those plugs asap!

I have had and seen nothing but bad things with results to misfires and driveabilty problems after low miles with this brand of plugs.

Glad to hear that you have good luck right now but I have had bad luck in the past with the regular *osch platinums.

Most techs agree that put back in what came out...this leads to the least problems.

Yes I have heard this information before from others.
I appreciate the information. I'll watch things pretty close. I have installed the Bosch +4's in 4 other cars so far and have had excellent results. I pulled a set out at 25K just to look at them and they looked almost brand new. But again thanks for the information. I appreciate it.

TSoA · Oct 25, 2003

Ghasp, Bosch Platinums? They are the last plug I would use. They are the source of much scorn at the Bosch Service Center my friend owns. These things are horrible, although Bosch Supers are great, even the .99 cent ones.

theguru · Oct 25, 2003

I'm using the NGK Iridiums. Seem pretty good. Costly @ abt $18aud each.

Fastr1 · Oct 25, 2003

Beware! I am an ASE Mastertech in both Med/Heavy truck as well as Mastertech in Automotive and my advice is Pull those plugs asap!

I have had and seen nothing but bad things with results to misfires and driveabilty problems after low miles with this brand of plugs.

Glad to hear that you have good luck right now but I have had bad luck in the past with the regular *osch platinums.

Most techs agree that put back in what came out...this leads to the least problems.

Leo · Oct 25, 2003

Why did you change the plugs? NGK Platinums last alot more than that. Like 60k. Put them back in I reckon...

eljefino · Oct 25, 2003

quote:

There is a growing consensus that the heat range of the platinums (note the outlandishly big insulator), although GREAT for extended plug life, is NOT SO GOOD for your engine. You'll also note that "one size fits many" is the application chart for the Bosch line ..while all the conventional plugs have a much wider variety.

Elaborate?

If a plug is colder than stock, but doesn't foul in your style of driving, what is the harm?

JeepZJ4.0 · Oct 26, 2003

Problem with *osch design is the small pure platium electrode. Yes its 99.9% pure platinum and its a marketing gimmick.... when that electrode carbons over, kiss your gas milage and performance goodbye! Autolite Platiums work the best in my experience. We had the double platinum version in our 89 Ford Aerostar...... wow! A lot peppier than the *osch platinums and kept that new feeling longer. The Grand Cherokee guys on JeepsUnlimited feel that the Autolites are the best platinums and Bosch Supers the best copper plug but even some say, just stick with the OEM plugs. We put the *osch Platinums in my Jeep and wow.... major power loss about 10K miles. Gas milage went down the drain. Perfomance wasn't that good to begin with after these plugs were put in. Copper burns better than platinums but platinums last longer.

[ October 26, 2003, 06:05 PM: Message edited by: JeepZJ4.0 ]

sprintman · Oct 26, 2003

I have the NGK Iridiums in both cars, niticeable difference from the day they were installed. NGK have a great web site that shows the flame pattern etc of these plugs. Better than Platinums according to NGK but not available for all engines yet .

vvk · Oct 26, 2003

I tried Bosch Platinums in my old SAAB once and that was enough for me. They were really bad. I had poor driveability and gas mileage from day one. I finally pulled them out at about 8k and the center electrode was GONE. I have never seen such poor performance from any other plugs.

NGK Platinums seem to be OK. I changed a set out of my Subaru at 45K and they were like new. There was no noticeable difference with new plugs.

I think regular copper NGKs are best plugs money can buy.

Pablo · Oct 26, 2003

Copper NGK's.

The rest are/is just hype.

Gary Allan · Oct 26, 2003

quote:

Elaborate?

If a plug is colder than stock, but doesn't foul in your style of driving, what is the harm?

But the big/long insulator INCREASES the heat range. o the plugs themselves have to be given equally varied thermal characteristics. This is done by varying the length of the path taken by heat as it travels from the very hot center electrode and insulator nose to the relatively cool areas around the body's threads and the plug washer. Plugs with a long insulator nose, which leads heat high into the plug body before it turns back toward the cooler cylinder head, are "hot."

This is how, allegedly, they achieve their LONG life. Hence, a growing "consensus" (not here apparently - this is after all a "oil" forum) concludes that these plugs are GREAT for longevity ..but "may" have ill effects upon the pistons, combustion chamber, valves (etc.) under some conditions.

I use PLUS+4's myself ..and have never had any trouble from them ..but probably will swap to a "proper" heat range "truck plug" to avoid any long term damage (as in potential).

Mark in NY · Dec 18, 2003

A quick reply because this topic can take on a life of its own but-
An ignition products engineer I spoke to privately summed it up - "these days with fuel management computers and injection systems providing a perfect mixture, you practicaly just blow on the mix and it ignites well".
That said- very small improvements are possible by plug selection. Remember anything you stick in the spark plug hole is going to disrupt flow. The less the better. Fine wire double platinum or the new iridiums would be the direction you want to go with most NA street cars. Amazingly enough - the recent lineup of Motorcraft plugs now are a great high performance bargain for the narrow range of engines they fit. They can be compared side by side (after 30 years of waiting) to hi-perf plugs from NGK and Denso for performance, although 60K is realistic life - not 100k.

Gas Milage Increase

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